Impact of a cost-sharing drug insurance plan on drug utilization among older people

OBJECTIVES: In August 1996, the Regie de l'assurance-maladie du Quebec (RAM Q), the government body responsible for medical insurance in the Canadian p rovince of Quebec, introduced a cost-sharing drug insurance plan. Before th is plan, individuals age 65 years and older had to pay Canadian (CDN)$2 per prescription, with the remaining cost paid by the RAMQ. With the new plan, beneficiaries may have to pay an amount between CDN$200 and CDN$925 per ye ar, depending on their income. Concerned that this financial constraint imp osed on older people might have an impact on the use of medications, we inv estigated whether the consumption of four classes of medications, antihyper tensive agents, anticoagulants, nitrates, and benzodiazepines, was affected by the drug plan implementation. DESIGN: Time series models with pre/post comparison group. SETTING: Administrative computerized databases of the RAMQ. PARTICIPANTS: Random sample of Quebec residents age 65 years and older regi stered in the provincial drug plan be tween August 1992 and June 1997: 54,7 71 users of nitrates, 133,146 users of antihypertensive agents, 45,534 user s of anti-coagulants, and 26,165 users of benzodiazepines. MEASUREMENTS: We modeled the monthly consumption of the medications under s tudy between August 1992 and June 1996. Monthly drug consumptions predicted from the models were compared with those observed for the 13 months (Augus t 1996 to August 1997) following the implementation of the new drug plan us ing 95% confidence intervals. The number of prescriptions dispensed served as an indicator for drug consumption. RESULTS: During the study period ave observed a nonstatistically significan t decrease in number of prescriptions of 5.1% for nitrates, 1.1% for antihy pertensive agents, and 0.8% for benzodiazepines, and a nonstatistically sig nificant increase of 1.6% for anticoagulants. CONCLUSION: Residents of Quebec age 65 years and older were not found to ha ve reduced significantly their consumption of nitrates, antihypertensive ag ents, anticoagulants, and benzodiazepines during the 13 months that followe d the implementation of a cost-sharing drug insurance plan.