Do psychiatric illnesses affect adherence to lifestyle recommendations in hypertensive veterans? Impact on diet and mediating effect of perceived stress

BACKGROUND: Primary care patients have a high prevalence of coexisting mental health conditions that may affect patients' abilities to follow lifestyle recommendations. We evaluated the ability of hypertensive veterans to adhere to appropriate diet and exercise guidelines.

METHODS: Diet was assessed by Willett Food Frequency Questionnaires and exercise by 7-day Physical Activity Recall. The Dietary Approaches to Stop Hypertension (DASH) Adherence Index (DAI; 0-100) was based on adherence to 10 components central to the DASH diet. Mental illness was determined from medical records. The 10-Item Perceived Stress Scale measured stress. Linear regression was used to determine if mental illness predicted poorer adherence to the DASH diet or exercise. Wilcoxon rank-sum tests compared differences between persons with and without psychiatric diagnoses.

RESULTS: We evaluated 175 hypertensive veterans (61 with major psychiatric illnesses such as depression, anxiety disorders, substance abuse, schizophrenia and PTSD). These psychiatric comorbidities were associated with poor adherence to the DASH diet (p<.03); but not with exercise. In particular, veterans with psychiatric comorbidities had lower Healthy Eating Index scores (p<.02), higher dietary sodium (p<.03) and higher saturated fat (p<.01). Once perceived stress was added to the Diet model, psychiatric comorbidities were no longer significant predictors of DASH adherence, which suggests that perceived stress is a mediating variable.

DISCUSSION: Patients with mental illnesses may be at greater risk for hypertensive complications due to poor adherence to DASH diet. By reducing perceived stress, we may help patients adhere to a heart-healthy diet.