Use of the Healthy Eating Index in Intervention Studies for Cardiometabolic Risk Conditions: A Systematic Review

Researchers and counselors need diet-assessment tools that characterize diet at baseline and over time in diet counseling and coaching interventions. Among possible tools, the Healthy Eating Index (HEI) is of interest in cardiometabolic treatment as it has undergone significant validation and development. The objective of this study was to systematically review relevant intervention studies using the HEI and its adaptations to examine whether diet interventions improve diet quality as measured by the HEI and the magnitude of change in included diet-quality scores following dietary intervention. Two databases [Cumulative Index to Nursing and Allied Health Literature (CINAHL) and PubMed] were searched for articles published from January 1995 to December 2019. The review included intervention studies in adults presenting with overweight/obesity and obesity-related chronic disease (metabolic syndrome, diabetes, prediabetes, hypertension, dyslipidemia) who received education or counseling, and the HEI was evaluated from baseline to follow-up (US or Canadian version) or Alternate HEI. Study quality was assessed using Cochrane risk of bias for randomized controlled trials (RCTs) or Cochrane Risk of Bias for Nonrandomized interventions (ROBINS-I). A total of 25 studies were included: 15 RCTs, 3 quasi-experimental studies, and 7 pre-post studies. Eight different versions of the HEI were used. Results demonstrated that diet quality assessed by HEI and its adaptations improved to a clinically relevant degree, especially in studies where multiple food behaviors/food-behavior goals were the focus and where an intensive, long-term intervention was compared with a no-treatment control group. There was wide variation in magnitude of change in included diet-quality indicators. Use of the HEI and its adaptations and other diet-quality tools is promising for better characterization of diet-counseling interventions and results when multiple food behaviors are a focus. Additional development is encouraged.