Prevalence and Risk Factors of Mortality in Emphysematous Pyelonephritis Patients: A Meta-Analysis

Emphysematous pyelonephritis (EP) is a severe necrotizing infection of the renal parenchyma which is associated with significant case mortality. We sought to identify the incidence and predictive risk factors associated with EP mortality.

Two electronic databases, PubMed and Web of Science, were searched from their inception until June 06, 2021 for relevant articles. Two independent teams reviewed abstracts and extracted data from the selected manuscripts. A meta-analysis has been reported in line with PRISMA 2020 and AMSTAR Guidelines.

Of the 1080 retrieved abstracts, 79 underwent full-text review and 45 studies were included in the final analysis, comprising a total cohort of 1303 patients and 177 mortalities. The pooled prevalence of mortality among the patients with EP disease was 13%. Our analysis found a significantly decreasing trend in mortality rates, an increasing trend in minimally invasive intervention and decreasing trends in emergency nephrectomy in the EP studies from 1985 to 2020. Significant risk factors that were associated with a negative impact on survival of EP patients included sepsis (OR = 15.99), shock (OR = 15.57), disturbance of consciousness (OR = 12.11), thrombocytopenia (OR 7.85), acute renal failure (OR = 5.41), Wan classification I (OR = 4.57), emergency nephrectomy (OR = 3.73), Huang-Tseng classification III-IV (OR = 2.4) and medical management alone (OR = 2.04). Female sex (OR = 0.52) and minimally invasive intervention (OR = 0.47) (percutaneous nephrostomy or ureteral stent placement) were associated with decreased mortality rates.

Our study results demonstrated several significant risk factors that could help guide treatment to reduce the mortality risk of EP patients. Clinically, early treatment with a combination of minimally invasive intervention and appropriate medical management may be protective for reducing mortality risk in EP patients.