Study finds higher drug co-pays discourage patients from starting treatment

April 28, 2009

Patients newly diagnosed with hypertension, diabetes or high cholesterol are significantly more likely to delay initiating recommended drug treatment if they face higher co-payments for medications, according to a new RAND Corporation study.

The delay was significant across all conditions, but the impact was largest among patients who had not previously used prescription drugs, according to the study published in the April 27 edition of the Archives of Internal Medicine.

While several studies have established that higher drug co-payments discourage some patients from taking their medications, the new RAND Health study is the first to examine the impact higher out-of-pocket costs have on patients who are beginning drug treatment after being diagnosed with a chronic illnesses.

"Our study clearly shows that out-of-pocket costs reduce patients' willingness to start treatment for their chronic illnesses," said lead author Dr. Matthew D. Solomon, the study's lead author and an adjunct researcher at RAND, a nonprofit research organization. "It is indisputable that avoiding treatment for these conditions will lead to higher rates of heart attack and stroke."

The study included 272,474 retirees who received health coverage from their former employers from 1997 to 2002 and were covered by 31 different health plans. Researchers focused on 17,183 people from this group who were newly diagnosed with diabetes, high blood pressure or high cholesterol, examining their records to see when they began to fill prescriptions for needed medications.

For each of the conditions, patients who had higher out-of-pocket costs were less likely to start prescription drug therapy compared to other patients in the study. For example, among those newly diagnosed with high blood pressure, those starting drug treatment within a year of diagnosis dropped from 55 percent to 40 percent when their co-payment doubled. After five years, the difference was 82 percent to 66 percent, according to the study.

Similar differences were seen among those diagnosed for the first time with diabetes and high cholesterol, according to researchers. Patients starting drug treatment within a year of diagnosis with high cholesterol dropped from 40 percent to 31 percent when patients' out-of-pocket costs doubled. After five years, the difference was 64 percent to 54 percent. Among patients with diabetes, those starting drug treatment within a year of diagnosis dropped from 46 percent to 40 percent when co-pays doubled. After five years, the difference was 69 percent to 63 percent

"Along with behavioral and lifestyle modification, prescription drug therapy is the cornerstone of management for these diseases," said Solomon, who also is a medical resident at Stanford University. "If left untreated, each of these conditions will increase a person's risk for having a potentially fatal cardiovascular event, such as a heart attack or stroke."

The study also showed that patients who had no experience with medications were even less likely to begin recommended drug treatment, an indication that some patients may have a preference against medication use.

Solomon said the new RAND study holds implications for policymakers and insurance officials interested in creating policies to improve medication compliance and raise the quality of care. In addition, it should highlight for physicians the types of patients who may be most likely to ignore recommended drug treatments.

"Epidemiologic studies tell us that we do a terrible job of treating patients with these conditions. Now we know one reason why," Solomon said.

Source: RAND Corporation