Hypertriglyceridaemic-waist phenotype and risk of diabetes in people with impaired fasting glucose in primary care: a cohort study

Abstract

Aim: We aimed to determine the prospective association between baseline triglyceridaemic–waist phenotypes and diabetic mellitus incidence in individuals with impaired fasting glucose seen in primary care. Methods: A cohort of 1101 participants (84.4% of the recruited individuals) with impaired fasting glucose were recruited from three primary care clinics during regular follow-ups to monitor their chronic conditions. Baseline triglyceridaemic–waist phenotypes were divided into four groups: (1) normal waistline and triglyceride level (n = 252); (2) isolated central obesity (n = 518); (3) isolated high triglyceride level (n = 80); and (4) central obesity with high triglyceride level (i.e. hypertriglyceridaemic–waist phenotype) (n = 251). The presence of diabetes at follow-up was determined by fasting plasma glucose (≥ 7.0 mmol/l) and/or 2-h 75-g oral glucose tolerance test (≥ 11.1 mmol/l) and/or HbA1c (47.5 mmol/mol; ≥ 6.5%) according to American Diabetes Association diagnostic criteria. Multivariable Cox proportional hazards regressions were established to assess the impact of different triglyceridaemic–waist phenotypes on time to diabetes onset. Results: After a mean follow-up period of 6.5 months (sd 4.7 months), the number of diabetes cases was significantly higher in the group with hypertriglyceridaemic–waist phenotype (52.2%) compared with the other three phenotype groups (group 1: 28.2%; group 2: 34.6%; group 3: 30.0%). Only the hypertriglyceridaemic–waist phenotype showed an increased risk of developing diabetes (hazard ratio 1.581, 95% CI 1.172–2.134; P = 0.003) compared with the group with normal waistline and triglyceride level after controlling for confounders. Conclusion: The combination of central obesity and hypertriglyceridaemia is associated with > 50% risk of progression to diabetes within 6 months among individuals with impaired fasting glucose seen in primary care.