Changes in Prescription of Psychotropic Drugs After Introduction of Polypharmacy Reduction Policy in Japan Based on a Large-Scale Claims Database

Abstract

Background and objectives: In Japan, polypharmacy reduction policy, which reduces the reimbursement of medical cost, was introduced to address unnecessary psychotropic polypharmacy. The rule was applied to the prescriptions of three or more anxiolytics or three or more hypnotics in the policy introduced in 2012. The prescriptions of four or more antidepressants or four or more antipsychotics were added to the rule in the policy revised in 2014. Furthermore, the prescriptions of three or more drugs of anxiolytics, hypnotics, antidepressants, or antipsychotics were subject to the reduction criteria of the policy revision in 2016. Benzodiazepine receptor agonists (BZs) are classified both into anxiolytics and hypnotics, and the reduction rule was not applied to the category of BZs before April 2018. This study aimed to examine the effect of the policy on the prescriptions of four drug categories as well as BZs from the point of view of the number of drugs and doses.

Methods: This was a retrospective observational study using a large-scale Japanese health insurance claims database. Patients who were prescribed at least one psychotropic drug (anxiolytic, hypnotic, antidepressant, or antipsychotic) during the study period (from April 2011 to March 2017) were selected. Segmented regression analysis was used to analyze the proportions of patients with three or more or four or more drugs as well as patients above clinically recommended doses, and the means of the average daily doses by drug category.

Results: A total of 312,167 patients were identified as a study population. The proportions of patients with three or more drugs in anxiolytics, hypnotics, antidepressants, and antipsychotics significantly decreased after the introduction or revisions of the policy, but not BZs. The proportions of patients with three or more drugs in March 2017 were 0.9%, 2.0%, 1.2%, 2.4%, and 8.9% in anxiolytics, hypnotics, antidepressants, antipsychotics, and BZs, respectively. The effect of the policy in reducing the proportions of patients above clinically recommended doses was identified in antipsychotics after the revision in 2016, but not identified in the sum of anxiolytics and hypnotics as well as BZs after the revision in 2014, and antidepressants after the revision in 2016. The proportions of monotherapy were increased from April 2011 to March 2017 only for antidepressants (76.9% → 80.8%) and antipsychotics (79.8% → 82.1%), and not changed or decreased for anxiolytics (85.2% → 85.7%), hypnotics (78.6% → 77.6%), sum of anxiolytics and hypnotics (68.1% → 65.7%), BZs (68.0% → 67.3%), and sum of psychotropic drugs (52.1% → 49.9%).

Conclusions: The polypharmacy reduction policy reduced the proportions of patients with three or more drugs in four drug categories, but not BZs. Only limited effects were seen for reducing the proportions of patients above clinically recommended doses. The policy was revised in April 2018 again. Further investigation is needed to examine the effect of the revision in 2018.