The effect of adding Pap smear information to a mammography reminder system in an HMO: results of randomized controlled trial

BACKGROUND: While reminders can promote cancer screening in primary care, little is known about the potential interaction between multiple reminders. METHODS: We conducted a randomized controlled trial to compare the effect of combined Pap smear plus mammogram reminders and mammogram-only reminders among 2471 women 40 years of age or older enrolled in a health maintenance organization serving a predominantly Medicaid-eligible population. Reminders included both a mailed letter for the woman and a medical record prompt. RESULTS: Intervention assignment was unassociated with differences in rates of visitation to family medicine or internal medicine or completion of mammography during the study year. Compared to women assigned to mammogram-only reminder treatment, those assigned to the combined Pap smear plus mammogram reminder intervention were more likely to visit a gynecologist (34% compared to 29%, adjusted odds ratio = 1.33, 95% confidence interval 1.08-1.63) and to complete a Pap smear (30% compared to 23%, adjusted odds ratio = 1.39, 95% confidence interval 1.07-1.89). CONCLUSIONS: In the study setting, the addition of Pap smear to mammography reminders has a procedure-specific effect, increasing gynecology visits and Pap smear use while neither increasing nor decreasing other primary care visits or mammography. We find no evidence of reinforcement or competition between these reminders.