Does a provider payment method affect membership retention in a health insurance scheme? a mixed method study of Ghana's capitation payment for primary care

Background: Ghana introduced a National Health Insurance Scheme (NHIS) in 2003 applying fee-for-service method for paying NHIS-credentialed health care providers. The National Health Insurance Authority (NHIA) later introduced diagnosis-related-grouping (DRG) payment to contain cost without much success. The NHIA then introduced capitation payment, a decision that attracted complaints of falling enrolment and renewal rates from stakeholders. This study was done to provide evidence on this trend to guide policy debate on the issue. Methods: We applied mixed method design to the study. We did a trend analysis of NHIS membership data in Ashanti, Volta and Central regions to assess growth rate; performed independent-sample t-test to compare sample means of the three regions and analysed data from individual in-depth interviews to determine any relationship between capitation payment and subscribers' renewal decision. Results: Results of new enrolment data analysis showed differences in mean growth rates between Ashanti (M = 30.15, SE 3.03) and Volta (M = 40.72, SE 3.10), p = 0.041; r = 0. 15; and between Ashanti and Central (M = 47.38, SE 6.49) p = 0.043; r = 0. 42. Analysis of membership renewal data, however, showed no significant differences in mean growth rates between Ashanti (M = 65.47, SE 6.67) and Volta (M = 69.29, SE 5.04), p = 0.660; r = 0.03; and between Ashanti and Central (M = 50.51, SE 9.49), p = 0.233. Analysis of both new enrolment and renewal data also showed no significant differences in mean growth rates between Ashanti (M = - 13.76, SE 17.68) and Volta (M = 5.48, SE 5.50), p = 0.329; and between Ashanti and Central (M = -6.47, SE 12.68), p = 0.746. However, capitation payment had some effect in Ashanti compared with Volta (r = 0. 12) and Central (r = 0. 14); but could not be sustained beyond 2012. Responses from the in-depth interviews did not also show that capitation payment is a key factor in subscribers' renewal decision. Conclusion: Capitation payment had a small but unsustainable effect on membership growth rate in the Ashanti region. Factors other than capitation payment may have played a more significant role in subscribers' enrolment and renewal decisions in the Ashanti region of Ghana.