Prospective population-based observational study to estimate the incidence of T2DM in a metropolitan population in the north of Madrid (Spain) and to determine the effect of baseline glycaemic status through an explanatory Cox model. SPRINDIAP-1 study (Secondary PRevention of INcident DIAbetes in patients with Prediabetes)

BackgroundT2DM (Type 2 Diabetes mellitus) is preceded by basal glycaemic states (BGS) such as normoglycaemia (NG) or pre-T2DM, including impaired fasting glucose (IFG); impaired glucose tolerance (IGT) or both (IFG-IGT). A better understanding of the role of pre-T2DM in the progression to T2DM may help in the prevention of T2DM in patients with pre-T2DM. MethodsPopulation-based cohort study to estimate the incidence of T2DM according to BGS and to study the adjusted effect of BGS on progression to T2DM using a Cox model (main model (MM) with reference category NG and sensitivity analysis (SA) in patients with pre-T2DM and reference IFG). Results1,209 patients aged 45-74 years (median follow-up=7.26 years). The crude T2DM incidence rate for the whole population was 11.21 per 1000 person-years (95%CI=9.09-13.68), 5.60 (95%CI=3.55-8.41) in patients with NG and 16.28 (95%CI=12.78-20.43) in patients with preT2DM. In both models, the significant variables showing risk of progression to T2DM were IGT BGS (MM: Hazard ratio HR=4.30; 95%CI=1.96-9.44; AS: HR=2.66, 95%CI=1.28-5.56) and IFG-IGT (MM: HR=3.71, 95%CI=1.97-6.99; AS: HR=2.45, 95%CI=1.41-4.23), and obesity (MM: HR=2.36, 95%CI=1.15-4.83; AS: HR=2.97, 95%CI=1.18-7.45). Being on diuretic treatment was a protective factor (MM: HR=0.47 CI95%=0.23-0.96; SA: HR=0.41, CI95%=0.19-0.92), as was, in SA only, self-perceived health status in the categories of: Very good (HR: 0.19, CI95%=0.06-0.67); Good (HR: 0.35, CI95%=0.13-0.96) and Fair (HR: 0.31, CI95%=0.11-0.93). ConclusionsOur T2DM incidence rates are in line with other Spanish studies. In people with NG or preT2DM, EBG (IGT and IFG-IGT) and obesity increase the risk of progression to T2DM and being on diuretics is a protective factor as is fair to very good self-perceived health in patients with preT2DM.