Pharmaceutical care (PC) has been shown to improve adherence to therapeutic interventions as well as improve clinical outcomes. We assessed the predictors of non-adherence to clinical follow-up (i.e., not attending three scheduled routine clinical visits over a 1 year period) among patients who participated in a clinical trial of PC intervention on adherence to HIV antiretroviral therapy uptake (the PC-HIV trial). A total of 332 patients participated: median age was 39 years, 63 % were male, 76 % had CD4 count ≥200 cells/mm³, and 52 % had undetectable viral load. About half, 52.7 %, were non-adherent to clinical follow-up. Identified risk factors for non-adherence were male gender, age <40 years, and being in the trial’s “control” group (adjusted odds ratio [AOR] 1.67, 95 % CI 1.05–2.66; AOR 2.21, 95 % CI 1.42–3.47; AOR 1.67, 95 % CI 1.07–2.61, respectively). Younger, male patients may benefit from interventions such as PC, which facilitates engagement in care.