Social Support in Older Adults With CKD: A Report From the CRIC (Chronic Renal Insufficiency Cohort) Study.

Plain-Language Summary Poor social support is a common and potentially modifiable factor associated with adverse outcomes in many disease states. However, it has not been well examined in the growing population of older adults with non–dialysis-dependent chronic kidney disease (CKD). We performed a cross-sectional analysis of data from participants in the Chronic Renal Insufficiency Cohort 65 years and older to examine possible associations between social support and the meaningful clinical outcomes of cognitive function, quality of life, and frailty. We found that higher social support was associated with better measures of cognitive function and quality of life and less frailty in older adults with CKD. This suggests that improving a social support network may have potential to positively affect outcomes.

Social support is an important aspect of many chronic conditions; social network strength is associated with meaningful outcomes in cardiovascular disease, pulmonary disease, dementia, cancer, diabetes, and end-stage kidney disease (ESKD). 1 , 2 , 3 , 4 , 5 , 6 In addition, social support appears to be particularly important in older populations. Social isolation and loneliness are very common in older adults, with an estimated prevalence of ~40% in some groups. 7 , 8 Though chronic kidney disease (CKD) disproportionately affects older adults, 9 there is a paucity of research investigating the influence of social support on outcomes in older adults with CKD not receiving dialysis. Consequently, there is a compelling need to better understand the significance of social support in older patients with CKD. Studying the impact of social support on older adults with CKD may allow for better risk assessment of patients with CKD newly diagnosed, as well as facilitate the creation of social support–based interventions that could potentially improve clinical outcomes.

Poor social support in older adults is associated with adverse outcomes such as poor quality of life, increased risk for falls, dementia, frailty, rehospitalization, and mortality. 7 , 8 , 10 , 11 Factors such as social support that influence cognitive function, quality of life, and frailty are important to investigate because these outcomes are meaningful in older adults with CKD. For example, cognitive impairment, specifically dementia, was found to be independently associated with increased risk for mortality and decreased functional status in older adults with ESKD. 12 Furthermore, health-related quality-of-life measures are associated with morbidity and mortality in older adults with CKD and also represent an important primary patient-centered outcome. 13 , 14 , 15

Frailty has been described as a biological syndrome related to declines across multiple physiologic systems, leading to reduced reserve and resistance to stressors. 16 , 17 It is associated with adverse health outcomes in older adults with CKD, including higher risk for mortality and hospitalization in older adults with ESKD and elevated risk for dialysis or mortality in adults with predialysis CKD. 12 , 18 Although social support has been linked to these important outcomes of cognitive impairment, quality of life, and frailty, it has not been closely examined in older adults with predialysis CKD. 4 , 7 , 8 , 10 , 11 , 19 , 20 , 21 , 22 , 23

In this article, we report the cross-sectional association between social support scores and quality of life, cognitive function, and frailty in participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study. We hypothesized that in older patients with CKD, higher social support is associated with better health-related quality of life, better cognitive function, and lower likelihood of frailty.

Methods

Study Population

The CRIC Study is a large, multicenter, longitudinal, observational cohort study that is composed of a diverse population of individuals with CKD. The design and baseline characteristics of the CRIC Study have been previously published. 24 , 25 During the first phase of recruitment, between 2003 and 2007, a total of 3,612 participants were enrolled into the study. These participants were between the ages of 21 and 74 years and had an age-stratified estimated glomerular filtration rate (eGFR) of 20 to 70 mL/min/1.73 m 2 between the ages of 21 and 44 years, 20 to 60 mL/min/1.73 m 2 between the ages of 45 and 64 years, and 20 to 50 mL/min/1.73 m 2 between the ages of 65 and 74 years. During a second phase of recruitment between 2013 and 2015, an additional 1,560 patients between the ages of 45 and 79 years with eGFRs between 45 and 70 mL/min/1.73 m 2 were enrolled into the study. However, participants with eGFRs between 61 and 70 mL/min/1.73 m 2 had to have proteinuria (defined as either protein excretion > 1+ on urinalysis, >300 mg/g on spot urinary albumin-creatinine ratio, or >500 mg/g on spot urinary total protein-creatinine ratio).

Participants were excluded if they were institutionalized, had received any kind of dialysis for more than a month, had an organ or bone marrow transplant, received immunosuppressive or other immunotherapy for primary kidney disease or systematic vasculitis that affects the kidneys within 6 months of enrollment, known cirrhosis, New York Heart Association class III or IV heart failure at baseline, previous diagnosis of multiple myeloma or renal carcinoma, received chemotherapy within 2 years of enrollment, pregnant or breast feeding, previously diagnosed polycystic kidney disease, or currently participating in an interventional trial.

We included 1,944 participants 65 years and older at the time of Lubben Social Network Scale (LSNS) administration in this analysis; data on social support (LSNS) were available for >95% (1,851) of this group. Measures of frailty, social support, cognitive function, and quality of life were all collected at the same time point.

