Correlates of viral load suppression among people living with HIV on antiretroviral treatment in Mbujimayi, Democratic Republic of Congo: a cross-sectional study

Context Acquired immunodeficiency syndrome (AIDS) remains a major global public health concern and one of the leading causes of mortality worldwide. Lifelong antiretroviral therapy (ART) enables viral load suppression or undetectability, reducing the risk of opportunistic infections and improving survival. However, some individuals fail to achieve viral suppression, and understanding the associated factors is critical. This study aimed to identify key determinants of successful viral suppression among people living with HIV (PLWH) on ART. Methods A cross-sectional study was conducted in Mbujimayi, Democratic Republic of Congo, involving 561 PLWH from ten healthcare facilities with available viral load results. Data on ART adherence, sexual behavior, and sociodemographic characteristics were collected. Viral load served as the primary outcome. Variables with p < 0.20 in bivariate analysis were included in a multivariable modified binomial logistic regression model to adjust for confounders. Statistical significance was set at p < 0.05. Results Participants had a median age of 49 years (IQR: 18) and a median ART duration of 9 years (IQR: 7); 66.31% were female, and 67.56% were in WHO clinical stage 3. Condom use was reported by 67.91%, while 84.3% had no casual sexual partners; 91.78% abstained from alcohol, and 86.45% adhered to ART. Multivariable analysis identified ART adherence (AOR 11.743 [95% CI: 4.153–33.204], p < 0.001), absence of casual sexual partners (AOR: 2.179 [95% CI: 1.221–3.888], p = 0,008 ), and condom use AOR: 1.764 [95% CI: 1.144–2.721], p = 0.010), and ART duration (AOR: 1.590 [1.086–2.328], p = 0.045) as significant predictors of viral suppression. However, no alcohol consumption was a protective factor (AOR: 0.486 [95% CI: 0.240–0.985]). Conclusion Strict ART adherence and stable sexual behaviors (absence of casual sexual partners, condom use) were associated with viral suppression. Strengthening health education and psychosocial support programs to promote adherence and safe sexual practices could improve treatment outcomes. These findings provide evidence to guide public health strategies for HIV management in resource-limited settings.