Chronic Obstructive Pulmonary Disease
Conditions
Keywords
COPD
Brief summary
Chronic obstructive pulmonary disease (COPD) is a serious respiratory disease in which the airways in the lungs are partially blocked, resulting in symptoms of chest tightness, coughing, and difficulty breathing. Currently, there are many available treatments for managing COPD symptoms and improving quality of life, including medications, lifestyle changes, oxygen therapy, and pulmonary rehabilitation. For people with severe COPD that is characterized by very low blood oxygen levels at rest, long term oxygen therapy can help to prolong life and promote feelings of well-being. However, the effectiveness of supplemental oxygen therapy for people with COPD that is characterized by only moderately low blood oxygen levels at rest or normal blood oxygen at rest and desaturation on exercise is not known. This study will evaluate the effectiveness of supplemental oxygen therapy in treating people with COPD who have moderately low blood oxygen levels at rest or who have normal blood oxygen levels at rest, but have low or very low blood oxygen levels during exercise.
Detailed description
COPD is the fourth leading cause of death in the United States, with more than 12 million people currently diagnosed with the disease. Risk factors for COPD include smoking, environmental exposure to lung irritants, and genetic predisposition. People with COPD often experience symptoms of chronic cough, shortness of breath, excess mucus production, and wheezing. In COPD, the airways in the lungs are chronically obstructed, and if left untreated, this obstruction can cause significant damage to the lungs and lasting disability. The quality of life of a person with COPD decreases as the disease progresses, making treating and managing COPD in the moderate stages important. Long-term oxygen therapy has been shown to help people with severe COPD that is characterized by very low blood oxygen levels at rest to live longer and healthier lives. This study will determine whether supplemental oxygen therapy is helpful for people with COPD that is characterized by moderately low blood oxygen levels at rest or normal oxygen levels at rest and low or very low levels during exercise. Participation in this study will last at least one year and up to 7 years. Potential participants will first undergo a screening visit that will include questionnaires, a breathing test, measurements of resting and walking blood oxygen levels, a brief physical exam, and a blood draw. Eligible participants will then return for a second screening visit, during which they will complete more questionnaires. At the end of the second visit, eligible participants will be assigned randomly to supplemental oxygen therapy or no oxygen therapy. Participants assigned to supplemental oxygen therapy will receive stationary and portable oxygen systems. Shortly after receiving the portable oxygen system, participants will return for a 1-hour visit to determine how much oxygen to use while walking and to learn how to use the equipment. Participants who have low blood oxygen levels during rest will be instructed to use supplemental oxygen 24 hours per day. Patients with normal resting blood oxygen levels, but low or very low blood oxygen levels during exercise will be instructed to use it during physical activity and sleep. Throughout the treatment period, participants will be asked to keep records of the number of oxygen tanks emptied or pounds of oxygen delivered, meter readings, and changes in equipment. Study officials will contact participants weekly for the first month, monthly for the next 5 months, and then every 2 months until the Year 1 study visit. Participants will also complete a form about their oxygen equipment and usage every 2 months. Participants assigned to receive no oxygen treatment will be contacted 1 week after study group assignment for a check-up. All participants will return for study visits once a year for up to 7 years. At each of these visits, participants will complete some of the same tests and questionnaires from the screening visit. At the Year 1 visit, participants will also undergo a blood draw. Both treatment groups will receive two phone calls each year to check on status and use of oxygen. Participants in both groups will be asked to complete a quality of life questionnaire by mail at 4 months and 16 months. Participants will also sign a release of medical records form each year and will have their Medicare claims collected for the time they are in the study.
Interventions
Oxygen dose at rest and during sleep will be 2 L/min via nasal cannula. The oxygen dose used while walking will be individually prescribed and will be sufficient to maintain oxygen saturation at 90% or above for at least 2 minutes while walking. Participants who have low blood oxygen levels at rest will be instructed to use oxygen 24 hours per day. Participants who have normal resting blood oxygen levels, but low or very low blood oxygen levels during exercise, will be instructed to use oxygen during physical activity and sleep.
