The Effect of a Digital Behavioral Weight Loss Intervention on Adherence to the Dietary Approaches to Stop Hypertension (DASH) Dietary Pattern in Medically Vulnerable Primary Care Patients: Results from a Randomized Controlled Trial

Abstract

BackgroundObesity treatment focuses primarily on reducing overall caloric intake with limited focus on improving diet quality. The Dietary Approaches to Stop Hypertension (DASH) dietary pattern is effective in managing hypertension and other chronic conditions, yet it is not clear whether behavioral weight control interventions improve DASH adherence. We conducted a post hoc analysis of a behavioral weight loss intervention that did not emphasize diet quality and examined whether the intervention impacted DASH adherence in medically vulnerable community health center patients. MethodsParticipants (n=306) were enrolled in Track, a randomized controlled weight loss intervention for patients with elevated cardiovascular risk. The trial compared usual care to an intervention with weekly self-monitoring, tailored feedback on diet and exercise goals, and dietitian and provider counseling in community health centers. Dietary intake was measured using the Block Food Frequency Questionnaires collected at baseline and 12 months. DASH adherence was determined using previously validated scoring indices that assessed adherence based on recommended nutrient or food group targets. Total scores for both indices ranged from 0 to 9, with higher scores indicating greater DASH adherence. ResultsThe mean (and standard deviation [SD]) age of participants was 51.1 (SD=8.8) years and the mean body mass index was 35.9 (SD=3.9). Most were female (69%) and black (51%); 13% were Hispanic. Half (51%) had an annual income <$25,000 and 33% had both diabetes and hypertension. At baseline, the mean DASH nutrient score was 1.81 (SD=1.42) with 6% achieving at least a score of 4.5. Similar scores were seen for the DASH foods index. The intervention group saw significantly greater, albeit small, improvements in mean DASH nutrient score (intervention: 1.28 [SD=1.5] vs control: 0.20 [SD=1.3]; P<0.001), and there was no difference in DASH food score between study arms. There were no significant predictors of change in DASH score and no association between DASH adherence and changes in blood pressure. Within the intervention arm, improvements in DASH nutrient score were associated with greater weight loss (r=−0.28; P=0.003). ConclusionAlthough the intervention was not designed to increase adoption of DASH, the Track intervention produced significant weight loss and small improvements in DASH adherence. Despite these small improvements, overall adoption of DASH was poor among the medically vulnerable patients enrolled in Track. To further reduce chronic disease burden, weight loss interventions should include a focus on both caloric restriction and increasing diet quality.