Объединение лиц с низкой окружностью теленка и пониженной массой с саркопией у пожилых людей с хроническими заболеваниями почек: перекрестное исследование.

Introduction

Sarcopenia is an aging-related disease featured by declined skeletal muscle quality and quantity [ 1 ]; a higher risk of several adverse outcomes, such as fractures, disability, poor quality of life, hospitalization, and mortality, occurs in patients with this disease [ 2 , 3 ]. Sarcopenia is a relevant condition to several chronic diseases in older adults, including end-stage kidney disease (ESKD), heart failure, hypertension, diabetes mellitus (DM), and metastatic cancer, and a worse long-term prognosis is anticipated in these populations [ 4–6 ]. Muscle strength declines approximately three times faster than lean muscle mass in septuagenarian adults [ 7 ]. In addition, reduced skeletal muscle strength has been associated with poorer prognosis and adverse outcomes in older individuals [ 8 ]. Accordingly, low muscle strength, defined as ‘possible sarcopenia’ in the AWGS 2019 criteria [ 1 ], may represent an early stage or prodrome of sarcopenia. Altogether, investigating the relationship between frequent chronic diseases and possible sarcopenia and sarcopenia in older people is a vital issue.

Pre-dialysis chronic kidney disease (CKD) is one of the most common chronic diseases in older adults, and it was proposed to be a condition associated with skeletal muscle loss [ 9 ]. Patients with pre-dialysis CKD and sarcopenia may have an increased risk of mortality and ESKD occurrence [ 10 ]. Several authors have investigated the association between sarcopenia and pre‐dialysis CKD, but their data are not univocal [ 11–15 ]. This result may be attributed to serum creatinine and creatinine-based glomerular filtration rate (GFR) being lower in patients with decreased muscle mass [ 16 ]. Owing to creatinine-based estimated GFR (eGFR) formulae being widely recommended as an initial renal function assessment tool [ 17 ], it is imperative to find an accurate strategy to estimate the association between sarcopenia and pre-dialysis CKD based on these creatinine-based eGFR equations for sarcopenia prevention and early recognition.

Previous literature reported low body mass index (BMI) is associated with sarcopenia in patients with CKD before the introduction of dialysis [ 11 , 13 , 15 , 18 , 19 ]. However, the specific cutoff value of low BMI was not mandated. Although calf circumference has been recommended as an indicator of case finding for sarcopenia in the consensus of the Asian Working Group for Sarcopenia (AWGS) 2019 [ 1 ], no researcher has investigated the correlation between calf circumference and sarcopenia in patients with pre-dialysis CKD to date. The primary aim of this study was to estimate the joint association of calf circumference and BMI with sarcopenia in older adults with pre-dialysis CKD. In addition, we evaluated the associations between low calf circumference, underweight status, and sarcopenia, and explored clinically applicable cutoff values for BMI within this population.

Methods

Participants

This retrospective, observational cross-sectional study was conducted using data from a community-dwelling older adult database in New Taipei City, Taiwan, covering the period from 1 January 2015 to 31 December 2022. Individuals with dementia, stroke, Parkinson’s disease, severe cognitive impairment, disability, cachexia, leg pitting edema (grade II or more), missing data, or aged below 60 years were excluded. A total of 3,629 eligible participants were included in the analysis. All participants had undergone standardized medical evaluations and assessments during regular health examinations conducted by trained healthcare professionals. The collected data were de-identified prior to analysis to ensure participant confidentiality. This study was approved by the Ethics Committee of Far Eastern Memorial Hospital, New Taipei City, Taiwan (IRB No. 112143-F) and was conducted in accordance with the ethical principles outlined in the 1964 Declaration of Helsinki and its later amendments. Due to the retrospective nature of this study, the requirement for individual informed consent was waived by the Institutional Review Board.

