Oldroyd 2005.
| Methods | Parallel, randomised, controlled, clinical trial, randomisation ratio 1:1 | |
| Participants |
Inclusion criteria: IGT (2‐h plasma glucose after an OGTT 140‐200 mg/dL (7.8‐11.0 mmol/L)) (WHO 1985); 24‐75 years; European origin Exclusion criteria: pregnant individuals, on therapeutic diets or whose medical condition prevented them from undertaking moderate physical activity Diagnostic criteria: IGT (2‐h plasma glucose after an OGTT 140‐200 mg/dL (7.8‐11.0 mmol/L)) (WHO 1985) |
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| Interventions |
Number of study centres: 1 Treatment before study: none Titration period: none |
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| Outcomes | Composite outcome measures reported: no | |
| Study details | Trial terminated early: no | |
| Publication details |
Language of publication: English Funding: non‐commercial funding (British Heart Foundation, Northern & Yorkshire NHS Research and Development and the Royal College of General Practitioners) Publication status: peer‐reviewed journal |
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| Stated aim of study | Quote from publication: "To evaluate the effectiveness of lifestyle interventions in people with impaired glucose tolerance (IGT)." | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk |
Quote from publication: "...using a random number table to the intervention or control group at the first appointment." Comment: adequate generation of random sequence ensured |
| Allocation concealment (selection bias) | Low risk |
Quote from publication: "Researchers performing the randomisation were blinded to the group allocation." "There were fewer women (10/32 (32%)) than men (22/32 (69%)) in the control group compared with the intervention group..." Comment: adequate allocation concealment ensured |
| Blinding of participants and personnel (performance bias) all‐cause mortality/cardiovascular mortality | Low risk | Comment: investigator‐assessed outcome measure. No blinding of participants described. The outcome was not likely to be influenced by lack of blinding |
| Blinding of participants and personnel (performance bias) incidence of T2DM | Low risk | Comment: investigator‐assessed outcome measure. No blinding of participants. The outcome was not likely to be influenced by lack of blinding |
| Blinding of participants and personnel (performance bias) measures of blood glucose control | Low risk | Comment: investigator‐assessed outcome measure. No blinding of participants described. The outcome was not likely to be influenced by lack of blinding |
| Blinding of outcome assessment (detection bias) all‐cause/cardiovascular mortality | Low risk | Comment: investigator‐assessed outcome measure. No blinding described. The outcome was not likely to be influenced by lack of blinding |
| Blinding of outcome assessment (detection bias) incidence of T2DM | Low risk | Comment: investigator‐assessed outcome measure. No blinding described. The outcome was not likely to be influenced by lack of blinding |
| Blinding of outcome assessment (detection bias) measures of blood glucose control | Low risk | Comment: investigator‐assessed outcome measure. No blinding described. The outcome was not likely to be influenced by lack of blinding |
| Incomplete outcome data (attrition bias) all‐cause/cardiovascular mortality | High risk |
Quote from publication: "Fourteen participants (five intervention, nine control) withdrew from the study over 24 months follow‐up. Reasons for withdrawing were family problems, work commitments or ill health." and "Nine participants (three intervention, six control) failed to attend assessments over 24 months follow‐up. In addition, one intervention participant died after a stroke between 12 and 24 months. Complete results are presented here for 69 participants after 6 months, 62 participants after 12 months and 54 participants after 24 months follow‐up (Fig. 1)." Comment: missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups. Detailed flow chart provided in publication. However, only 69% of the participants completed the study. This proportion of missing outcomes could have induced clinically relevant bias in intervention effect estimate |
| Incomplete outcome data (attrition bias) incidence of T2DM | High risk |
Quote from publication: "Fourteen participants (five intervention, nine control) withdrew from the study over 24 months follow‐up. Reasons for withdrawing were family problems, work commitments or ill health." and "Nine participants (three intervention, six control) failed to attend assessments over 24 months follow‐up. In addition, one intervention participant died after a stroke between 12 and 24 months. Complete results are presented here for 69 participants after 6 months, 62 participants after 12 months and 54 participants after 24 months follow‐up (Fig. 1)." Comment: missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups. Detailed flow chart provided in publication. However, only 69% of the participants completed the study. This proportion of missing outcomes could have induced clinically relevant bias in intervention effect estimate |
| Incomplete outcome data (attrition bias) measures of blood glucose control | High risk |
Quote from publication: "Fourteen participants (five intervention, nine control) withdrew from the study over 24 months follow‐up. Reasons for withdrawing were family problems, work commitments or ill health." and "Nine participants (three intervention, six control) failed to attend assessments over 24 months follow‐up. In addition, one intervention participant died after a stroke between 12 and 24 months. Complete results are presented here for 69 participants after 6 months, 62 participants after 12 months and 54 participants after 24 months follow‐up (Fig. 1)." Comment: missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups. Detailed flow chart provided in publication. However, only 69% of the participants completed the study. This proportion of missing outcomes could have induced clinically relevant bias in intervention effect estimate |
| Selective reporting (reporting bias) | Unclear risk | Comment: no study protocol available |
| Other bias | Low risk | Comment: no other sources of bias identified |