The Impact of Body Mass Index and Medical Conditions on Home-based Anal Self-Sampling

Purpose. Self-sampling is increasingly being used in screening programs, yet no studies to date have examined the impact of bodily characteristics on self-sampling experiences. Our objective was to assess whether body mass index (BMI) and physical disability were associated with anal self-sampling difficulty. Methods. We recruited sexual minority men (SMM) and trans persons in Milwaukee, Wisconsin to participate in an anal cancer screening study. Between January 2020 and August 2022, 240 participants were randomized to a home (n=120) or clinic (n=120) screening arm. Home participants received a mailed at-home anal self-sampling kit and were asked to attend a baseline clinic visit where biometric measurements were collected. Participants were asked to complete a survey about their experience with the kit. This research utilizes data from participants who used the kit and completed a baseline clinic visit and post-swab survey (n=82). We assessed the impact of BMI and physical disability on reported body or swab positioning difficulty. Results. Most participants reported no or little difficulty with body positioning (90.3%) or swab positioning (82.9%). Higher BMI was significantly associated with greater reported difficulty with body positioning (aOR=1.10, 95% CI 1.003-1.20, p =.04) and swab positioning (aOR=1.11, 95% CI 1.02-1.20, p =.01). Physical disability was not significantly associated with body or swab positioning difficulty. Specimen adequacy did not differ by BMI category ( p =.76) or physical disability ( p =.88). Conclusion. Anal self-sampling may be a viable option to reach obese persons who may be more likely to avoid screening due to weight-related barriers.