Virological monitoring and resistance to first-line highly active antiretroviral therapy in adults infected with HIV-1 treated under WHO guidelines: a systematic review and meta-analysis

Summary Antiretroviral-therapy rollout in resource-poor countries is often associated with limited, if any, HIV-RNA monitoring. The effect of variable monitoring on the emergence of resistance after therapy with commonly used drug combinations was assessed by systematic review of studies reporting resistance in patients infected with HIV with a CD4 count of fewer than 200 cells per μL treated with two nucleoside analogues (including a thymidine analogue) and a non-nucleoside reverse transcriptase inhibitor. 8376 patients from eight cohorts and two prospective studies were analysed. Resistance at virological failure to non-nucleoside reverse transcriptase inhibitors at 48 weeks was 88·3% (95% CI 82·2–92·9) in infrequently monitored patients, compared with 61·0% (48·9–72·2) in frequently monitored patients (p