Risk of Progression to High-grade Anal Intraepithelial Neoplasia in HIV-infected MSM

Objective: To assess the value of several factors to predict the risk of progression to high-grade anal intraepithelial neoplasia (HGAIN) in a cohort of HIV-infected MSM.

Design: Longitudinal study of 556 HIV-infected MSM who underwent screening for anal dysplasia (include anal cytology and high-resolution anoscopy at each visit).

Methods: Progression rate to HGAIN was estimated by Kaplan-Meier analysis. Predictors of progression were assessed by Cox-proportional hazards regression.

Results: Sixty-eight incidents HGAIN cases over 649 person-years of follow-up were diagnosed, resulting in a progression rate of 10.5 cases/100 person-years [95% confidence interval (CI), 8.1-13.3). The cumulative incidence of HGAIN was 7.2% at 12 months (95% CI, 4.3-10.1) and 16.2% at 24 months (95% CI, 11.7-20.7). Independent risk factors for progression were as follows: abnormal cytology [hazard ratio (HR), 2.5 (95% CI, 1.2-4.9) if low-grade squamous intraepithelial lesion, HR 2.76 (95% CI, 1.4-5.3) if atypical squamous cells of uncertain significance and HR 7.73 (95% CI, 2.3-25.4) if high-grade squamous intraepithelial lesion], abnormal high-resolution anoscopy (HR 3.57; 95% CI, 2-6.4) and infection by 16 or 18 human papillomavirus (HR 1.63; 95% CI, 1-2.6). To be receiving HAART (HR 0.4; 95% CI, 0.2-0.7) and have stable sexual couple (HR 0.62; 95% CI, 0.4-0.9) were protective factors. Patients with favorable predictors had an incident rate of 2.86 cases/100 person-years (95% CI, 3.5-10.3).

Conclusion: The rate of progression to HGAIN varies according to different predictors that should be considered when assessing the particular risk of each patient. Patients with low risk of progression could be screened at longer intervals.

Brief Summary: We describe the risk of progression to HGAIN in a cohort of 556 HIV-infected MSM. The incidence rate of HGAIN varies widely according to different predictors. These factors should be considered when assessing the particular risk of each patient.