Clinical Differences in COPD Patients with Variable Patterns of Hypoxemia

Erin R Narewski; Amanda L Blackford; Matthew R Lammi; Anne L Fuhlbrigge; Xavier Soler; Richard Albert; Gerard J Criner; Long-Term Oxygen Treatment Trial Research Group

doi:10.15326/jcopdf.5.3.2017.0175

Clinical Differences in COPD Patients with Variable Patterns of Hypoxemia

Chronic Obstr Pulm Dis. 2018 Apr 28;5(3):167-176. doi: 10.15326/jcopdf.5.3.2017.0175.

Authors

Erin R Narewski¹, Amanda L Blackford², Matthew R Lammi³, Anne L Fuhlbrigge⁴, Xavier Soler⁵, Richard Albert⁶, Gerard J Criner¹; Long-Term Oxygen Treatment Trial Research Group

Affiliations

¹ Department of Thoracic Medicine and Surgery, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania.
² Division of Biostatistics and Bioinformatics, Bloomberg School of Health, Johns Hopkins University, Baltimore, Maryland.
³ Division of Pulmonary and Critical Care Medicine, School of Medicine, Louisiana State University, New Orleans.
⁴ Channing Laboratory, Brigham and Women's Hospital and Division of Pulmonary and Critical Care Medicine, Harvard Medical School, Boston, Massachusetts.
⁵ Division of Pulmonary and Critical Care Medicine, School of Medicine, University of California- San Diego.
⁶ Division of Pulmonary and Critical Care Medicine, School of Medicine, University of Colorado, Denver.

Abstract

Background: Chronic obstructive pulmonary disease (COPD) patients enrolled into the Long-term Oxygen Treatment Trial had hypoxemia at rest, hypoxemia on exertion, or hypoxemia both at rest and on exertion. We hypothesized that patients with different patterns of hypoxemia may have significant differences in clinical features. Methods: All patients had COPD and oxygen saturation measured by pulse oximetry (blood oxygenation [SpO₂]) at rest and during the 6-minute walk test (6MWT). Hypoxemia at rest was defined as resting SpO₂ between 89-93%. SpO₂ < 90% for at least 10 seconds and ³ 80% for at least 5 minutes during ambulation characterized hypoxemia on exertion. Severe exercise hypoxemia (< 80% for > 1 minute) was exclusionary. Results: Of 738 patients studied, 133 (18.0%) had mild-moderate hypoxemia at rest only, 319 (43.2%) had hypoxemia on exertion only, and 286 (38.8%) had hypoxemia at both rest and exertion. Patients with hypoxemia at rest only were more likely to be current smokers, had higher body mass index (BMI) and a higher incidence of self-reported diabetes. Patients with hypoxemia on exertion only were more severely obstructed compared to the other groups. General and disease-specific quality of life scores were similarly impaired in all groups. Quality of well-being scores were more impaired in those with hypoxemia at rest only. Conclusions: COPD patients with mild-moderate hypoxemia have distinct clinical characteristics based on the pattern of oxygen desaturation at rest and with exertion.

Keywords: LOTT; Long-term Oxygen Treatment Trial; chronic obstructive pulmonary disease; copd; long-term oxygen treatment.

Grants and funding

This project is supported through federal funding from the National Heart, Lung, and Blood Institute, the National Institutes of Health, the Department of Health and Human Services [contracts HHSN268200736183C, HHSN268200736184C, HHSN268200736185C, HHSN268200736186C, HHSN268200736187C, HHSN268200736188C, HHSN268200736189C, HHSN268200736190C, HHSN268200736191C, HHSN268200736192C, HHSN268200736193C, HHSN268200736194C, HSN268200736195C, HHSN268200736196C, HHSN268200736197C, Y1-HR-7019-01, and Y1-HR-8076-01] in cooperation with the Centers for Medicare and Medicaid Services, and the Department of Health and Human Service.