Effects of Referral Bias on Estimates of Anal Intraepithelial Neoplasia Progression and Regression Rates in a 3-State Markov Model

Medicine
William C MathewsChristopher Jackson

Abstract

The study aim is to compare anal intraepithelial neoplasia (AIN) progression and regression rates in a cytology inception cohort to estimates based on the subcohort referred for ≥1 high-resolution anoscopies (HRAs).A cytology-based retrospective cohort was assembled including the anal cytology histories and invasive anal cancer (IAC) outcomes of all HIV-infected adults under care between 2001 and 2012. A 3-state Markov model (<HSIL↔HSIL→IAC) was estimated separately for all patients and for the subcohort undergoing ≥ 1 HRAs with biopsy. Cytology was adjusted for misclassification. State transition rates (per person-year) and covariate hazard ratios were estimated using the R package msm.Of 2804 eligible patients in the inception cohort, 629 (22%) were in the HRA subcohort and 2175 (78%) in the non-HRA subcohort. Patients in the HRA subcohort were more likely to have baseline CD4<350, viral load >400, and to have HSIL at baseline and thereafter. They also had more anal cytology examinations (median 6 vs 3) and longer follow-up (median 5.5 vs 3.6 years). State transition rates were overestimated in the HRA subcohort relative to inception cohort, but the degree of discordance varied by transition: for <HSIL to HSIL (0.44 vs 0.04);...Continue Reading

References

Jan 1, 1987·Journal of Chronic Diseases·K L Ales, M E Charlson
Apr 29, 2008·Bulletin of the World Health Organization·Anne AndermannVéronique Déry
Feb 26, 2009·The Journal of Infectious Diseases·Alexandra de PokomandyUNKNOWN HIPVIRG Study Group

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Citations

Mar 24, 2017·Journal of Racial and Ethnic Health Disparities·Edward R CachayWm Christopher Mathews
Oct 23, 2018·Diseases of the Colon and Rectum·Luis C Cajas-MonsonBard C Cosman
Oct 11, 2019·Cancer Epidemiology, Biomarkers & Prevention : a Publication of the American Association for Cancer Research, Cosponsored by the American Society of Preventive Oncology·Mette T FaberSusanne K Kjaer

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Methods Mentioned

BETA
biopsy

Software Mentioned

R package msm

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