Utilization of essential medications by vulnerable older people after a drug benefit cap: importance of mental disorders, chronic pain, and practice setting.

OBJECTIVE: To identify specific characteristics of patients, physicians, and treatment settings associated with decreased receipt of essential medications in a chronically ill, older population following a Medicaid three-prescription monthly reimbursement limit (cap). DESIGN: Quasi-experiment with bivariate and multivariate regression. SETTING: Patients in the New Hampshire Medicaid program and their regular prescribing physicians. PARTICIPANTS: Three hundred and forty-three chronically ill Medicaid enrollees with regular use of essential medications for heart disease, asthma/chronic obstructive pulmonary disease, diabetes mellitus, seizure, or coagulation disorders who received an average of three or more prescriptions per month during the baseline year. MEASUREMENTS: Postcap patient-level change in standard monthly dose of essential medications compared with the baseline period, presence of 11 comorbidities (defined by regular use of specific indicator drugs), practice setting, and location of regular prescribing physician. RESULTS: The mean percentage change in standard doses of essential medications following the cap was −34.4%. Larger changes were significantly associated with several baseline measures: greater numbers of precap medications, greater numbers of comorbidities, longer hospitalizations, and greater use of ambulatory services. The three comorbidities associated with the largest relative reduction in essential drug use were psychoses/bipolar disorders, anxiety/sleep problems, and chronic pain. Patients of physicians in group practices, clinics, or hospitals tended to have smaller dose reductions than those whose physicians were in solo or small-group practice. CONCLUSIONS: Patients most at risk of reduced access to essential medications because of a reimbursement cap include those with multiple chronic illnesses requiring drug therapy, especially illnesses with a mental health component. Physicians in clinics or large group practices may have maintained patient medication regimens more effectively.