Usefulness of the Duke Activity Status Index to Assess Exercise Capacity and Predict Risk Stratification in Patients with Pulmonary Arterial Hypertension

Exercise capacity is an important component of risk assessment for pulmonary arterial hypertension (PAH). We investigated the association of the Duke Activity Status Index (DASI) with peak oxygen consumption (peakVO(2)) and explored whether the DASI can discriminate the high-risk individuals in patients with PAH, according to peakVO(2) < 11 mL/min/kg. A total of 89 patients were evaluated using cardiopulmonary exercise testing (CPET) and DASI. The correlation between the DASI and peakVO(2) was measured by univariate analysis, and a receiver operating characteristic (ROC) curve analysis was conducted. The DASI was correlated with peakVO(2) in the univariate analysis. The ROC curve analysis revealed that the DASI had a discriminative value for identifying the individuals with a high risk in PAH patients (p < 0.001), with an area under ROC curve (AUC) of 0.79 (95% CI: 0.67-0.92). Similar results were observed in patients with PAH associated with congenital heart disease (CHD-PAH), (p = 0.001), with an AUC of 0.80 (95% CI: 0.658-0.947). Therefore, DASI reflects exercise capacity in patients with PAH and has good ability to discriminate patients with a low risk and a high risk, and it may be included in the risk assessment of PAH.