Study Measures

Data on social support were collected in participants 65 years and older between 2013 and 2015 using the abbreviated LSNS. 26 The abbreviated LSNS is a validated measure of social support in older adults consisting of 6 questions that assess social connections between participants in 2 different domains: with family and with friends 26 ( Item S1 ). It is scored on a scale of 0 to 30; a higher score reflects a higher level of social support, and a score <12 is considered a low level of social support. 26 An abbreviated LSNS score of 12 has been suggested to represent a meaningful cut point to identify individuals who are socially isolated. 26

Data on education, income, physical health, and quality of life were collected on a variety of self-reported questionnaires such as the Kidney Disease Quality of Life (KDQOL) 27 health care resource use, medical history, and Multi-Ethnic Study of Atherosclerosis (MESA) Physical Activity Questionnaire. The KDQOL is scored in 5 different domains, with lower scores indicating lower quality of life. These 5 components include burden, effects, and symptoms of kidney disease and mental and physical health measures. Patients with KDQOL scores below average are at higher risk for poor health outcomes. 27

Cognitive function was measured using the Modified Mini-Mental State Examination (MMSE), Trail Making Test parts A and B (TMT-A and TMT-B), and the Buschke Selective Reminding Test. The MMSE has a range of 0 to 100, with lower scores indicating poorer cognitive abilities. 28 TMT-A and -B are timed trials, with longer times indicating more difficulty with the task. 29 The Buschke Selective Reminding Tests are scored based on the words remembered through 6 different trials initially and a final trial 20 minutes later. Higher scores indicate better memory. 30

Frailty was defined as having 3 or more of the following 5 criteria: unintentional weight loss > 5% of body weight in the last year, slow walking speed from a 15-foot timed walk, grip strength measured with a digital hand grip dynomameter (Creative Health Products), low physical activity based on the MESA Physical Activity Questionnaire, and self-reported exhaustion determined from 2 questions on the Center for Epidemiologic Studies-Depression scale. 16 , 31 Prefrailty was defined as having only 1 or 2 of these 5 criteria. 16 , 31

Statistical Analysis

We conducted a cross-sectional analysis of patient demographics, socioeconomic status, laboratory values, self-reported forms, and clinical characteristics as it relates to social support. In addition, we stratified older adults into those aged 65 to 71 years and those 71 years and older. Each age category represents approximately one-half of the entire cohort.

Linear regression models were used to determine the association between the primary predictor, the social support score based on the LSNS (ie, independent variable) and measures of quality of life (KDQOL) and cognitive function (MMSE, TMT-A and -B, and Buschke Selective Reminding Tests 1, 2, and 3), which were continuous dependent variables. Logistic regression was used to assess the association between LSNS score and frailty (ie, dependent variables), adjusting for age group, and was reported as odds ratio (OR) with 95% CI.

Covariate adjustments were included in sequential models sequentially as follows. Model 0 was adjusted for age. Model 1 was adjusted for age, clinical site, income, education, and race/ethnicity. Model 2 includes covariates in model 1 plus history of hypertension, heart failure, stroke, coronary artery disease, peripheral vascular disease, diabetes, systolic blood pressure, and hemoglobin A 1c level. Model 3 includes covariates in models 1 and 2 plus eGFR and proteinuria. These covariates were selected because they were suspected to be potential confounders of the association between social support and the primary outcomes of cognitive function, quality of life, and frailty. All analyses were performed using SAS (SAS Institute Inc), version 9.4, and P < 0.05 was considered as statistical significance.

Results

Mean age of the study population who completed the LSNS (n = 1,851) was 71.7 years; 42.5% were women, 50.0% were non-Hispanic Whites, and 67.7% of participants had at least some college education. Almost all participants had a reported history of hypertension (92.9%); most also had diabetes (54.7%), and slightly less than half had a reported history of cardiovascular disease (43.2%). Mean LSNS score was 16.2. Mean eGFR was 50.3 mL/min/1.73 m 2 , and median urinary protein-creatinine ratio was 0.13 g/g (interquartile range, 0.06-0.40; Tables 1 and S1 ).

