Statin adherence goes down with cost-sharing

Requiring patients to help pay for their statin medications has a negative impact on adherence to the therapy, according to a study published in the April 10, 2007, issue of Circulation. Researchers found that addition of a fixed $20 co-payment or 25% coinsurance reduces adherence to statin therapy by 5%, with larger reductions in adherence observed in low-income patients.

"Fixed copayment and coinsurance coverage for statins worsens the already poor situation with statin adherence," said lead researcher Sebastian Schneeweiss of Harvard Medical School, "and the recommendation for health plans is to think seriously about giving away those medications for free, particularly in post-myocardial infarction patients."

Schneeweiss told WebMD's Heartwire that although treatment guidelines and health plan performance measures recommend statin therapy after acute myocardial infarction, adherence to the therapy is often less than 60% six months after starting treatment, even among patients with comprehensive drug plans. With the cost of health care spending increasing, he said, researchers wanted to evaluate the consequences of co-payment and coinsurance policies on starting statin therapy after acute myocardial infarction and adherence to therapy among those started on statins.

"It is known, and frequently described, that medication cost-sharing by patients out of pocket is associated with less drug use and sometimes adverse outcomes," Schneeweiss said. "We wanted to specifically look at statins because statins are a preventive medication, and we're not treating symptoms that patients feel, making the adherence issue worse with statins than with other medications. Also, statins are expensive, so paying 25% of the cost out-of-pocket is quite a bit for these drugs."

Researchers studied 51,561 patients who started statin therapy in the Canadian province of British Columbia. The provincial drug insurance plan provided full prescription drug coverage for the elderly until January 2002 when a $25 (Canadian) prescription copay was implemented ($10 for low-income seniors). In May 2003, the copay was replaced with 25% coinsurance in which patients pay a percentage of the cost plus an income-based deductible policy. Those coverage changes allowed investigators to examine the impact of different cost-sharing interventions on adherence to statin therapy and starting statin therapy after an acute myocardial infarction.

Relative to the time of full coverage, adherence to new statin therapy was reduced 5.4% after nine months of follow-up under the fixed copay policy and was reduced 5.4% under the subsequent coinsurance policy. The proportion of new acute-myocardial infarction patients starting statin therapy increased steadily over the study period, similar to a Pennsylvania control population with full coverage.

"With fixed cost sharing and coinsurance, in both cases we saw a 5% reduction in adherence in the proper use of these medications," Schneeweiss said. "Adherence is already bad with statins, but if you reduce this further, we end with only about 50% of people taking their medication. This is quite poor and will result in many outcomes that could have been avoided. Also, if you turn this around, if you think in terms of interventions on how to improve adherence, this costs a lot of money to boost adherence by 5%."

Schneeweiss said that while the cost-sharing efforts are intended to reduce health care system costs, they could instead lead to more expense, especially if patients stop taking their medications. He said an earlier study he worked on found that insurers could save significantly if aspirin, ACE inhibitors, beta blockers, and statins were provided free to acute myocardial infarction patients.