Detecting anal human papillomavirus infection in men who have sex with men living with HIV: implications of assay variability.

BACKGROUND: Incidence of anal cancer (AC) caused by persistent human papillomavirus (HPV) infection has risen in the last years in men who have sex with men (MSM) living with HIV. There is consensus that this population should be screened for anal precancerous lesions, but the role of HPV DNA testing in AC screening programmes is still under debate. OBJECTIVES: This study employed two molecular test to detect anal HPV DNA and compared assay performance and prognostic value for the diagnosis of histology proven high-grade intraepithelial anal lesions. METHODS: MSM living with HIV attended their regular check-up visits consisting of detection of anal HPV infection, anal cytology, digital anorectal examination and high resolution anoscopy. HPV DNA was detected using Hybrid Capture 2 High-Risk test (HC2, total assay) and LINEAR ARRAY HPV Genotyping Test (LA, type-specific assay) RESULTS: Among 274 participant, prevalence of HPV DNA was 48.5% by HC2 and 89.4% by LA. HPV16 (30.6%) and HPV6 (19.6%) were the most common genotypes identified. Prevalence of multiple HPV infections was 56.2%. Agreement between HPV DNA assays was 75.2% (κ=0.51; 95% CI 0.42 to 0.60). Total HPV detection demonstrated high sensitivity (90%; 95% CI 68.3 to 98.8) and moderate specificity (58.4%; 95% CI 50.2 to 66.3), while type-specific HPV16/18 genotyping provided an increase in specificity and showed the highest area under the curve (0.81; 95% CI 0.74 to 0.89) and Youden's index (0.63). CONCLUSIONS: Both methodologies identified a high prevalence of anal HPV infection and multiple HPV infections in MSM living with HIV, showing a moderate overall agreement between them. Either total HPV detection or type-specific HPV16/18 detection together with a threshold ≥atypical squamous cells of undetermined significance for abnormal cytology showed an acceptable diagnostic accuracy.