David J. Templeton (Australia)
Sydney Local Health District Department of Sexual Health MedicinePresenter of 1 Presentation
PREVALENCE AND PREDICTORS OF LOSS TO FOLLOW-UP OF GAY AND BISEXUAL MEN (GBM) IN THE LONGITUDINAL STUDY FOR THE PREVENTION OF ANAL CANCER (SPANC) (ID 207)
Abstract
Introduction
Loss-to-follow-up (LTFU) in cohort studies may result in biased estimates of outcomes, due to differences between those retained and those LFTU. To our knowledge, LTFU has never been investigated in studies of anal human papillomavirus and/or anal high-grade squamous intraepithelial lesions (HSIL).
Methods
SPANC was a prospective, 3-year, cohort study of the natural history of anal HPV and HSIL conducted from 2010-2018. GBM aged ≥ 35 years were recruited from community-based settings. Characteristics of participants LTFU after their baseline visit were compared with those who attended at least one further visit using logistic regression.
Results
Among 617 men enrolled, 220 (35.7%) were HIV-positive, median age 49 years. Overall, 85 participants (13.8%) were LTFU (including 30 (13.8%) HIV-positive participants). Independent predictors of LTFU were: lower level of education (p-trend=0.020), younger age (p-trend=0.004), never having smoked cigarettes (p-trend=0.066), and at 2-week interview, reporting feeling more tense during the initial examination (p-trend=0.020) and higher levels of psychological distress (p-trend=0.012). HIV status, HSIL diagnosis, pain and/or bleeding following study procedures were not independently associated with LTFU. In a subanalysis of LTFU among HIV-positive participants, independent predictors of LTFU were reporting a more unpleasant experience with digital-anorectal examination (p=0.048), never having smoked cigarettes (p-trend=0.012) and higher nadir T-cell count (p-trend=0.018).
Conclusions
In addition to a poorer experience of study procedures and subsequent distress, there were some characteristics of participants LTFU in SPANC which are known to be associated with a lower risk of anal cancer including younger age, never smoking, and higher nadir T-cell count. Given that participants were solely informed that GBM (especially HIV-positive) are at elevated risk of anal cancer, it is possible that following an unpleasant examination experience, some men sought further risk factor information online which may have, partly, influenced their decision to discontinue in the study.