Acute renal failure in critically ill patients.: A prospective epidemiological study

Aims: To determine factors which may predict mortality in patients admitted to intensive care unit who present acute renal failure. Methods: Prospective observational study of the patients admitted to a multi-disciplinary intensive care unit over a year. The inclusion criteria were a creatinine plasmatic value greater than or equal to 2 mg/dl (177 mumol/l) or an increase (30% or higher) of its basal value on admittance. Results: One hundred and twenty-seven patients (age = 65.83 +/- 15.06 years; 38% male) with acute renal faiure, were prospectively enrolled in the study (13% of intensive care unit admissions). The univariate analysis showed that hospital origin, acute tubular necrosis, late ARF, oliguria, maintained hypotension, sedation or coma, oncological disease and need of mechanical ventilation were significantly associated with mortality (p < 0.05). This association was also found for sepsis (OR: 41.5), multiorganic failure (OR: 3.58) and respiratory, cardiovascular or haematological failure according to the SOFA score. The multivariate analysis found that four clinical variables had an independent predictive value for mortality risk: acute tubular necrosis [OR: 4.57 (2.32-9.00)], use of vasoactive drugs [OR: 2.32 [1.22-4.40)], oliguria [OR: 2.15 (1.12-4.13)] and the acute renal failure starting during admission [OR: 2.06 (1.09-3.88)]. Conclusion: Data related to renal failure have worse prognosis than other demographic or clinical data in critically ill patients with acete renal failure. Multicentric studies with unified criteria are needed to analyse the most important prognostic factors.