Epidemiology of Diphtheria and Predictors of Outcome in Nigeria: A Single-Center  Study from July 2023 to April 2024

Background: Despite recurrent outbreaks of diphtheria in Nigeria, there is a lack of in-depth analysis of hospitalization outcomes. Herein, we describe the sociodemographic, clinical, and laboratory features that were associated with hospitalization outcomes (defined as death or discharge) during the recent diphtheria outbreak in Nigeria. Methods This prospective observational study included 246 diphtheria cases managed in a dedicated isolation ward of a health facility in northwestern Nigeria from July 1, 2023, to April 30, 2024. We adopted the case definition for diphtheria from the Nigeria Center for Disease Control and Prevention (NCDC). Results The median age (interquartile range) was 7.00 (4–10) years, and half of the patients were aged 5–10 years (49.6%). The common clinical features were fever (95.9%), sore throat (91.9%), painful swallowing (90.7%), pseudomembrane (93.1%), and cervical-submandibular lymphadenopathy (91.5%). Most children were unvaccinated (158; 64.2%), and 199 (80.9%) received diphtheria antitoxin. Of the 246 cases of diphtheria, 58 in-hospital deaths occurred, with a crude mortality rate of 23.6%. After adjusting for confounders, the variables that predicted hospitalization deaths were neck swelling with an adjusted odds ratio (AOR) of 9.8 (95% CI 1.686–56.469), abnormal respiratory findings (AOR, 149.987 [95% CI, 15.600–1442.023] ), hypoxemia (AOR, 37.785 [95% CI, 4.255–331.962] ), and elevated serum creatinine above 1.5 mg/dL (AOR 107.783, 95% CI, 7.944–1462.376). Conclusions Diphtheria, a re-emerging disease, constitutes a significant burden in Nigeria, especially among children. Neck swelling, hypoxemia, abnormal respiratory findings and impaired renal function are predictive of hospitalized death.