Table 3.
Univariate analyses of the predictive factors (measured at inclusion) of lung function deterioration*
| Characteristic | Deterioration (n = 23) | No deterioration (n = 35) | HR (95% CI) | P value |
|---|---|---|---|---|
| Demographic features | ||||
| Age, yrs | 41.1 ± 12.0** | 32.0 ± 8.2 | 1.7 (1.2-2.4)† | 0.002 |
| Sex, n (%) | ||||
| Male | 12 (52) | 15 (43) | 1.0 | |
| Female | 11 (48) | 20 (57) | 0.98 (0.4-2.3) | 0.97 |
| Smoking status, n (%) | ||||
| Smokers | 20 (87) | 19 (54) | 1.0 | |
| Non-smokers | 3 (13) | 16 (46) | 0.25 (0.1-0.85) | 0.027 |
| Clinical features, n (%) | ||||
| Asymptomatic | 6 (26) | 15 (43) | 0.6 (0.2-1.7) | 0.38 |
| Cough | 10 (48) | 10 (34) | 1.3 (0.5-3.2) | 0.54 |
| Dyspnoea | 13 (57) | 12 (34) | 2.0 (0.8-4.6) | 0.11 |
| Lung function parameters | ||||
| FEV1 | ||||
| % predicted | 85.9 ± 13.7 | 87.8 ± 20.4 | 0.9 (0.7-1.2)† | 0.45 |
| ≤59% predicted, n (%) | 5 (14) | 1 (4) | 1 · 0 | |
| 60-79% of predicted | 7 (20) | 6 (26) | 2.8 (0.3-23.3) | 0.35 |
| ≥80% predicted | 23 (66) | 16 (70) | 2.6 (0.3-19.7) | 0.36 |
| FVC | ||||
| % predicted | 92.4 ± 19.6 | 93.4 ± 17.1 | 0.9 (0.7-1.2)† | 0.92 |
| TLC | ||||
| % predicted | 101.0 ± 18.0 | 100.3 ± 13.4 | 1.0 (0.8-1.3)† | 0.98 |
| Restriction, n (%)‡ | 3 (13) | 2 (6) | 1.9 (0.5-6.4) | 0.32 |
| RV | ||||
| % predicted | 118.8 ± 33.4 | 115.0 ± 38.4 | 1.0 (0.9-1.1)† | 0.67 |
| RV/TLC | 36.1 ± 9.6 | 32.0 ± 9.6 | 1.0 (1.0-1.02) | 0.58 |
| Air trapping, n (%)‡ | 10 (43) | 11 (32) | 1.7 (0.7-3.9) | 0.23 |
| FEV1 /FVC | 74.1 ± 9.8 | 76.5 ± 8.1 | 0.98 (0.9-1.0) | 0.42 |
| Airflow obstruction, n (%)‡ | 10 (43) | 5 (14) | 2.9 (1.3-6.8) | 0.014 |
| DLCO | ||||
| % predicted | 63.8 ± 12.9 | 64.6 ± 13.2 | 0.3 (0.0-9.3)† | 0.50 |
| <72% predicted, n (%) | 17 (74) | 24 (69) | 1.0 | |
| ≥72% predicted | 6 (26) | 11 (31) | 0.7 (0.3-1.7) | 0.42 |
| 6-Minute walk distance, m | ||||
| % of the predicted value | 78.7 ± 14.0 | 73.2 ± 10.1 | 1.4 (0.9-2.0)† | 0.09 |
| PaO2 | 81.4 ± 9.7 | 90.8 ± 9.0 | 0.94 (0.91-0.98)† | 0.0014 |
| Lung HRCT§ | ||||
| Nodular score | 8.4 ± 4.8 | 7.8 ± 4.3 | 1.1 (0.7-2.0)║ | 0.46 |
| Cystic score | 8.0 ± 3.9 | 8.4 ± 5.7 | 1.0 (0.7-1.4)║ | 0.89 |
| SGRQ score | 25.7 ± 20.1 | 15.1 ± 16.8 | 1.3 (1.1-1.6)† | 0.012 |
Definition of abbreviations: HR hazard ratio, CI confidence interval, FEV 1 forced expiratory volume in 1 second, FVC forced vital capacity, TLC total lung capacity, RV residual volume, DL CO diffusion capacity for carbon monoxide, PaO 2 arterial partial oxygen pressure, HRCT high-resolution computed tomography, SGRQ St George’s ;Respiratory Questionnaire.
*Lung function deterioration was defined by a decrease of at least 15% in FEV1, FVC and/or DLCO compared with the baseline values.
**Plus-minus values are the means ± SDs.
†Reported HRs are given for an increase of 10 units.
‡Lung function restriction was defined as a TLC <80% of the predicted value, air trapping as an RV/TLC ratio >120% of the predicted value and obstruction as an FEV1/FVC ratio <70%.
§HRCT was available at inclusion for 56 patients (22 and 34 patients in each group). The maximal values for the HRCT nodular and cystic scores were 18 and 24, respectively.
║Reported HRs are given for an increase of 4 points.
¶SGRQ was available for 55 patients at inclusion (23 and 32 patients in each group). The scores ranged from 0 to 100, with higher scores indicating worse functioning.