Low social support, defined as LSNS score < 12, was seen in 404 of 1,851 (22%) participants with available LSNS scores. Participants with higher social support (≥12) when compared with participants with lower social support were more likely to be older, women, and non-Hispanic; have a household income > $20,000; be nonsmokers; have more than a high school education; and be more likely to work/volunteer ( Table 1 ). Table 1 Baseline Characteristics of the Study Population With Lubben Social Network Scale Score, Stratified by Level of Social Support Variable All Patients With Lubben Social Network Scale Score (N = 1,851) Lubben Social Network Scale Score < 12 (n = 404) - Lubben Social Network Scale Score ≥ 12 (n = 1,447) P Age, y 71.7 (4.76) 71.2 (4.92) 71.9 (4.67) 0.02 Female sex 786 (42.5%) 152 (37.62%) 634 (43.82%) 0.03 Race/ethnicity Non-Hispanic White 925 (49.97%) 193 (47.77%) 732 (50.59%) 0.006 Non-Hispanic Black 728 (39.33%) 154 (38.12%) 574 (39.67%) Hispanic 133 (7.19%) 45 (11.14%) 88 (6.08%) Other 65 (3.51%) 12 (2.97%) 53 (3.66%) Education <High school 285 (15.40%) 84 (20.79%) 201 (13.9%) 0.002 High school graduate 312 (16.86%) 72 (17.82%) 240 (16.60%) Some college 510 (27.55%) 110 (27.23%) 400 (27.66%) ≥College graduate 743 (40.14%) 138 (34.16%) 605 (41.84%) Household income ≤$20,000 408 (22.04%) 119 (29.46%) 289 (19.97%) <0.001 $20,001-$50,000 525 (28.36%) 128 (31.68%) 397 (27.44%) $50,001-$100,000 396 (21.39%) 79 (19.55%) 317 (21.91%) >$100,000 255 (13.78%) 25 (6.19%) 230 (15.90%) Do not wish to answer 267 (14.43%) 53 (13.12%) 214 (14.79%) Smoking Lifetime smoked ≥100 cigarettes 1,027 (55.5%) 238 (58.91%) 789 (54.53%) 0.12 Current smoker 119 (6.43%) 36 (8.91%) 83 (5.74%) 0.02 Work as a volunteer or for money Works to earn money 377 (20.74%) 51 (12.91%) 326 (22.91%) <0.001 Volunteers 488 (26.84%) 56 (14.18%) 432 (30.36%) <0.001 Physical characteristics Systolic BP, mm Hg 127.47 (19.45) 127.08 (19.23) 127.58 (19.51) 0.66 Diastolic BP, mmHg 65.91 (10.92) 66.19 (10.91) 65.83 (10.92) 0.58 Body mass index, kg/m 2 31.70 (6.67) 32.21 (6.63) 31.56 (6.68) 0.10 Diabetes 1,013 (54.73%) 232 (57.43%) 781 (53.97%) 0.22 Hypertension 1,718 (92.92%) 380 (94.06%) 1,338 (92.60%) 0.31 History of cardiovascular disease 800 (43.22%) 187 (46.29%) 613 (42.36%) 0.16 Renal and laboratory data eGFR, a mL/min/1.73 m 2 50.30 (16.65) 49.82 (16.37) 50.44 (16.74) 0.54 Urinary protein-creatinine ratio, g/g b 0.14 [0.07-0.43] 0.15 [0.07-0.42] 0.13 [0.07-0.44] 0.43 Hemoglobin A 1c , mg/dL 6.41 (1.31) 6.65 (1.59) 6.35(1.22) <0.001 Medications No. of total medications 1.66 (0.88) 1.76 (0.87) 1.64 (0.87) 0.02 ACEI or ARB 1,210 (66.45%) 273 (69.29%) 937 (65.66%) 0.18 Loop diuretics 533 (29.27%) 131 (33.25%) 402 (28.17%) 0.05 Statins 1,285 (70.57) 288 (73.10%) 997 (69.87%) 0.21 Lubben Social Support Scale Lubben Social Support Scale score 16.2(5.93) 7.84 (2.63) 18.49 (4.28) <.001 Note: Values expressed as mean (standard deviation), number (percent), or median [interquartile range]. Abbreviations: ACEI, angiotensin-converting enzyme inhibitor; ZRB, angiotensin receptor blocker; BP, blood pressure; eGFR, estimated glomerular filtration rate. a eGFR using CRIC equation. b From spot sample.

Participants with higher social support had higher average scores in quality of life as measured by the KDQOL-36 with regard to burden, effects of kidney disease, symptoms of kidney disease, mental health, and physical health ( Table 2 ). Additionally, those with higher social support scored higher on all cognitive function measures, including the MMSE, TMT-A and -B, and Buschke Selective Reminding Tests ( Table 2 ). Participants with higher social support were less likely than those with lower social support to be frail (25.69% vs 40.98%; P < 0.001) Table 2 Quality-o- Life, Cognitive, and Frailty Measures Stratified by Level of Social Support Variable All Patients With Lubben Social Network Scale Score (N = 1,851) Lubben Social Network Scale Score < 12 (n = 404) Lubben Social Network Scale Score ≥ 12 (n = 1,447) P Kidney Disease Quality of Life scores KDQOL Burden 88.42 (19.87) 82.64 (24.86) 90.02 (17.92) <0.001 Missing 16 (0.9%) 5 (1.2%) 11 (0.8%) KDQOL Effects 91.23 (13.38) 86.99 (17.34) 92.40 (11.79) <0.001 Missing 16 (0.9%) 5 (1.2%) 11 (0.8%) KDQOL Symptoms 83.42 (14.48) 80.25 (15.81) 84.30 (13.97) <0.001 Missing 16 (0.9%) 5 (1.2%) 11 (0.8%) KDQOL Mental health composite 51.57 (9.71) 47.66 (10.90) 52.655 (9.06) <0.001 Missing 27 (1.5%) 7 (1.7%) 20 (1.4%) KDQOL Physical health composite 40.43 (11.37) 38.80 (11.26) 40.88 (11.36) 0.001 Missing 27 (1.5%) 7 (1.7%) 20(1.4%) Cognitive testing Modified Mini-Mental State Examination 90.98 (8.25) 88.90 (9.49) 91.55 (7.78) <0.001 Missing 116 (6.3%) 29 (7.2%) 87 (6.01%) Trail Making test Part A, s 50.51 (32.57) 55.93 (34.74) 49.05 (31.82) 0.001 Missing 156 (8.4%) 43 (10.6%) 113 (7.8%) Noncomplete 4 (0.22%) 2( 0.49%) 2 (0.14%) Trail Making Test Part B, s 134.26 (69.52) 145.7 (69.69) 131.35 (69.21) <0.001 Missing 185 (0.1%) 52 (12.87%) 133 (9.19%) Noncomplete 89 (4.8%) 32 (7.92%) 57 (3.94%) Buschke Selective Reminding Test 1 6.22 (2.18) 5.70 (2.08) 6.37 (2.19) <0.001 Missing 182 (9.8%) 48 (11.9%) 134 (9.3%) Buschke Selective Reminding Test 2 47.55 (12.43) 43.66 (12.27) 48.60 (12.27) <0.001 Missing 204 (11.0%) 52 (12.9%) 152 (10.5%) Buschke Selective Reminding Test 3 7.37 (3.14) 6.39 (3.02) 7.63 (3.12) <0.001 Missing 205 (11.1%) 53 (13.2%) 152 (10.5%) Frailty status Not frail 67 (3.9%) 5 (1.4%) 62 (4.6%) Prefrail 1,147 (67.1%) 211 (57.7%) 936 (69.7%) Frail 495 (29.0%) 150 (41.0%) 345 (25.7%) <0.001 Missing, n 142 38 104 Abbreviation: KDQOL, Kidney Disease Quality of Life.