Sponsors
Centers for Medicare and Medicaid Services
National Heart, Lung, and Blood Institute (NHLBI)
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
40 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age at least 40 years * COPD * Dyspnea, determined by Modified Medical Research Council (MMRC) scale of at least 1 * Dyspnea and lung disease process dominated by COPD in judgment of the study physician * Participant must meet one of the following: * Post-bronchodilator forced expiratory volume in 1 second (FEV1) percent less than or equal to 70% predicted * Post-bronchodilator forced expiratory volume in 1 second (FEV1) percent \>70% predicted and LOTT study physician determines that there is radiologic evidence of emphysema * Post-bronchodilator FEV1/forced vital capacity (FVC) less then 0.70 * Participant must meet either of the following oxygen saturation criteria: * Oxygen saturation of at least 89% and no greater than 93% after sitting quietly on room air, without hyperventilation and without pursed lips breathing during oximetry * Resting oxygen saturation 94% or greater and desaturation during exercise defined as saturation below 90% for at least 10 seconds during the 6 minute walk test * If participant is on supplemental oxygen at the start of screening, all of the following must be met prior to randomization: * Participant agrees to stop using oxygen if randomized to no oxygen * Participant's physician agrees in writing to rescind order for oxygen if participant is randomized to no oxygen * Participant must report not using oxygen on the day of randomization and must report not using oxygen for the 4 calendar days prior to randomization * Satisfactory resolution of logistics of continuation with same oxygen company with waiver of cost sharing obligations or switch to new company that will waive cost sharing obligations if participant is randomized to oxygen * At least 10 pack-years of tobacco cigarette smoking before study entry * Agreement not to smoke while using supplemental oxygen * Medicare beneficiary with both Part A and Part B coverage or insurance OR personally willing to cover costs typically covered by Medicare * Approval of study physician for randomization to either treatment group * Completion of all required prerandomization assessments within 60 days of initiating study entry * Randomization within 60 days of initiating eligibility evaluation * Consent
Exclusion criteria
* Less than 30 days post treatment for acute exacerbation of COPD as of initiating eligibility evaluation (less than 30 days from last dose of antibiotics or since a new or increased dose of systemic corticosteroids was initiated); chronic use of systemic corticosteroids while health is stable is not exclusionary * COPD exacerbation requiring antibiotics, new or increased dose of systemic corticosteroids, or oxygen treatment after screening starts and prior to randomization (chronic use of corticosteroids while health is stable is not exclusionary) * Less than 30 days post discharge from an acute care hospital after acute care hospitalization for COPD or other condition, as of initiating eligibility evaluation (participant may be in a rehab hospital at time of screening) * New prescription of supplemental oxygen after screening starts and before randomization * Thoracotomy, sternotomy, major cardiopulmonary intervention (e.g., lung resection, open heart surgery, etc.), or other procedure in the 6 months before study entry likely to cause instability of pulmonary status * Non-COPD lung disease that affects oxygenation or survival * Epworth Sleepiness Scale score greater than 15 * Desaturation below 80% for at least 1 minute during the 6-minute walk test * Disease or condition expected to cause death, inability to perform procedures for the trial, or inability to comply with therapy within 6 months of random assignment, as judged by the study physician * Participation in another intervention study
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Death or Hospitalization, Whichever Occurs First | Through study completion. Median follow-up was 18.4 months. | The primary outcome event is death or hospitalization, whichever occurs first. The difference between treatment groups on the primary outcome was assessed with a time-to-event analysis by calculation of the between group hazard ratio for the primary composite outcome; the statistical significance of the hazard ratio was determined from the log rank test. The uncertainty in the hazard ratio is expressed in the 95% confidence interval on the hazard ratio. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Health Care Utilization | Through study completion. Median follow-up was 18.4 months. | Health care utilization is measured by the rate of all hospitalizations. |
