Table 2.
Unadjusted comparisons of lung function measures and incidence of first hospitalization or mortality due to chronic lower respiratory disease, according to Pi10 quartile, among Multi-Ethnic Study of Atherosclerosis Lung Study participants without prevalent clinical chronic lower respiratory disease
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | P Value | |
|---|---|---|---|---|---|
| Lung function | |||||
| No. with complete spirometry follow-up* | 457 | 458 | 458 | 457 | |
| FEV1, % predicted, mean (SD) | 100.5 (15.5) | 98.1 (14.4) | 97.2 (14.6) | 96.5 (15.2) | 0.0003 |
| FEV1/FVC, percent, mean (SD) | 0.79 (0.05) | 0.78 (0.05) | 0.79 (0.05) | 0.78 (0.05) | 0.694 |
| Change in FEV1†, ml/yr, mean (SD) | −25.6 (1.8) | −25.9 (1.7) | −29.0 (2.2) | −31.9 (1.9) | 0.0090 |
| Incident COPD‡, n (%) | 2 (0.5%) | 8 (1.9%) | 15 (3.5%) | 15 (3.5%) | 0.007 |
| Events | |||||
| Number with complete events follow-up§ | 1,508 | 1,508 | 1,509 | 1,508 | |
| Events follow-up, n (IDR) | |||||
| CLRD event | 10 (5.1) | 20 (10.2) | 21 (10.7) | 33 (17.1) | 0.005 |
| COPD event | 8 (4.1) | 15 (7.6) | 13 (6.6) | 25 (12.9) | 0.021 |
| Asthma event | 2 (1.0) | 5 (2.5) | 8 (4.1) | 8 (4.1) | 0.185 |
| All-cause mortality | 227 (115.4) | 223 (113.0) | 268 (136.2) | 283 (145.3) | 0.005 |
Definition of abbreviations: CLRD = chronic lower respiratory disease; COPD = chronic obstructive pulmonary disease; FEV1 = forced expiratory volume in 1 second; FVC = forced vital capacity; IDR = incidence density rate; Pi10 = average wall thickness for a hypothetical airway of 10-mm lumen perimeter on computed tomography; SD = standard deviation.
Excludes participants without valid spirometry in both 2004–2006 and 2010–2012 as well as those with valid spirometry demonstrating airflow limitation in 2004–2006, defined as FEV1/FVC less than 0.70, and those with prevalent CLRD, defined as self-reported asthma or emphysema and/or inhaler use at study baseline.
Estimated from a mixed model including only time as a predictor. P value was estimated from the multiplicative interaction term in a model including average wall thickness for a hypothetical airway of 10-mm lumen perimeter on computed tomography (Pi10) quartile, time, and Pi10 quartile × time.
Incident COPD was defined as FEV1/FVC less than 0.70 on post-bronchodilator spirometry in 2010–2012.
Excludes all participants with prevalent CLRD, defined as self-reported asthma or emphysema and/or inhaler use at study baseline. Events are defined as hospitalizations/mortality assigned the primary discharge diagnosis or underlying cause of asthma (International Classification of Diseases, 9th Revision [ICD-9], code 493; International Classification of Diseases, 10th Revision [ICD-10], code J45-6), COPD (ICD-9 code 496, ICD-10 code J44), chronic bronchitis (ICD-9 code 490-1, ICD-10 code J40-2), or emphysema (ICD-9 code 492, ICD-10 code J43). COPD events are defined as those coded as COPD, chronic bronchitis, or emphysema.