In fully adjusted linear regression models, higher social support was associated with higher quality of life. The β coefficient was 2.57 (95% CI, 1.57-3.56), 2.21 (95% CI, 1.52-2.9), 1.64 (95% CI, 0.88-2.41), 1.91 (95% CI, 1.40-2.43), and 0.64 (95% CI, 0.03-1.24) per each 1 standard deviation (SD) higher in LSNS score for KDQOL burden, effects, symptoms, mental health, and physical health, respectively; P < 0.05; Table 3 ). There was a significant interaction ( P for interaction = 0.02) with age on the relationship between social support and KDQOL mental health composite score. For participants aged 65 to 71 years, each 1-SD higher LSNS score was associated with a higher KDQOL mental health composite score of 2.50. For participants 71 years and older, each 1-SD change in LSNS score was associated with an increase in KDQOL mental health composite score of 1.30. Table 3 Association Between Social Support and Quality of Life Primary Predictor: LSNS Score per 1-SD Change in LSNS Score KDQOL Burden KDQOL Effects KDQOL Symptoms KDQOL SF-12 Mental Component Score KDQOL SF-12 Physical Component Score β Coefficient (95% CI) P β Coefficient (95% CI) P β Coefficient (95% CI) P β Coefficient (95% CI) P β Coefficient (95% CI) P Model 0 2.95 (2.04-3.85) <0.001 2.27 (1.67-2.88) <0.001 2.07 (1.41-2.72) <0.001 2.23 (1.79-2.66) <0.001 1.19 (0.67-1.71) <0.001 Model 1 2.58 (1.69-3.47) <0.001 2.07 (1.46-2.67) <0.001 1.69 (1.03-2.34) <0.001 2.02 (1.58-2.46) <0.001 0.9 (0.39-1.41) <0.001 Model 2 2.64 (1.73-3.54) <0.001 2.16 (1.55-2.77) <0.001 1.70 (1.02-2.37) <0.001 2.03 (1.58-2.48) <0.001 0.84 (0.31-1.37) 0.002 Model 3 2.57 (1.57-3.56) <0.001 2.21 (1.52-2.9) <0.001 1.64 (0.88-2.41) <0.001 1.91 (1.40-2.43) <0.001 0.64 (0.03-1.24) 0.04 Note: Model 0 adjusted for age. Model 1 adjusted for age, clinical site, income, education, and race/ethnicity. Model 2 adjusted for covariates in model 1 plus history of hypertension, heart failure, stroke, coronary artery disease, peripheral vascular disease, diabetes, systolic blood pressure, and hemoglobin A 1c level. Model 3 adjusted for covariates in models 1 and 2 and estimated glomerular filtration rate and proteinuria. Abbreviations: KDQOL, Kidney Disease Quality of Life; LSNS, Lubben Social Network Scale; SD, standard deviation; SF-12, 12-Item Short Form Health Survey.

Social support was independently associated with all measures of cognitive function ( Tables 4 and 5 ). In the fully adjusted linear regression model, higher social support scores were associated with higher MMSE scores (0.81 units higher per 1-SD change in LSNS score; P < 0.001) and shorter time to complete the timed tests (−2.53 seconds for TMT-A and −6.53 seconds for TMT-B per 1-SD higher LSNS score; P < 0.01). Although there was no interaction with age and the relationship between social support and the MMSE, TMT-A, and TMT-B scores, age modified the associations between social support and the Buschke Selective Reminder Tests; each 1-SD change in LSNS score was associated with a 0.04 increase in Buschke Selective Reminder Test 1 score in 65- to 71-year-old participants versus a 0.34 increase in those 71 years and older ( P for interaction = 0.009). Similarly, the association between social support scores and Buschke Selective Reminder Tests 2 and 3 was stronger in participants 71 years and older compared with those between the ages of 65 and 71 years. Table 4 Association Between Social Support and Cognitive Function (Modified Mini Mental State Examination and Trail Making Test parts A and B) Predictor: LSNS Score per 1-SD Change in LSNS Score Modified Mini Mental State Examination Score Trail Making Test Part A Trail Making Test Part B β Coefficient (95% CI) P β Coefficient (95% CI) P β Coefficient (95% CI) P Model 0 1.20 (0.81 to 1.59) <0.001 −3.59(−5.24 to −1.94) <0.001 −8.48(−12.09 to −4.88) <0.001 Model 1 0.81(0.48 to 1.13) <0.001 −2.91(−4.44 −1.38) <0.001 −7.00(−10.08 to −3.92) <0.001 Model 2 0.75(0.42 to 1.08) <0.001 −2.45(−3.98 to −0.93) 0.002 −6.47(−9.57 to −3.37) <0.001 Model 3 0.81(0.44 to 1.19) <0.001 −2.53(−4.29,−0.76) 0.005 −6.53(−10.07 to −2.99) 0.0003 Note: Model 0 adjusted for age. Model 1 adjusted for age, clinical site, income, education, and race/ethnicity. Model 2 adjusted for covariates in model 1 plus history of hypertension, heart failure, stroke, coronary artery disease, peripheral vascular disease, diabetes, systolic blood pressure, and hemoglobin A 1c level. Model 3 adjusted for covariates in models 1 and 2 and estimated glomerular filtration rate and proteinuria. Abbreviations: LSNS, Lubben Social Network Scale; SD, standard deviation. Table 5 Association Between Social Support and Cognitive Function (Buschke selective reminder tests) Predictor: LSNS Score per 1-SD Change in-LSNS Score Buschke Selective Reminder Test 1 Buschke Selective Reminder Test 2 Buschke Selective Reminder Test 3 β Coefficient (95% CI) P β Coefficient (95% CI) P β Coefficient (95% CI) P Model 0 0.28 (0.17-0.38) <0.001 2.12 (1.53- 2.71) <0.001 0.52 (0.37-0.67) <0.001 Model 1 0.22 (0.12-0.32) <0.001 1.69 (1.14-2.24 <0.001 0.43 (0.28--0.57) <0.001 Model 2 0.19 (0.09-0.30) 0.0002 1.5 (0.94-2.06) <0.001 0.39 (0.25-0.54) <0.001 Model 3 0.19 (0.07-0.30) 0.001 1.59 (0.96-2.22) <0.001 0.40 (0.23-0.56) <0.001 Note: Model 0 adjusted for age. Model 1 adjusted for age, clinical site, income, education, and race/ethnicity. Model 2 adjusted for covariates in model 1 plus history of hypertension, heart failure, stroke, coronary artery disease, peripheral vascular disease, diabetes, systolic blood pressure, and hemoglobin A 1c level. Model 3 adjusted for covariates in models 1 and 2 and estimated glomerular filtration rate and proteinuria. Abbreviations: LSNS, Lubben Social Network Scale; SD, standard deviation.