| Adherence | Through study completion. Median follow-up was 18.4 months. | Adherence is measured by self-reported hours of home oxygen per day |
| COPD Exacerbation | Through study completion. Median follow-up was 11.4 months | Rate of all COPD exacerbations |
| Preference-weighted Health-related Quality of Life | Baseline to 1 year | Preference-weighted health-related quality of life is measured by change in the Quality of Well-being Scale total daily score, follow-up value minus baseline value. The total daily score ranges from 0 to 1 with higher score indicating more better quality of life. Death is scored 0. Greater change, follow-up minus baseline, indicates improvement in quality of life compared to baseline. Change scores may range from -1 to +1. |
| Disease-specific Quality of Life | Baseline to 1 year | Disease-specific quality of life is measured by the change in the St George's Respiratory Questionnaire total score, follow-up value minus baseline value. The total score ranges from 0 to 100 with lower score indicating fewer respiratory symptoms. Change in score, follow-up minus baseline may range from -100 to +100, with lower values indicating improvement in disease-specific quality of life. |
| General Quality of Life | Baseline to 1 year | General quality of life is measured by the change in the physical component summary subscale of the SF-36 quality of life questionnaire, follow-up value minus baseline value. The physical component summary subscale score ranges from 0 to 100 with higher values indicating better physical functioning. The change in score, follow-up minus baseline value, ranges from -100 to +100 with higher values indicating improvement in physical functioning. |
| Death | Through study completion. Median follow-up was 41.5 months. | The difference between treatment groups in mortality is assessed with a time-to-event analysis by calculation of the between group hazard ratio for death; the statistical significance of the hazard ratio was determined from the log rank test. The uncertainty in the hazard ratio is expressed in the 95% confidence interval on the hazard ratio. |
| Anxiety | Baseline to 1 year | Anxiety is measured by the change in the Hospital Anxiety and Depression Scale (HADS) anxiety score, follow-up value minus baseline value. The HADS anxiety score ranges from 0 to 21 with higher values indicating greater anxiety. The change in score, follow-up minus baseline value, ranges from -21 to +21 with higher values indicating increase in anxiety |
| Depression | Baseline to 1 year | Depression is measured by the change in the Hospital Anxiety and Depression Scale (HADS) depression score, follow-up value minus baseline value. The HADS depression score ranges from 0 to 21 with higher values indicating greater depression. The change in score, follow-up minus baseline value, ranges from -21 to +21 with higher values indicating increase in depression |
| Development of Severe Resting Desaturation | Baseline to 1 year | Severe resting desaturation is defined as resting room air SpO2 \<=88% |
| 6-minute Walk Distance | Baseline to 1 year | Change in distance walked during 6-minute walk test, follow-up value minus baseline value (feet) |
| Dyspnea | Baseline to 1 year | Change in dyspnea is measured by change in the St George's Respiratory Questionnaire (SGRQ) total score, follow-up value minus baseline value. The SGRQ total score ranges from 0 to 100, with higher values indicating worse dyspnea. The change in score, follow-up value minus baseline value, ranges from -100 to +100, with higher values indicating increase in dyspnea. |
| Sleep Quality | Baseline to 1 year | Sleep quality is measured by the change in the Pittsburgh Sleep Quality Index total score, follow-up value minus baseline value. The Pittsburgh Sleep Quality Index total score ranges from 0 to 21 with higher values indicating worse sleep quality. The change in score, follow-up minus baseline value, ranges from -21 to +21 with higher values indicating worsening in sleep quality. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Supplemental Oxygen Therapy Participants will receive treatment with supplemental oxygen therapy.