Assessment

Assessment of sarcopenia

Based on the consensus of the AWGS [ 20 ], the participants’ handgrip strength, skeletal muscle mass index (SMI), and physical performance were evaluated. Each older adult received a handgrip strength test on the full elbow extension dominant hand via a Smedley dynamometer (Takei Ltd., Niigata, Japan) and recorded in kilograms-force (kgf). For reference, 1 kgf is equivalent to 9.81 N. Handgrip strength less than 28.0 kgf for men and 18.0 kgf for women were categorized as low muscle strength [ 1 ]. A multifrequency bioelectrical impedance analyzer (BC-418; Tanita, Tokyo, Japan) was used to assess the appendicular skeletal muscle mass (ASM), and the measured ASM was divided by the square of the body height (m 2 ) to acquire the skeletal muscle mass index (SMI). SMI less than 7.0 kg/m 2 for men and 5.7 kg/m 2 for women were classified as low muscle mass [ 1 ]. In physical performance evaluation, the older adult participants were asked to walk at a normal pace for 6 m. A gait speed less than 1 m/s was defined as a slow gait speed [ 1 ]. Based on the diagnostic criteria of AWGS 2019 [ 1 ], these older people were sub-classified into ‘possible sarcopenia’ and ‘sarcopenia and severe sarcopenia’ groups. Since emerging reports emphasized the clinical significance of possible sarcopenia [ 8 , 21 ] and the bidirectional transition character among these three sarcopenic statuses [ 22 ], we defined an overall sarcopenia group in this study. This group comprised individuals with ‘possible sarcopenia’ as well as those with ‘sarcopenia and severe sarcopenia,’ consistent with our previous report [ 23 ]. Nevertheless, we acknowledge that this approach may obscure differences between stages, and the findings should be interpreted with this limitation in mind.

Assessment of kidney function

The guidelines of Kidney Disease Improving Global Outcomes (KDIGO) [ 17 ] were applied to recognize the participants with CKD. The subject’s self-report and medical record review were used to confirm the duration of kidney function or structure abnormalities (persisted ≥3 months) for CKD diagnosis. For participants with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m 2 , CKD was confirmed only when evidence of persistent kidney damage was present, including documented albuminuria or structural or functional kidney abnormalities lasting for at least 3 months, as verified by self-report and medical record review. Participants without such evidence were not classified as having CKD. After the blood sample was drawn by veinous puncture and serum creatinine concentration was measured, the estimated glomerular filtration rate was appraised by the Berlin Initiative Study (BIS) equation: 3736×(serum creatinine value in μmol/L) −0.87 ×age −0.95 ×(0.82 if female) [ 24 ]. Estimated GFR results were expressed in ml/min/1.73 m 2 after normalization via the Du Bois and Du Bois method [ 25 ], with participants subsequently categorized into CKD stages according to KDIGO guidelines [ 17 ]. Subjects with eGFR ≥90, 60–89, and <60 mL/min/1.73 m 2 were sub-classified into G1, G2, and G3-5 groups, respectively.

BMI classification, calf circumference measurement, comorbidities, and other variables

The personal characteristics of age, sex, height, body mass, and calf circumference values were measured by well-trained investigators. The comorbidities included diabetes mellitus, hypertension, ischemic heart disease, depression, and osteoporosis.

BMI was calculated by the formula: body mass (kg)/height (m) 2 . Since all participants were Taiwanese and no foreign nationals were included, the participants’ BMIs were classified into three categories: underweight (<18.5 kg/m 2 ), normal (18.5–23.9 kg/m 2 ), and overweight/obese (≥24 kg/m 2 ), according to the guidelines of the Health Promotion Administration, Ministry of Health and Welfare, Taiwan [ 26 ]. These cutoffs reflect population-specific recommendations for Taiwan populations, for whom metabolic risks have been shown to occur at lower BMI levels compared with Western populations [ 27 ]. The maximum value of both calves was measured with a nonelastic tape while the participant was sitting with the knee bending at 90°. A calf circumference less than 33 cm in women or 34 cm in men was defined as low calf circumference [ 1 ].

Statistical analyses

Number and percentage were presented as categorical variables (including sex, comorbidities, BMI level, and calf circumference). Continuous variables (including age and BMI) were presented as mean ± standard deviation (SD). The chi-square test was used to assess the difference of categorical variables among sarcopenia levels, but when the number of columns was less than five, Fisher’s exact test was used. Analysis of variance (ANOVA) was used to test the balance of continuous variables among sarcopenia levels.

Polytomous logistic regression was used to calculate the odds ratio (OR) and 95% confidence intervals (CIs) of sarcopenia levels and sarcopenia-associated risk factors. Standard logistic regression was used to assess the group of all sarcopenia and associated risk factors. The multivariable model was adjusted for variables with a significant difference in Table 1 . The joint effect of all sarcopenia with CKD stage, BMI level, and calf circumference was also assessed. For exploratory analyses, calf circumference was normalized to body height by calculating the calf circumference-to-height ratio (calf circumference [cm]/height [cm]) to account for potential differences in overall body size. All statistical significance was defined as p -value <0.05 at two-tailed testing by SAS, version 9.4 (SAS Institute, Cary, North Carolina).

