Effect of frailty, physical performance, and chronic kidney disease on mortality in older patients with diabetes : a retrospective longitudinal cohort study

Background Declined renal function is associated with physical function impairment and frailty in a graded fashion. This study aimed to examine the relationship between renal function, frailty and physical performance with mortality in older patients with diabetes, while also determining their combined effects on patient outcome. Methods A retrospective longitudinal study was conducted in elderly patients with diabetes. Kidney disease staging was based on clinical practice guidelines of the International Society of Nephrology, and chronic kiney disease (CKD) was defined as urinary albumin to creatinine ratio (UACR) > 30 mg/g, persistent reduction in estimated glomerular filtration rate (eGFR) below 60 mL/min per 1.73 m 2 or both. The modified Rockwood frailty index (RFI) was composed of cumulative health deficits, and physical function was determined by handgrip strength (HGS). Additionally, a timed up and go (TUG) test was assessed at baseline. Kaplan-Meier survival and Cox proportional hazard analyses were used to analyze the association between CKD, frailty, physical function and mortality. Results For the 921 enrolled patients, their mean age was 82.0 ± 6.7 years. After a median 2.92 (interquartile range [IQR] 1.06–4.43) year follow-up, the survival rate was 67.6% and 85.5% in patients with and without CKD, respectively. The mortality hazard ratio (crude HR) with CKD was 5.92 for those with an RFI higher than 0.313 (95% CI 3.44–10.18), 2.50 for a TUG time longer than 21 s (95% CI 1.22–5.13), and 2.67 for an HGS lower than 10.57 kg in females or 20.4 kg in males (95% CI 1.12–6.37). After multivariate adjustment, the mortality hazard ratio for an RFI ≥ 0.313 was 5.34 (95% CI 2.23–12.80) in CKD patients, but not in patients without CKD. In subgroup analysis, patients experiencing CKD and frailty, or physical function impairment, had the lowest survival proportion followed by only frailty/declined physical function, only CKD, without CKD, and non-frailty/non-physical impairment. Conclusion CKD, frailty and physical function impairment were all associated with an increased mortality risk in older patients with diabetes, while the combined effects of these 3 factors were seen on patient outcome.