Abstract 5591: Factors associated with HPV vaccine initiation among males aged 11-26 years attending outpatient clinics in the Baltimore Metro Area during 2012 - 2013

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Introduction: Few studies have examined factors associated with HPV vaccine initiation among males, particularly after the Advisory Committee on Immunization Practices upgraded their recommendation in late 2011. The aim of our study was to identify demographic characteristics and care-seeking behaviors associated with HPV vaccine initiation among a large clinical population of age-eligible males. Methods: This is a cross-sectional analysis of electronic health record data from 15,970 males aged 11-26 years attending 24 Johns Hopkins Community Physicians clinics from January 2012 - April 2013 in Baltimore, MD. Our outcome was receipt of first dose of the HPV vaccine series (“initiation”). We calculated mutually adjusted odds ratios (aOR) of initiation and 95% Confidence Intervals (95% CI) using multivariate logistic regression models with generalized estimating equations to account for clustering within clinics for age (continuous), race (black, Asian, other vs. white), insurance type (public, military, vs. private), number of clinic visits (1 vs. 2+), attendance to a preventive care visit during the study period (vs. not), and practice specialty (Internal Medicine, Pediatrics, Med-Peds vs. Family Practice). Results were stratified by the following age groups: 11-12 years (target age for vaccination, “target”), 13-21 years (catch-up age for vaccination, “catch-up”), and 22-26 years (permissive age for vaccination, “permissive”). Results: A total of 2,193 (14%) males initiated the HPV vaccine. Initiation varied by age; 23.2%, 16.5%, and 1.9% in the target, catch-up, and permissive age groups respectively. Among the target age group, black race (aOR 1.3; 95% CI 1.0-1.7), 1 clinic visit (aOR 0.7; 95% CI 0.5-0.9), and attendance to a preventive care visit (aOR 8.1; 95% CI 4.9-13.4) were significantly associated with odds of initiation. Among the catch-up age group, age (aOR 0.9; 95% CI 0.9-0.95), black race (aOR 1.2; 95% CI 1.0 - 1.4), 1 clinic visit (aOR 0.6; 95% CI 0.5-0.7), attendance to a preventive care visit (aOR 4.6; 95% CI 3.6-5.8) and Internal Medicine practice (aOR 0.4; 95% CI 0.3-0.5) were significantly associated with odds of initiation. Among the permissive age group, age (aOR 0.8; 95% CI 0.7 - 1.0), 1 clinic visit (aOR 0.4, 95% CI 0.3-0.5) attendance to a preventive care visit (aOR 5.1; 95% CI 3.0-8.9), military insurance (aOR 3.0; 95% CI 1.4 - 6.4) and Internal Medicine practice (aOR 0.5; 95% CI 0.3-0.8) were significantly associated with odds of initiation. Discussion: Overall, HPV vaccine initiation rates fell below state and national averages. In line with other studies, initiation was highest among black males. Among all ages, preventive care visits were associated with initiation. More education on the value of catch-up vaccination among adult-focused specialties (e.g. Internal Medicine) may increase HPV vaccination initiation among males aged 13 - 26 years. Citation Format: Megan Clarke, Darcy F. Phelan-Emrick, Francesca Coutinho, Betty Chou, Corinne E. Joshu. Factors associated with HPV vaccine initiation among males aged 11-26 years attending outpatient clinics in the Baltimore Metro Area during 2012 - 2013. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5591. doi:10.1158/1538-7445.AM2015-5591