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Ellen Tufvesson,1 Finn Radner,1 Georgia Papapostolou,1 Linnea Jarenbäck,1 Saga Jönsson,1 Ulf Nihlén,1 Jaro Ankerst,1 Alf Tunsäter,1 Stefan Peterson,2 Leif Bjermer,1 Göran Eriksson1 1Department of Clinical Sciences Lund, Respiratory Medicine and Allergology, Lund University, Skane University Hospital, Lund, Sweden; 2Regional Cancer Centre South, Region Skane, Lund, SwedenCorrespondence: Ellen TufvessonDepartment of Clinical Sciences Lund, Respiratory Medicine and Allergology, Lund University, Skane University Hospital, Lund 22185, SwedenTel +46 73 640 19 16Email ellen.tufvesson@med.lu.sePurpose: 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 comparative studies. The overall best results were observed with a low linear increase during endurance.Keywords: COPD, exercise testing, constant endurance test, endurance time |