Results

All 3,629 eligible participants aged over 60 years (mean age 71.9 ± 5.95 years; men 46.7%) were collected in this study: 2,622 participants were normal (72.3%); 866 participants were possible sarcopenia (23.9%); and 141 participants were sarcopenia and severe sarcopenia (3.89%). Participants with greater sarcopenia severity were older, with mean ages of 70.8 ± 5.04 years in the non-sarcopenia group, 74.8 ± 6.90 years in the possible sarcopenia group, and 76.4 ± 7.21 years in the sarcopenia and severe sarcopenia group ( p < 0.0001) ( Table 1 ). Participants with greater sarcopenia severity had a higher proportion of men, increasing from 42.2% in the non-sarcopenia group to 56.5% in the possible sarcopenia group and 71.6% in the sarcopenia and severe sarcopenia group ( p < 0.0001). Because age and sex showed significant differences in Table 1 ( p < 0.0001), they were considered potential confounders for sarcopenia severity. Except for the CKD stage, the highest proportion of comorbidities was found in the possible sarcopenia group, with the least proportion in the sarcopenia and severe sarcopenia group. Normal participants had the highest CKD stage G1 proportion, and the sarcopenia and severe sarcopenia participants had the least. Sarcopenia and severe sarcopenia participants had the lowest BMI (20.5 ± 2.36 kg/m 2 ), and the highest proportion of low calf circumference (17.7%). Detailed descriptive statistics were provided in Tables S1–S3 .

In standard logistic regression, sarcopenia and severe sarcopenia and overall sarcopenia risk increased with aging (OR = 1.15 and 1.13, 95% CI = 1.12–1.19 and 1.11–1.15, respectively) in the multivariable model. Compared to women, men had a higher sarcopenia and severe sarcopenia and overall sarcopenia risk (OR = 5.83 and 2.19, 95% CI = 3.80–8.93 and 1.86–2.58, respectively) ( Table 2 ). Compared to normal participants, older underweight adults (BMI <18.5 kg/m 2 ), and low calf circumference (<33 cm in women and <34 cm in men) had a higher sarcopenia and severe sarcopenia risk (OR = 5.47 and 11.6; 95% CI = 2.91–10.3 and 7.29–18.4, respectively). Participants with DM, underweight, and low calf circumference presented a higher overall sarcopenia risk (OR = 1.38, 1.76, and 1.69; 95% CI = 1.14–1.67, 1.10–2.81, and 1.42–2.01, respectively). The overall sarcopenia risk decreased when the CKD stage increased. The lowest risk of overall sarcopenia was in CKD stage G3-5 (OR = 0.54, 95% CI = 0.39–0.76) and then in CKD stage G2 (OR = 0.60, 95% CI = 0.45–0.81), compared to the participants with CKD stage G1.

In polytomous logistic regression, the participants with DM, and low calf circumference had a higher possible sarcopenia risk (OR = 1.41 and 1.31; 95% CI = 1.16–1.72 and 1.09–1.58, respectively) ( Table 2 ). The participants with hypertension had a lower sarcopenia and severe sarcopenia risk (OR = 0.57, 95% CI = 0.36–0.91). Possible sarcopenia risk and sarcopenia and severe sarcopenia risk also decreased with the CKD stage increasing.

Table 3 presents the joint effect of overall sarcopenia risk with CKD stage, BMI level, and calf circumference after adjusting for age, sex, DM, hypertension, and osteoporosis. Compared to the participants with CKD stage G3-5, normal BMI level, and normal calf circumference, the highest overall sarcopenia risk was in the participants with CKD stage G3-5, underweight, and low calf circumference (OR = 5.45, 95% CI = 1.04–28.6), followed by: the participants with CKD stage G2, underweight, and low calf circumference (OR = 3.10, 95% CI = 1.73–5.55); with CKD stage G1, normal/overweight, and low calf circumference (OR = 2.83, 95% CI = 1.65–4.84); with CKD stage G1, normal/overweight, and normal calf circumference (OR = 2.03, 95% CI = 1.36–3.03); with CKD stage G2, normal/overweight, and low calf circumference (OR = 1.92, 95% CI = 1.47–2.50); and with CKD stage G3-5, normal/overweight, and low calf circumference (OR = 1.75, 95% CI = 1.29–2.38). Figure 1 presents the forest plot of joint associations of CKD stage, BMI, and calf circumference with overall sarcopenia.