Supplemental oxygen therapy: Oxygen dose at rest and during sleep will be 2 L/min via nasal cannula. The oxygen dose used while walking will be individually prescribed and will be sufficient to maintain oxygen saturation at 90% or above for at least 2 minutes while walking. Participants who have low blood oxygen levels at rest will be instructed to use oxygen 24 hours per day. Participants who have normal resting blood oxygen levels, but low or very low blood oxygen levels during exercise, will be instructed to use oxygen during physical activity and sleep. | 368 |
| No Supplemental Oxygen Therapy Participants will receive no supplemental oxygen therapy, unless the participant becomes severely hypoxemic at rest (e.g., meets conventional Medicare criteria for 24-hour supplemental oxygen due to severe hypoxemia at rest). | 370 |
| Total | 738 |
Baseline characteristics
| Characteristic | Total | No Supplemental Oxygen Therapy | Supplemental Oxygen Therapy |
|---|---|---|---|
| Age, Continuous | 68.8 years STANDARD_DEVIATION 7.5 | 69.3 years STANDARD_DEVIATION 7.4 | 68.3 years STANDARD_DEVIATION 7.5 |
| Current tobacco-cigarette smoker | 202 Participants | 92 Participants | 110 Participants |
| Ethnicity (NIH/OMB) Hispanic or Latino | 14 Participants | 4 Participants | 10 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 724 Participants | 366 Participants | 358 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Medicare coverage | 541 Participants | 273 Participants | 268 Participants |
| Nadir SpO2 during 6-min walk while breathing ambient air 86% through 88% | 208 Participants | 103 Participants | 105 Participants |
| Nadir SpO2 during 6-min walk while breathing ambient air Greater than 88% | 203 Participants | 102 Participants | 101 Participants |
| Nadir SpO2 during 6-min walk while breathing ambient air Less than 86% | 171 Participants | 85 Participants | 86 Participants |
| Nadir SpO2 during 6-min walk while breathing ambient air Unknown | 156 Participants | 80 Participants | 76 Participants |
| Oxygen desaturation type qualifying patient for enrollment Exercise desaturation only | 319 Participants | 171 Participants | 148 Participants |
| Oxygen desaturation type qualifying patient for enrollment Resting and exercise | 286 Participants | 139 Participants | 147 Participants |
| Oxygen desaturation type qualifying patient for enrollment Resting desaturation only | 133 Participants | 60 Participants | 73 Participants |
| Quality of Well-Being Scale mean daily score | 0.56 units on a scale STANDARD_DEVIATION 0.13 | 0.56 units on a scale STANDARD_DEVIATION 0.13 | 0.56 units on a scale STANDARD_DEVIATION 0.13 |
| Race/Ethnicity, Customized Race African American only | 80 Participants | 34 Participants | 46 Participants |
| Race/Ethnicity, Customized Race Caucasian only | 621 Participants | 322 Participants | 299 Participants |
| Race/Ethnicity, Customized Race Other | 37 Participants | 14 Participants | 23 Participants |
| Region of Enrollment United States | 738 participants | 370 participants | 368 participants |
| Sex: Female, Male Female | 196 Participants | 94 Participants | 102 Participants |
| Sex: Female, Male Male | 542 Participants | 276 Participants | 266 Participants |
| SpO2 at rest while breathing ambient air | 93.4 SpO2 (percent saturation) STANDARD_DEVIATION 2 | 93.5 SpO2 (percent saturation) STANDARD_DEVIATION 1.9 | 93.3 SpO2 (percent saturation) STANDARD_DEVIATION 2.1 |
| St George's Respiratory Questionnaire total score | 50.0 units on a scale STANDARD_DEVIATION 17.9 | 50.2 units on a scale STANDARD_DEVIATION 17.1 | 49.8 units on a scale STANDARD_DEVIATION 18.7 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 66 / 368 | 24 / 125 | 49 / 245 |
| other Total, other adverse events | 30 / 368 | 10 / 125 | 0 / 245 |
| serious Total, serious adverse events | 2 / 368 | 0 / 125 | 0 / 245 |
Outcome results
Primary
Death or Hospitalization, Whichever Occurs First
The primary outcome event is death or hospitalization, whichever occurs first. The difference between treatment groups on the primary outcome was assessed with a time-to-event analysis by calculation of the between group hazard ratio for the primary composite outcome; the statistical significance of the hazard ratio was determined from the log rank test. The uncertainty in the hazard ratio is expressed in the 95% confidence interval on the hazard ratio.
