Medication adherence improves patient outcomes, but U.S. patients generally have low rates of compliance. To help patients stay on top of their dosing regimens, physicians need to identify those most likely to be nonadherent and the reasons for their recalcitrance to implement interventions. But adherence itself bears costs, as do interventions. Payers want proof that strategies are both cost-effective and feasible.
Patients with chronic diseases such as hypertension, dyslipidemia or congestive heart failure (CHF) benefit from medical therapy but only if they actually take their drugs as prescribed. Conditions such as acute MI require that patients receive and adhere to medication plans ordered by their physicians at discharge. But the PARIS Registry, which is tracking more than 5,000 patients for two years after stent implantation, found that the incidence of nonadherence to dual-antiplatelet therapy was 2 percent at 30-day follow-up, putting nonadherent patients at risk of stent thrombosis. According to the World Health Organization, only half of patients with chronic diseases in developed countries take their medications as prescribed, to the detriment of their health and the healthcare systems that may absorb the costs of subsequent emergent care and hospitalizations.
Someone—whether a patient, his or her insurance company, Medicare, other government payers or providers—has to foot the bill for these pharmaceuticals. “Medication adherence is a measure of prescription drug utilization, so increasing adherence generally means you spend more on medication,” says M. Christopher Roebuck, MBA, a health economist and principal of RxEconomics in Hunt Valley, Md.
But do the savings from reduced hospitalizations offset the costs of adherence? Numerous studies have shown that adherence leads to lower overall healthcare costs, but the research is observational and consequently cannot establish a causal link.
As the former director of strategic research at CVS Caremark, Roebuck collaborated with colleagues at the retail pharmacy as well as at the Centers for Medicare & Medicaid Services to answer that question using two powerful tools: the pharmacy benefits manager’s database of prescription drug claims from sponsors of health insurance plans and an econometrics fixed-effects method to tease out confounding variables that hamper observational studies (Health Affairs 2011;30:91-99). The researchers focused on four chronic vascular conditions that are both costly and prevalent: CHF, hypertension, diabetes and dyslipidemia.
They extracted pharmacy data on people with continuous health insurance between 2005 and 2008 for a sample that included 16,353 patients with CHF, 112,757 with hypertension, 42,080 with diabetes and 53,041 with dyslipidemia. For costs, they looked at annual pharmacy, medical and total healthcare costs.
They found that adherence carried a price. Annual pharmacy spending for adherent patients with CHF was $1,058 more; for hypertension, $429 more; for diabetes, $656 more; and for dyslipidemia, $601 more. But annual medical spending was lower, with reduced average spending for CHF, hypertension, diabetes and dyslipidemia, totaling $8,881, $4,337, $4,413 and $1,860, respectively. The adherence effects were more pronounced for patients who were 65 years or older.
“Those savings certainly speak to the value of medication adherence,” Roebuck says. Of course, cost savings is a critical part of the equation for payers, who want reassurance that the money doled out for medications leads to lower healthcare use and consequently fewer and lower payouts. But that is not the same as improving adherence. “How you move the needle on adherence is another ball of wax.”
Adherence rates can vacillate over time, according to Barbara J. Riegel, DNSc, RN, who studies nonadherence in HF patients. As director of the Biobehavioral Research Center at the University of Pennsylvania School of Nursing in Philadelphia, she and colleagues test disease management approaches for these patients.
“Even the patients who were serious about taking their medicine regularly weren’t 100 percent perfect,” says Riegel in reference to one nonadherence study involving 202 chronic HF patients. “They were good most of the time.”
Compounding the problem, many patients with cardiovascular disease struggle with comorbidities that make simultaneous control of multiple conditions difficult to achieve. In a study involving two different