Table 2.
Association of risk factors with risk of pulmonary exacerbations from First and multiple event models.
| FEA | MEA | FEA Adjusted | MEA Adjusted | |||||
|---|---|---|---|---|---|---|---|---|
| Characteristic | 95% CI | P- value |
95% CI | P- value |
95% CI | P- value |
95% CI | P-value |
| Gender: Female | 1.12 (0.98-1.27) | 0.084 | 1.29 (1.1-1.51) | 0.002 | 1.17(1.02,1.35) | 0.024 | ||
| Caucasian | 0.83 (0.62-1.1) | 0.194 | 1.04 (0.71-1.52) | 0.9 | ||||
| 2CFTR mutation: heterozygous F508del | 0.86 (0.75-0.99) | 0.03 | 0.87 (0.73-1.03) | 0.11 | ||||
| CFTR mutation: Other | 0.74 (0.58-0.94) | 0.01 | 0.68 (0.51-0.9) | 0.008 | ||||
| Age at enrollment (years) | 1.04 (1.03-1.06) | <0.001 | 1.09 (1.07-1.12) | <0.001 | 1.03 (1.01-1.05) | <0.001 | 1.07(1.05,1.09) | <0.001 |
| Weight percentile at enrollment | 0.83 (0.78-0.89) | <0.001 | 0.75 (0.7-0.81) | <0.001 | 0.87 (0.81-0.93) | <0.001 | 0.79(0.73,0.84) | <0.001 |
| Pseudomonas + culture at most recent encounter | 1.58 (1.31-1.9) | <0.001 | 1.13 (1.02-1.25) | 0.02 | 1.29 (1.06-1.56) | 0.009 | ||
| Flu vaccination in previous year | 0.87 (0.72-1.05) | 0.156 | 0.8 (0.72-0.89) | <0.001 | 0.84(0.75,0.94) | 0.002 | ||
| Cigarette smoke exposure in previous year | 1.33 (1.16-1.52) | <0.001 | 1.33 (1.18-1.49) | <0.001 | 1.27 (1.1-1.46) | <0.001 | 1.21(1.08,1.35) | <0.001 |
| Hot tub use in previous year | 0.86 (0.75-1) | 0.045 | 0.93 (0.85-1.02) | 0.109 | ||||
| Swimming pool use in previous year | 0.7 (0.57-0.86) | 0.001 | 0.81 (0.72-0.91) | 0.001 | 0.76 (0.62-0.94) | 0.010 | 0.82(0.73,0.93) | 0.002 |
| Cold symptoms in week prior to most recent encounter | 1.76 (1.55-2) | <0.001 | 1.42 (1.33-1.52) | <0.001 | ||||
| Increased cough in week prior to most recent encounter | 2 (1.88-2.12) | <0.001 | 1.65 (1.59-1.71) | <0.001 | 1.9 (1.79-2.02) | <0.001 | 1.61(1.56,1.67) | <0.001 |
| Oral antibiotics used since previous encounter | 2.08 (1.82-2.38) | <0.001 | 1.63 (1.5-1.76) | <0.001 | 1.69 (1.47-1.94) | <0.001 | 1.49(1.37,1.61) | <0.001 |
| Respiratory culture at previous encounter positive for any CF pathogen3 | 1.4 (1.18-1.65) | <0.001 | 1.27 (1.14-1.41) | <0.001 | 1.18 (0.99-1.4) | 0.062 | 1.17(1.05,1.31) | 0.003 |
| <30 days since previous PEx | 2.84 (2.24-3.61) | <0.001 | 2.73(2.14,3.47) | <0.001 |
PEx – Pulmonary exacerbation; FEA – first event analysis adjusting only for age at enrolment; MEA – multiple event analysis adjusting only for age at enrolment; FEA adjusted - multivariable first event analysis.
MEA adjusted - multivariable multiple event analysis.
The hazard ratio in the MEA is the hazard (instantaneous probability) of a new event given the history of the events and covariates. For instance, the hazard of experiencing a new exacerbation is 29% higher for females than for males.
The reference level of CFTR mutation is homozygous F508 del.
The pathogens are Staphylococcus aureus, Haemophilus influenzae, and Pseudomonas aeruginosa.