Objectives: 

Five years after the first Portuguese nationwide study on the prevalence of diabetes (PREVADIAB) showed that 11,7% of the cohort population had diabetes while nearly 25% already showed prediabetes, we aimed to evaluate the evolution of glycemic control and the validity of questionnaire-based risk assessment on a follow-up study.

Materials: 

Individuals without diabetes on the first PREVADIAB, aged 23-83 years, were recalled, being representative of the overall distribution observed on the first study (n=187). An OGTT was performed to evaluate glycemic control. WHO criteria were used for diagnosis. The Finnish Diabetes Risk Score (FINDRISC) was applied on the original study and on follow-up.

Results: 

Initial IFG+IGT showed the most precarious condition, with 60% of individuals now diagnosed with diabetes. IGT or IFG showed equivalent results, with respectively 17,1 and 15% progressing to diabetes. Of individuals originally assessed as having normal glycemic control, only 4,9% progressed to diabetes. The prevalence of diabetes on follow-up was 11,2%; while IFG was 5,3%, IGT 17,1%, and IFG+IGT 6,4%, to a cumulative impact of prediabetes of 28,8%. In terms of matching the initial risk assessment to developed diabetes, while no individual initially characterized with the lower risk score progressed to diabetes or IFG+IGT, 40% of individuals initially characterized with the higher risk score progressed to either diabetes (20%) or IFG+IGT (20%) on these 5 years. On the other hand, risk score was not related to dysglycemia diagnosis, at either baseline or follow-up evaluation.

Conclusions: 

IFG+IGT were shown as a high risk population targeted for intensive intervention, due to an expectancy of quick progression to diabetes. Also, although it did not show to be applicable to diagnosis, the FINDRISC seems to be an adequate tool to evaluate risk of diabetes development on the non-diabetic Portuguese general population.

Supported by DGS - Portuguese Ministry of Health.