Factors associated with compliance to thiazide diuretics among 8551 Chinese patients

Good compliance to anti-hypertensive medications has been recognized as a crucial factor to achieve optimal blood pressure control, but there were few studies addressing this issue among ethnic Chinese patients. This study aims to evaluate the factors associated with compliance to thiazide diuretics in a Chinese hypertensive population.

From a clinical database, all adult Chinese patients aged ≥ 18 years who were prescribed a thiazide diuretic from the public health care sector in one large Territory of Hong Kong during January 2004 to June 2007 and attended at least twice for anti-hypertensive drug refill were included. Medication Possession Ratios were used to measure drug compliance for each patient, with a level ≥ 80% defined as compliant. We used binary logistic regression analysis to evaluate the factors associated with good compliance.

From 8551 eligible patients, 84·5% were compliant (defined as MPR ≥ 80%). Fee payers (adjusted odds ratio [aOR] 1·28; 95% CI 1·12-1·46, P < 0·001) and follow-up visitors (aOR 2·47, 95% CI 2·13-2·87, P < 0·001) were significantly associated with better anti-hypertensive compliance. Patients who were newly prescribed thiazide diuretics and those with poorer socioeconomic status were more likely to be non-compliant to anti-hypertensive therapies. Patients' age, gender and number of co-morbidities were not significant associated factors.

Among Chinese patients, those who were newly prescribed thiazide diuretics and those with poorer socioeconomic status were more likely to be non-compliant to anti-hypertensive therapies. Closer monitoring and more intensive compliance-enhancing strategies had to be targeted towards these patients to enhance clinical outcomes.