A new maximal bicycle test using a prediction algorithm developed from four large COPD studies

Abstract

Background: Maximum exercise workload (WMAX) is today assessed as the first part of Cardiopulmonary Exercise testing. The WMAX test exposes patients with COPD, often having cardiovascular comorbidity, to risks. Our research project was initiated with the final aim to eliminate the WMAX test and replace this test with a predicted value of WMAX, based on a prediction algorithm of WMAX derived from multicentre studies.Methods: Baseline data (WMAX, demography, lung function parameters) from 850 COPD patients from four multicentre studies were collected and standardized. A prediction algorithm was prepared using Random Forest modelling. Predicted values of WMAX were used in a new WMAX test, which used a linear increase in order to reach the predicted WMAX within 8 min. The new WMAX test was compared with the standard stepwise WMAX test in a pilot study including 15 patients with mild/moderate COPD.Results: The best prediction algorithm of WMAX included age, sex, height, weight, and six lung function parameters. FEV1 and DLCO were the most important predictors. The new WMAX test had a better correlation (R2 = 0.84) between predicted and measured WMAX than the standard WMAX test (R2 = 0.66), with slopes of 0.50 and 0.46, respectively. The results from the new WMAX test and the standard WMAX test correlated well.Conclusion: A prediction algorithm based on data from four large multicentre studies was used in a new WMAX test. The prediction algorithm provided reliable values of predicted WMAX. In comparison with the standard WMAX test, the new WMAX test provided similar overall results.

<p>Reduced Variability of Endurance Time in New Protocols for Exercise Tests in COPD</p>

“…International Journal of Chronic Obstructive Pulmonary Disease 2020:15 previously described. 16 At all visits, patients received a fast-acting bronchodilator, ie, all measurements and exercise tests are post-bronchodilator administration. Before all exercise tests, patients filled out the Clinical COPD Questionnaire (CCQ) and underwent a physical examination including vital signs, ECG and dynamic spirometry.…”

“…Borg dyspnoea score and Borg leg discomfort score 17 were reported every second minute, and measurements of ECG and blood pressure were performed before and after exercise. Both studies included measurements of W MAX from the standard maximum test (Study A) and/or the new maximum test (Study A 16 and Study B). The new maximum test included an initial phase of pedalling for 3 min at 40% (Study A) or 30% (Study B) of the predicted W MAX , followed by an instant increase to 75% (Study A) or 70% (Study B), followed by a stepwise (Study A) or linear (Study B) increase in workload until exhaustion.…”

“…Study A, consisted of a screening visit (visit 1), not including any exercise tests, followed by 4 visits with exercise testing (Figure 1; Study A). At visit 2, enrolled patients were randomized to either the standard W MAX test or the new W MAX test as previously reported, 16 in order to obtain the measured W MAX to be used as the basis for the starting values for each ET.…”

“…The existing protocols for a standard W MAX test may lead to either an underestimation or overestimation of maximum workload, leading to too long and short endurance time, respectively. In a previous study, 16 a prediction algorithm for calculation of W MAX in COPD patients was developed based on bicycle exercise ET results from large industry-sponsored clinical trials. The best algorithm included anthropometrics and six lung function parameters, of which forced expiratory volume in 1 second (FEV 1 ) and diffusion capacity for carbon monoxide (DLCO) were the best predictors.…”

A new protocol for exercise testing in COPD; improved prediction algorithm for WMAX and validation of the endurance test in a placebo-controlled double bronchodilator study

“…We embarked on a development programme with the objective to improve the protocol for the W MAX test and the standard CWRET. In the first of our studies 17 in patients with moderate to severe COPD, a protocol for a new, individualized, W MAX test was developed. This test will hereafter be denoted individualized cardiopulmonary exercise test (ICPET).…”