Acute renal failure predictors in elderly patients with chronic kidney disease.

Introduction: Acute renal failure (ARF) is a very common problem in the elderly and is associated with high morbidity and mortality rates. This study analysed ARF predictors in a cohort of elderly subjects and their impact on the evolution of renal function.

Patients And Method: A group of 80 elderly individuals were recruited between January and April 2006, and 56 of these who were still alive after 36 months were retrospectively studied, examining episodes of ARF, their causes, and the need for dialysis.

Results: Twelve patients (21.4%) developed ARF: 4 (33.3%) related to heart failure, 4 (33.3%) due to infection/sepsis, 2 (16.7%) due to volume depletion, and another 2 were multifactorial (16.7%). No patients required dialysis therapy. Patients with ARF were older (P=.017), had worse renal function at baseline (P=.031), higher levels of uric acid (P=.002), and lower haematocrit (P=.003). Patients with ARF had a mean baseline serum creatinine of 1.57 ± 0.59 mg/dl and peak creatinine levels during episodes of ARF averaged 4.25 ± 4.26 mg/dl (P=.035). Mean renal function at 36 months in patients with ARF had decreased (P=.024). In a logistic regression analysis (independent variables: baseline MDRD, age, gender, Charlson index, serum creatinine, urea, and uric acid), age (RR: 1.20, 1.01-1.43, P=.039), uric acid (RR: 2.65, 1.11-6.30, P=.027), and haematocrit (RR: 0.64, 0.43-0.96, P=.031) were independently associated with the development of ARF.

Conclusions: Baseline levels of uric acid and haematocrit are independent risk factors for the development of ARF in the elderly. Although these episodes may be functional in nature and not require dialysis, this can still cause a deterioration of renal function over time.