Effectiveness of dietetic intervention for people with type 2 diabetes: A meta-analysis

Background: Diet is central to treatment of type 2 diabetes. This review aimed to compare the effectiveness of nutrition therapy delivered by dietitians to nutrition advice delivered by other healthcare professionals in adults with type 2 diabetes on metabolic parameters.

Methods: Cochrane CENTRAL, CINAHL, EMBASE, MEDLINE and PsychINFO were searched for randomised controlled trials of three months duration or longer, published from 1st January 2008 to 18th June 2019. Relevant data were extracted from studies with additional author information. Random-effects meta-analysis assessed mean changes in HbA1c and other clinical parameters. PROSPERO registration number: CRD42019130528.

Results: Of 2477 records identified, fourteen studies, involving 3338 participants, were eligible for qualitative synthesis and meta-analysis. The mean changes [95% CI] at follow-up in HbA1c, BMI, weight, LDL cholesterol, systolic and diastolic blood pressure were -0·47 [-0·92, -0·02] %, -0·38 [-0·63, -0·13] kg/m², -1·49 [-2·14, -0·84] kg, -0·15 [-0·33, 0·04] mmol/L, -0·75 [-2·45, 0·96] mm Hg and -1·17 [-4·52, 2·17] mm Hg respectively in favour of the intervention group. The quality of evidence was limited due to heterogeneity, risk of bias, publication bias and indirectness.

Conclusions: Nutrition therapy provided by dietitians was associated with better clinical parameters of type 2 diabetes, including clinically significant improved glycaemic control, across diverse multiethnic patient groups from all six inhabited continents. This conclusion should be reflected in clinical guidelines.