Functional status, pre-dialysis health and clinical outcomes among elderly dialysis patients

BACKGROUND: Elderly patients comprise the fastest growing population initiating dialysis in United States. The impact of poor functional status and pre-dialysis health status on clinical outcomes in elderly dialysis patients is not well studied.

METHODS: We studied a retrospective cohort of 49,645 incident end stage renal disease patients that initiated dialysis between January 1, 2008 and December 31, 2008 from the United States Renal Data System with linked Medicare data covering at least 2 years prior to dialysis initiation. Using logistic regression models adjusted for pre-dialysis health status and other cofounders, we examined the impact of poor functional status as defined from form 2728 on 1-year all-cause mortality as primary outcome, type of dialysis modality (hemodialysis vs. peritoneal dialysis), and type of initial vascular access (arteriovenous access vs. central venous catheter) among hemodialysis patients as secondary outcomes.

RESULTS: Mean age was 72 ± 11 years. At dialysis initiation, 18.7% reported poor functional status, 88.9% had at least 1 pre-dialysis hospitalization, and 27.8% did not receive pre-dialysis nephrology care. In adjusted analyses, 1-year mortality was higher in patients with poor functional status (OR, 1.48; 95% CI, 1.40-1.57). Adjusted odds of being initiated on hemodialysis than peritoneal dialysis (odds ratio [OR], 1.39; 95% confidence interval [CI], 1.16-1.66) were higher in patients with poor functional status. Poor functional status decreased the adjusted odds of starting hemodialysis with arteriovenous access as compared to central venous catheter (OR, 0.79; 95% CI, 0.72-0.86).

CONCLUSION: Poor functional status in elderly patients with end stage renal disease is associated with higher odds of initiating hemodialysis; increases the risk of central venous catheter use, and is an independent predictor of 1-year mortality.