Participants with higher social support were more likely to be nonfrail (OR, 1.77; P < 0.05) and prefrail (OR, 1.33; P < 0.05; Table 6 ) than participants with lower social support; this association was consistent across age groups. In sensitivity analysis comparing high social support (LSNS score ≥ 12) versus low social support (LSNS score < 12), high social support remained associated with improved KDQOL scores for burden, effects, symptoms, and mental composite score but not with the physical composite score. The association between the binary predictors of high versus low social support and cognitive measures of the MMSE, TMT-B, and Buschke Selective Reminder Tests 1,2, and 3 also remained robust in this sensitivity analysis ( Tables S2-S4 ). Table 6 Association Between Social Support and Frailty Primary Predictor: LSNS Score per 1-SD Change in LSNS Score Nonfrail Pre frail OR (95% CI) P OR (95% CI) P Model 0 2.04 (1.56-2.68) <0.001 1.392 (1.25-1.55) <0.001 Model 1 2.06 (1.54-2.75) <0.001 1.36 (1.21-1.52) <0.001 Model 2 2.06 (1.53-2.77) <0.001 1.37 (1.22-1.54) <0.001 Model 3 1.77 (1.24-2.53) 0.002 1.33 (1.16-1.53) <0.001 Note: Model 0 adjusted for age. Model 1 adjusted for age, clinical site, income, education, and race/ethnicity. Model 2 adjusted for covariates in model 1 plus history of hypertension, heart failure, stroke, coronary artery disease, peripheral vascular disease, diabetes, systolic blood pressure, and hemoglobin A 1c level. Model 3 adjusted for covariates in models 1 and 2 and estimated glomerular filtration rate and proteinuria. Abbreviations: LSNS, Lubben Social Network Scale; OR, odds ratio; SD, standard deviation.

Discussion

In this large multicenter well-curated study of CKD, we demonstrate that 22% of older patients with CKD had scores consistent with poor social support. Higher social support in this cohort was associated with better quality of life and cognitive performance and lower measures of frailty. With the exception of the mental health composite score and selective reminder tests, the associations between social support and quality-of-life measures, cognitive assessments, and frailty were consistent across age strata.

Few studies in predialysis CKD populations have examined the relationship between social support and sociodemographic, psychosocial, and other clinically meaningful measures such as cognitive function or frailty. Our results are consistent with previously reported data; in an urban and primarily African American hemodialysis population, Kimmel et al 22 found a positive correlation between measures of social support and quality of life and an inverse correlation between measures of social support and patient perception of the effects of their illness. In the study of African American adults with hypertensive CKD, Porter et al 14 found a positive association between social support and quality-of-life physical and mental health measures. Taken together with the results from our study, social support and quality of life in patients with CKD appear to relate to each other, with higher social support associated with higher quality of life. Our analysis of CRIC participants adds to this body of knowledge by reporting findings in a diverse racial ethnic group of older patients with non–dialysis-dependent CKD.

The importance of quality of life to patient outcomes has been shown in ESKD and non–dialysis-dependent CKD populations. 6 , 13 , 15 For example, Mapes et al 15 found that lower quality-of-life measures were associated with increased risk for mortality and hospitalization in patients with ESKD, whereas Porter et al 13 found that lower quality-of-life measures in patients with CKD not receiving dialysis were associated with higher risk for incident cardiovascular disease and mortality. In fully adjusted models from our study, a 1-SD change in LSNS score was associated with a 1.91 change in the mental component score and 0.64 change in the physical component score of the KDQOL.

