Table 3.
Overview of ILD Phenotypic Clusters, Disease Severity, and Clinical Outcomes
| Variable | Cluster 1: Younger White Female With Obesity and Organic Environmental Exposure | Cluster 2: Younger Black Female With High Gamma Gap and High ANA Titer | Cluster 3: Elderly White Male Smoker With Emphysema | Cluster 4: Elderly White Male Smoker With Honeycombing and Environmental Exposure |
|---|---|---|---|---|
| Clinical characteristics | ||||
| Age | Younger | Younger | Elderly | Elderly |
| Sex | Female | Female | Male | Male |
| Race/ethnicity | White | Black | White | White |
| BMI | Obese | Overweight | Overweight | Overweight |
| Tobacco pack-years | > 10 | < 10 | > 10 | > 10 |
| Crackles | + | + | + | + |
| Clubbing | +/– | +/– | +/– | +/– |
| FVC percent predicted | > 60% | < 60% | > 60% | > 60% |
| FEV1 percent predicted | > 70% | < 70% | > 70% | > 70% |
| Dlco | > 50% | < 50% | < 50% | < 50% |
| S:F ratio | > 410 | > 410 | ∼ 410 | < 410 |
| Gamma gap | < 3.5 | > 3.5 | < 3.5 | ∼ 3.5 |
| ANA titer | < 1:320 | > 1:320 | < 1:320 | ∼ 1:320 |
| Honeycombing | +/– | +/– | +/– | + |
| Emphysema | +/– | +/– | + | +/– |
| Hypothyroidism | +/– | +/– | +/– | +/– |
| GERD | + | +/– | +/– | + |
| Organic environmental exposure | + | +/– | +/– | + |
| Inorganic environmental exposure | +/– | – | +/– | +/– |
| PA diameter | < 30 mm | ∼ 30 mm | ∼ 30 mm | ∼ 30 mm |
| Aortic diameter | < 34 mm | < 34 mm | > 34 mm | > 34 mm |
| Disease severity indices | ||||
| GAP-ILD score, median | 2 | 2 | 3 | 3 |
| CPI score, mean | 44.8 | 53.6 | 51.2 | 54.5 |
| Annual FVC decline | ∼ 2% | < 2% | ∼ 2% | ∼ 4% |
| Annual Dlco decline | ∼ 3% | < 2% | ∼ 2% | ∼ 6% |
| Survival outcomes | ||||
| Median survival time, mo | 109 | > 120 | 52 | 40 |
| Predicted mortality rate | ||||
| 1-y | 5.7% | 2.6% | 10.9% | 15.9% |
| 2-y | 9.5% | 7.9% | 21.0% | 25.9% |
| 3-y | 12.4% | 13.2% | 29.3% | 32.9% |
| 5-y | 18.6% | 15.8% | 37.7% | 41.8% |
| 10-y | 22.9% | 21.9% | 42.8% | 44.7% |
ANA = antinuclear antibody; CPI = composite physiologic index; Dlco = diffusing capacity of the lungs for carbon monoxide; GERD = gastroesophageal reflux disease; – = usually absent (absent in majority of cohort); PA = pulmonary artery; + = usually present (present in majority of cohort); +/– = may be present or absent; S:F = SpO2:FiO2 ratio. See Table 1 and 2 legends for expansion of other abbreviations.