Risk factors for mortality in patients with emphysematous pyelonephritis: A meta-analysis

Purpose: Emphysematous pyelonephritis, an infection most commonly seen in cases of diabetes mellitus, is associated with considerable case fatality. We identified the factors associated with mortality in patients with emphysematous pyelonephritis and estimated the magnitude of the associations. Materials and Methods: PubMed (R) was searched to identify studies reporting on risk factors of mortality in patients with emphysematous pyelonephritis. A meta-analysis of the eligible studies was performed. Results: Seven study cohorts, representing 175 patients with emphysematous pyelonephritis, were included in the metaanalysis. The overall mortality rate was 25%, ranging from 11% to 42%. Conservative treatment alone (OR 2.85, 95% CI 1.19-6.81), bilateral emphysematous pyelonephritis (OR 5.36, 95% CI 1.41-20.33), type I emphysematous pyelonephritis (OR 2.53, 95% CI 1.13-5.65) and thrombocytopenia (OR 22.68, 95% CI 4.4-116.32) were associated with increased mortality. Systolic blood pressure less than 90 min Hg, serum creatinine greater than 2.5 mg/dl and disturbance of consciousness were also found to be associated with increased mortality. However, this finding was based on limited data. On the other hand, there was no association between mortality and diabetes mellitus (OR 0.32, 95% CI 0.05-1.99) in patients with emphysematous pyelonephritis. Conclusions: The accumulated and analyzed evidence suggests that conservative treatment, type I emphysematous pyelonephritis, bilateral emphysematous pyelonephritis and thrombocytopenia seem to be significant risk factors for mortality in patients with emphysematous pyelonephritis. These data may be taken into consideration when treating patients with this devastating infection.