Evaluation of polypharmacy in Japan using the national health insurance claims database in 2015-2017

There is growing awareness of polypharmacy as a global issue. Several countries have introduced policies to optimize multidrug prescriptions. In Japan, hospital prescription fee “F100” and outpatient prescription fee “F400” have been instituted to promote the correct use of drugs, the medical treatment fee is restricted when seven or more types of drugs are prescribed. However, non-polypharmacy patients who need multiple drugs are also comprehensively evaluated within the purview of the same drug insurance claim criteria. Thus, the current state of such policies is still unclear. This study identified the age group in which drug claims have changed based on drug insurance claim criteria and elucidated the relationship between policy interventions and multidrug prescriptions. We analyzed F100 and F400 cases using open data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan from April 2015 to March 2017. These sources include a population of about 69 million patients. Moreover, the growth rate of the number of patients who were prescribed seven or more types of drugs was evaluated. F100 prescription claims decreased by − 12.7% (n = 3,239,070) in 2016 as compared to 2015 (n = 3,700,396), and the number of F400 prescription claims decreased by − 7.7% (n = 28,745,468) in 2016 as compared to 2015 (n = 31,142,484), for seven or more types of drugs. The drug insurance claim rate among people over the age of 65 was 74.2% to F100 and 77.9% to F400, and this age group represented the highest proportion among all age groups. The rate of health insurance claims for multidrug prescriptions clearly decreased after the institution of policy interventions to optimize the use of seven or more types of drugs. The present study suggests that the prescription fee restriction could reduce the rate of multidrug prescriptions and consequent decreases the risk of adverse drug-related events in polypharmacy patients. Policy interventions related to the optimization of drug prescriptions encourage behavioral factors of healthcare providers. Polypharmacy treatment must be established through prescriptions information linkage between clinical practices and community.