A Cochrane review included 12 studies with a total of 2 230 adults and children. Under intensive glucose control, the risk of developing microvascular complications was reduced compared to conventional treatment for retinopathy, nephropathy, and neuropathy . Regarding the progression of these complications after manifestation, the effect was weaker (retinopathy) or possibly not existent (nephropathy) . Major macrovascular outcomes (stroke and myocardial infarction) occurred very rarely. intensive glucose control increased the risk for severe hypoglycaemia, however the results were heterogeneous and only the 'Diabetes Complications Clinical Trial' (DCCT) showed a clear increase in severe hypoglycaemic episodes under intensive treatment. A subgroup analysis according to the baseline haemoglobin A1c (HbA1c) of participants in the trials (low quality evidence) suggests that the risk of hypoglycaemia is possibly only increased for patients who started with relatively low HbA1c values (< 9.0%). Several of the included studies also showed a greater weight gain under intensive glucose control, and the risk of ketoacidosis was only increased in studies using insulin pumps in the intensive treatment group (very low quality evidence).
| Outcomes | Relative effect (95% CI) | Assumed risk - Control | Corresponding risk - Intensive treatment (95% CI) | No of participants (studies) Quality of evidence |
|---|---|---|---|---|
| Manifestation of retinopathy Follow-up: 5 - 6.5 years | RR 0.27 (0.18 to 0.42) | 232 per 1000 | 63 per 1000 (42 to 97) | 768 (2) High |
| Manifestation of nephropathy Follow-up: 3.5 - 6.5 years | RR 0.56 (0.46 to 0.68) | 284 per 1000 | 159 per 1000 (131 to 193) | 1475 (3) Moderate |
| Manifestation of neuropathy Follow-up: 5 - 6.5 years | RR 0.35 (0.23 to 0.53) | 139 per 1000 | 49 per 1000 (32 to 74) | 1203 (3) High |
| Progression of retinopathy Follow-up: 5 - 6.5 years | RR 0.61 (0.49 to 0.76) | 387 per 1000 | 236 per 1000 (190 to 294) | 764 (2) Moderate |
| Progression of nephropathy Follow-up: 5 - 6.5 years | RR 0.79 (0.37 t0 1.70) | 14 per 1000 | 11 per 1000 (5 to 24) | 179 (3) Very low |
A topic in Clinical Evidence summarizes the results of one systematic review including 16 RCTs. Compared to conventional control, intensive glycaemic control reduced progression of nephropathy in people with type 1 diabetes and either normal albumin excretion of microalbuminuria (7 RCTs, 266 people, OR 0.34, 95% CI 0.20 to 0.58). Severe hypoglycaemia increased by 9.1 episodes/100 person years, 95% CI -1.4 to 19.6.