To provide some context to the clinical significance of these associations, consider that Mapes et al 15 found in a large international dialysis population from the Dialysis Outcomes and Practice Patterns Study (DOPPS) that for each 10-point lower score on the mental health component summary and physical component summary of the KDQOL, there was a 1.13 and 1.29 relative risk increase for death and hospitalization, respectively. Social support networks can help provide patients with the tools they need to ensure their basic needs are being met by helping with finances, housing costs, and food acquisition. This reinforces the need to study factors that are associated with quality of life, and social support may be one such factor that is potentially modifiable.

Our results also corroborate prior research that describes relationships between social networks and cognitive function. For example, interactions in larger social networks in adults older than 50 years were associated with maintenance of cognitive function and lower risk for incident dementia. 4 , 20 Our study complements this existing literature by demonstrating the association between social support and cognition in a CKD population, using a more extensive battery of cognitive tests compared with many prior reports. Cognitive impairment has also been associated with increased risk for mortality. 32

Considering the relationship between social support and cognitive function seen in our study, it is plausible that social support may affect how cognitive function affects mortality. The influence of family or friends to help guide patients through a complex health system, gain access to the health system, or promote adherence to complicated treatment regimens in older adults may be magnified in those who are cognitively impaired.

Our results appear to also be clinical meaningful. For example, changes in MMSE score over a 3-year span in a cohort of older Chinese adults of >1.62 points per year were associated with 75% higher risk for death. 33 The magnitude of change associated with a 1-SD increase in LSNS score in our study in a fully adjusted model was similar at 0.81.

Frailty is commonly recognized as a biological syndrome in older adults characterized by a decline in multiple physiologic systems, leading to decreased reserve, reduced resistance to stressors, and increased risk for adverse health outcomes. 16 , 17 In a general geriatric population in the United Kingdom, poor social support predicted the development of frailty. 21 In both dialysis patients and those with non–dialysis-dependent CKD, frailty has also been shown to be associated with mortality. 34 , 35 In addition, previous studies in CRIC found that severity of CKD was associated with frailty. 31 We extend these findings by demonstrating an association between social support and frailty; strong social support may modify the susceptibility of frail patients with CKD to adverse outcomes by allowing for more access to medical care or improving treatment adherence.

The associations observed in this study between social support and quality of life, frailty, and cognitive function are significant for several reasons. Cognitive function, frailty, and quality of life represent meaningful outcomes for patients. Our findings suggest that these outcomes may share a potentially modifiable factor in social support. A systematic review examining interventions to address social isolation in older adults found that 79% of group-based interventions and 55% of 1-on-1 interventions led to improvement in at least 1 participant-based outcome. 36 Therefore, social support represents an appealing target for intervention because it is linked to a number of important outcomes in older patients with CKD, and evidence exists that social support may be improved by interventions such as home visiting programs, social activity programs, physical activity programs, self -management groups, counseling groups, and discussion groups. 36 It is also worth noting that the older adults most likely to benefit from social support, the adults with impaired cognitive function, lower quality of life, and increased frailty, are the older adults least likely to have strong social support.

The strengths of this analysis include the fact that CRIC is a diverse well-characterized large cohort with CKD. By virtue of the multicenter design, CRIC participants come from many different cities within the United States and have mild to advanced CKD. Consequently, our results may be generalizable to a wide range of patients with mild to advanced CKD.

However, there are several limitations to this study. The main one is that this is a cross-sectional observational study and thus we cannot assume causality or direction. It is possible that low quality of life, cognitive impairment, and frailty could lead to a low LSNS score. Additionally, there may be unmeasured confounders that could have some impact on the outcomes. For instance, although we collect data on depression, this information is not collected at the same time as social support data and was unable to be used in this analysis.

In summary, among older patients with CKD, social support is associated with a variety of domains that directly affect patient’s health and quality of life. Our study sets the stage for future trials to determine whether modifying social support leads to improved clinical outcomes.

References

1 Mookadam F. Arthur H.M. Social support and its relationship to morbidity and mortality after acute myocardial infarction: systematic overview Arch Intern Med 164 14 2004 1514 1518 15277281 10.1001/archinte.164.14.1514

2 Grodner S. Prewitt L.M. Jaworski B.A. Myers R. Kaplan R.M. Ries A.L. The impact of social support in pulmonary rehabilitation of patients with chronic obstructive pulmonary disease Ann Behav Med 18 3 1996 139 145 24203764 10.1007/BF02883389

3 Kroenke C.H. Kubzansky L.D. Schernhammer E.S. Holmes M.D. Kawachi I. Social networks, social support, and survival after breast cancer diagnosis J Clin Oncol 24 7 2006 1105 1111 16505430 10.1200/JCO.2005.04.2846

4 Crooks V.C. Lubben J. Petitti D.B. Little D. Chiu V. Social network, cognitive function, and dementia incidence among elderly women [see comment in PubMed Commons] Am J Public Health 98 7 2008 1221 1227 18511731 10.2105/AJPH.2007.115923 PMC2424087

5 Shao Y. Liang L. Shi L. Wan C. Yu S. The effect of social support on glycemic control in patients with type 2 diabetes mellitus: the mediating roles of self-efficacy and adherence J Diabetes Res 2017 2017 2804178 28626769 10.1155/2017/2804178 PMC5463190

6 Kimmel P.L. Peterson R.A. Weihs K.L. Psychosocial factors, behavioral compliance and survival in urban hemodialysis patients Kidney Int 54 1 1998 245 254 9648085 10.1046/j.1523-1755.1998.00989.x

