Routine Oxygen Therapy Does Not Improve Health-Related Quality of Life in Patients With Acute Myocardial Infarction-Insights From the Randomized DETO2X-AMI Trial

Abstract

Background: After decades of ubiquitous oxygen therapy in all patients with acute myocardial infarction (MI), recent guidelines are more restrictive based on lack of efficacy in contemporary trials evaluating hard clinical outcomes in patients without hypoxemia at baseline. However, no evidence regarding treatment effects on health-related quality of life (HRQoL) exists. In this study, we investigated the impact of routine oxygen supplementation on HRQoL 6-8 weeks after hospitalization with acute MI. Secondary objectives included analyses of MI subtypes, further adjustment for infarct size, and oxygen saturation at baseline and 1-year follow-up. Methods: In the DETermination of the role of Oxygen in suspected Acute Myocardial Infarction (DETO2X-AMI) trial, 6,629 normoxemic patients with suspected MI were randomized to oxygen at 6 L/min for 6-12 h or ambient air. In this prespecified analysis, patients younger than 75 years of age with confirmed MI who had available HRQoL data by European Quality of Life Five Dimensions questionnaire (EQ-5D) in the national registry were included. Primary endpoint was the EQ-5D index assessed by multivariate linear regression at 6-10 weeks after MI occurrence. Results: A total of 3,086 patients (median age 64, 22% female) were eligible, 1,518 allocated to oxygen and 1,568 to ambient air. We found no statistically significant effect of oxygen therapy on EQ-5D index (-0.01; 95% CI: -0.03-0.01; p = 0.23) or EQ-VAS score (-0.57; 95% CI: -1.88-0.75; p = 0.40) compared to ambient air after 6-10 weeks. Furthermore, no significant difference was observed between the treatment groups in EQ-5D dimensions. Results remained consistent across MI subtypes and at 1-year follow-up, including further adjustment for infarct size or oxygen saturation at baseline. Conclusions: Routine oxygen therapy provided to normoxemic patients with acute MI did not improve HRQoL up to 1 year after MI occurrence. Clinical Trial Registration: ClinicalTrials.gov number, NCT01787110.

Keywords: Registry-based randomized clinical trial; health-realted quality of life; myocardial infarction; oxygen therapy; patient reported clinical outcomes; secondary prevention.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2021 Hofmann, Befekadu Abebe, Herlitz, James, Erlinge, Yndigegn, Alfredsson, Kellerth, Ravn-Fischer, Völz, Lauermann, Jernberg, Lindahl and Langenskiöld.

Figures

Figure 1

Enrollment, randomization, and analysis (study flow chart). Eligible patients with suspected myocardial infarction were evaluated for inclusion in the main study, randomly assigned to a study group (oxygen vs. ambient air), and analyzed during the study period. In the present prespecified subgroup analysis, only patients with confirmed MI below the age of 75 who are subject for follow-up in the national registry were included. DETO2X-AMI, Determination of the Role of Oxygen in Acute Myocardial Infarction; MI, myocardial infarction; EQ-5D, European Quality of Life Five Dimensions questionnaire; DETO2X-HRQoL, DETO2X health-related quality of life subgroup analysis; STEMI, ST-elevation myocardial infarction; NSTEMI, Non-ST-elevation myocardial infarction.

Figure 2

Cumulative distribution of EQ-5D index for patients with confirmed myocardial infarction at weeks 6–10. Cumulative distribution of EQ-5D index. For each EQ-5D index value displayed, the graph shows the proportion of patients below that cut point.

Figure 3

Cumulative distribution of EQ-VAS for patients with confirmed myocardial infarction at weeks 6–10. Cumulative distribution of EQ-VAS. For each EQ-5D index value displayed, the graph shows the proportion of patients below that cut point.

Figure 4

EQ-5D dimensions on visit 1. The EQ-5D is a generic instrument that measures patients' health-related quality of live five dimensions (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression). The patients' self-rate their current health state using a three-item ordinal response scale (no/moderate/severe problem). p-values for comparison of oxygen vs. ambient air were non-significant for all dimensions. Missing observations: 8.2% in the oxygen group and 7.7% in the ambient-air group.