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

Baptista 2006.

Study characteristics
Methods Randomisation: randomised, computer‐generated
Blinding: double‐blind
Duration: 14 weeks
Country: Venezuela
Participants Diagnosis: schizophrenia or schizoaffective disorder (criteria unavailable)
N = 40
Age: 47.65 years
Sex: male and female
Setting: inpatients
History: participants had severe schizophrenia or related disorder who had been stabilised for > 5 years with conventional antipsychotic drugs.
Excluded: chronic disease and hormone replacement therapy, abnormal physical and lab exam results
Interventions

  1. Metformin (850‐1750 mg/d) in combination with olanzapine (10 mg/d); N = 20

  2. Placebo in combination with olanzapine (10 mg/d); N = 20


Standard care included maintaining a balanced diet (of 2500‐3000 kcal/d)
Outcomes Able to use:

  1. Primary outcomes

    1. Weight measures

      1. Body weight

      2. BMI

      3. Waist circumference

  2. Secondary outcomes

    1. Mental state

      1. BPRS

    2. Physiological: laboratory outcomes

      1. Glucose (basal, post‐load)

      2. Insulin (basal)

      3. HOMA‐IR

      4. TGS

      5. Total cholesterol

      6. LDL cholesterol

      7. HDL cholesterol

      8. VLDL cholesterol
Notes A balanced diet, 2500 to 3000 KCal/d was provided
92.5% study completers
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Quote: "...the computer‐based random allocation of patients to either the Olanzapine (10mg daily at bedtime) plus Metformin group (850 to 1750 mg daily, N =20) or the Olanzapine plus placebo group ..." Pg 193
Allocation concealment (selection bias) Low risk Quote: "...the computer‐based random allocation of patients to either the Olanzapine (10mg daily at bedtime) plus Metformin group (850 to 1750 mg daily, N =20) or the Olanzapine plus placebo group ..." Pg 193
Comment: as a computer‐generated program is used for treatment assignment, likely low risk of selection bias
Blinding of participants and personnel (performance bias)
All outcomes Unclear risk Blinding methods (e.g. use of identical placebo pills) not mentioned
Blinding of outcome assessment (detection bias)
All outcomes Unclear risk Not enough information provided to assess the risk of detection bias.
Incomplete outcome data (attrition bias)
All outcomes Low risk Quote: "Two patients taking placebo and one taking Metformin dropped out of the study owing to change in residence" Pg 193
Comment: valid dropout reasons. No other dropouts
Selective reporting (reporting bias) Low risk Have reported on all outcomes mentioned in the 'Methods' section.
Other bias Low risk No obvious bias