7 Nicholson N.A. Review of social isolation: an important but underassessed condition in older adults J Primary Prevent 33 2012 137 152 10.1007/s10935-012-0271-2 22766606

8 Cohen-Mansfield J. Hazan H. Lerman Y. Shalom V. Correlates and predictors of loneliness in older-adults: a review of quantitative results informed by qualitative insights I nt Psychogeriatr 28 4 2016 557 26424033 10.1017/S1041610215001532

9 US Renal Data System USRDS 2017 Annual Data Report: Epidemiology of Kidney Disease in the United States 2017 National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases

10 Perissinotto C.M. Stijacic Cenzer I. Covinsky K.E. Loneliness in older persons: a predictor of functional decline and death Arch Intern Med 172 14 2012 1078 1084 22710744 10.1001/archinternmed.2012.1993 PMC4383762

11 Jarach C.M. Tettamanti M. Nobili A. D'avanzo B. Social isolation and loneliness as related to progression and reversion of frailty in the Survey of Health Aging Retirement in Europe (SHARE) Age Ageing 50 1 2021 258 262 32915990 10.1093/ageing/afaa168 PMC7793602

12 Kallenberg M.H. Kleinveld H.A. Dekker F.W. Functional and cognitive impairment, frailty, and adverse health outcomes in older patients reaching ESRD—a systematic review Clin J Am Soc Nephrol 11 9 2016 1624 1639 27342598 10.2215/CJN.13611215 PMC5012494

13 Porter A.C. Lash J.P. Xie D. Predictors and outcomes of health-related quality of life in adults with CKD Clin J Am Soc Nephrol 11 7 2016 1154 1162 27246012 10.2215/CJN.09990915 PMC4934840

14 Porter A. Fischer M.J. Brooks D. Quality of life and psychosocial factors in African Americans with hypertensive chronic kidney disease Transl Res 159 1 2012 4 11 22153804 10.1016/j.trsl.2011.09.004 PMC3240805

15 Mapes D.L. Lopes A.A. Satayathum S. Health-related quality of life as a predictor of mortality and hospitalization: the Dialysis Outcomes and Practice Patterns Study (DOPPS) Kidney Int 64 1 2003 339 349 12787427 10.1046/j.1523-1755.2003.00072.x

16 Fried L.P. Tangen C.M. Walston J. Frailty in older adults: evidence for a phenotype J Gerontol A Biol Sci Med Sci 56 2001 M146 M156 11253156 10.1093/gerona/56.3.m146

17 Clegg A. Young J. Iliffe S. Rikkert M.O. Rockwood K. Frailty in elderly people Lancet 381 9868 2013 752 762 23395245 10.1016/S0140-6736(12)62167-9 PMC4098658

18 Roshanravan B. Khatri M. Robinson-Cohen C. A prospective study of frailty in nephrology-referred patients with CKD Am J Kidney Dis 60 6 2012 912 921 22770927 10.1053/j.ajkd.2012.05.017 PMC3491110

19 Evans I.E.M. Llewellyn D.J. Matthews F.E. Woods R.T. Brayne C. Clare L. CFAS-Wales research team Social isolation, cognitive reserve, and cognition in healthy older people PLoS One 13 8 2018 e0201008 10.1371/journal.pone.0201008 PMC6097646 30118489

20 Holtzman R.E. Rebok G.W. Saczynski J.S. Kouzis A.C. Wilcox Doyle K. Eaton W.W. Social network characteristics and cognition in middle-aged and older adults J Gerontol B Psychol Sci Soc Sci 59 6 2004 P278 P284 15576855 10.1093/geronb/59.6.p278

21 Ding Y.Y. Kuha J. Murphy M. Multidimensional predictors of physical frailty in older people: identifying how and for whom they exert their effects Biogerontology 18 2 2017 237 252 28160113 10.1007/s10522-017-9677-9 PMC5350240

22 Kimmel P.L. Peterson R.A. Weihs K.L. Aspects of quality of life in hemodialysis patients J Am Soc Nephol 6 1995 1418 1426 10.1681/ASN.V651418 8589317

23 Gallicchio L. Hoffman S.C. Helzlsouer K.J. The relationship between gender, social support, and health-related quality of life in a community-based study in Washington County, Maryland Qual Life Res 16 5 2007 777 786 17286195 10.1007/s11136-006-9162-4

24 Feldman H.I. Appel L.J. Chertow G.M. Chronic Renal Insufficiency Cohort (CRIC) Study Investigators. The Chronic Renal Insufficiency Cohort (CRIC) Study: design and methods J Am Soc Nephrol 14 7 suppl 2 2003 S148 S153 12819321 10.1097/01.asn.0000070149.78399.ce

25 Lash J.P. Go A.S. Appel L.J. Chronic Renal Insufficiency Cohort (CRIC) Study Group. Chronic Renal Insufficiency Cohort (CRIC) Study: baseline characteristics and associations with kidney function Clin J Am Soc Nephrol 4 8 2009 1302 1311 19541818 10.2215/CJN.00070109 PMC2723966

26 Lubben J. Blozik E. Gillmann G. Performance of an abbreviated version of the Lubben Social Network Scale among three European community-dwelling older adult populations Gerontologist 46 4 2006 503 513 16921004 10.1093/geront/46.4.503

27 Hays R.D. Kallich J.D. Mapes D.L. Coons S.J. Carter W.B. Development of the Kidney Disease Quality of Life (KDQOL) instrument Qual Life Res 3 5 1994 329 338 7841967 10.1007/BF00451725

