To determine whether the 6-minute walk test (6MWT) is a predictor of peak oxygen uptake (
O2) in patients with idiopathic pulmonary arterial hypertension (IPAH).
A total of 157 patients treated for IPAH completed a 6MWT in accordance with American Thoracic Society standards. Heart rate, pulse oximetry, and Borg rating of perceived exertion were determined at baseline and posttest. A cardiopulmonary exercise test (CPET) was performed on a cycle ergometer using a ramp protocol. Participants were stratified post hoc by age into 3 groups: children (n = 26), adolescents (n = 49), and adults (n = 82). Multiple linear regression analysis was performed to predict peak
O2 from the 6MWT.
The regression equation generated for the children was the only model to strongly predict peak
O2 (r = 0.87; P < .001). Similar models for adolescent (r = 0.59; P < .001) and adult groups (r = 0.68; P < .001) did not achieve the same level of correlation.
Six-Minute Walk Test was able to accurately predict peak
O2 in children (6-12 years) with IPAH; however, the model was weaker for predicting peak
O2 in older populations. These findings suggest that 6MWT may be as valid a test for predicting peak
O2 in children with IPAH as CPET measured peak
O2. In older IPAH populations, CPET is the only reliable method for the evaluation of peak