Impact of noncommunicable diseases (NCDs) on COVID-19 mortality: A study of risk factors and outcomes in a Southeast Asian population

This study investigated the association between noncommunicable disease (NCD) comorbidities and clinical outcomes of COVID-19 infection, and examined the effects of demographic factors, vaccination status, and symptom presentation on COVID-19 disease fatality in Brunei Darussalam. This was a retrospective cohort study of 7760 polymerase chain reaction (PCR)-confirmed COVID-19 cases in Brunei Darussalam from 7 August to 6 October 2021. Demographic information, vaccination status, symptoms, disease severity, and NCD comorbidities were included in the analysis. Log-binomial regression models were used to identify factors associated with mortality. Of the 7760 COVID-19 patients included in the study, 20.3% had at least one NCD, 1.0% were admitted to the intensive care unit (ICU) for treatment, and 0.9% died. Among patients admitted to the ICU, 53.3% had NCD comorbidities, and nearly 9 out of 10 deaths (89.4%) occurred among patients with NCDs. Mortality risk was significantly associated with male sex, older age, non-vaccination status, symptomatic presentation, and the presence of NCD comorbidity (relative risk [RR]:1.97-13.08). Cardiovascular disease was the most significant predictor of mortality, followed by diabetes and chronic kidney disease. ICU admission risk was significantly associated with NCD comorbidities (RR:3.11) and non-vaccination status (RR:3.07), with younger age groups showing significantly lower risk than the 50-59 reference group (RR:0.19-0.41). These findings highlight the disproportionate impact of COVID-19 on older adults, men, and individuals living with NCDs in Brunei Darussalam. Strengthening NCD prevention and control measures, together with public health education on the importance of vaccination and protecting clinically vulnerable populations should remain an important component of future pandemic preparedness planning and response efforts.