title: Relationship between body mass index and insulin resistance in patients treated with second generation antipsychotic agents.
abstract: Second generation antipsychotics (SGAs) can increase weight gain and weight-induced insulin resistance. Recent studies have suggested weight-independent effects of certain SGAs on insulin resistance; however the magnitude of these effects and the relationship between BMI and insulin resistance in patients on SGAs are not established. To evaluate, the relationship between body mass index (BMI) and insulin resistance in 54 patients being stably treated with olanzapine (n=19), risperidone (n=16), or aripiprazole (n=19) was compared with data from a large reference population (n=201) not on SGAs. Insulin resistance was directly quantified by measuring the steady-state plasma glucose (SSPG) concentration during the insulin suppression test. The relationship between BMI and SSPG was similar between the SGA (r=0.58) and the reference population (r=0.50). When SSPG was standardized based on expected values for the reference population, patients on olanzapine had a higher degree of insulin resistance (mean z-score+/-SD, 0.68+/-0.9) than expected for level of BMI compared with those on aripiprazole (-0.25+/-1) and risperidone (-0.3+/-0.9), F(2,51)=6.28 (p=0.004). Thus, olanzapine group was 0.76 SD above the reference population or in the 78 percentile for insulin resistance. SSPG was correlated with fasting plasma insulin concentration (0.78 (0.64-0.87), p<0.001) but not fasting glucose concentration (0.15 (-0.13-0.40), p=0.29). In conclusion, BMI contributes a quarter to a third of the variance in insulin resistance in the SGA population similar to the reference population. Olanzapine also appears to have an independent effect on insulin resistance that is above and beyond obesity.
authors: Department of Medicine, 300 Pasteur Drive, S025, Stanford, CA 94305-5103, USA. sunhkim@stanford.edu
authors: Sun H
authors: SH
authors: Kim
authors: Lilla
authors: L
authors: Nikolics
authors: Fahim
authors: F
authors: Abbasi
authors: Cindy
authors: C
authors: Lamendola
authors: James
authors: J
authors: Link
authors: Gerald M
authors: GM
authors: Reaven
authors: Steven
authors: S
authors: Lindley
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D001786:Blood Glucose / Q000187:drug effects; D015992:Body Mass Index; D016208:Databases, Factual / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D001523:Mental Disorders / Q000097:blood / Q000188:drug therapy; D008875:Middle Aged; D012016:Reference Values; D013223:Statistics as Topic; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D001786:Blood Glucose