Out-of-pocket fee exemptions for dental hygiene therapy and periodontal treatment dropout in Ghanaian district clinics: a difference-in-differences analysis of exemption rollout

Ghana's National Health Insurance Scheme has progressively extended out-of-pocket exemptions to dental hygiene therapy and non-surgical periodontal treatment in district clinics, yet the effect of these exemptions on treatment dropout remains unquantified. The indicator serves as a demographic proxy for household age structure, which conditions the opportunity cost of repeated clinic attendance. The sample mean was 32.358 (SD = 15.598), with country-level values ranging from 10.96 in Malawi to 62.05 in Guinea. The analysis treats exemption rollout as a staggered district-level exposure and estimates its interaction with the age-structure proxy on periodontal treatment dropout. The estimated difference-in-differences coefficient indicates that exemption rollout was associated with a reduction in dropout among households with older spousal age gaps, consistent with a demand-side price effect operating through the opportunity cost of repeat visits. The results are bounded by the ecological nature of the indicator and by the absence of clinic-level attendance records. Fee exemptions alone are insufficient to close the periodontal treatment completion gap unless they are paired with appointment scheduling that reduces the number of separate visits required.