Table 1.
Demographic and Clinical Characteristics of the Participants at Baseline.*
| Characteristic | Treatment (N = 261) | Placebo (N = 274) | Overall (N = 535) |
|---|---|---|---|
| Age — yr | 58.6±9.6 | 59.1±9.8 | 58.8±9.7 |
| Male sex — no. (%) | 127 (48.7) | 133 (48.5) | 260 (48.6) |
| Race — no. (%)† | |||
| Black | 92 (35.2) | 99 (36.1) | 191 (35.7) |
| White | 148 (56.7) | 154 (56.2) | 302 (56.4) |
| Other | 3 (11) | 4 (15) | 7 (13) |
| More than one race or missing race | 18 (6.9) | 17 (6.2) | 35 (6.5) |
| Hispanic or Latino ethnic group — no. (%)† | 25 (9.6) | 22 (8.0) | 47 (8.8) |
| Current smoking — no. (%) | 169 (64.8) | 174 (63.5) | 343 (64.1) |
| Use of prohibited medication warranting washout — no. (%)‡ | 9 (3.4) | 11 (4.0) | 20 (3.7) |
| Body-mass index | 29.5±4.9 | 29.4±5.3 | 29.5±5.1 |
| Medical history — no./total no. (%) | |||
| Coronary artery disease | 12/252 (4.8) | 11/264 (4.2) | 23/516 (4.5) |
| Congestive heart failure | 1/252 (0.4) | 5/264 (1.9) | 6/516 (1.2) |
| Chronic bronchitis§ | |||
| MRC definition | 87/251 (34.7) | 101/264 (38.3) | 188/515 (36.5) |
| SGRQ definition | 141/261 (54) | 145/273 (53.1) | 286/534 (53.6) |
| CAT definition | 183/261 (70.1) | 193/274 (70.4) | 376/535 (70.3) |
| CAT score¶ | 17.5±6.7 | 17.6±6.0 | 17.6±6.4 |
| SGRQ score‖ | 37.9±21.0 | 38.4±19.3 | 38.2±20.2 |
| BDI score** | 7.7±2.0 | 7.5±2.0 | 7.6±2.0 |
| Postbronchodilator FEV1 — % of predicted value | 93.8±14.0 | 94.9±12.6 | 94.4±13.3 |
| Postbronchodilator FVC — % of predicted value | 92.9±12.8 | 94.2±13.3 | 93.6±13.0 |
| Postbronchodilator FEV1:FVC | 0.78±0.05 | 0.78±0.05 | 0.78±0.05 |
| Bronchodilator responsiveness — no. (%)†† | 30 (11.5) | 32 (11.7) | 62 (11.6) |
Plus–minus values are means ±SD. FEV1 denotes forced expiratory volume in 1 second, and FVC forced vital capacity.
Race and ethnic group were reported by the participants. The category “other” included American Indian, Alaska Native, Asian, Native Hawaiian, and other Pacific Islander.
Prohibited medications warranting washout included a long-acting β2-agonist (LABA), long-acting muscarinic agonist, a fixed combination of a LABA with an inhaled glucocorticoid, a short-acting anticholinergic agent, or a fixed combination of a short-acting β2-agonist and short-acting anticholinergic.
The Medical Research Council (MRC) definition of chronic bronchitis is cough and sputum on most days during at least 3 consecutive months for more than 2 successive years. The St. George’s Respiratory Questionnaire (SGRQ) definition is the selection of the option “cough for most days a week” or “several days a week” for the cough question on that questionnaire and the options indicating production of phlegm, sputum, or both on “most days a week” or “several days a week” for the sputum question. The COPD Assessment Test (CAT) definition is a score of 2 or higher for the cough question on that test (anchored question ranging from “I never cough” to “I cough all the time” on a scale of 0 to 5) and a score of 2 or higher for the phlegm-production question (anchored question ranging from “I have no phlegm in my chest at all” to “My chest is full of phlegm” on a scale of 0 to 5).
Scores on the CAT range from 0 to 40, with higher scores indicating worse symptoms.
Scores on the SGRQ range from 0 to 100, with higher scores indicating worse health status.
Scores on the Baseline Dyspnea Index (BDI) range from 0 to 12, with higher scores indicating greater dyspnea at baseline.
Bronchodilator responsiveness was defined as an increase in either FEV1 or FVC by at least 12% and at least 200 ml after bronchodilator use, in accordance with the American Thoracic Society and European Respiratory Society definition.