CBE Research Seminar Series: Comparing Clinical Effectiveness and Drug Toxicity With Hydrochlorothiazide and Chlorthalidone Using Two Potency Ratios in a Managed Care Population

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YEREVAN, Armenia – On May 5th, the American University of Armenia (AUA) College of Business & Economics (CBE) hosted a seminar led by MSE Program Chair and Associate Professor Vahram Ghushchyan. He presened his research on “Comparing Clinical Effectiveness and drug Toxicity with Hydrochlorothiazide and Chlorthalidone Using Two Potency Rations in a Managed Care Population”. The seminar was part of the CBE Research Seminar Series aimed to host faculty presentations on their research findings, create a more vibrant research environment, and promote scientific collaboration among the AUA faculty.

This study compared the clinical effectiveness and drug toxicity of chlorthalidone and hydrochlorothiazide. Electronic health records and claims data were used to identify patients initially prescribed chlorthalidone or hydrochlorothiazide. A total of 214 patients prescribed chlorthalidone 25 mg were matched with 428 patients prescribed hydrochlorothiazide 25 mg (1:1 potency ratio) and 214 patients prescribed hydrochlorothiazide 50 mg (1:2 potency ratio). Mean systolic blood pressure/diastolic blood pressure values at least 30 days after initial prescription were lower with chlorthalidone (132.2/74 mm Hg) compared with hydrochlorothiazide 25 mg (137.0/77.5 mm Hg) and hydrochlorothiazide 50 mg (138.6/78.5 mm Hg) (P<.05 for all comparisons). Goal systolic blood pressure/diastolic blood pressure values were achieved in a higher percentage of patients prescribed chlorthalidone (45.0%/78.3%) than with either hydrochlorothiazide 25 mg (32.1%/63.9%) or hydrochlorothiazide 50 mg (32.8%/68.9%) (P<.05 for all comparisons). Mean serum potassium was 3.94 mEq/L with chlorthalidone 25 mg, 4.13 mEq/L with hydrochlorothiazide 25 mg (P<.01 vs chlorthalidone), and 3.96 mEq/L with hydrochlorothiazide 50 mg. These findings indicate that chlorthalidone 25 mg is associated with a better antihypertensive response than hydrochlorothiazide 25 mg or 50 mg, without clinically significant differences in serum potassium.

Dr. Ghushchyan is an associate professor at the College of Business and Economics of the American University of Armenia. He is also the founding chair of Master of Science in Economics program. Dr. Ghushchyan joined the AUA as a full-time faculty member in 2013. His teaching interests are in applied econometrics. Prior to joining AUA Dr. Ghushchyan held a Research Professor position at the University of Colorado AMC. He is an author of numerous publications which can be found at:  

Dr. Ghushchyan received his PhD. in Economics from the University of Colorado, Boulder, in 2006. His research interests are in the areas of health economics and outcomes research.

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Founded in 1991, the American University of Armenia (AUA) is a private, independent university located in Yerevan, Armenia and affiliated with the University of California. AUA provides US-style education in Armenia and the region, offering high-quality, graduate and undergraduate studies, encouraging civic engagement, and promoting public service and democratic values.