Estimated 2 and 5 Year Transition Probabilities (95% C.I) for Progression and Regression in 3-State Hidden Markov Model Adjusted for Cytology Misclassification Assumptions, by IAC-Exclusion Window (≤180 vs.≤30 days)₁.

1.Model estimates fit with time-updated infrared coagulation (IRC) indicator and standardized to reflect transition probabilities for those who never underwent IRC. Thus, these transition probabilities estimate the untreated natural history of AIN. 2.IAC exclusion window: Cases of invasive anal carcinoma (IAC) diagnosed within 180 or 30 days of the first cytology result, respectively, were considered prevalent cases and were therefore excluded from analysis. 3.Transition from HSIL: HSIL: high grade squamous intraepithelial lesion; IAC: invasive anal carcinoma.