Risk factors for anal high-grade squamous intraepithelial lesions in HIV-positive MSM: is targeted screening possible?

HIV-positive MSM are at increased risk for developing anal squamous cell carcinoma. Detection of precursor lesions of anal cancer [anal high-grade squamous intraepithelial lesions (HSIL)] is cumbersome and expensive. Our objective was to identify potential risk factors for anal HSIL in HIV-positive MSM to develop more stringent screening criteria. We studied a cohort of MSM screened by high-resolution anoscopy at three HIV clinics in Amsterdam, the Netherlands. For every first high-resolution anoscopy performed in a patient, we analyzed five demographic and seven HIV-related potential risk factors for four different outcome measures: histologically proven anal HSIL vs. no squamous intraepithelial lesions (SIL), HSIL-anal intraepithelial neoplasia 2 vs. no SIL, HSIL-anal intraepithelial neoplasia 3 vs. no SIL, and HSIL vs. no HSIL. We used univariable and multilevel, multivariable logistic regression. From 2008 through 2015, 497 out of 1678 (30%) screened HIV-positive MSM had anal HSIL. The mean age was 49 years (SD 9.6), 96% used combination antiretroviral therapy, and median duration of combination antiretroviral therapy use was 7.8 years (interquartile range 4.0-12.4). Increasing age [adjusted odds ratio (aOR) 0.82, 95% confidence interval (CI) 0.70-0.94, P = 0.006] and years living with suppressed viral load [1-5 years suppressed aOR 0.52 (95% CI 0.34-0.80), 5.01-10 years aOR 0.47 (95% CI 0.29-0.74), >10 years aOR 0.54 [0.34-0.87], all compared to less than 1 year suppressed, P = 0.009] were found to be protective for HSIL vs. no SIL. Young HIV-positive MSM without viral suppression are statistically at highest risk for anal HSIL, but given the high prevalence among all virally suppressed men, we advise that all HIV-positive MSM should be screened for HSIL