To the Editor: A recently published consensus statement on monitoring patients treated with second-generation antipsychotics recommends that patients have weight, blood pressure (BP), fasting blood glucose (FBG), and lipid profile (FLP) measurements obtained before and 12 weeks after initiation of medication and annually thereafter (1). To our knowledge, there are no published data on rates of monitoring of patients treated with second-generation antipsychotics. The purpose of this investigation was to benchmark monitoring practices among commercially insured, ambulatory patients after initiation of a second-generation antipsychotic medication.
This retrospective analysis was conducted at Kaiser Permanente Colorado (KPCO), a health maintenance organization with approximately 410,000 commercially insured members. All commercially insured members 18 years of age or older who were newly initiated on clozapine, risperidone, olanzapine, quetiapine, ziprasidone, or aripiprazole (index antipsychotic) between April 1 and June 30, 2004, and who had a minimum of one additional claim for the index medication within 90 days of their initial dispensing date (index date) were included. The study was approved by the KPCO Institutional Review Board.
Newly initiated was defined as having no claims for the index or another second-generation antipsychotic within 150 days before the index date. Electronic medical records were searched to determine dates of measurements for weight, systolic BP, FBG, and FLP within 90 days before and seven days after (baseline) index medication dispensing and between 71 and 98 days after dispensing (follow-up). Proportions of patients with baseline and both measurements were determined. Stepwise logistic regression modeling was performed to attempt to identify characteristics predictive of having had both a baseline and a follow-up measurement for weight and BP.
Ninety-seven patients were included in the analysis, 63 (65 percent) of whom were women. The patients' mean±SD age was 57.0±24.4 years. Index antipsychotics included risperidone (49 patients, or 51 percent), quetiapine (35 patients, or 36 percent), olanzapine (12 patients, or 12 percent), and aripiprazole (1 patient, or 1 percent). No patients included in the analysis were taking clozapine or ziprasidone. Preexisting hypertension was present for 35 patients (36 percent), dyslipidemia for 15 (16 percent), diabetes for 12 (12 percent), and obesity for 13 (13 percent).
Baseline BP was available for 60 patients (62 percent), weight for 53 (55 percent), FBG for seven (7 percent), and FLP for 16 (17 percent). No patients had all measurements monitored at baseline and follow-up. Baseline and follow-up BP and weight assessments were recorded for 21 (22 percent) and 20 (21 percent) patients, respectively. No characteristics were found to be associated with having had both a baseline and follow-up measurement for weight or BP.
Our study was undertaken to benchmark practices within our system before adoption of a new monitoring statement. Among a cohort of patients newly initiated on a second-generation antipsychotic, we found that none were monitored according to the recently published consensus statement (1). Because this study was retrospective, we were unable to determine if the performed measures were specifically for monitoring or were incident to other patient care visits.
Given the increase in cardiovascular risk as a result of changes in metabolism posed by second-generation antipsychotics (2,3), monitoring for adverse outcomes is an important consideration when using these agents. In the absence of a systematic approach to implementing patient monitoring, diverse practice approaches may leave a majority of patients without the recommended monitoring.
The authors are affiliated with the Pharmacy Department, Kaiser Permanente Colorado, Aurora. Dr. Olson and Dr. Duagn are also with the School of Pharmacy, University of Colorado at Denver and Health Sciences Center.
The study was funded by Kaiser Permanente Colorado. The authors acknowledge Jolene R. Bostwick, Pharm.D., for her contributions.
American Diabetes Association, American Psychiatric Association, American Association of Clinical Endocrinologists, et al: Consensus development conference on antipsychotic drugs and obesity and diabetes. Diabetes Care 27:596-601, 2004
Allison DB, Mentore JL, Moonseong H, et al: Antipsychotic-induced weight gain: a comprehensive research synthesis. American Journal of Psychiatry 156:1686-1696, 1999
Lindenmayer JP, Czobor P, Volavka J, et al: Changes in glucose and cholesterol levels in patients with schizophrenia treated with typical or atypical antipsychotics. American Journal of Psychiatry 160:290-296, 2003