Robinson 1998.
| Methods |
Two cross‐over randomised controlled clinical trials Randomisation ratio: 1:1 Superiority design |
|
| Participants |
Inclusion criteria: study I: DM2 patients with insulin monotherapy for at least 1 year after secondary failure of maximum dose oral antihyperglycaemic agents; study II: see study I plus taking metformin (100‐2550 mg/day as the sole oral antihyperglycaemic agent for at least 1 year Exclusion criteria: women of childbearing age, unable to give informed consent Diagnostic criteria: fasting plasma glucose > 7.8 mmol/L on 2 occasions |
|
| Interventions |
Number of study centres: 2 Treatment before study: study I: insulin 71 (47) U/day, study II : insulin 41 (16) U/day + metformin 1000‐2550 Titration period: 6 weeks |
|
| Outcomes | Primary outcome(s) (as stated in the publication): HbA1c, glucose, lipids, blood pressure, insulin dose, hypoglycaemia | |
| Study details |
Total study duration: 12 weeks (intervention period study I) Run‐in period: 6 weeks Study terminated early (for benefit/because of adverse events): no |
|
| Publication details |
Language of publication: English Funding source: Lipha Pharmaceuticals Publication status: peer‐reviewed journal |
|
| Stated aim of study | Quote from publication: "To test the hypothesis that metformin therapy, given as an adjunct to insulin therapy, improves metabolic control in insulin‐treated type 2 diabetes mellitus patients with sub optimal glycaemic control." | |
| Notes | 2 studies, only study I fulfilled our inclusion criteria | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk |
Quote from publication: "patients were randomised..." Comment: not possible to judge whether the sequence generation was adequate |
| 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: (from abstract) "Two randomised double‐blind placebo‐controlled crossover studies were run." Comment: probably the participants and the personnel were blinded |
| Blinding of participants and personnel (performance bias) HbA1c, FPG, lipids | Low risk |
Quote from publication: (from abstract) "Two randomised double‐blind placebo‐controlled crossover studies were run." Comment:probably the participants and the personnel were blinded |
| Blinding of participants and personnel (performance bias) Insulin dose | Low risk |
Quote from publication: (from abstract) "Two randomised double‐blind placebo‐controlled crossover studies were run." 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 weight gain 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 described |
| Other bias | Unclear risk | Comment: funded by a pharmaceutical company |