Diet quality and therapeutic targets in patients with type 2 diabetes: evaluation of concordance between dietary indexes

BACKGROUND: This study aimed to evaluate the concordance between two dietary indexes, the Healthy Eating Index (HEI) and the Diabetes Healthy Eating Index (DHEI), in evaluating diet quality and its possible association with therapeutic targets in patients with type 2 diabetes. METHODS: Cross-sectional study of outpatients with type 2 diabetes mellitus treated at a university hospital. Dietary information was obtained from a quantitative food frequency questionnaire (previously validated for use in patients with type 2 diabetes) and converted into daily intakes. Diet quality was assessed using two dietary indexes: HEI (12 components, nine food groups and three moderation components) and DHEI (10 components, six food groups, three nutrient groups, and one for variety of diet). In both indexes, the sum of the scores for each component yields an overall score converted on a scale from 0 to 100%; diet quality is subsequently ranked as low (<51%), needing improvement (51–80%), or high (>80%). Patients underwent clinical and laboratory assessment. Those with fasting blood glucose values 70–130 mg/dL, A1c < 7%, total cholesterol <200 mg/dL, LDL-cholesterol <100 mg/dL, and triglycerides <150 mg/dL were considered to meet therapeutic targets. All analyses were conducted in PASW Statistics 18.0, and p < 0.05 deemed significant. RESULTS: We analyzed 148 patients with type 2 diabetes (73% white, mean age 63.2 ± 9.4 years, median diabetes duration 10 [IQR 5–19] years, mean A1c% 8.4 ± 2.0%, and mean BMI 30.5 ± 4.2 kg/m(2)). Mean energy intake was 2114 ± 649 kcal/day. DHEI scores were 17.0 (95%CI -6.8 to 41.0) points lower than HEI scores (55.9 ± 14.2% vs. 72.9 ± 10.7%, respectively; P < 0.001), suggesting there is no agreement (Bland-Altman method), and the Pearson correlation coefficient was 0.55 (P < 0.001). More patients were classified as having a low-quality diet by the DHEI than by the HEI (38.5% vs. 1.4%; P < 0.001). A higher proportion of patients (35.7%) with out-of-target total cholesterol levels had a low-quality diet evaluated by the DHEI (P = 0.03). We did not find associations between overall score of HEI and therapeutic targets. CONCLUSIONS: In its intended population of patients with type 2 diabetes, the DHEI seems to be a more rigorous tool to evaluate association between diet quality and changes in metabolic parameters. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12937-017-0296-8) contains supplementary material, which is available to authorized users.