Discussion

To our knowledge, this study is among the first to examine the joint association of calf circumference and body mass index with sarcopenia across all sarcopenia categories in older adults with CKD not yet requiring dialysis. Our findings highlight that the combined assessment of low calf circumference (<33 cm in women and <34 cm in men) and underweight status (BMI <18.5 kg/m 2 ) provides additional information beyond either measure alone for identifying sarcopenia in this population. Furthermore, calf circumference appeared to be more closely associated with sarcopenia than BMI, supporting its clinical utility as a simple anthropometric measure in older adults with CKD.

Several eGFR equations are recommended as the initial kidney function assessment tools in clinical practice [ 17 ]. However, kidney function may be overestimated by creatinine-based eGFR in patients with muscle wasting or low muscle mass [ 16 ]. This phenomenon could be the major reason that the clinical significance of sarcopenia in patients with non‐dialysis‐dependent CKD is underestimated [ 13 , 14 , 16 ]. This limitation has been recognized as an important factor that may obscure the clinical significance of sarcopenia in patients with non-dialysis-dependent CKD. Cystatin C-based equations have been proposed as an alternative approach to mitigate the influence of reduced muscle mass on eGFR estimation and may provide a more accurate assessment of kidney function in patients with muscle wasting [ 28–30 ]. However, cystatin C is not routinely measured in clinical practice worldwide and therefore has limited practicality for everyday clinical decision-making. In addition, serum cystatin C concentrations can be affected by factors unrelated to kidney function, including age, sex, smoking status, steroid use, and obesity, which may reduce its specificity in the evaluation of sarcopenia in pre-dialysis CKD populations [ 11 , 31 , 32 ]. Given these considerations, our study emphasizes the importance of optimizing sarcopenia identification and risk stratification using currently recommended and widely available creatinine-based eGFR equations in conjunction with simple anthropometric measures that are readily applicable in routine clinical settings.

In this study, the BIS eGFR equation, which has shown reasonable accuracy in estimating CKD stage for adults aged >70 years with mild to moderate kidney function impairment [ 24 ], was applied. Consistent with a prior report using the BIS equation to estimate CKD stage [ 13 ], no statistically significant association between sarcopenia and pre-dialysis CKD stage was observed in our analysis ( Table 2 ). Notably, the observed trend toward lower odds of sarcopenia in more advanced CKD stages is counterintuitive and should be interpreted with considerable caution. A likely explanation is misclassification of CKD stage related to the use of creatinine-based eGFR in older adults with reduced muscle mass, which may lead to overestimation of kidney function and attenuation or reversal of true associations. This limitation is inherent to creatinine-based equations in sarcopenic populations and may substantially bias the observed relationship between CKD stage and sarcopenia. In addition, healthy participant bias and selection effects in this community-based cohort may have further influenced these findings.

In subgroup analyses, compared with CKD stage G3–5 participants with normal BMI and calf circumference, higher odds of overall sarcopenia were observed among CKD stage G3–5 older adults with normal or overweight BMI and low calf circumference, as well as among those with underweight and low calf circumference ( Table 3 ). The overall sarcopenia group comprised individuals with possible sarcopenia, sarcopenia, and severe sarcopenia. This approach was adopted in light of emerging evidence highlighting the clinical relevance of possible sarcopenia as an early and potentially reversible condition associated with adverse outcomes [ 8 , 21 ], as well as the dynamic and bidirectional transitions among these sarcopenic states [ 22 ]. Therefore, to capture the full spectrum of sarcopenia-related conditions and to enhance statistical power, we combined these categories into an overall sarcopenia group [ 23 ]. However, this grouping may obscure differences between clinically distinct stages, and the results should be interpreted with this consideration in mind. The subgroup with both underweight and low calf circumference included a small number of participants ( N = 9), resulting in wide confidence intervals and limited statistical precision; therefore, these findings should be interpreted with caution.

Previous studies have suggested that reduced calf circumference may serve as a useful marker for sarcopenia identification in patients with end-stage kidney disease undergoing maintenance hemodialysis, although these investigations were based on relatively small samples and did not evaluate the combined effects of BMI and calf circumference or potential sex-specific differences [ 33 ]. In contrast, the present study explored the joint association of underweight status (BMI < 18.5 kg/m 2 ) and low calf circumference (<33 cm in women and <34 cm in men) with sarcopenia among older adults with non-dialysis-dependent CKD. While these cutoff values may facilitate sarcopenia identification in Asian pre-dialysis CKD populations, our subgroup findings should be considered exploratory. Larger, well-powered longitudinal studies are warranted to confirm these associations and clarify their clinical implications.

