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. 2022 Oct 3;2022(10):CD013337. doi: 10.1002/14651858.CD013337.pub2

Wu 2008.

Study characteristics
Methods Randomisation: randomised, computer‐generated
Blinding: double‐blind
Duration: 12 weeks
Country: China
Participants Diagnosis: DSM‐IV schizophrenia
N = 40
Age: 18‐50 years; mean: 25.1 years
Sex: male and female
Setting: inpatients
History: first‐episode psychotic, no use of any antipsychotic or recreational drugs for at least 3 months before enrolment
Excluded: pregnant or lactating women, patients with mental retardation, addictive disorder, specific systemic disease, other medical condition e.g. diabetes mellitus, dyslipidaemia, cardiovascular disorder, hypertension
Interventions

  1. Metformin (750 mg/d; as 250 mg 3 times/d) in combination with olanzapine (15 mg/d); N = 18

  2. Placebo (3 times/d) in combination with olanzapine (15 mg/d); N = 18


Standard care included providing lifestyle counselling to patients.
Outcomes Able to use:

  1. Primary outcomes

    1. Weight measures

      1. Change in body weight

      2. Change in BMI

      3. Change in waist circumference

      4. Change in waist‐to‐hip ratio

      5. Proportion of participants who gained > 7% of their body weight at 3 months

    2. Physiological: laboratory measures

      1. Change in fasting glucose

      2. Change in insulin

      3. Change in HOMA‐IR

  2. Secondary outcomes

    1. Mental state

      1. SAPS

      2. SANS

      3. Adverse events (number of people who developed nausea)


Unable to use:

  1. Lactic acid (data not available)

  2. Liver (data not available)

  3. Renal function (data not available)

  4. Blood counts (data not available)

  5. ECG (data not available)
Notes Only completer data are provided, however study authors did an ITT analysis which was found to have similar results. 92.7% study completers.
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Quote: "Participants were randomly assigned through a computer generated table..." Pg 353.
Allocation concealment (selection bias) Low risk Quote: "To ensure concealment of the randomisation, which was conducted independently of the investigators by a research pharmacist at a separate facility, medication was provided in coded containers containing the identical appearing pills of metformin or placebo supplies by manufacturer." Pg 353.
Blinding of participants and personnel (performance bias)
All outcomes Low risk Identical appearing placebo pills were used and incidence of adverse effects were similar in both study groups.
Blinding of outcome assessment (detection bias)
All outcomes Unclear risk Information is unavailable.
Incomplete outcome data (attrition bias)
All outcomes Low risk >90% of the study population is analysed, with 92.5% study completers.
Selective reporting (reporting bias) Unclear risk Study protocol is unavailable.
Other bias Low risk No obvious bias.

BAS: Barnes Akathisia Scale; BMI: body mass index; BPRS: Brief Psychiatric Rating Scale; CCMD‐3: Chinese Classification of Mental Disorders; CGI: Clinical Global Impressions Scale; DSM‐IV: Diagnostic and Statistics Manual ‐ Fourth Edition; ECG: electrocardiogram; FBS: fasting blood sugar; HAM‐D: Hamilton Depression Scale; HDL: high‐density lipoprotein; HOMA‐IR: Homeostatic Model Assessment for Insulin Resistance; ITT: intention‐to‐treat; LDL: low‐density lipoprotein; PANSS: Postitive and Negative Symptom Scale; SANS: Scale for the Assessment of Negative Symptoms; SAPS: Scale for the Assessment of Positive Symptoms; SAS: Sedation‐Agitation Scale; SSRI: selective serotonin reuptake inhibitors; TGS: triglycerides; VLDL: very low‐density lipoprotein