Continuity of antipsychotic medication management for Medicaid patients with schizophrenia

The purpose of this study was to examine whether medication refill behavior varies by the number of prescribers of antipsychotic medication a patient has.

A total of 7,868 patients with schizophrenia were identified from North Carolina Medicaid records for the period 2001-2003. Medication switching and adherence outcomes in 2003 were constructed from Medicaid pharmacy claims. Adherence was categorized into four levels (nonadherence, partial adherence, full adherence, or excess filler). Patients were stratified into four groups on the basis of the number of providers who prescribed antipsychotics in 2002 (one prescriber, two prescribers, three prescribers, or four or more prescribers). Medication switching was modeled via logistic regression, and the four-level adherence outcome was modeled via ordered logistic regression, with both regressions controlling for the number of prescribers, age, gender, race, and comorbidity. Medication switching in 2003 was also controlled for in the adherence regression. Predicted probabilities of being in the four adherence groups were estimated to examine the impact of the number of prescribers on adherence.

Fifty-seven percent of Medicaid patients with schizophrenia had one prescriber for antipsychotic medication, 29% had two prescribers, 10% had three prescribers, and 4% had four or more prescribers in 2002. Patients with more prescribers were significantly more likely than patients with one prescriber to switch medications (p<.01 for patients with three prescribers) and to be either fully adherent or excess fillers (p<.001).

Patients with schizophrenia who received medication from multiple prescribers frequently changed medications and filled prescriptions too soon. Care coordination, such as with medical homes, may be effective in improving medication use in this vulnerable population.