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

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

Reduced variability of endurance time in new protocols for exercise tests in COPD

Purpose: For exercise testing of COPD patients, a standard endurance test (ET) with constant workload is recommended. The test suffers from large inter-individual variability and need for large sample sizes in order to evaluate treatment effects. Methods: A new protocol for ET in COPD was designed. In contrast to the standard ET, the new ET involved an increasing workload in order to reduce the standard deviation of endurance time. Two new ETs were compared with the standard ET. In Study A, the new ET started at 75% of the patient’s maximum workload (WMAX) and increased stepwise with 3%/2 min until exhaustion. Study B started at 70% of WMAX and increased linearly with 1%/ min. Results: In Study A, that included 15 patients, the standard deviation and range for endurance time and work capacity were narrower for the new versus the standard ET. However, the higher mean workload at end and the low mean work capacity relative to the standard ET indicated that the stepwise increase was too aggressive. In Study B, that included 18 patients, with a modified protocol, the averages for endurance time, workload at end and work capacity were similar for new and standard ET, while the standard deviations and ranges for endurance time and work capacity were kept more narrow in the new ET. The variances for endurance time were not equal between the standard ET and the two new ETs (p<0.05 for both according to Levene’s test). Conclusion: The new ET reduced the number of patients with extreme endurance times (short and long) compared to the standard test. The new test showed a significant lower variance for endurance time, which potentially can lead to fewer patients needed in com-parative studies. The overall best results were observed with a low linear increase during endurance

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

Two new protocols have been developed for bicycle exercise testing in chronic obstructive pulmonary disease (COPD) with an individualized cardiopulmonary exercise test (ICPET) and subsequent customized endurance test (CET), which generate less interindividual spread in endurance time compared with the standard endurance test. Main objectives of this study were to improve the prediction algorithm for WMAX for the ICPET and validate the CET by examining treatment effects on exercise performance of indacaterol/glycopyrronium (IND/GLY) compared with placebo. Methods: COPD patients, with forced expiratory volume in 1 s (FEV1) 40–80% predicted, were recruited. Pooled baseline data from two previous studies (n = 38) were used for the development of an improved WMAX prediction algorithm. Additional COPD patients (n = 14) were recruited and performed the ICPET, using the new prediction formula at visit 1. Prior to the CET at visits 2 and 3, they were randomized to a single dose of IND/GLY (110/50 µg) or placebo. Results: The improved multiple regression algorithm for WMAX includes diffusing capacity for carbon monoxide (DLCO), FEV1, sex, age and height and correlated to measured WMAX (R2 = 0.89 and slope = 0.89). Treatment with IND/GLY showed improvement in endurance time versus placebo, mean 113 s [95% confidence interval (CI): 6–220], p = 0.037, with more prominent effect in patients with FEV1 < 70% predicted. Conclusion: The two new protocols for ICPET (including the new improved algorithm) and CET were retested with consistent results. In addition, the CET showed a significant and clinically relevant prolongation of endurance time for IND/GLY versus placebo in a small number of patients

Eye tracking: empirical foundations for a minimal reporting guideline

In this paper, we present a review of how the various aspects of any study using an eye tracker (such as the instrument, methodology, environment, participant, etc.) affect the quality of the recorded eye-tracking data and the obtained eye-movement and gaze measures. We take this review to represent the empirical foundation for reporting guidelines of any study involving an eye tracker. We compare this empirical foundation to five existing reporting guidelines and to a database of 207 published eye-tracking studies. We find that 10 reporting guidelines vary substantially and do not match with actual reporting practices. We end by deriving a minimal, flexible reporting guideline based on empirical research (Section 6)

Retraction Note:Eye tracking

The authors have retracted this article because a number of statements are supported by two references, Holmqvist (2015) and Holmqvist (2016), which should not have been used. Saga Lee Örbom, Ignace T. C. Hooge, Diederick C. Niehorster, Robert G. Alexander, Richard Andersson, Jeroen S. Benjamins, Pieter Blignaut, Anne-Marie Brouwer, Lewis L. Chuang, Kirsten A. Dalrymple, Denis Drieghe, Matt J. Dunn, Ulrich Ettinger, Susann Fiedler, Tom Foulsham, Jos N. van der Geest, Dan Witzner Hansen, Samuel B. Hutton, Enkelejda Kasneci, Alan Kingstone, Paul C. Knox, Ellen M. Kok, Helena Lee, Joy Yeonjoo Lee, Jukka M. Leppänen, Stephen Macknik, Päivi Majaranta, Susana Martinez-Conde, Antje Nuthmann, Marcus Nyström, Jacob L. Orquin, Jorge Otero-Millan, Soon Young Park, Stanislav Popelka, Frank Proudlock, Frank Renkewitz, Austin Roorda, Michael Schulte-Mecklenbeck, Bonita Sharif, Frederick Shic, Mark Shovman, Mervyn G. Thomas, Ward Venrooij, Raimondas Zemblys and Roy S. Hessels agree with this retraction. Kenneth Holmqvist is deceased

Eye tracking: empirical foundations for a minimal reporting guideline

In this paper, we present a review of how the various aspects of any study using an eye tracker (such as the instrument, methodology, environment, participant, etc.) affect the quality of the recorded eye-tracking data and the obtained eye-movement and gaze measures. We take this review to represent the empirical foundation for reporting guidelines of any study involving an eye tracker. We compare this empirical foundation to five existing reporting guidelines and to a database of 207 published eye-tracking studies. We find that 10 reporting guidelines vary substantially and do not match with actual reporting practices. We end by deriving a minimal, flexible reporting guideline based on empirical research (Section 6).<br/

Analysis of Outcomes in Ischemic vs Nonischemic Cardiomyopathy in Patients With Atrial Fibrillation A Report From the GARFIELD-AF Registry

IMPORTANCE Congestive heart failure (CHF) is commonly associated with nonvalvular atrial fibrillation (AF), and their combination may affect treatment strategies and outcomes