Wulffelé 2002.
| Methods |
Parallel randomised controlled clinical trial Randomisation ratio: 1:1 Superiority design |
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| Participants |
Inclusion criteria: people with type 2 diabetes on insulin therapy Exclusion criteria: significant surgery within 3 months before entry into the study, major organ or system disease, medication use affecting glucose metabolism or sulphonylurea activity Diagnostic criteria: not stated |
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| Interventions |
Number of study centres: 3 Treatment before study: intervention: 71 (33) insulin, placebo: insulin 70 (33) U/day. Insulin regimen: 4 times daily intermediate plus short‐acting insulin or twice daily mix‐insulin Titration period: 12 weeks (optimisation of insulin therapy, cessation of metformin, cessation of antihypertensive and lipid‐lowering medication) |
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| Outcomes | Primary outcome(s) (as stated in the publication): glucose, HbA1c, lipids, insulin dose, blood pressure, weight, BMI, waist‐hip‐ratio | |
| Study details |
Total study duration: 16 weeks Run‐in period: 12 weeks Study terminated early (for benefit/because of adverse events): no (results of the interim analysis) |
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| Publication details |
Language of publication: English Funding source: Byk, Lifescan, Merck Lipha, MSD, Novo Nordsik Publication status: peer‐reviewed journal |
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| Stated aim of study | Quote from publication: "To investigate the metabolic effects of metformin, as compared with placebo, in type 2 diabetes patients intensively treated with insulin." | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote from publication: "...all subject were randomly assigned..." |
| Allocation concealment (selection bias) | Unclear risk | Comment: not possible to judge whether the allocation to the intervention and control group was concealed |
| Blinding of participants and personnel (performance bias) Adverse events | Low risk |
Quote from publication: "...all subjects were randomly assigned in a double‐blind fashion..." Comment: probably the participants and the personnel were blinded |
| Blinding of participants and personnel (performance bias) HbA1c, FPG, lipids | Low risk |
Quote from publication: "...all subjects were randomly assigned in a double‐blind fashion..." Comment: probably the participants and the personnel were blinded |
| Blinding of participants and personnel (performance bias) Insulin dose | Low risk |
Quote from publication: "...all subjects were randomly assigned in a double‐blind fashion..." Comment: probably the participants and the personnel were blinded |
| Blinding of outcome assessment (detection bias) Adverse events | Unclear risk | Comment: unclear if the outcome assessor was blinded |
| Blinding of outcome assessment (detection bias) HbA1c, FPG, lipids | Unclear risk | Comment: unclear if the outcome assessor was blinded |
| Blinding of outcome assessment (detection bias) Insulin dose | Unclear risk | Comment: unclear if the outcome assessor was blinded |
| Incomplete outcome data (attrition bias) Adverse events | Low risk | Comment: data on adverse events were collected and reported |
| Incomplete outcome data (attrition bias) HbA1c, FPG, lipids | Low risk | Comment: outcome data were collected and reported |
| Incomplete outcome data (attrition bias) Insulin dose | Low risk | Comment: data on insulin dose were collected and reported |
| Selective reporting (reporting bias) | Low risk | Comment: all outcomes of interest were reported |
| Other bias | Unclear risk | Comment: funded by a pharmaceutical company |