RT Journal Article SR Electronic T1 Prediction of maximal oxygen uptake from 6-min walk test in pulmonary hypertension JF ERJ Open Research JO erjor FD European Respiratory Society SP 00664-2021 DO 10.1183/23120541.00664-2021 VO 8 IS 2 A1 Paula Appenzeller A1 Fiorenza Gautschi A1 Julian Müller A1 Mona Lichtblau A1 Stéphanie Saxer A1 Simon R. Schneider A1 Esther I. Schwarz A1 Silvia Ulrich YR 2022 UL http://openres.ersjournals.com/content/8/2/00664-2021.abstract AB Maximal oxygen uptake (V′O2max), assessed by cardiopulmonary exercise testing (CPET), is an important parameter for risk assessment in patients with pulmonary hypertension (PH). However, CPET may not be available for all PH patients. Thus, we aimed to test previously published predictive models of V′O2max from the 6-min walk distance (6MWD) for their accuracy and to create a new model.We tested four models (two by Ross et al. (2010), one by Miyamoto et al. (2000) and one by Zapico et al. (2019)). To derive a new model, data were split into a training and testing dataset (70:30) and step-wise linear regression was performed. To compare the different models, the standard error of the estimate (SEE) was calculated and the models graphically compared by Bland–Altman plots. Sensitivity and specificity for correct prediction into low-risk classification (V′O2max >15 mL/min/kg) was calculated for all models.A total of 276 observations were included in the analysis (194/82 training/testing dataset); 6MWD and V′O2max were significantly correlated (r=0.65, p<0.001). Linear regression showed significant correlation of 6MWD, weight and heart rate response (HRR) with V′O2max and the best fitting prediction equation was: V′O2max = 1.83 + 0.031 × 6MWD (m) – 0.023 × weight (kg) – 0.015 × HRR (bpm). SEEs for the different models were 3.03, 3.22, 4.36 and 3.08 mL/min/kg for the Ross et al., Miyamoto et al., Zapico et al. models and the new model, respectively. Predicted mean V′O2max was 16.5 mL/min/kg (versus observed 16.1 mL/min/kg).6MWD and V′O2max reveal good correlation in all models. However, the accuracy of all models is inadequate for clinical use. Thus, CPET and 6MWD both remain valuable risk assessment tools in the management of PH.Although maximal oxygen uptake and the 6-min walk distance show good correlation in pulmonary hypertension, all predictive models are of inadequate accuracy for clinical use and cardiopulmonary exercise testing remains an irreplaceable tool https://bit.ly/33HBQFk