Importance of medication adherence in treatment needed diabetic retinopathy

We aim to investigate the role of medication adherence history in treatment needed diabetic retinopathy (TNDR). We conducted a retrospective nested case–control study using 3 population-based databases in Taiwan. The major one was the 2-million-sample longitudinal health and welfare population-based database from 1997 to 2017, a nationally representative random sample of National Health Insurance Administration enrolled beneficiaries in 2010 (LHID2010). The national death registry and national cancer registry were also checked to verify the information. The outcome was defined as the TNDR. The Medication possession ratio (MPR) was defined as the ratio of total days of diabetes mellitus (DM) medication supply divided by total observation days. MPR ≥ 80% was proposed as good medication adherence. The association of MPR and the TNDR was analyzed. Other potential confounders and MPR ratio were also evaluated. A total of (n = 44,628) patients were enrolled. Younger aged, male sex and patients with less chronic illness complexity or less diabetes complication severity tend to have poorer medication adherence. Those with severe comorbidity or participating pay-for-performance program (P4P) revealed better adherence. No matter what the characteristics are, patients with good MPR showed a significantly lower likelihood of leading to TNDR after adjustment with other factors. The protection effect was consistent for up to 5 years. Good medication adherence significantly prevents treatment needed diabetic retinopathy. Hence, it is important to promote DM medication adherence to prevent risks of diabetic retinopathy progression, especially those who opt to have low medication adherence.