Table A2.
Cox proportional hazards model coefficients and reference values.
| Covariate | Coefficient* |
Mean characteristics of reference population | |
|---|---|---|---|
| β | SE | ||
| Age (per year) | 0.011 | 0.0049 | 19.8$ |
| Sex (female = 1) | 0.15 | 0.074 | 0.48 |
| ppFEV1 (per %) | −0.042 | 0.0025 | 77.1 |
| Weight-for-age Z score | −0.28 | 0.041 | −0.85‡ |
| Pancreatic sufficiency (yes = 1) | −0.14 | 0.23 | 0.126 |
| Diabetes mellitus (yes = 1) | 0.44 | 0.098 | 0.19 |
| Staphylococcus aureus (yes = 1) | −0.25 | 0.09 | 0.68 |
| Burkholderia cepacia (yes = 1) | 1.41 | 0.19 | 0.03 |
| Annual number of acute exacerbations (maximum 5) | 0.35 | 0.024 | 0.7 |
| PEx B. cepacia | −0.28 | 0.06 | 0.0286§ |
Mean estimates obtained from US CFFPR 2011, except where indicated.
*
Unless specified, coefficients for each covariate are unitless.
$
Data not available from the US CFFPR 2011 report. Data reported in US CFFPR 2012 are used as proxy.
‡
Liou et al. 2001.21
§
Assumed equal to mean B. cepacia mean* acute exacerbations.
PEx, pulmonary exacerbation; ppFEV1, percentage of predicted forced expiratory volume in 1 second; SE, standard error.