Long-term survival probability and predictors of mortality among adult patients living with HIV initiating combination antiretroviral therapy in Oman: an ambidirectional cohort study, 1992-2024.

BACKGROUND

Acquired immunodeficiency syndrome (AIDS) remains a major global public health challenge despite substantial advances in combination antiretroviral therapy (cART). Evidence on long-term survival and mortality predictors among adult patients living with HIV in Oman remains limited. This study evaluated long-term survival probability and predictors of mortality among adults living with HIV initiating cART in Oman over 32 years.

METHODS

An ambidirectional cohort study was conducted using data from the HIV/AIDS registry at the national tertiary referral hospital, the Royal Hospital in Oman, covering the period from January 1992 to December 2024. A total of 549 adult patients living with HIV who initiated cART were included in the study. Clinical and laboratory data were extracted from electronic medical records and analyzed using descriptive statistics, Kaplan-Meier survival analysis, and multivariable Cox proportional hazards regression.

RESULTS

Among 549 adult patients living with HIV, 99 deaths occurred during follow-up, including 83 AIDS-related and 16 non-AIDS-related deaths. The overall mortality incidence rate was 1.5 deaths per 1,000 person-months (95% CI: 1.21-1.80). Median survival was not reached during follow-up because the cumulative survival probability remained above 50%. In the adjusted Cox model, participants aged 18-27 years (AHR = 0.36, 95% CI: 0.20-0.67) and 28-37 years (AHR = 0.36, 95% CI: 0.21-0.64) had significantly lower mortality hazards compared with those aged > 47 years. Patients diagnosed at WHO clinical stage 1 (AHR = 0.15, 95% CI: 0.07-0.32), stage 2 (AHR = 0.24, 95% CI: 0.07-0.78), and stage 3 (AHR = 0.42, 95% CI: 0.27-0.67) had lower mortality risk than those diagnosed at stage 4. Hemoglobin ≤ 10 g/dL was independently associated with increased mortality (AHR = 1.75, 95% CI: 1.09-2.81). Although crude analyses showed higher mortality among males, gender was not independently associated with mortality after adjustment for confounders. Timing of cART initiation was also not independently associated with mortality after adjustment.

CONCLUSION

Long-term survival probability among adult patients living with HIV in Oman was favorable, with a median survival of over 32 years of follow-up. Younger age at diagnosis, earlier WHO clinical stage, and higher hemoglobin levels were independently associated with lower mortality risk. These findings highlight the importance of early HIV diagnosis and sustained clinical monitoring to improve long-term outcomes.