Human papillomavirus-associated anal squamous intraepithelial lesions in men who have sex with men and transgender women living with and without HIV in Karachi Pakistan: implications for screening and prevention

BACKGROUND: Anal squamous intraepithelial lesions (ASIL), strongly related to human papilloma virus (HPV) infection, is more prevalent among men who have sex with men (MSM). However, no such data are available for Pakistan yet, and neither HPV vaccination nor anal-cytology screening is implemented in Pakistan. The purpose of this first ever study was to assess the prevalence of HPV-related anal cytological abnormalities among MSM and transgender women living with and without HIV infection in Pakistan. METHODS: We conducted a cross-sectional study from March 2016 to November 2017 at sexual health centers run by the Perwaaz Trust and the National AIDS Control Program in Karachi. The study enrolled MSM and transgender women aged greater-than-and-equal-to-18-years who reported anal sex in the preceding 6 months. We collected two anal samples for liquid-based cytology and HPV type testing by PCR, and socio-demographic and behavioral data were collected through face-to face interviews. ASIL and its associations with biological and behavioral risk factors were analyzed through Cox regression for prevalence ratios (PR) and corresponding 95% confidence intervals (CIs). RESULTS: Out of 271 qualifying participants, 79% were MSM and 21% transgender women. The mean age was 28.8 (± 8) years. Almost 35% (93/271) of the study population had ASIL detected, ASIL was significantly more common among participants living with HIV than in HIV negative ((50/118) 42.4%; vs. (43/153) 28.1%) (p ≤ 0.001). Among ASIL, 66% (61/93) had low-grade squamous intraepithelial lesions (LSIL), and 3.6% (3/93) had high-grade squamous intraepithelial lesions (HSIL). The overall, HPV16 positivity was 35.5% (33/93) among all abnormal anal lesions and all 3 HSIL were HPV16 positive, however, HPV16 positivity could show its association with ASIL detection in univariate model only (PR(crude): 2.11(1.39–3.18)). Moreover, any HR-HPV type (PR 3.04; 95% CI 1.75–5.26), concurrent sexually transmitted infection (STI) (2.13; (1.28–3.55)) and HIV + /HPV + coinfection (1.75; (1.07–2.88)) remained independently associated with ASIL in the multivariate model. CONCLUSIONS: Abnormal anal cytology among MSM and transgender is prevalent enough to consider optimal screening regimens. Further studies are required to see if periodic anal cytology can be made part of HIV care and treatment programs among MSM in Pakistan. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12879-021-06850-w.