Nearly one-third of initial prescriptions remain unfilled

(HealthDay)—A sizable number of patients fail to fill their initial drug prescriptions, according to research published in the April 1 issue of the Annals of Internal Medicine.

Robyn Tamblyn, Ph.D., of McGill University in Montreal, and colleagues examined data from 15,961 patients in a primary care network to estimate the incidence of primary nonadherence. Primary nonadherence was defined as failure to fill an incident prescription within nine months.

The researchers found that 31.3 percent of 37,506 incident prescriptions remained unfilled. Prescriptions for drugs in the upper quartile of cost were the least likely to be filled (odds ratio [OR], 1.11; 95 percent confidence interval [CI], 1.07 to 1.17). Compared with anti-infectives, prescriptions for skin agents, gastrointestinal drugs, and autonomic drugs also were less likely to be filled. Prescription nonadherence was less likely with increasing patient age (OR per 10 years, 0.89; 95 percent CI, 0.85 to 0.92), elimination of copayments for prescription drugs in low-income groups (OR, 0.37; 95 percent CI, 0.32 to 0.41), and greater proportion of all physician visits with the prescribing physician (OR per 0.5 increase, 0.77; 95 percent CI, 0.70 to 0.85).

"Primary nonadherence is common and may be reduced by lower drug costs and copayments, as well as increased follow-up care with prescribing physicians for patients with chronic conditions," the authors write.

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