Clinical Profile and Outcome of Louse-Borne Relapsing Fever Among Patients Seen at Zewditu Memorial Hospital and Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia: A Cross-Sectional Study

Abstract

Background: Louse-borne relapsing fever (LBRF), caused by Borrelia recurrentis, is a re-emerging vector-borne febrile illness that remains endemic in the highlands of Ethiopia, particularly among populations living in crowded, unhygienic conditions. Although it is among the leading causes of hospital admission in Ethiopia, data on its clinical profile and outcome in Addis Ababa are lacking. Objective: To assess the clinical profile, associated factors, and outcome of patients with LBRF at Zewditu Memorial Hospital (ZMH) and Tikur Anbessa Specialized Hospital (TASH), Addis Ababa, Ethiopia. Methods: An institution-based, multicentre, retrospective cross-sectional study was conducted among 172 patients treated for LBRF at ZMH and TASH between July 2022 and July 2023. Data were extracted from medical records using a structured checklist and analyzed using SPSS version 26. Descriptive statistics summarized socio-demographic and clinical characteristics; univariate and multivariable binary logistic regression identified factors associated with in-hospital mortality, with adjusted odds ratios (AOR), 95% confidence intervals (CI), and p-values used to test significance. Results: Males predominated (82.6%), and nearly half of patients (49.4%) were aged 14-20 years; most (70.3%) were living on the street. Fever (84.3%) and headache (25.6%) were the most common presenting symptoms. Hematologic complications (85.5%), hypotension (53.5%), and sepsis (17.4%) were the most frequent complications. The in-hospital mortality rate was 4.1%. Onmultivariable analysis, hematologic complications (AOR=0.11, 95% CI 0.018-0.739, p=0.023) and sepsis (AOR=0.14, 95% CI 0.02-0.993, p=0.0049) were significantly associated with mortality. Conclusion: LBRF predominantly affects young, socially marginalized men in Addis Ababa. Hematologic complications and sepsis were the strongest predictors of mortality, and the overall case fatality rate was comparable with reports from other Ethiopian settings. Early identification and management of these complications, together with targeted public health measures for high-risk populations, may help reduce mortality from LBRF. Keywords: Louse-borne relapsing fever; Mortality; Cross-sectional study; Addis Ababa; Ethiopia