Time frame: Through study completion. Median follow-up was 18.4 months.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Supplemental Oxygen Therapy | Death or Hospitalization, Whichever Occurs First | 34.2 Composite events/100 person-years |
| No Supplemental Oxygen Therapy | Death or Hospitalization, Whichever Occurs First | 36.4 Composite events/100 person-years |
p-value: 0.5295% CI: [0.79, 1.12]Log Rank
Secondary
6-minute Walk Distance
Change in distance walked during 6-minute walk test, follow-up value minus baseline value (feet)
Time frame: Baseline to 1 year
Population: Change in 6 minute walk distance from baseline to 1 year is analyzed for patients with both baseline and 1 year values
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | 6-minute Walk Distance | -53 feet | Standard Deviation 281 |
| No Supplemental Oxygen Therapy | 6-minute Walk Distance | -85 feet | Standard Deviation 245 |
p-value: 0.37t-test, 2 sided
Secondary
Adherence
Adherence is measured by self-reported hours of home oxygen per day
Time frame: Through study completion. Median follow-up was 18.4 months.
Population: Patients providing at least 1 self-report are included.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | Adherence | 13.6 hours per day of supplemental oxygen | Standard Deviation 6.1 |
| No Supplemental Oxygen Therapy | Adherence | 1.8 hours per day of supplemental oxygen | Standard Deviation 3.9 |
Secondary
Anxiety
Anxiety is measured by the change in the Hospital Anxiety and Depression Scale (HADS) anxiety score, follow-up value minus baseline value. The HADS anxiety score ranges from 0 to 21 with higher values indicating greater anxiety. The change in score, follow-up minus baseline value, ranges from -21 to +21 with higher values indicating increase in anxiety
Time frame: Baseline to 1 year
Population: Patients with both the baseline and 1 year values are included; a subset of clinics administered the HADS questionnaire.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | Anxiety | -0.1 units on a scale | Standard Deviation 3.3 |
| No Supplemental Oxygen Therapy | Anxiety | 0.3 units on a scale | Standard Deviation 3.2 |
p-value: 0.28t-test, 2 sided
Secondary
COPD Exacerbation
Rate of all COPD exacerbations
Time frame: Through study completion. Median follow-up was 11.4 months
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Supplemental Oxygen Therapy | COPD Exacerbation | 73.1 COPD exacerbations per 100 person-years |
| No Supplemental Oxygen Therapy | COPD Exacerbation | 67.7 COPD exacerbations per 100 person-years |
p-value: 0.1295% CI: [0.98, 1.19]Fisher Exact
Secondary
Death
The difference between treatment groups in mortality is assessed with a time-to-event analysis by calculation of the between group hazard ratio for death; the statistical significance of the hazard ratio was determined from the log rank test. The uncertainty in the hazard ratio is expressed in the 95% confidence interval on the hazard ratio.
Time frame: Through study completion. Median follow-up was 41.5 months.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Supplemental Oxygen Therapy | Death | 5.2 Deaths/100 person-years |
| No Supplemental Oxygen Therapy | Death | 5.7 Deaths/100 person-years |
p-value: 0.5395% CI: [0.64, 1.25]Log Rank
Secondary
Depression
Depression is measured by the change in the Hospital Anxiety and Depression Scale (HADS) depression score, follow-up value minus baseline value. The HADS depression score ranges from 0 to 21 with higher values indicating greater depression. The change in score, follow-up minus baseline value, ranges from -21 to +21 with higher values indicating increase in depression
Time frame: Baseline to 1 year
Population: Patients with both baseline and 1 year values are included
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | Depression | 0.4 units on a scale | Standard Deviation 3 |
| No Supplemental Oxygen Therapy | Depression | 0.7 units on a scale | Standard Deviation 2.8 |
p-value: 0.41t-test, 2 sided
Secondary
Development of Severe Resting Desaturation
Severe resting desaturation is defined as resting room air SpO2 \<=88%
Time frame: Baseline to 1 year
Population: Participants completing the 1 year saturation assessment are analyzed
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Supplemental Oxygen Therapy | Development of Severe Resting Desaturation | 7 Participants |
| No Supplemental Oxygen Therapy | Development of Severe Resting Desaturation | 3 Participants |
95% CI: [0.54, 8]
Secondary
Disease-specific Quality of Life
Disease-specific quality of life is measured by the change in the St George's Respiratory Questionnaire total score, follow-up value minus baseline value. The total score ranges from 0 to 100 with lower score indicating fewer respiratory symptoms. Change in score, follow-up minus baseline may range from -100 to +100, with lower values indicating improvement in disease-specific quality of life.
