The association between four dietary indices and mortality risk in cardiovascular disease patients

Background Four dietary patterns were linked to lower mortality rates in cardiovascular patients. This study investigated the relationship between these dietary patterns and mortality risk in U.S. cardiovascular patients from 2005–2006 to 2017–2018. Methods Data were collected from adults aged 19 years and older participating in the National Health and Nutrition Examination Survey (NHANES, N = 3475) from 2005–2006 to 2017–2018. Dietary patterns were assessed for each survey cycle using 24-hour dietary recalls, and scores for the four dietary indices were calculated.Survey-weighted multivariable Cox proportional hazards regression models were applied to evaluate the associations between the four dietary indices and overall mortality risk, as well as cause-specific mortality in cardiovascular disease patients. Results Among 3475 cardiovascular patients, the weighted mean age was 65.03 years (SE = 0.35). In partially adjusted models, the Planetary Healthy Diet Index-United States (HR = 0.986, 95% CI: 0.981–0.991, P  < 0.001), Healthy Eating Index (HR = 0.992, 95% CI: 0.987–0.997, P  = 0.003), and Mediterranean Diet Score (HR = 0.879, 95% CI: 0.806–0.959, P  = 0.004) were associated with a reduced risk of death. Conversely, the Dietary Inflammation Index was linked to an increased risk of death (HR = 1.140, 95% CI: 1.081–1.203, P  < 0.001). In fully adjusted models, the Planetary Healthy Diet Index-United States (HR = 0.992, 95% CI: 0.986–0.998, P  = 0.007) and Dietary Inflammation Index (HR = 1.093, 95% CI: 1.036–1.152, P  = 0.001) remained significantly associated with mortality risk. Conclusions Results indicated that in cardiovascular patients, higher Healthy Eating Index, Mediterranean Diet Score, and Planetary Healthy Diet Index-United States (PHDI-US) were associated with reduced mortality, whereas a higher Dietary Inflammation Index (DII) was linked to increased mortality. The Dietary Inflammation Index (DII) score was strongly associated with mortality risk in patients with coronary heart disease or stroke, while the Planetary Healthy Eating Index (PHDI-US) score was closely associated with mortality risk in patients with congestive heart failure, coronary heart disease, and angina pectoris.