Predictors of CKD and rate of decline in eGFR in the elderly: A case-cohort study.

We wanted to examine the predictors of annual estimated glomerular filtration rate (eGFR) decline during a five-year follow-up in elderly individuals with pre-existing chronic kidney disease (CKD) stage 3 or greater (defined as baseline eGFR of less than 60 ml/min per 1.73 m2 or a urinary albumin-to-creatinine ratio > 30 mg/g), and to examine the difference in risk factors when compared to a co-hort without CKD. Our research team identified 599 patients who were 65 years of age or older with and without CKD stage 3 or greater at baseline. Data regarding various predictors such as age, sex, race, proteinuria, medication use, contrast exposure, acute kidney injury episodes, coronary artery disease, congestive heart failure, dyslipidemia, gout etc. were obtained. Semi-partial correlations were used to determine the fac-tors providing the largest unique contribution to the overall variability in eGFR. Semi-partial correlations identified age, proteinuria, and intravenous contrast ex-posure as the most significant predictors of eGFR decline in this population. Overall, patients in the pre-existing CKD cohort were more likely to be older, Af-rican American and with co-morbidities like diabetes, hypertension, etc. In this group, the unadjusted rate of decline in eGFR varied from 0.5% to 8.3% per year. This study identifies important risk factors for eGFR decline in the population aged > 65 years. It also concludes that each episode of acute kidney injury, wheth-er related to contrast or other nephrotoxins, increases the risk for CKD progression and eGFR decline in the elderly.