28 Teng E.L. Chui H.C. The Modified Mini-Mental State (3MS) Examination J Clin Psychiatry 48 1987 314 318 3611032

29 Reitan R.M. Validity of the Trail Making Test as an indicator of organic brain damage Percept Mot Skills 8 1958 271 276

30 Buschke H. Fuld P.A. Evaluating storage, retention, and retrieval in disordered memory and learning Neurology 24 1974 1019 1025 4473151 10.1212/wnl.24.11.1019

31 Reese P.R. Cappola A.R. Shults J. Physical performance and frailty in chronic kidney disease Am J Nephrol 38 4 2013 307 315 24107579 10.1159/000355568 PMC4019506

32 Sachs G.A. Carter R. Holtz L.R. Cognitive impairment: an independent predictor of excess mortality: a cohort study Ann Intern Med 155 5 2011 300 308 21893623 10.7326/0003-4819-155-5-201109060-00007

33 Lv X. Li W. Ma Y. Cognitive decline and mortality among community-dwelling Chinese older people BMC Med 17 2019 63 30871536 10.1186/s12916-019-1295-8 PMC6419492

34 McAdams-DeMarco M.A. Law A. Salter M.L. Frailty as a novel predictor of mortality and hospitalization in individuals of all ages undergoing hemodialysis J Am Geriatr Soc 61 6 2013 896 901 23711111 10.1111/jgs.12266 PMC3938084

35 Delgado C. Grimes B.A. Glidden D.V. Shlipak M. Sarnak M.J. Johansen K.L. Association of frailty based on self-reported physical function with directly measured kidney function and mortality BMC Nephrol 16 2015 203 26645070 10.1186/s12882-015-0202-6 PMC4673778

36 Dickens A.P. Richards S.H. Greaves C.J. Campbell J.L. Interventions targeting social isolation in older people: a systematic review BMC Public Health 11 2011 647 21843337 10.1186/1471-2458-11-647 PMC3170621

Supplementary Material

Supplementary File (PDF) Item S1, Tables S1-S4

Article Information

Authors’ Full Names and Academic Degrees

Anne Slaven, MSSA, Jesse Hsu, PhD, Jeffrey R. Schelling, MD, Sankar D. Navaneethan, MD, Hernan Rincon-Choles, MD, Mara A. McAdams-DeMarco, PhD, Marleen Schachere, RN, Noreen O’Malley, RN, Jennifer Deluca, Eva Lustigova, MPH, Xue Wang, MS, John Kusek, PhD, Anna C. Porter, MD, James P. Lash, MD, Mahboob Rahman, MD, and Edward Horwitz, MD; on behalf of the CRIC Study investigators.

Authors’ Contributions

Research idea and study design: AS, JRS, SDN, HR-C, MAM-D, JK, ACP, JPL, MR, EH; data acquisition: AS, MS, NO, JD, EL; data analysis/interpretation: AS, JH, JRS, SDN, HR-C, MAM-D, JD, EL, XW, ACP, JPL, MR, EH; statistical analysis: JH, XW; supervision or mentorship: JRS, JK, JPL, MR. Each author contributed important intellectual content during manuscript drafting or revision and accepts accountability for the overall work by ensuring that questions pertaining to the accuracy or integrity of any portion of the work are appropriately investigated and resolved.

Support

Funding for the CRIC Study was obtained under a cooperative agreement from 10.13039/100000062 National Institute of Diabetes and Digestive and Kidney Diseases (U01DK060990, U01DK060984, U01DK061022, U01DK061021, U01DK061028, U01DK060980, U01DK060963, and U01DK060902). In addition, this work was supported in part by the 10.13039/100007928 Perelman School of Medicine at the University of Pennsylvania Clinical and Translational Science Award 10.13039/100000002 National Institutes of Health (NIH)/ 10.13039/100006108 National Center for Advancing Translational Sciences (NCATS) UL1TR000003, 10.13039/100007880 Johns Hopkins University UL1 TR-000424, 10.13039/100008510 University of Maryland General Clinical Research Center M01 RR-16500, 10.13039/100012729 Clinical and Translational Science Collaborative of Cleveland , UL1TR000439 from the NCATS component of the NIH and NIH Roadmap for Medical Research, 10.13039/100008269 Michigan Institute for Clinical and Health Research (MICHR) UL1TR000433, 10.13039/100008522 University of Illinois at Chicago Clinical and Translational Science Awards UL1RR029879, Tulane COBRE for Clinical and Translational Research in Cardiometabolic Diseases P20 GM109036, Kaiser Permanente NIH/National Center for Research Resources UCSF-CTSI UL1 RR-024131. R01-DK072231 (Dr Lash), K24-DK092290 (Dr Lash).

Financial Disclosure

The authors declare that they have no relevant financial interests.

Peer Review

Received November 17, 2020. Evaluated by 2 external peer reviewers, with direct editorial input by the Statistical Editor and the Editor-in-Chief. Accepted in revised form April 18, 2021.

Complete author and article information provided before references.

Supplementary File (PDF)

Item S1: Lubben Social Network Scale-6 Item version

Table S1: Baseline characteristics of study population stratified by age

Table S2: Association between social support (binary Lubben Scale score) and quality of life

Table S3: Association between social support (binary Lubben score) and cognitive function (MMSE, Trails Making Test parts A and B)

Table S4: Association between social support (binary Lubben score) and cognitive function (Buschke Selective Reminder Tests 1, 2, and 3)