Verrillo 1988.
| Methods |
Parallel randomised controlled clinical trial Randomisation ratio: 1.1 Superiority design |
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| Participants |
Inclusion criteria: age: 18‐50 years; diabetes for 15‐30 years, supine systolic blood pressure under 150 mm Hg and a supine diastolic blood pressure under 95 mm Hg, no evidence of ischaemic heart disease according to Minnesota code, urinary protein excretion below 0.5 g/day; background retinopathy Exclusion criteria: ‐ Diagnostic criteria: no residual endogenous insulin secretory capacity defined as a plasma C‐peptide concentration below 0.1 pmol per mL in the postabsorptive state, and 6 min after the intravenous injection of 1 mg glucagon |
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| Interventions |
Number of study centres: ‐ Treatment before study: subcutaneous injections of intermediate‐acting insulin preparations, often mixed with short acting insulin, not more than twice daily |
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| Outcomes | Outcomes reported in abstract of publication: plasma glucose profile, glycosylated haemoglobin, retinal morphology, retinopathy | |
| Study details |
Run‐in period: ‐ Study terminated before regular end: no |
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| Publication details |
Language of publication: English Funding: ‐ Publication status: peer‐reviewed journal/full article |
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| Stated aim of study | Quote from publication: "…to evaluate (a) the degree of glycaemic control which can be achieved and maintained in patients with IDDM by using a more intensive insulin regimen employing long‐acting insulin as basal cover and soluble insulin at mealtimes, and (b) what is the effect of this treatment on the rate of deterioration of already established retinopathy” | |
| Notes | IDDM: insulin dependent diabetes mellitus | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote from publication: "Originally, the patients were identified in a screening for retinopathy by ophthalmoscopy through dilated pupils in our outpatient clinic. Of the 54 consecutive insulin‐treated diabetic patients with background retinopathy, 44 agreed to take part in the study. They were randomly allocated to one of the treatment regimens – UCT or ICT. Block randomizations was performed to ensure comparable groups". Comment: sequence generation not described |
| Allocation concealment (selection bias) | Unclear risk | Comment: not described |
| Blinding of participants and personnel (performance bias) Objective Outcomes | Low risk | Quote from publication: "The UCT patients attended to the routine diabetic clinic; ICT patients were seen in the outpatient clinic every four weeks for the first year and then every eight weeks" Comment: not blinded, , but risk of bias considered low for objective outcomes |
| Blinding of participants and personnel (performance bias) Subjective Outcomes | High risk | Comment: not blinded |
| Blinding of outcome assessment (detection bias) Objective Outcomes | Low risk | Quote from publication: "Colour photographs and angiograms were evaluated blindly by a senior ophthalmologist, the identity of the patient and number of examination being masked" Comment: outcomes assessment blinded |
| Blinding of outcome assessment (detection bias) Subjective Outcomes | Unclear risk | Comment: not described |
| Incomplete outcome data (attrition bias) All outcomes | High risk | Quote from publication: "Subsequent to randomizations…., six patients were lost to follow‐up" Comment: drop‐outs not considered in analysis |
| Selective reporting (reporting bias) | Unclear risk | Comment: incomplete reporting on some outcomes (e.g. mild hypoglycaemia) |
| Other bias | Unclear risk | Comment: no other risks of bias found, but reporting insufficient to make judgement |