Concurrent validity between field tests and cardiopulmonary exercise testing in patients with idiopathic pulmonary fibrosis

Abstract

ABSTRACT Background Maximal treadmill cardiopulmonary exercise testing is the gold standard for assessing functional capacity in patients with idiopathic pulmonary fibrosis (IPF). Purpose Primarily to investigate the concurrent validity between three field tests and cardiopulmonary exercise testing in these patients. Methods Patients performed the cardiopulmonary exercise testing, a six-minute walk test, an incremental shuttle walk test, and, the Glittre–ADL test. For cardiopulmonary exercise testing, the ten seconds with the higher average of the peak oxygen uptake obtained within the last 30 seconds were considered; for six-minute walk test and incremental shuttle walk test, the longer distance; and for the Glittre-ADL test, the shorter time spent. Concurrent validity was assessed using different regression models based on the best adjustment of the data. Results Twenty-two patients with IPF were assessed, aged: 68 ± 8.1 years, 13 male. Patients presented a peak oxygen uptake of 16.5 ± 3.6 mL.kg−1.min1, achieving a distance of 512.6 ± 102.8 meters in the six-minute walk test and 415.7 ± 125.1 meters in incremental shuttle walk test. The walking distance in the six-minute walk test and the incremental shuttle walk test explained, respectively, 64% and 56% peak oxygen uptake variance observed in the cardiopulmonary exercise testing (R2 = 0.64,p < .001; R2 = 0.56,p < .001). The time spent in the Glittre-ADL test was 233.4 ± 88.7 seconds and explained 47% of the peak oxygen uptake variance observed in cardiopulmonary exercise testing (R2 = 0.47,p = .001). Conclusion The six-minute walk test, incremental shuttle walk test, and Glittre-ADL test were considered valid tests to explain the peak oxygen uptake variance obtained by the cardiopulmonary exercise testing in patients with IPF.