Chronic obstructive pulmonary disease (COPD) patients have multiple comorbidities and high all cause mortality and cardiovascular(CV) risk. Previously, Dietary Approaches to Stop Hypertension (DASH) diet showed beneficial effects on CV disease. The Mediterranean diet is associated to lung function improvement. However, the joint effect of Mediterranean diet and DASH diet on reduction COPD mortality is unknown.

Materials and Method:
We reviewed the data derived from the National Health and Nutrition Examination Survey (NHANES) cohort between 2007 and 2012. Total 12,060 cases were analyzed. Among them, 1610 cases diagnosed as obstructive lung disease.Adherence to DASH diet by DASH score ( >2 or less than 2) and adherence to Mediterranean diet (aMED >3 or less than 3) were recorded.Joint effects of adherence to DASH diet and aMED on mortality including all cause and cardiovascular(CV) were calculated separately.

Of the 12,060 cases, 1,610 belong to COPD group. In COPD group, the mean DASH score and aMED was 2.44 and 3.34 respectively. For good adherence to Mediterranean diet ( aMED>3 vs. less than3 ),the adjusted hazard ratio(HR) for all cause and CV mortality reduced from 1.448 to 1.014 (p=0.0053) and 1.487 to 0.959 (p=0.16). When addition of DASH diet (score >2) to Mediterranean diet (aMED >3), the change of HR for all cause and CV mortality were 0.718 to 0.724 ( p=0.975 ) and 0.69 to 0.708 ( p=0.95 ) as compared Mediterranean diet alone.

In our study, we found Mediterranean diet really reduce all cause and cardiovascular mortality for COPD group. The joint effect of DASH and Mediterranean diet did not provide additional survival benefit.