Time frame: Baseline to 1 year
Population: Participants with both the baseline and 1 year values are included
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | Disease-specific Quality of Life | -1.1 units on a scale | Standard Deviation 13.5 |
| No Supplemental Oxygen Therapy | Disease-specific Quality of Life | 0.6 units on a scale | Standard Deviation 12.7 |
p-value: 0.21t-test, 2 sided
Secondary
Dyspnea
Change in dyspnea is measured by change in the St George's Respiratory Questionnaire (SGRQ) total score, follow-up value minus baseline value. The SGRQ total score ranges from 0 to 100, with higher values indicating worse dyspnea. The change in score, follow-up value minus baseline value, ranges from -100 to +100, with higher values indicating increase in dyspnea.
Time frame: Baseline to 1 year
Population: Patients with both the baseline and 1 year SGRQ total score are included
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | Dyspnea | -1.1 units on a scale | Standard Deviation 13.5 |
| No Supplemental Oxygen Therapy | Dyspnea | 0.6 units on a scale | Standard Deviation 12.7 |
p-value: 0.21t-test, 2 sided
Secondary
General Quality of Life
General quality of life is measured by the change in the physical component summary subscale of the SF-36 quality of life questionnaire, follow-up value minus baseline value. The physical component summary subscale score ranges from 0 to 100 with higher values indicating better physical functioning. The change in score, follow-up minus baseline value, ranges from -100 to +100 with higher values indicating improvement in physical functioning.
Time frame: Baseline to 1 year
Population: Participants with both the baseline and 1 year values are included; the SF-36 was administered at a subset of clinics
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | General Quality of Life | -0.5 units on a scale | Standard Deviation 7.1 |
| No Supplemental Oxygen Therapy | General Quality of Life | -1.0 units on a scale | Standard Deviation 7.4 |
p-value: 0.71t-test, 2 sided
Secondary
Health Care Utilization
Health care utilization is measured by the rate of all hospitalizations.
Time frame: Through study completion. Median follow-up was 18.4 months.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Supplemental Oxygen Therapy | Health Care Utilization | 56.9 Hospitalizations per 100 person-years |
| No Supplemental Oxygen Therapy | Health Care Utilization | 56.2 Hospitalizations per 100 person-years |
p-value: 0.8195% CI: [0.91, 1.13]Fisher Exact
Secondary
Preference-weighted Health-related Quality of Life
Preference-weighted health-related quality of life is measured by change in the Quality of Well-being Scale total daily score, follow-up value minus baseline value. The total daily score ranges from 0 to 1 with higher score indicating more better quality of life. Death is scored 0. Greater change, follow-up minus baseline, indicates improvement in quality of life compared to baseline. Change scores may range from -1 to +1.
Time frame: Baseline to 1 year
Population: Participants with both the baseline and 1 year values were included
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | Preference-weighted Health-related Quality of Life | -0.04 units on a scale | Standard Deviation 0.24 |
| No Supplemental Oxygen Therapy | Preference-weighted Health-related Quality of Life | -0.04 units on a scale | Standard Deviation 0.14 |
p-value: 0.73t-test, 2 sided
Secondary
Sleep Quality
Sleep quality is measured by the change in the Pittsburgh Sleep Quality Index total score, follow-up value minus baseline value. The Pittsburgh Sleep Quality Index total score ranges from 0 to 21 with higher values indicating worse sleep quality. The change in score, follow-up minus baseline value, ranges from -21 to +21 with higher values indicating worsening in sleep quality.
Time frame: Baseline to 1 year
Population: Participants with both the baseline and 1 year values are included
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Supplemental Oxygen Therapy | Sleep Quality | -0.3 units on a scale | Standard Deviation 3.4 |
| No Supplemental Oxygen Therapy | Sleep Quality | 0.4 units on a scale | Standard Deviation 3.2 |
p-value: 0.03t-test, 2 sided