Calf circumference is a simple, noninvasive anthropometric measure that has been commonly used as a marker for sarcopenia prediction in older populations [ 34 , 35 ]. Previous studies have reported associations between lower calf circumference and adverse clinical outcomes, including increased cardiovascular and all-cause mortality among patients with CKD stages 3–5, suggesting its potential relevance in CKD populations [ 36 ]. However, data specifically examining the relationship between calf circumference and sarcopenia in individuals with pre-dialysis CKD remain limited. In this study, calf circumference cutoff values were defined according to the Asian Working Group for Sarcopenia (AWGS) 2019 recommendations [ 1 ]. Although these thresholds are well established in general older populations, they have not been specifically validated in CKD cohorts, where disease-related factors may complicate anthropometric interpretation. A significant confounding factor is orthostatic fluid shift; transition to a seated or standing position induces a rapid, gravity-driven accumulation of fluid in the lower limbs, which significantly increases calf cross-sectional area and volume [ 37 , 38 ]. The SCOPE study reported that older men with more advanced CKD (eGFR 15–30 mL/min/1.73 m 2 ) exhibited paradoxically higher calf circumference despite lower BMI and poorer nutritional indices, a finding likely attributable to lower limb edema and hypoalbuminemia in advanced CKD [ 39 ]. Such extracellular volume expansion not only leads to an overestimation of muscle mass via calf circumference but also compromises the accuracy of bioelectrical impedance analysis (BIA) [ 40 ]. Since BIA resistance is heavily influenced by the ionic media in total body water, an expanded extracellular volume compartment can lead to an overestimation of appendicular muscle mass. In addition, because body mass and muscle cross-sectional area are positively correlated under normal body composition [ 41 ], calf circumference is expected to scale with overall body size. Therefore, normalization of calf circumference, such as adjustment for body height, has been proposed to reduce inter-individual variability. In our exploratory analyses, height normalization attenuated the association between calf circumference and overall sarcopenia, particularly for possible sarcopenia. Because possible sarcopenia is defined primarily by reduced muscle strength rather than reduced muscle mass according to the AWGS 2019 criteria, anthropometric measurements may have limited discriminatory ability at this early stage of disease. These exploratory findings also suggest that body size should be considered when interpreting calf circumference measurements in older adults with CKD. However, because height-normalized calf circumference has not yet been validated for CKD populations or recommended by current sarcopenia guidelines, the clinical implications of normalization remain uncertain. Future prospective studies are warranted to determine whether body size-adjusted calf circumference provides additional clinical value beyond the currently recommended absolute calf circumference thresholds.

In concordance with the findings of previous publications [ 34 , 35 ], our analysis demonstrated a significant association between low calf circumference and sarcopenia among older adults across CKD stages ( Table 2 ). This finding should be interpreted as calf circumference reflecting underlying muscle mass and nutritional status, rather than implying a causal or protective biological effect. Taken together, our results add to the existing literature by suggesting the potential clinical utility of calf circumference as a pragmatic screening indicator for sarcopenia in pre-dialysis CKD. However, further studies are needed to validate these findings in CKD populations, particularly those incorporating volume status, nutritional biomarkers, and sex differences to refine calf circumference-based cutoffs and improve interpretability in this complex population.

Many studies have documented that low BMI is related to the development of sarcopenia in older people [ 13 , 15 , 42 , 43 ]. Nevertheless, the evidence about the association between BMI and sarcopenia in older people with CKD before the introduction of dialysis is insufficient. According to the diagnostic criteria of the European Working Group on Sarcopenia in Older People 2010, Kim et al. stated BMI <21 kg/m 2 could be an effective predictor for sarcopenia in older Japanese women [ 42 ]. In the present study, under the latest guidelines of BMI classification of Taiwan and the diagnostic criteria for sarcopenia in AWGS 2019 [ 1 ], compared with the comparisons (BMI ≥18.5 kg/m 2 ), an adjusted 5.47-fold increased odds for the occurrence of sarcopenia in both older men and women who were underweight (BMI < 18.5 kg/m 2 ) was further discovered ( Table 2 ). Dubey and coworkers conducted a small sample size study to evaluate the impact of low BMI on the development of sarcopenia in younger CKD patients (mean age: 50.2 years) before dialysis [ 44 ]. The authors pointed out that a BMI cutoff of 18 is ineffective in sarcopenia identification. Our results corroborate the research of Dubey et al. [ 44 ]; in our sub-group analysis, no statistical significance for the increment of overall sarcopenia association was found in the older underweight (BMI < 18.5 kg/m 2 ) CKD stage G3–5 patients after adjustment ( Table 3 ). Taken together, we suggested low BMI could be an uninformative biomarker for sarcopenia identification in older patients with pre-dialysis CKD, despite its noteworthy relationship with sarcopenia in older adults. Further prospective population-based cohort studies with more sarcopenia patients are needed to validate our findings.

