Clinical spectrum, outcome and impact of nephrectomy in critically-ill adult patients with emphysematous pyelonephritis: the PYELEMPHY observational retrospective multicenter Study

Background: Emphysematous pyelonephritis (EPN) is a rare, life-threatening necrotizing urinary tract infection marked by gas formation in the renal parenchyma and perirenal tissues. Evidence on its management and outcomes in the intensive care unit (ICU) remains limited. We aimed to describe the clinical profile, outcomes, and effect of nephrectomy in adults admitted to the ICU for infectious EPN. Main results: A national, multicenter, retrospective cohort study including adults admitted with infectious EPN to 48 French ICUs from 2001 to 2021 was conducted. A total of 109 patients were included. Median age was 62 years [IQR 54-72], and 64% were women. Overweight or obesity was present in 74%, and diabetes in 63%. Septic shock occurred in 72%. Urinary tract obstruction was identified in 46%. Initial management relied on antibiotics and/or minimally invasive drainage in 53% of cases. Early nephrectomy (≤24 h after ICU admission) was performed in 14 patients (14%), and delayed nephrectomy in eight (7%) at a median of 4 days [IQR 3-9]. Among the 75 patients discharged from the ICU without nephrectomy, four (4%) required subsequent nephrectomy. ICU mortality was 15% (n = 16). At day 90, vital status was known for 105 patients; 18 had died. In multivariable analysis, higher Simplified Acute Physiology Score II independently predicted increased 90-day mortality (HR per point 1.08; 95% CI 1.05-1.12; p < 0.001). Early nephrectomy was associated with lower mortality (HR 0.18; 95% CI 0.04-0.90; p = 0.037). Major adverse kidney events at day 90 occurred in 40%. Using the propensity-weighted model, early nephrectomy showed a trend toward lower MAKE90, although the association did not reach statistical significance (adjusted OR = 0.32; 95% CI: 0.10-1.02; p = 0.054). Conclusion: EPN requiring ICU admission carries substantial mortality. Early nephrectomy may improve survival, without increasing long-term renal complications.