We would like to thank the authors of the letter for their contribution which is relevant to clinical practice.
We conducted a randomized, placebo-controlled, single-blind cross-over study on patients with chronic obstructive pulmonary disease and isolated exercise-induced hypoxemia and found a significant increase in 6-minute walking distance (6MWD) of 28 m with oxygen administration compared to compressed room air administration (1). This value lies within the range of the minimal clinically important difference which is assumed to be between 25 m and 33 m. However, a closer look reveals significant interindividual differences with regard to these short-term oxygen effects: Only 47% of patients experienced a clinically relevant 6MWD improvement in response to oxygen administration. This is, of course, only a short-term effect and its clinical and prognostic significance is still not fully understood.
Both the British (2) and the German oxygen therapy guidelines (3) recommend to perform tests to establish the individual benefits (endurance capacity, paO2 ≥60 mmHg) prior to prescribing outpatient oxygen therapy (level of evidence B). Against the background of a lack of data on long-term effects of oxygen therapy during exercising and the reported therapy-related costs, we think that this recommendation is reasonable. Therefore, we share the view of our colleagues from Hannover in terms of a personalized approach to prescribing oxygen therapy.
We hope that the question of isolated exercise-induced hypoxemia, which is important and highly relevant for clinical practice, will be adequately reviewed in the update of the German guideline on oxygen therapy (which is currently being revised). Further studies are needed to improve our understanding in this matter.
Prof. Dr. med. Andreas Rembert Koczulla
Philipps-Universität Marburg (Standort Schönau)
Deutsches Zentrum für Lungenforschung (DZL)
Schön Klinik Berchtesgadener Land
Schönau am Königssee
Conflict of interest statement
The authors of both contributions declare that no conflict of interest exists.
|1.||Jarosch I, Gloeckl R, Damm E, et al.: Short-term effects of supplemental oxygen on 6-min walk test outcomes in patients with COPD: a randomized, placebo-controlled, single-blind, crossover trial. Chest 2017; 151: 795–803 CrossRef MEDLINE|
|2.||Hardinge M, Annandale J, Bourne S, et al.: British thoracic society guidelines for home oxygen use in adults. Thorax 2015; 70 (Suppl 1): i1–43 CrossRef CrossRef|
|3.||Magnussen H, Kirsten AM, Köhler D, Morr H, Sitter H, Worth H: Leitlinien zur Langzeit-Sauerstofftherapie. Pneumologie 2008; 62: 748–56 CrossRef MEDLINE|
|4.||Koczulla AR, Schneeberger T, Jarosch I, Kenn K, Gloeckl R: Long-term oxygen therapy—current evidence and practical, day to day considerations. Dtsch Arztebl Int 2018; 115: 871–7 VOLLTEXT|