Predictors of prognosis and risk of acute renal failure in bacterial endocarditis

Abstract

Background: The epidemiology, criteria for diagnosis and treatment of bacterial endocarditis has changed substantially in the past 2 decades, yet little attention has been given to the changing etiologies of renal insufficiency and the predictors of renal failure or the relationship between renal failure and mortality in patients with bacterial endocarditis.

Objective: To study the risk factors for the development of acute renal failure and death among patients with definite bacterial endocarditis.

Setting: Tertiary referral university medical center.

Methods: Retrospective chart review of 204 consecutive episodes of definite bacterial endocarditis as defined by the Duke criteria. Logistic regression was used to identify clinical and biochemical predictors of death and the development of acute renal failure.

Results: Two hundred and four episodes of endocarditis identified in 185 patients were evaluated. The overall mortality for the group was 20%. The presence of prosthetic valve endocarditis and thrombocytopenia was associated with increased risk of death in hospital. One third of the patients developed acute renal failure (defined as a serum Cr of 2 mg/dl or above). The presence of acute renal failure increased the odds (OR) of dying by 5 (p = 0.0001). Clinical and biochemical variables at presentation that were significantly associated by univariate analysis with the risk of developing acute renal failure were: increased age, a history of hypertension, thrombocytopenia, the presence of Staphylococcus aureus, and prosthetic valve infection. Age (OR 2.9, p = 0.002) and the degree of thrombocytopenia (OR 0.2, p = 0.0001) were independently associated with an increased risk of developing acute renal failure. Patients who developed acute renal failure as a result of septic syndrome or following cardiac surgery had a higher mortality when compared to other causes of acute renal failure.

Conclusion: Acute renal failure associated with bacterial endocarditis remains a frequent clinical problem that is often associated with a fatal outcome. Patients with increased age, and the degree of thrombocytopenia were independent risk factors for developing acute renal failure.