Clinico-Epidemiological Characteristics, Hospital Care Interventions, and Clinical Outcomes of Patients with SARS-CoV-2 in Nepal: The Mediating Role of Age

Coronavirus disease 2019 (COVID-19) outcomes among hospitalized patients are influenced by demographic characteristics, clinical presentation, and requirements for hospital-based care. Age is an important determinant of COVID-19 outcomes; however, its statistical role in the relationships between hospital-care interventions and survival has received limited attention in resource-constrained settings. This prospective observational analytical study assessed clinico-epidemiological characteristics, hospital-care interventions, clinical outcomes, and the mediating role of patient age group among adults hospitalized with SARS-CoV-2 infection in Nepal. A total of 348 adults with laboratory-confirmed SARS-CoV-2 infection were consecutively recruited at a tertiary care teaching hospital from March 30, 2022 to June 30, 2023 and followed until discharge or in-hospital death. Associations with survival were examined using Chi-square/Fishers exact tests and multivariable binary logistic regression. Mediation analyses were performed using Hayes PROCESS Macro version 4.2, Model 4, with 5,000 bias-corrected bootstrap samples. Of 348 participants, 277 (79.6%) survived and 71 (20.4%) died. Older adults constituted 41.1% of participants. Hypertension (29.3%) and diabetes mellitus (23.0%) were the most common comorbidities, while fever (81.0%), cough (75.9%), and dyspnea (48.0%) were the predominant symptoms. Age group and dyspnea remained independently associated with hospital survival in multivariable analysis. Steroid therapy, oxygen therapy, and respiratory support were significantly associated with survival in unadjusted analyses. Age group partially statistically mediated the steroid therapy-survival relationship (indirect effect = -0.1371; 95% bootstrap CI: -0.3053 to -0.0154), while the direct effect remained significant (c' = -2.8670; p = 0.0049). No significant age-mediated indirect effects were observed for oxygen therapy or respiratory support. These findings highlight the importance of age and respiratory presentation in hospital outcomes and suggest age-related heterogeneity in the steroid therapy-survival relationship. The mediation finding should be interpreted as statistical rather than causal because age precedes treatment exposure.