How much does a reminder letter increase cervical screening among under-screened women in NSW?

To evaluate a direct mail-out campaign to increase Pap screening rates in women who have not had a test in 48 months.

Ninety thousand under-screened women were randomised to be mailed a 48-month reminder letter to have a Pap test (n=60,000), or not to be mailed a letter (n=30,000). Differences in Pap test rates were assessed by Kaplan-Meier survival analysis, by chi2 tests of significance between Pap test rates in letter versus no-letter groups, and by proportional hazards regression modelling of predictors of a Pap test with letter versus no-letter as the main study variable. T-tests were conducted on mean time to Pap test to assess whether time to Pap test was significantly different between the intervention and control groups.

After 90 days following each mail-out, Pap test rates in the letter group were significantly higher than in the non-letter group, by approximately two percentage points. After controlling for potential confounders, the hazard ratio of a Pap test within 90 days of a mail-out in the letter group was 1.5 compared with 1.0 in the no-letter group. Hazard ratios of having a Pap test within 90 days decreased significantly with time since last Pap test (p<0.0001); were significantly higher than 1.0 for most non-metropolitan areas of NSW compared with metropolitan areas; and increased significantly with age (p<0.0001). Pap test hazard ratios were not associated with socio-economic status of area of residence, but the hazard ratio was significantly higher than 1.0 if the reminder letter was sent after the Christmas/New Year break. No significant differences in mean time to Pap test were found between the letter and no-letter groups.

Being sent a reminder letter is associated with higher Pap testing rates in under-screened women.