Prescribing patterns of antipsychotic drugs in Taiwan -- Analysis of Psychiatric Inpatient Medical Claim dataset
Date Issued
2006
Date
2006
Author(s)
Li, Tz-Mei
DOI
zh-TW
Abstract
Background
Pharmacotherapy is one of the most important treatments of schizophrenia. The effects of antipsychotic drugs are mainly symptom control and prevention of relapse. In contrast to conventional typical antipsychotic drugs, atypical antipsychotic drugs not only cause fewer extrapyramidal side effects, but also improve cognitive function and negative symptoms. With the emergence of atypical antipsychotics, the change on the prescribing pattern of schizophrenia is expected. The objectives of this study are to analyse the utilization of the antipsychotic agents in Taiwan from 1997 to 2001, to assess the polypharmacy in antipsychotic agents on the prescriptions of outpatients and inpatients, and to explore the drug switching pattern before and after the use of clozapine during the years 1998-2003.
Methods
The sampling datasets from the Psychiatric Inpatient Medical Claim Dataset (PIMC) served as data sources. The patients with the primary or the secondary diagnosis of 295.xx on admission to hospital during 1996-2001 and with the age greater than 18 years were included. The measurement units used for calculating prescription day of inpatients’ antipsychotic drugs were the defined daily doses published by WHO. The inclusion criteria of antipsychotic drug user were : 1. prescription days greater than 7 days or who had ≧ 2 outpatient prescriptions in one year. 2. prescription day greater than 7 days for each inpatient admission. SAS 8.2 database software was used for data linkage and processing.
Results
After data exclusion, medical records of 46,312 patients (male: 26,656, female: 19,656) during the years 1997-2001 were collected for this study.
1. Medication trend: based on prescription number counting, most utilized antipsychotic drug was sulpiride, followed by haloperidol from 1997 to 2001. During the five years, the utilization of typical antipsychotics was gradually decreased (β= -0.43，p<0.0001), however, the use of atypical antipsychotic (except clozapine) was continuously increased (β=0.62，p<0.0001). The use of clozapine was also increased (β=0.25，p=0.0501).
2. Polypharmacy: among inpatients, the frequency of antipsychiatric agent monotherapy was increased yearly (β=0.20，p=0.0046), and the frequency of polypharmacy decreased (β=-0.20，p=0.0046) from 1997 to 2001. Among outpatients, the frequency of monotherapy use also increased (β=0.21，p=0.0053), and the frequency of polypharmacy use decreased (β=-0.21，p=0.0053) from 1997 to 2001.
3. Clozapine switching and monitoring: during 1998-2003, before initiation of clozapine, 53.2% patients had been treated with typical antipsychotics alone, 5.4% patients had been treated with atypical antipsychotics alone , and 41.4% patients were treated with both typical and atypical antipsychotics. After clozapine therapy, 44.3% patients use clozapine continuously, 36.7% patients were switched to typical antipsychotics, and 19% patients were switched to the other atypical antipsychotics. Among the those who initiate of clozapine during 1998-2003, 12.5% patients had no blood test claim data after using clozapine, and only 3.2% patients had blood monitoring weekly.
Conclusions
Findings from this study indicated that the prescribing patterns of schizophrenia in Taiwan from 1997 to 2001 were changed. The utilization of typical antipsychotics decreased, and the use of atypical antipsychotics increased gradually. Although polypharmacy of antipsychotic agents was debatable, the trend of polypharmacy use was decreased gradually. Among the first users of clozapine during 1998-2003, 46.8% patients have used atypical antipsychotics as their appropriate therapy. And 12.5% patients had no blood test claim data after clozapine therapy.
Subjects
抗精神分裂藥物
處方型態
健保資料庫
antipsychotic drugs
prescribing pattern
drug switching
Type
text
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