Table 3.
Factors associated with survival
| Hazard ratio (95% confidence interval) | p-value | |
|---|---|---|
| First-degree family member with pulmonary fibrosis (n = 116) | 1.18 (0.86–1.63) | 0.30 |
| Other family member with pulmonary fibrosis (n = 24) | 1.35 (0.69–2.63) | 0.38 |
| Any family member with pulmonary fibrosis (n = 125) | 1.18 (0.86–1.62) | 0.29 |
| Current smoker (n = 33) * | 0.46 (0.21–0.97) | 0.04 |
| Former smoker (n = 298) * | 1.01 (0.68–1.50) | 0.97 |
| Significant exposure to asbestos, dusts, fumes, or radiation (n = 79) | 1.12 (0.85–1.47) | 0.44 |
| Gastro-oesophageal reflux (n = 149) | 0.98 (0.75–1.30) | 0.91 |
| Cardiovascular disease (n = 188) | 1.41 (1.07–1.86) | 0.01 |
| Chest X-ray prior to start of symptoms showing potential interstitial lung abnormalities (n = 56) # | 1.65 (0.88–3.08) | 0.56 |
| CT-scan prior to start of symptoms showing potential interstitial lung abnormalities (N = 34) $ | 0.98 (0.37–2.58) | 0.97 |
| Symptoms started directly after infectious episode (n = 40) | 0.82 (0.51–1.34) | 0.43 |
| Symptoms started directly after surgery (n = 5) | 0.65 (0.16–2.64) | 0.55 |
| Treatment with steroids prior to diagnosis (n = 103) ^ | 1.10 (0.81–1.49) | 0.55 |
| Treatment with other immunosuppressant prior to diagnosis (n = 23) | 0.94 (0.53–1.65) | 0.82 |
| Other ILD diagnosis prior to diagnosis of IPF (n = 67) | 1.01 (0.71–1.44) | 0.96 |
| Cardiology workup for symptoms prior to pulmonology visit (n = 45) | 0.96 (0.64–1.44) | 0.83 |
| Time from start of symptoms to first visit with pulmonologist (n = 409) | 1.00 (0.99–1.01) | 0.81 |
| Time from start of symptoms to diagnosis (n = 409) | 1.00 (1.00–1.00) | 0.97 |
| Consensus diagnosis of IPF (n = 190) | 0.89 (0.68–1.17) | 0.40 |
| Received treatment with antifibrotic therapy after diagnosis | 0.52 (0.37–0.75) | < 0.001 |
Hazard ratios are derived from a multivariate model that corrected for diffusion capacity of the lung for carbon monoxide, forced vital capacity, sex, and age at diagnosis. * compared to never smokers as a reference category. # compared to patients in whom a chest X-ray was performed but did not reveal potential interstitial lung abnormalities. $ compared to patients in whom a CT-scan was performed but did not reveal potential interstitial lung abnormalities. ^ prednisolone equivalent > = 10 mg/daily for > 4 weeks