Factors Associated with Virological Non-Suppression Among People Living with HIV Receiving Antiretroviral Therapy in Kazakhstan: A National Registry-Based Study

Background: Virological suppression is a key outcome of antiretroviral therapy. Despite progress in HIV treatment in Kazakhstan, virological non-suppression remains a relevant clinical and public health issue requiring further analysis. This study aimed to assess the prevalence of virological suppression (VS) and to identify factors associated with the absence of VS among people living with human immunodeficiency virus (HIV) who are receiving antiretroviral therapy (ART) in Kazakhstan. Methods: A retrospective cross-sectional analytical study was conducted using secondary analysis of a de-identified national registry database of people living with HIV (PLHIV) receiving ART in the Republic of Kazakhstan as of 30 September 2025. The primary outcome was virological non-suppression (VNS), defined as the last viral load (VL) value of at least 200 copies per milliliter. The analysis included sex, age, presumed route of HIV transmission, the first available cluster of differentiation 4 (CD4) cell count recorded in the registry, the last recorded percentage category of adherence to ART, and the aggregated category of ART regimen. The main descriptive, bivariate, and multivariable analyses were performed using a complete-case approach. Independent associations were assessed using multivariable logistic regression, and the results were presented as adjusted odds ratios (aORs) with 95 percent confidence intervals (CIs). Results: The initial registry extraction included 33,614 records, of which 32,130 patients were included in the final analytical sample. VS was achieved in 29,454 (91.7%) patients, whereas VNS was observed in 2676 (8.3%) patients. In the multivariable model, higher adjusted odds of VNS were observed among men compared with women (aOR 1.14; 95% CI 1.02–1.26), as well as among patients with a first CD4 count < 200 cells/μL compared with those with a first CD4 count of ≥500 cells/μL (aOR 1.25; 95% CI 1.09–1.44). The strongest association was found for reduced adherence to therapy. Compared with adherence of at least 95%, the adjusted odds of VNS were markedly higher among patients with adherence of 85–94% (aOR 28.66; 95% CI 25.85–31.77) and among those with adherence below 85% (aOR 61.05; 95% CI 50.50–73.81). In all age groups older than 25 years, the adjusted odds of VNS were lower than among patients younger than 25 years. Lower adjusted odds of VNS were also observed among patients with homosexual transmission, vertical transmission, and other or unspecified transmission routes compared with heterosexual transmission. Among ART regimens, regimens containing non-nucleoside reverse transcriptase inhibitors (NNRTIs) were associated with lower adjusted odds of VNS than dolutegravir-containing regimens (DTG-containing regimens) (aOR 0.68; 95% CI 0.52–0.88), whereas no statistically significant differences were identified for regimens containing protease inhibitors (PIs). Conclusions: Despite the high overall level of VS among PLHIV receiving ART in Kazakhstan, VNS remains concentrated in clinically and programmatically important subgroups. It was most strongly associated with reduced adherence and was also associated with younger age, marked baseline immunosuppression, and male sex in the primary model. These findings support the need for targeted interventions focused on adherence support, early diagnosis, and differentiated long-term follow-up of patients.