Approaches to Estimating Clearance Rates for Human Papillomavirus Groupings: A Systematic Review and Real Data Examples.

ABSTRACT

INTRODUCTION: Approaches to estimating clearance rates, an important metric of human papillomavirus (HPV) clearance, for HPV groupings differ between studies. We aimed to identify the approaches used in the literature for estimating grouped HPV clearance rates. We investigated whether these approaches resulted in different estimations, using data from existing studies. METHODS: In this systematic review, we included articles that reported clearance rates of HPV groupings. We identified approaches to data in the HAVANA cohort, comprising adolescent girls, and the H2M cohort, comprising men who have sex with men. We estimated clearance rates for six HPV groupings (bivalent-, quadrivalent- and nonavalent vaccine-related, and low-risk, high-risk, and any HPV). RESULTS: From 26 articles, we identified 54 theoretically possible approaches to estimating clearance rates. These approaches varied regarding definitions of clearance events and person-time, and prevalence or incidence of infections included in the analysis. Applying the nine most-used approaches to the HAVANA ( n = 1,394) and H2M ( n = 745) cohorts demonstrated strong variation in clearance rate estimates depending on the approach used. For example, for grouped high-risk HPV in the H2M cohort, clearance rates ranged from 52.4 to 120.0 clearances/1000 person-months. Clearance rates also varied in the HAVANA cohort, but differences were less pronounced, ranging from 24.1 to 57.7 clearances/1000 person-months. CONCLUSIONS: Varied approaches from the literature for estimating clearance rates of HPV groupings yielded different clearance rate estimates in our data examples. Estimates also varied between study populations. We advise clear reporting of methodology and urge caution in comparing clearance rates between studies.