A Systematic Literature Review of the Epidemiology of Complicated Urinary Tract Infection

Urinary tract infections (UTIs) are common bacterial infections and present with heterogeneous clinical phenotypes. Whereas many uncomplicated UTIs resolve spontaneously or with antibiotic treatment, a complicated UTI (cUTI) presents with greater morbidity and a higher risk of treatment failures. The goal of this study was to estimate the real-world epidemiology of cUTI, including acute pyelonephritis (AP) and catheter-associated UTIs (CAUTIs), and its associated mortality internationally. A systematic literature search was conducted using PubMed, Embase, Cochrane, and EconLit databases for relevant articles published between July 2013 and July 2023 covering Europe and the following countries: France, Italy, Germany, Spain, the UK, China, Japan, and the US (US). Search terms relating to cUTI, AP, CAUTI, outcomes of interest (epidemiology), and real-world research designs were used. There were no language limitations (protocol registry: PROSPERO-CRD42023454794). Database searches yielded 1014 unique records, of which 91 met the prespecified inclusion criteria; bibliography and conference abstract searches yielded 27 additional records for a total of 118 records for inclusion. Disease presentation and reported outcomes varied widely across studies, and most studies reporting incidence and prevalence of cUTI were from the US (21 of 29). No studies reporting incidence or prevalence rates of cUTI in China, Germany, or the UK were identified. Overall, high antibiotic resistance rates were reported in both inpatient and outpatient settings. The inpatient cohort mortality rates were highly variable (0–50%) depending on the patient population. While disease presentation and reported outcomes varied widely across studies, cUTIs represent a considerable burden in terms of incidence, prevalence, drug resistance, and mortality, yet vast knowledge gaps remain in the literature. There is a crucial need to address these gaps to effectively evaluate new treatments and improve future analyses of cUTI burden and outcomes.