Disparities in HPV Vaccine Series Completion by Adolescent Males: A Retrospective Cohort Study
Human papillomavirus (HPV) vaccine has been recommended for male patients for the prevention of genital warts and precancerous anal lesions since 2009. Our objective was to characterize race and insurance-based disparities in HPV vaccine completion among male patients who initiated the HPV vaccine series. This was a retrospective cohort study of adolescent male patients in a primary care network who initiated the HPV vaccine series from October 2009 to December 2013. We measured vaccine series completion as the primary outcome. We evaluated associations between outcomes and race and insurance status, controlling for potential confounders and effect modification with multivariable logistic regression. Analyses were stratified by vaccine recommendation era (permissive vs routine). In total, 42% of males in the cohort (16,691) completed the vaccine series. In the permissive vaccine era (2009-2011), non-black patients (53%) were more likely to complete than black patients (32%) and non-Medicaid patients (49%) were more likely to complete than Medicaid patients (33%). These differences persisted in the routine recommendation era (2012-2013). In both the permissive and routine eras, Medicaid insurance was associated with a larger reduction in the predicted probability of vaccine series completion for non-black patients. Adherence to the recommended vaccination schedule was low, with a median time to completion of 8.9 months. Using the updated completion schedule (2016), we found that completion rates were greater (54.1%) with continued differences based on race (60% vs 45.7% for non-black vs black patients) and insurance (57.4% vs 46.4% completion for non-Medicaid vs Medicaid patients). We found significant disparities in HPV vaccine series completion rates among male patients based on race and insurance, unchanged based on era of initiation or visit frequency.