The effect of guideline revisions on vascular complications of type 2 diabetes

The aim of this study was to investigate the impact of implementation and revision of the 'Diabetes Mellitus type II' guideline by the Dutch College of General Practitioners (DCGP) on the prevalence and incidence of macrovascular and microvascular complications.

The DiaGene study is a case-control study (n = 1886 patients of type 2 diabetes) with extensive, retrospectively collected complication data, as well as prospective follow up of complications. The study incorporates all lines of diabetes care. Cases were divided into categories according to the date of onset of diabetes and publication dates of the DCGP. Logistic regression models were used to investigate the associations between guideline version and complications. To investigate a possible trend between guideline version and complications, the 'guideline category' was also used as a continuous variable. All models were adjusted for clinical covariables.

The 1999 and 2006 guidelines versions were associated with significantly lower risk of retinopathy than the group that started without a guideline [OR 0.32 (95% CI 0.14-0.72, p = 0.006) and 0.31 (95% CI 0.11-0.91, p = 0.034), respectively]. A significant trend in reduction of peripheral artery disease (PAD) over the guideline versions was found, adjusted for age, sex and diabetes duration (odds ratio (OR) 0.70, 95% CI 0.51-0.97, p trend = 0.029) and for retinopathy in all models (OR = 0.52, 95% CI 0.37-0.73, p trend < 0.001).

The introduction of the first diabetes guideline and subsequent revisions have reduced the risk of macrovascular and microvascular complications of type 2 diabetes, most strongly in diabetic retinopathy. This indicates that real-time diabetes care has improved over time.