Prognosis of ARF in hospitalized elderly patients

Background: Differentiation between hospital-acquired acute renal failure (ARF) and community-acquired ARF may have epidemiological implications that lead to different prognoses in hospitalized patients. Such a comparison has not yet been made among elderly individuals. Methods: We performed a 3-year prospective study in a tertiary referral hospital of 325 patients aged 60 years or older who presented with ARF. Patients were divided into 2 groups; those with hospital-acquired ARF (n=154) and community-acquired ARF (n=171), and were followed up in relation to mortality. Multiple logistic regression was used in the analysis. Results: The overall mortality rate in this elderly population was 54%; 59% for the group with hospital-acquired ARF and 41% for the group with community-acquired ARF (P<0.001). Groups differed (P<0.01) in relation to cause of ARF, preexisting diseases, organ failure, sepsis, and performance of dialysis, among other factors. The adjusted mortality risk for the group with hospital-acquired ARF was 2.23 times greater than for the group with community-acquired ARF (95% confidence interval [CI], 1.21 to 4.08). In the group with hospital-acquired ARF, factors associated with mortality were neurological failure (odds ratio [OR], 2.97; 95% CI, 1.17 to 7.60), hematologic failure (OR, 4.30; 95% CI, 1.63 to 11.34), and oliguria (OR, 12.14; 95% CI, 4.62 to 31.87). In the group with community-acquired ARF, significant factors were neoplasia, cardiac disease, hepatic disease, cardiovascular failure, oliguria, and sepsis. Conclusion Differentiation between hospital-acquired ARF and community-acquired ARF is important in determining the prognosis of ARF in the elderly. Mortality risk factors are different in these 2 groups, and knowledge of their characteristics may allow better management of such patients.