Co-Payment Exemption and Healthcare Utilization after the Great East Japan Earthquake: A natural experiment study (Japanese)

After the Great East Japan Earthquake on March 11, 2011, survivors who suffered severe damages were exempted from paying their co-payments. They were located mainly in three prefectures: Miyagi, Fukushima, and Iwate. In Miyagi, which experienced the largest number of deaths, the exemption was suspended between April 1, 2013 and March 31, 2014 (FY2013) due to a political decision, while Fukushima and Iwate still hold this exemption. This study aimed to describe the trajectory of healthcare utilization via: 1) healthcare expenditure/capita/month, 2) number of medical visits/capita/month, and 3) healthcare expenditure/visit before and after the exemption period. We also examined associations between changes in healthcare utility and the exemption. first, we employed differences in differences (DID) analyses to compare healthcare utilization in Miyagi with that in the other prefectures. Healthcare utilization in Miyagi decreased just after the disaster and soon spiked higher than the previous level. This phenomenon was also observed in Fukushima and Iwate. Another sharp spike in healthcare utilization was observed just before the exemption suspension, while similar spikes were not observed in Fukushima or Iwate during the same period. The rapid increase in Miyagi was more significant in medical/dental service for outpatients than for inpatients. Second, we stratified DID analyses within Miyagi by co-payment level (30% or less). In Japan, the co-payment paid is typically 30% of the total medical/dental costs, however, elderly and preschool children are subject to co-pay of 10% or 20% respectively. Among thwho pay 30% rate, healthcare utilization decreased through the exemption suspension, while it remained stable among those who pay 10%-20%. During the same period, we did not observe a significant increase in mortality, a proxy of "adverse effect" of the exemption suspension, at least on the ecological level. These results suggested that the co-payment exemption helped the survivors, especially those with a relatively high co-payment rate of 30%, to obtain healthcare service one year after the disaster. Further research with individual-level data is needed to find out how long the exemption period should last and who should be eligible for the exemption for a longer period.