Abstract:
Background: Despite advances in human immunodeficiency virus (HIV) care globally, HIV remains a major public health challenge, particularly in the Middle East and North Africa (MENA) region. Although combination antiretroviral therapy (cART) has substantially improved outcomes among people living with HIV, progression to acquired immunodeficiency syndrome (AIDS) continues to occur. Evidence on the long-term incidence, AIDS-free survival, and predictors of AIDS occurrence among adults living with HIV in Oman remains limited. This study aimed to estimate the incidence rate of AIDS occurrence, evaluate AIDS-free survival, and identify demographic and clinical predictors of AIDS occurrence among adults living with HIV in Oman.
Methods: An ambidirectional cohort study was conducted among 549 adults living with HIV receiving care at a national tertiary referral hospital in Oman from 1992 to 2024. Data were obtained from medical records. The primary outcome was AIDS occurrence, defined as a CD4 count ≤200 cells/mm³. The incidence rate of AIDS occurrence was calculated using person-time methods. Time to AIDS occurrence was analyzed using survival analysis. Kaplan–Meier analysis was used to estimate AIDS-free survival and compare survival distributions using the log-rank test. Multivariable Cox proportional hazards regression was performed to identify independent predictors of AIDS occurrence. Statistical significance was set at p ≤ 0.05.
Results: Among 549 adults living with HIV, 324 AIDS cases occurred during follow-up, yielding an incidence rate of 8.4 cases per 1,000 person-months. The incidence rate was higher among males (10 per 1,000 person-months) and individuals aged >47 years (39 per 1,000 person-months), while the lowest rate was observed among those aged 18–27 years (4 per 1,000 person-months). Multivariable Cox proportional hazards regression identified younger age at diagnosis as associated with a lower hazard of AIDS occurrence compared with individuals aged >47 years (18–27 years: adjusted hazard ratio [AHR] = 0.38, 95% confidence interval [CI]: 0.25–0.59). Earlier year of HIV diagnosis (≤2008) was associated with a lower hazard of AIDS occurrence compared with diagnosis in 2020 or later (AHR = 0.37, 95% CI: 0.25–0.56). Among individuals receiving cART, optimal adherence was associated with a reduced hazard of AIDS occurrence (AHR = 0.73, 95% CI: 0.57–0.94). Cancer comorbidity was associated with a lower hazard of AIDS occurrence (AHR = 0.33, 95% CI: 0.12–0.89), whereas cotrimoxazole use was associated with an increased hazard of AIDS occurrence (AHR = 6.77, 95% CI: 4.54–10.14), likely reflecting its use among individuals with advanced HIV disease.
Conclusions: Despite access to cART, AIDS occurrence remained substantial among adults living with HIV in Oman, particularly among males and older adults. This 32-year ambidirectional cohort study provides important evidence on the long-term incidence, AIDS-free survival, and predictors of AIDS occurrence in a Middle Eastern setting. Early HIV diagnosis, sustained adherence to cART, and targeted clinical monitoring of high-risk individuals may help reduce AIDS occurrence and improve long-term outcomes.
Keywords: HIV; AIDS occurrence; incidence rate; AIDS-free survival; Kaplan–Meier analysis; Cox proportional hazards regression; Oman
Biography:
Zainab Mahmood Dilsahd Al-Zadjali is a fourth-year PhD candidate in the Department of Public Health and Family Medicine, College of Medicine and Health Sciences, at Sultan Qaboos University, Oman. She holds a Master of Science in Epidemiology and Medical Statistics from Sultan Qaboos University, an MBA from the University of Bedfordshire, and a Bachelor of Nursing Science from Cardiff University. Her research interests include HIV/AIDS, communicable disease epidemiology, public health, and health services research. She has basic experience in statistical analysis, is familiar with SPSS, and has first-author and co-authored publications. She has presented her research at national and international conferences and workshops.
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