Body Mass Index and Mortality in Adults Hospitalized with COVID-19 at a Tertiary Referral Hospital in Northern Jordan, 2020–2021: A Single-Center Retrospective Secondary Analysis

Background and Objectives: A previous analysis of the same Jordanian hospital cohort reported obesity as nonsignificant in a broad mortality model but did not characterize BMI dose–response or nonlinearity. We examined BMI and in-hospital mortality in a focused secondary analysis of adults hospitalized during 2020–2021. Materials and Methods: The archived extract contained 1399 adults and 559 deaths. The primary exposure was obesity (BMI ≥ 30 vs. <30 kg/m2). Logistic regression adjusted for age using a four-knot restricted cubic spline, sex, and smoking status; an expanded model additionally included comorbidities. Modified Poisson regression estimated adjusted risk ratios. Results: Mortality was 41.4% with obesity and 38.8% without obesity. The primary adjusted OR was 1.124 (95% CI 0.892–1.416; p = 0.322) and adjusted RR was 1.066 (0.938–1.212; p = 0.327). BMI-category and spline global tests were nonsignificant, but intervals were wide at the extremes. Conclusions: No statistically clear BMI–mortality association was identified in this selected early-pandemic hospitalized cohort. The findings do not establish equivalence and may not transfer to later pandemic eras; interpretation is limited by unresolved derivation differences from the parent cohort and unavailable acute-severity and timing variables.