Low copays, mail-order pharmacies may reduce adherence disparities to hypertension meds

An analysis of more than 44,000 patients recently diagnosed with high blood pressure in Kaiser Permanente Northern California identified important differences in medicine-taking behaviors among racial and ethnic groups. Lower copayments and the use of mail-order pharmacy increased refills of blood pressure medicine, and these factors were associated with reduced disparities.

Kaiser Permanente scientists published the retrospective study on adherence to medications prescribed for high blood pressure, also known as hypertension, in the Dec. 10 online edition of Archives of Internal Medicine.

"The differences that we found occur early on after a patient has been diagnosed with hypertension," explained Alyce S. Adams, PhD, research scientist with the Kaiser Permanente Division of Research and lead author of the study. "In fact, as early as the first refill, some patients are forgoing their hypertension medication."

Hypertension is a major risk factor for heart disease, and even modest reductions in blood pressure are associated with significant reductions in heart attacks, strokes and deaths related to cardiovascular disease. Its impact is devastating to communities of color, particularly among blacks, where males have the highest hypertension death rates of any other racial, ethnic, or gender group. This is attributable in part to significantly lower control rates as compared to whites, according to a 2010 report from the U.S. Centers for Disease Control.

According the CDC, only about 54 percent of people diagnosed with hypertension nationally have it under control. Kaiser Permanente Northern California has become a national model for hypertension control, with about 87 percent of its members controlling their blood pressure and experiencing concurrent dramatic reductions in strokes and heart attacks.

"This research points to specific strategies that have the potential to reduce disparities in blood pressure by easing access to important medications," Adams said. "Our findings suggest that while racial and ethnic differences in medication adherence persist—even in settings with high-quality care—interventions such as targeted copay reductions and mail-order pharmacy incentives have the potential to reduce these disparities."

Using Kaiser Permanente Northern California's integrated electronic health record system, the researchers identified 44,167 patients who had been prescribed antihypertensive medications for the first time in 2008. Because more than 95 percent of Kaiser Permanente patients obtain prescriptions from the health plan's in-house pharmacy, the researchers were able to monitor when, whether and how these patients refilled their hypertension medications.

Primary nonadherence or failing to pick up a prescribed medication was rare. More than one-third of patients failed to refill a medication within 90 days of the first fill (called "early nonpersistence"), and this varied considerably by race. After adjusting for other variables, black (43.6 percent), Asian (38.8 percent) and Latino (41.6 percent) patients all had significantly higher odds of early nonpersistence than white (31 percent) patients.

Nonadherent patients were defined as those with gaps in medication refills for more than 20% of the days in the measurement period, or having medication available less than 80% of the time. Of the nonadherent patients studied, 28 percent were black, 26.9 percent were Latino, 20.3 percent were Asian, and 16.7 percent were white. The impact of race and ethnicity on nonadherence was significantly reduced when the authors accounted for differences in copayment and enrollment in mail-order pharmacy; both mail-order pharmacy enrollment and lower copayments were significantly associated with a lower likelihood of being nonadherent.

Journal reference: JAMA Internal Medicine

Provided by Kaiser Permanente