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Member Research and Reports

Member Research and Reports

UAB Researchers Assess Time Trends in Low Adherence to Antihypertensive Medication

Dr. Gabriel S. Tajeu, a post-doctoral fellow in the department of epidemiology at the University of Alabama at Birmingham, recently led a study to determine time trends in rates of discontinuation and low adherence to antihypertensive medication among a 5 percent sample of Medicare beneficiaries. Discontinuation and low adherence to a prescribed medication regimen can adversely affect patient outcomes as well as healthcare costs.

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[Photo: Dr. Gabriel S. Tajeu]

Dr. Tajeu and fellow researchers — including colleagues from UAB’s department of epidemiology, Dr. Paul Muntner, professor and vice chair; Ms. Lei Huang, statistician; and UAB alum Dr. Shia T. Kent — analyzed data on 41,135 Medicare beneficiaries initiating antihypertensive medication treatment between 2007 and 2012 to determine time trends in rates of discontinuation (in which subjects did not take antihypertensive medication for the last 90 days of the year following initiation) and low adherence (in which subjects took antihypertensive medication less than 80 percent of the time during the year following initiation) to antihypertensive medication.

“Discontinuation was stable during the study period (21.0 percent in 2007 and 21.3 percent in 2012; P-trend=0.451). Low adherence decreased from 37.4 percent in 2007 to 31.7 percent in 2012 (P-trend<0.001). After multivariable adjustment, the relative risk of low adherence for beneficiaries initiating treatment in 2012 versus in 2007 was 0.88 (95 percent confidence interval, 0.83-0.92). Low adherence was more common among racial/ethnic minorities, beneficiaries with Medicaid buy-in (an indicator of low income), and those with polypharmacy, and was less common among females, beneficiaries initiating antihypertensive medication with multiple classes or a 90-day prescription fill, with dementia, a history of stroke, and those who reached the Medicare Part D coverage gap in the previous year,” reports Dr. Tajeu and colleagues.