Use of mood stabilizers by hospitalized geriatric patients with bipolar disorder.

Bipolar disorder is a clinically important condition in the geriatric psychiatric population, with reported prevalences ranging from 4 to 19 percent (1,2). However, study of bipolar disorder among elderly patients has been limited. A search of MED LINE for the 20-year period from 1977 to 1997 revealed that the most recent comprehensive review that summarized approaches to pharma cotherapy for elderly patients with bipolar disorder was done by Young (3) in 1997. The review indicated that minimal research had been conducted on the clinical efficacy of the various mood stabilizers among elderly patients compared with younger patients. In a five-year retrospective analysis of an adult hospital population irrespective of age (the mean age was about 43 years), Frye and associates (4) compared the efficacy of the three mood stabilizers—valp roic acid, carbamazepine, and lithium—and the combination of them in treatment of patients with classic and dysphoric mania. Length of stay in the hospital was used as the major outcome measure. Some patients who were treated with valproic acid received a highload dosage of 20 mg per kilogram of body weight. The analysis by Frye and associates indicated that when used alone, valproic acid had significantly better efficacy than either lithium or carbamazepine in helping patients achieve hospital discharge. Most studies of geriatric populations have examined only lithium treatment for patients with acute mania (5), despite the findings by Pur year and Kunik (6) that valproic acid is well tolerated by elderly patients. With the Food and Drug Administration’s 1995 approval of valproic acid for use in treatment of bipolar disorder, the need to study its clinical efficacy among elderly patients was apparent. Our study examined the comparative efficacy of selected mood stabilizers among elderly patients. Our hypothesis was that valproic acid would be superior to other agents. Methods The study focused on an inpatient geriatric population with bipolar disorder and was modeled after the study by Frye and associates (4). We did a retrospective chart review at a university-affiliated county hospital in New York State. The charts of psychiatric patients age 60 or older with a discharge diagnosis of bipolar disorder were reviewed for the four-year period from 1993 to 1996. Of 122 charts identified for the study, 72 satisfied all inclusion and exclusion criteria for analysis. Patients were included if they met DSM-IV criteria for bipolar disorder at admission and were maintained on mood stabilizer monotherapy with lithium, carbamazepine, or valproic acid during hospitalization. If patients had more than one course of mono therapy while hospitalized, the monotherapy that resulted in discharge was used in the analysis of length of treatment. Patients were excluded if their hospital stay was lengthened because of medical illness, if they were not placed on a mood stabilizer, or if they were treated with more than one mood stabilizer simultaneously. Data gathered from the 72 charts included demographic information such as age, gender, family history of psychiatric illness, number of years with the diagnosis of bipolar disorder, and number of previous psychiatric hospitalizations. Assessment and treatment data included mood stabilizer used, blood levels of the medication at discharge, length of treatment with the mood stabilizer in days, and Global Assessment of Functioning (GAF) score at admission and discharge.