Prevalence and factors associated with drug resistance mutations among HIV − 1 patients failing to achieve virological suppression on second line treatment in Tanzania

Human Immunodeficiency Virus / Acquired Immunodeficiency Syndrome (HIV/AIDS) is a major public health problem affecting an estimated 38.4 million people globally, with 54% of them being from the Eastern and Southern African regions. Despite progress in the availability of multiple classes of antiretroviral drugs and early initiation of treatment with cART, many patients still fail to achieve viral suppression on first and second-line regimens due to drug resistance that is driven by continuous acquisition of drug resistance mutation (DRMs). DRMs are prevalent among adults failing treatment regimens, ranging between 50 and 97%. This study aimed to determine the prevalence and factors associated with drug resistance mutations among patients failing to achieve virologic suppression on second-line treatment in Tanzania. A facility-based analytical retrospective study was conducted at Temeke Hospital, Dar es Salaam, Tanzania. Data was extracted from medical records of 176 patients with viral load > 1000c/ml who underwent drug resistance testing during the period between February 2021 and July 2023. Data was analyzed using SPSS V26 and summarized using descriptive statistics. A multivariable logistic regression model was used to estimate the adjusted odds ratio with a 95% confidence interval for biodemographic factors associated with antiretroviral drug resistance mutations. We found high prevalence of DRMs at 71.1% (95% CI; 63.7–77.6) whereby NNRTI mutations were present in 69.3% (n = 122), NRTI in 52.8%(n = 93) and PI in 23.9% (n = 42) while 26.7%(n = 47) had triple class DRMs. Protease inhibitors had the lowest prevalence of DRMs while NNRTI was the highest. Older age [AOR = 1.037, 95% CI; (1.004–1.071)] and number of regimen changes [AOR = 1.479, 95% CI; (1.026–2.131)] were independently significantly associated with higher DRMs at p < 0.05. The prevalence of DRM is high. PI appear to have the least prevalence of DRM, followed NRTIs. This supports the utilization of PIs and selected NRTI in second- and third-line regimens as they less affected by DRMs. Closer monitoring is recommended for older patients and patients with multiple regimen changes as they are likely to harbour DRMs.