Factors associated with loss to follow-up after occupational HIV exposure among health care workers attending the Groote Schuur Hospital Occupational Health Clinic
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 (ART) like zidovudine were used. Methods A retrospective cohort study was conducted of HCWs attending a referral hospital’s Occupational Health Clinic (OHC) in Cape Town, South Africa, for post-exposure prophylaxis (PEP) during a period when tenofovir (TDF) was available. Data was obtained from an existing database maintained by the OHC. Our primary outcome was to identify factors associated with LTFU at the 3-month visit, with secondary outcomes evaluating factors associated with LTFU at the 6-week and 6-months visits. We selected 7 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 to 0.9]), HCW category of doctor (aOR 2.7 [95% CI, 1.3 to 5.5]), and time from exposure to receiving PEP of more than 24 hours (aOR 5.9 [95% CI, 1.3 to 26.9]). Discussion Our finding that LTFU increases with successive visits is consistent with other studies. It is believed higher LTFU in younger HCWs may be related to the greater change and instability they experience in their younger years. Doctors are more likely to be LTFU than other HCWs which could be related to concerns of confidentiality in performing HIV testing at their facility. Additionally, doctors may be making their own assessments of the risk of exposure. Lastly, doctors may be submitting their own blood samples for HIV testing instead of attending the OHC. One study showed longer time from exposure to receiving PEP was not associated with attendance of visits, but we showed this did influence LTFU at the 3-month visit. This could be explained by HCWs who present after 24 hours having a perceived lower benefit from PEP. Newer studies have shown that completion of PEP is based on the tolerability of ART and not on whether dual or triple therapy are used. This could explain why in our cohort there was no correlation between type of ART and LTFU. There is literature to support increased attendance of follow-up visits by contacting HCWs by telephone or mail. Furthermore, the WHO has recently advised the final follow-up visit to be at 3 months rather than 6 months. We suspect with fewer visits, there may be less LTFU. Conclusion We identified factors associated with LTFU of HCWs after occupational HIV exposure, which could be used to target interventions to improve follow-up.
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