Associations among medication regimen complexity, medical specialty, and medication possession ratio in newly diagnosed hypertensive patients: A population-based study

The aim of this study was to explore the associations among the medication regimen complexity index (MRCI), medical specialty, and medication possession ratio (MPR) in newly diagnosed hypertensive patients. Data from 19,859 newly diagnosed hypertensive patients were collected from 2,000,000 random samples of the National Health Insurance Research Database in Taiwan. All study participants were followed for 1 year after the first diagnosis of hypertension. MPR was defined as total days of antihypertensive drugs supplied/365 days. MRCI was calculated on the basis of the type of dosage forms, dosing frequency, and additional directions for use of antihypertensive drugs. Patients were further restricted to those who visited the same medical specialty to examine specialty-specific variations in the MRCI and MPR. The mean MPR was 54.83%, and the sample sizes for the low-, medium-, and high-MPR groups were 9806 (49.38%), 4619 (23.26%), and 5434 (27.36%), respectively. More than 50% of the patients visited the same medical specialty during the 1-year follow-up. The mean MRCI was 3.64; the cardiology specialty had the highest MRCI, and the family medicine specialty had the lowest. Multiple linear regression analyses showed that MRCI was negatively associated with MPR (β = −7.75, P ≤ .01) whether or not the patients visited the same medical specialty. For the patients who visited the same medical specialty, those treated by endocrinology and metabolism specialists had a significantly higher MPR (β = 9.87, P ≤ .01) than that of those treated by family medicine specialists. MRCI and medical specialty were both significantly associated with the MPR of newly diagnosed hypertensive patients.