RESUMO
BACKGROUND: Prospective randomized trials have demonstrated that motivational telephone calls increase adherence to screening mammography. To better understand the effects of motivational calls and to maximize adherence, we conducted a randomized trial among women aged 50-79 years. METHODS: We created a stratified random sample of 5062 women due for mammograms within the Group Health Cooperative of Puget Sound, including 4099 women with prior mammography and 963 without it. We recruited and surveyed 3743 (74%) of the women before mailing a recommendation. After 2 months, 1765 (47%) of the 3743 women had not scheduled a mammogram and were randomly assigned to one of three intervention groups: a reminder post-card group (n = 590), a reminder telephone call group (n = 585), and a motivational telephone call addressing barriers group (n = 590). The telephone callers could schedule mammography. We used Cox proportional hazards models to estimate the hazard ratio (HR) and 95% confidence interval (CI) for documented mammography use by 1 year. RESULTS: Women who received reminder calls were more likely to get mammograms (HR = 1.9; 95% CI = 1.6-2.4) than women who were mailed postcards. The motivational and reminder calls (average length, 8.5 and 3.1 minutes, respectively) had equivalent effects (HR = 0.97; 95% CI = 0.8-1.2). After we controlled for the intervention effect, women with prior mammography (n = 1277) were much more likely to get a mammogram (HR = 3.4; 95% CI = 2.7-4.3) than women without prior use (n = 488). Higher income, but not race or more education, was associated with higher adherence. CONCLUSIONS: Reminding women to schedule an appointment was as efficacious as addressing barriers. Simple intervention groups should be included as comparison groups in randomized trials so that we better understand more complex intervention effects.