Muscle loss in individuals with pre-dialysis CKD arises from multiple contributing factors and should not be ascribed solely to dietary protein restriction [ 45 ]. Although a reduced protein intake (approximately 0.6–0.8 g/kg/day) is commonly recommended to slow disease progression [ 46 ], short-term adherence to low-protein diets does not appear to compromise muscle mass or strength [ 47 ]. Sustained or overly restrictive protein intake may lead to protein–energy wasting and increase the risk of sarcopenia [ 48 ]. CKD-specific conditions, such as diminished appetite, metabolic alterations, chronic inflammation, and disrupted muscle protein turnover, further contribute to muscle deterioration. These findings highlight the importance of a balanced nutritional strategy, prioritizing sufficient protein and energy intake adjusted to CKD stage, rather than indiscriminate protein restriction, to maintain muscle health in pre-dialysis CKD patients. In this study, our findings suggest that anthropometric indicators reflecting nutritional and muscle status, such as BMI and calf circumference, are significantly associated with sarcopenia in this population, underscoring the importance of integrated nutritional and body composition assessment.

Our study has several limitations. Due to the cross-sectional design, causal relationships between BMI, calf circumference, and sarcopenia in older adults with pre-dialysis CKD cannot be established. In addition, multivariable adjustment was limited to variables with significant univariate associations, while several a priori confounders, including nutritional intake, physical activity, and inflammatory markers, were unavailable and therefore not included. Second, muscle mass was assessed using bioelectrical impedance analysis, which may be affected by hydration status, particularly in CKD stages 3–5. Although participants with clinically evident lower-limb edema (pitting edema grade ≥ II) were excluded, objective indices of volume status were not available, and residual misclassification cannot be excluded. The Tanita device applied in this study is based on reference ranges derived from healthy populations and has not been systematically validated in CKD cohorts. Third, a large proportion of the participants may have been relatively healthy, as enrollment required the ability to participate independently in a community-based survey. Our study population demonstrated a similar age and sex distribution and a comparable prevalence of sarcopenia to that reported in a previous investigation of community-dwelling older adults [ 49 ]. Selection bias cannot be excluded, as individuals with severe comorbidities or poor physical performance may have been underrepresented; for example, those with dementia, stroke, Parkinson’s disease, severe cognitive impairment, disability, cachexia, and leg edema were excluded. For a more comprehensive evaluation of the association between calf circumference, BMI, and sarcopenia in pre-dialysis CKD, future population-based prospective cohort studies conducted in clinical settings and incorporating objective assessments of volume status are warranted. Finally, although the majority of participants were classified as CKD stages G1–2, potential misclassification was minimized by restricting CKD diagnosis in this subgroup to individuals with documented, persistent markers of kidney damage in accordance with KDIGO recommendations.

Conclusions

In this study, low calf circumference and underweight were independently associated with sarcopenia in older adults with CKD. Combined assessment of calf circumference and BMI may facilitate sarcopenia identification in this population. Exploratory analyses suggested that body size may influence the association between calf circumference and sarcopenia, indicating that further studies are needed to determine the optimal normalization strategy before height-normalized calf circumference can be recommended for clinical practice.

Supplementary Material

Supplemental Material

Funding Statement

This study was supported by Far Eastern Memorial Hospital, New Taipei City, Taiwan (FEMH-2026-C-070), Chang Gung Memorial Hospital, Linkou, Taiwan (CORPG3N0331), and China Medical University Hospital, Taiwan (DMR-111-139 and DMR-114-046).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, YFH. The data are not publicly available due to privacy/ethical restrictions.

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Associated Data

Supplementary Materials

Supplemental Material

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author, YFH. The data are not publicly available due to privacy/ethical restrictions.