Paula Moyer, MA

October 14, 2005

Oct. 14, 2005 (San Diego) — Patients with schizophrenia who are treated with ziprasidone (Geodon) are more likely to persist with treatment if their starting dose is higher rather than lower, according to investigators who presented their findings presented here at the American Psychiatric Association 57th Institute on Psychiatric Services.

"The results we saw in this Medicaid population were similar to earlier results seen in patients from a managed care database," presenting investigator David J. Harrison, PhD, told Medscape in a telephone interview. However, he stressed that the findings should be viewed within the overall context of identifying the optimal treatment for an individual patient. Dr. Harrison is the senior manager in United States Outcomes Research at Pfizer, in New York City. Pfizer, the manufacturer of Geodon, funded the study.

"Optimizing a patient's experience with the initial treatment with a drug is key to long-term compliance, and I wouldn't write a prescription for any patient based on a database analysis," he added. "However, we found that patients who are started on 120 to 160 mg daily of ziprasidone are more likely to persist with treatment than those started at doses of 40 to 60 mg daily."

Dr. Harrison pointed out that the concern about adherence has ramifications beyond schizophrenia. "Approximately 20% to 30% of patients don't refill prescriptions of any type, whether they're antipsychotics or statins," he said. In schizophrenia, the investigators reported, the issue of nonadherence is more widespread and the consequences more dire: 40% to 50% of patients with schizophrenia do not adhere to their prescribed medications and are therefore at risk for exacerbation of psychosis and rehospitalization.

To determine whether there is a relationship between the starting dose of ziprasidone and persistence with treatment among patients with schizophrenia, the investigators reviewed the records of 1,197 adult Medicaid recipients who had been diagnosed with schizophrenia and had received their first prescription for oral ziprasidone between July 1, 2001, and Sept. 30, 2005. The patients had been enrolled in Medicaid for at least 180 days before receiving the prescription.

The investigators categorized the patients by whether their starting dose was low (20-60 mg daily), medium (61-119 mg daily), or high (120-160 mg daily). There were 517 patients with a low starting dose, 339 with a medium starting dose, and 341 patients with a high starting dose. The investigators measured persistence by the subjects' refill patterns and allowed gaps of up to 15 days between expected refill dates. The investigators then compared the subjects' persistence across starting doses and considered several demographic and medical issues in addition to starting dose, including age, sex, race, and year of treatment initiation.

During the 30-month study period, the discontinuation rates were greater for patients who were started on low or medium doses compared with those receiving high doses of ziprasidone (P = .001 for low starting doses and P = .02 for medium doses). At 90, 180, and 365 days after initiation of treatment, the discontinuation rate was also higher in the low-dose group than in the high-dose group (P < .05).

When the investigators considered demographic and medical factors, they found lower rates of persistence among African-American patients and those who had had more hospitalizations in the 180 days prior to starting oral ziprasidone.

APA 57th IPS: Poster 13. Presented Oct. 9, 2005.

Reviewed by Gary D. Vogin, MD


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