Factors associated with loss to follow-up after occupational HIV exposure in Cape Town, South Africa: a retrospective cohort study

BACKGROUND There is limited data on factors associated with loss to follow-up (LTFU) of health care workers (HCWs) following occupational exposure to HIV, and most studies were conducted in an era when poorly tolerated antiretrovirals like zidovudine were used. METHODS A retrospective cohort study was conducted of HCWs attending a referral hospital's Occupational Health Clinic in Cape Town, South Africa for post-exposure prophylaxis (PEP) during a period when tenofovir was available. Our primary outcome was LTFU at the 3-month visit. We selected seven variables a priori for our logistic regression model and ensured there were at least 10 outcome events per variable to minimize bias. RESULTS Two hundred and ninety-three folders were evaluated for descriptive analysis. LTFU worsened with successive visits: 36% at 6 weeks, 60% at 3 months, and 72% at 6 months. In multivariate analysis at the 3-month visit LTFU was associated with age (adjusted odds ratio (aOR), 0.6 per 10-year increase [95% CI, 0.5-0.9]), HCW category of doctor (aOR 2.7 [95% CI, 1.3-5.5]), and time from exposure to receiving PEP of more than 24 h (aOR 5.9 [95% CI, 1.3-26.9]). CONCLUSION We identified factors associated with LTFU of HCWs after occupational HIV exposure, which could be used to target interventions to improve follow-up.