Medication Adherence Leads to Lower Health Care Use and Costs Despite Increased Drug Spending

Study Questions:

Does medication adherence lead to lower health care costs despite increase in drug costs?


Data were extracted from integrated pharmacy and medical administrative claims data from the CVS Caremark data on people who had continuous health insurance coverage sponsored by one of nine U.S. employers from January 1, 2005, through June 30, 2008. Data were analyzed for the following four chronic vascular conditions: congestive heart failure (CHF), hypertension, diabetes, and dyslipidemia. Analysis included annual numbers of inpatient hospital days, emergency department visits, and outpatient physician visits, and three measures of health services cost: annual pharmacy, medical, and total health care costs. Adherence was defined as a medication possession ratio of 0.80 or greater, and any less was defined as nonadherent.


There were approximately 135,000 patients, and groups were relatively balanced by gender. CHF patients tended to be older (average 77 years old) than patients with the other three conditions (averages 65-68 years old). Adherence rates varied from 34% to 51%. Total health care costs per patient per year averaged $39,076 for CHF, $14,813 for hypertension, $17,955 for diabetes, and $12,688 for dyslipidemia. Total outpatient pharmacy costs ranged from $2,867 to $3,780 per patient per year. Adherence was associated with significantly lower annual inpatient hospital days, ranging from 1.18 fewer days for dyslipidemia to 5.72 fewer days for CHF. Annual emergency department visits were minimally lower and doctor visits were higher in the adherent cohort. Adherence reduced average annual medical spending by $8,881 in CHF, $4,337 in hypertension, $4,413 in diabetes, and $1,860 in dyslipidemia. Adherence benefits were greater in those over 65 years old. Benefit-cost ratios ranged from 2:1 for adults under age 65 with dyslipidemia, to more than 13:1 for older patients with hypertension.


In light of the Affordable Care Act’s expansion of access to medical care, policy makers must now search for ways to improve health outcomes while reducing spending. Given the findings in the CVS Caremark study, plan sponsors, government payers, and patients should consider participating in programs that improve medication adherence, as long as intervention costs do not exceed the estimated health care savings.


The findings speak for themselves and support the thesis that medical care can be cost-effective, but requires adherence to avoid waste. Among the opportunities to increase adherence and reduce cost include electronic monitoring/tracking with regular physician feedback, physician incentive for adherence, and nurse- or pharmacist-led counseling. It would have been of value to see the threshold of adherence that is associated with maximal and minimal benefit-cost ratios for each condition.

Keywords: Pharmacists, Government, Medication Adherence, Cost-Benefit Analysis, Health Services, Counseling, Health Care Costs, Emergency Service, Hospital, Drug Costs, Patient Protection and Affordable Care Act, United States

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