Pharmaceutical Research

New studies reveal the impact of drug copayment and coinsurance policies on statin and beta-blocker therapy after heart attack

Statins are among the most effective drugs to prevent coronary heart disease and reduce the risk for heart attack and stroke, while beta-blockers are typically prescribed as long-term therapy for patients who have been hospitalized for a heart attack.

Two new studies led by Sebastian Schneeweiss, M.D., Sc.D., of Harvard Medical School, and supported in part by the Agency for Healthcare Research and Quality (HS10881), investigated the use of these drugs among elderly British Columbia residents. The first study found that only about half of patients adhere to statin therapy a year after starting the medication. While fewer than one in five seniors adhere to beta-blocker therapy, a second study found that copayments or coinsurance do not worsen this situation. Both studies are summarized below.

Schneeweiss, S., Patrick, A.R., Maclure, M., and others. (2007, April). "Adherence to statin therapy under drug cost sharing in patients with and without acute myocardial infarction." Circulation 115, p. 2128-2135.

Only 55.8 percent of patients with full prescription drug coverage adhere to statin therapy a year after starting on the medication. The addition of a $20 copayment or 20 percent coinsurance to each dispensing of a statin will further reduce adherence by 5 percentage points, according to a new population-based study. However, these cost-sharing policies don't seem to affect initiation of statin therapy after hospitalization for a heart attack.

A closer look at the reasons for reduced statin adherence revealed that patients' insurance status and actual out-of-pocket payments were significant predictors for stopping statin use. This finding has important implications for the new Medicare Part D drug coverage for seniors. Policies that simply share the financial burden of buying drugs with patients will lead to suboptimal use of critical life-prolonging drugs such as statins. Consideration should be given to fully exempting high-risk patients from drug cost-sharing, including patients who have had a heart attack, suggest the researchers.

The researchers examined adherence to statin therapy among three groups of patients in the British Columbia, Canada, PharmaCare program: those who began statin therapy during full drug coverage (2001), coverage with a $10 or $25 copay (2002), and coverage with a 25 percent coinsurance benefit (2003-2004). They followed each group 9 months after each policy change. Adherence to statin therapy was defined as 80 percent or more days covered. Relative to full-coverage policies, adherence to new statin therapy was significantly reduced from 55.8 to 50.5 percent under a fixed copayment and the subsequent coinsurance policy. Sudden changes to full out-of-pocket spending, similar to Medicare's Part D "doughnut hole," almost doubled the risk of stopping statins.

Schneeweiss, S., Patrick, A.R., Maclure, M., and others. (2007, August). "Adherence to beta-blocker therapy under drug cost-sharing in patients with and without acute myocardial infarction." American Journal of Managed Care 13(8), pp. 445-452.

The researchers compared new use of beta-blockers following a heart attack among elderly British Columbia residents who began beta-blocker therapy during periods of full drug coverage (2001), a $10 or $25 copay depending on income (2002), and 25 percent coinsurance (2003-2004). All groups quickly reduced their beta-blocker adherence (drug supply for 80 percent of the month) by 6.3 percent per month after beginning therapy, with a decline to about 70 percent compliance at 6 months. This decline stabilized after 9 months to a decline in adherence of about 1 percent per month. Adherence was only marginally reduced by 1.3 percentage points as a consequence of the copayment policy and 0.8 percentage points due to the coinsurance policy.

The proportion of patients who began beta-blocker therapy after a heart attack and continued therapy remained steady at about 61 percent during the study period. This adherence rate was similar to that observed in a control group of elderly Pennsylvania residents with full drug coverage. The lack of impact of cost-sharing on drug use may have been due to the availability of low-cost beta-blockers in British Columbia. For example, the median cost, including insurance and out-of-pocket costs, for a 90-day beta-blocker supply was $29 under full coverage, and $22 and $23 under cost-sharing, indicating that patients switched to lower-cost beta-blockers.

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