Abstract Body

Background and purpose

Good medication adherence is associated with decreased healthcare expenditure; however, adherence is usually assessed for single medications. We explored associations of adherence to 23 chronic medications with emergency room (ER) visits and hospitalizations.

Methods

Individuals aged 50-74 years, with a diagnosis of diabetes mellitus or hypertension, treated with at least one antihypertensive or antidiabetic medication during 2017 were included. We determined personal adherence rates by calculating the mean adherence rates of the medications prescribed each individual. Adherence rates were stratified by quintiles. We retrieved information about all the ER visits, and hospitalizations in internal medicine and surgery wards during 2016-2018.

Results

Of 268,792 persons included, 50.6% were men. The mean age was 63.7 years. Hypertension was recorded for 217,953 (81.1%); diabetes for 160,082 (59.5%); and both diabetes and hypertension for 109,225 (40.6%). The mean number of antihypertensive and antidiabetic medications used was 2.2±1.1. In total, 51,301 (19.1%) of the cohort visited the ER at least once during 2017; 21,740 (8.1%) were hospitalized in internal medicine wards; and 10,167 (3.8%) in surgery wards during 2017. Comparing the highest adherence quintile to the lowest, odds ratios were 0.64 (0.61, 0.67) for ER visits, 0.56 (0.52, 0.60) for hospitalization in internal wards; and 0.63 (0.57, 0.70) for hospitalization in surgery wards. Odds ratios were similar for the three consecutive years 2016-2018.

Conclusion

Better medication adherence was associated with fewer ER visits and hospitalizations among persons with diabetes and hypertension. Investing in improving medication adherence may reduce health resources and improve patients' health.