Profiles of discontinuation and switching of thiazide diuretics: a cohort study among 9398 Chinese hypertensive patients.

This study tested the hypothesis that younger, male patients or new clinic visitors, who were prescribed thiazide diuretics were more likely to have drug discontinuation and switching. All adult patients who visited any primary care clinic in one territory of Hong Kong, and who were prescribed a thiazide diuretic from January 2004 to June 2007 were included. The rates of discontinuation and switching, separately, 180 days after thiazide prescriptions were measured. Factors associated with discontinuation and switching were evaluated by multiple regression analyses. Among 9398 patients, 12.5% discontinued and 10.8% switched their prescriptions, whereas prescriptions of other patients remained the same. Younger patients (< 50 years (reference value); adjusted odds ratio (AOR) for 50-59 years=0.74, 95% confidence interval (CI) 0.61-0.90, P=0.002; AOR (60-69 years)=0.57, 95% CI 0.46-0.70, P < 0.001; AOR (≥ 70 years)=0.88, 95% CI 0.73-1.06, P=0.174), male subjects (AOR=1.23, 95% CI 1.07-1.40, P=0.003) and new visitors (AOR (repeat visitors)=0.55, 95% CI 0.47-0.65, P < 0.001) were more likely to be discontinuers. These associations between younger age (< 50 years (reference value); AOR (50-59) years=0.85, 95% CI 0.70-1.04, P=0.112; AOR (60-69 year)=0.79, 95% CI 0.65-0.98, P=0.028; AOR (≥ 70 years)=0.70, 95% CI 0.57-0.85, P < 0.001), male gender (AOR=1.29, 95% CI 1.12-1.48, P < 0.001) and new visitors (AOR (repeat visitors)=0.57, 95% CI 0.48-0.67, P < 0.001) were also significant for medication switching. Clinicians should monitor the medication-taking behavior more closely among patients aged 50-59 years, male subjects and new clinic visitors when thiazide was prescribed.