A mixed methods study of non-occupational post-exposure prophylaxis at an STI clinic in Singapore: Five-year retrospective analysis and providers' perspectives

BACKGROUND: This mixed methods study aims to describe 1) characteristics of the population treated with non-occupational post-exposure prophylaxis (nPEP), 2) predictors of loss to follow-up (LTFU) and nPEP adherence, and 3) to evaluate the nPEP prescribing practices against current management guideline. METHODS: This study was conducted at the Department of Sexually Transmitted Infections Control Clinic in Singapore using clinical data from 2010 to 2016. Explanatory sequential mixed method design was adopted. Predictors of LTFU and nPEP adherence were assessed using modified Poisson regression with robust sandwich variance. Subsequently, nine in-depth interviews with healthcare providers were conducted to gain their insights into barriers and facilitators to nPEP implementation. Transcripts were coded and themes were explored using applied thematic analysis. RESULTS: Of 502 nPEP cases reviewed, 46% were LTFU, 42% were adherent to nPEP and 431 prescription decisions were made in accordance with the guideline. Tourists (aRR, 2.29 [1.90–2.74]; p<0.001) and men who have sex with men/bisexual men (aRR, 1.32 [1.09–1.59]; p = 0.004) were significant predictors of LTFU. Absence of side effects (aRR, 1.14 [1.02–1.27]; p = 0.024) and nPEP treatment with TDF/FTC/ATV/r (aRR, 1.15 [1.03–1.29]; p = 0.017) were positively associated with nPEP adherence. Stigma, types of antiretroviral regimen, side effects, and patients’ perception of risk and treatment benefits derived qualitatively further reinforced corresponding quantitative findings. CONCLUSION: Tailored socio-behavioral interventions are needed to address inherent differences within heterogeneous populations requesting nPEP, stigma, and patients’ perceptions of nPEP in order to improve follow-up and its adherence.