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Study suggests income to co-pay ratio directly affects medication adherence


PHILADELPHIA As co-payments and prescription costs rise, adherence to medications drops, unsurprisingly, especially among lower-income patients, a new study has suggested.

A Journal of General Internal Medicine study funded by GlaxoSmithKline examined the connection between income level and medication compliance as co-payments for drugs increase, for sufferers of chronic conditions.

The study, Effects of Increased Patient Cost Sharing on Socioeconomic Disparities in Health Care, demonstrated that adherence to most—though not all—medication classes dropped as co-pay and prescription costs rose. This effect was more pronounced as incomes fell, as broadly established using the average income by zip-code.

Among the subjects of the study—29,764 patients with Type 2 diabetes and 13,081 with congestive heart failure—the average age of the diabetics was 53 years, and 44.4 percent were female, while the CHF patients averaged about three to four years older.

The study found, not surprisingly, that for each medication class, individuals in high-income areas were consistently more adherent than individuals in low-income areas—in some cases by 20 percent or more. In addition, there was a notable decrease in medication adherence across all drug categories in response to a 10 percent increase in drug co-payment, with the largest decreases in adherence again occurring in the lowest income groups.

“Based on our analysis, it is likely that increased co-payments, intended to control costs, will exacerbate the disparities seen across socioeconomic groups,” said study co-author Michael Chernew, a professor in the Department of Health Care Policy at Harvard Medical School.

With chronic illness, adherence is of paramount importance in controlling the disease; a lack of compliance with medication schedules leads to worsening of the condition, which leads to increased healthcare costs across the board. In fact, studies show that $3 of every $4 spent on health care in the United States goes to treating the 45 percent of Americans with at least one chronic disease and that the seven most common chronic diseases directly and indirectly cost the economy $1.3 trillion each year.

So while raising co-payments in order to save money works for employers in the short run, it rather behooves them instead to help their employees find ways to lower their healthcare costs, in the long run.

“We must encourage employers and health plans to develop benefit strategies that improve the health of all patients—especially those with chronic diseases—which can lead to lower total healthcare costs,” said Michael Sokol, medical director for GSK’s Health Management Innovations team.

The full text of the study can be found here.

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