Table 2.
Factors that influence exacerbation features
| Factors influencing exacerbation features | Features of the exacerbations | |||||
|---|---|---|---|---|---|---|
|
|
||||||
| Treated exacerbation frequency | Likelihood of episode being treated | Exacerbation length in days | Delay in days | Day 1 symptoms score | Resolution of length in days | |
| Spirometry FEV1 | ns | ar = −0.386; P = 0.038 | ns | cr = 0.272; P = 0.036 | cr = −0.234;P= 0.003 | ns |
| FEV1/FVC | br = −0.460; P = 0.013 (N = 21) | br = 0.461; P < 0.001 (N = 17) | br = −0.322;P< 0.001 (N = 81 treated episodes) | |||
| KCO% pred | r= −0.432;P= 0.022 (N = 21) | ns | ns | ns | ns | r= −0.647;P= 0.007 N = 15 |
| Delay in treatment initiation in days | All treated (N = 81 episodes) dr = 0.317; P = 0.006 Antibiotic only treated (N = 49 episodes) er = 0.503; P < 0.001 |
– | r = −0.368; P = 0.004 (N = 81 treated episodes) | ns | ||
| Anthonisen criteria types | Chi-square,P< 0.001 | Chi-square, P = 0.001 (N = 17) | – | Type 1 > Type 2 > Type 3, P < 0.001 (N = 21) | – | |
| Lung densitometry (PD15) | ns | – | r = −0.361; P = 0.003 (N = 81 episodes) | r= 0.786;P< 0.001 (N = 15) | r = −0.170; P = 0.035 (N = 81 episodes) | ns |
| Cold symptom | – | Chi-square,P< 0.001 | Chi-square, P < 0.001 | ns | Chi-square, P < 0.001 (N = 21) | ns |
Notes:
FEV1% predicted;
FEV1/VC ratio;
absolute FEV1;
all episodes treated with antibiotics;
episodes also treated with steroids excluded. The features of the exacerbations are outlined as frequency of treated episodes, the likelihood of the episode being treated, length of the episode, delay in commencing treatment, severity of symptoms on day 1 of the episode, and time to resolution following the start of therapy. The factors that relate to these features are shown (see text for further details for each feature). Correlation coefficients (positive or negative) and P-values of the correlations are reported. The factor that is the best independent predictor of the feature from multivariate analysis is highlighted in bold font.
Abbreviations: FEV1, forced expiratory volume in one second; FVC, forced vital capacity; KCO, corrected gas transfer; PD15, 15th percentile lung density; N, number of patients; ns, not significant.