Impact analysis of the discontinuation of reimbursement: the case of oral contraceptives.

BACKGROUND

We studied the impact of suspending oral contraceptive (OC) reimbursement in the Netherlands for women >21 years starting 1 January 2004. Discontinuation and switching patterns and the time course of the policy intervention's effects were determined.

STUDY

DESIGN

The intervention cohort contained OC users on 1 January 2004; the control cohort users on 1 January 2003. Follow-up duration was 1 year. Discontinuation and switching patterns were assessed using relative risks (RR). Weekly refill fractions were calculated to determine the time course of the policy effects.

RESULTS

Our intervention cohort contained 434,917 OC users; the control cohort 489,904 users. When we excluded patients not affected by the policy intervention (i.e., all patients younger than 20 years), discontinuation rates were 15.3% (intervention cohort) and 12.3% (control cohort) (RR=1.24; 95% CI=1.23-1.26) and increased with age. Switching to cheaper OCs was greatest in the intervention cohort, particularly in the 40- to 44-year age group. Differences in cumulative refill fractions showed large variation over time.

CONCLUSION

The OC reimbursement intervention led to an increase in the discontinuation rate of 24%. The effect increased with older age groups. Considering the time course of effects of policy interventions is of critical importance.