Associations of Moderate Low-Carbohydrate Diets With Mortality Among Patients With Type 2 Diabetes: A Prospective Cohort Study

Abstract

Context: A statement of context for the abstract was added in Objective as follows: Lower-carbohydrate-diet (LCD) has been reported to have beneficial effects on cardiovascular risk factor profile in general population. However, whether adherence to an LCD could benefit long-term survival among individuals with diabetes is unclear.

Objective: This work aimed to investigate the associations of different types of lower-carbohydrate diets with mortality among individuals with type 2 diabetes (T2D).

Methods: This prospective study included 5677 patients with T2D. The overall, unhealthy, and healthy lower-carbohydrate-diet (LCD) scores were calculated based on the percentage of energy from total and subtypes of carbohydrate, protein, and fat. Deaths were determined via linkage to the National Death Index records until December 31, 2015. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% CIs of mortality.

Results: During a median of 6.3 years of follow-up (39 401 person-years), 1432 deaths were documented. After multivariable adjustment including lifestyle factors, diabetes duration, and glycated hemoglobin A1c, patients in the third quartile of overall LCD score had the lowest risk of mortality (HR: 0.65; 95% CI, 0.50-0.85), compared with the first quartile. The multivariable-adjusted HRs (95% CIs) of mortality across quartiles of healthy lower-carbohydrate-diet score were 1.00 (reference), 0.78 (0.64-0.96), 0.73 (0.58-0.91), and 0.74 (0.58-0.95) (Ptrend = .01). Isocalorically replacing 2% of energy from carbohydrates with plant-based protein or polyunsaturated fatty acids was associated with 23% to approximately 37% lower total mortality. Similar results were observed when analyses were stratified by age, sex, race/ethnicity, smoking status, body mass index, physical activity, and diabetes duration.

Conclusion: Healthy LCD score was significantly associated with a lower risk of mortality in adults with T2D. Adherence to a well-balanced moderate lower-carbohydrate diet that emphasizes healthy carbohydrates, plant-based protein, and polyunsaturated fat may prevent premature death among patients with T2D.

Keywords: lower-carbohydrate-diet; mortality; prospective study; type 2 diabetes.