High Co-Payments Associated With Delay in Starting Drug Therapy in Patients with Chronic Diseases

High co-payments are associated with delayed initiation of medication in patients with newly diagnosed hypertension, diabetes and elevated cholesterol levels, according to a report in the April 27 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Rising prescription drug costs in the past decade have caused more restrictive insurance benefits, including an increase in cost sharing (i.e., ‘co-payments’), multi-tier formularies and mandatory generic substitution, according to background information in the article. “Several studies have demonstrated that these new arrangements reduce overall drug utilization and expenditures and that the chronically ill are sensitive to out-of-pocket costs. However, detailed mechanisms outlining how these reductions occur are lacking,” the authors write. “The interruption of drug therapy can have negative health consequences for the chronically ill, particularly for elderly patients who have the highest rates of chronic disease and prescription drug use.”

Matthew D. Solomon, M.D., Ph.D., of Stanford University School of Medicine, Stanford, Calif., and colleagues analyzed data from 17,183 older adults with employer-provided drug coverage from 1997 to 2002 from 31 different health plans. The researchers examined the time it took patients to start drug therapy after being diagnosed with hypertension (high blood pressure), diabetes or hypercholesterolemia (elevated cholesterol levels).

Five years after diagnosis, 21.5 percent of patients with hypertension, 36 percent of patients with hypercholesterolemia and 32.5 percent of patients with diabetes remained untreated with medications. Higher co-payments were associated with delayed initiation of therapy. In statistical models, “doubling co-payments resulted in large reductions in the predicted proportion of patients initiating pharmacotherapy at one and five years after diagnosis: for hypertension, 54.8 percent vs. 39.9 percent at one year and 81.6 percent vs. 66.2 percent at five years; for hypercholesterolemia, 40.2 percent vs. 31.1 percent at one year and 64.3 percent vs. 53.8 percent at five years; and for diabetes, 45.8 percent vs. 40 percent at one year and 69.3 percent vs. 62.9 percent at five years,” the authors write.

Those with no previous use of drug therapy (26.1 percent of hypertension patients, 10.4 percent of hypercholesterolemia patients and 12.9 percent of diabetes patients) had a median (midpoint) initiation of drug use at 833 days, more than 1,170 days and more than 1,402 days after diagnosis, respectively. This group was also more price sensitive than those with a history of medication use.

“These results raise concerns about high cost-sharing levels for elderly, insured patients without experience using prescription drugs. Based on our findings, high cost-sharing levels could be a barrier to treatment for this population and possibly result in poor health outcomes,” the authors conclude. “Policy makers and physicians should consider the effects of benefits design on patient behavior to encourage the adoption of necessary care.”

Arch Intern Med. 2009;169[8]:740-748.