Efficacy of patient letter reminders on cervical cancer screening - A meta-analysis

OBJECTIVE: To perform a meta-analysis on existing randomized controlled trials to investigate the efficacy of patient letter reminders on increasing cervical cancer screening using Pap smears. METHODS: A search was conducted for all relevant published and unpublished studies between the years 1966 and 2000. Eligibility criteria included randomized controlled studies that examined populations due for Pap smear screening. The intervention studied was in the form of a reminder letter. The Mantel-Haenszel method was used to measure the summary effect of the intervention. A test for homogeneity using the Mantel-Haenszel method was performed. RESULTS: Ten articles fulfilled the inclusion criteria, including one unpublished study. The test for homogeneity showed evidence of heterogeneity (chi (2) = 31, 9 df, P < .001). An analysis for causes of heterogeneity was pursued. Division into subpopulations based on socioeconomic status resolved the heterogeneity (chi (2) = 5.2, 8 df, P = .75). The studies evaluating those in lower socioeconomic groups had a smaller response (odds ratio [OR], 1.16; 95% confidence interval [CI], 0.99 to 1.35) than those studies using mixed populations (OR, 2.02; 95% CI, 1.79 to 2.28). The pooled odds ratio showed that patients who received the intervention were significantly more likely to return for screening than those who did not (OR, 1.64; 95% CI, 1.49 to 1.80). CONCLUSIONS: Patient reminders in the form of mailed letters increase the rate of cervical cancer screening. Patient letter reminders have less efficacy in lower socioeconomic groups.