Table 3.
Univariate and multivariate Cox regression analysis of factors associated with mortality.
| Variables | Crude HR (95% CI) | p value | Adjusted HR (95% CI)a | p value | Adjusted HR (95% CI)b | p value | Adjusted HR (95% CI)c | p value |
|---|---|---|---|---|---|---|---|---|
| Pseudomonas aeruginosa | 1.26 (0.90–1.76) | .176 | – | – | – | – | – | – |
| Female vs male | 0.90 (0.67– 1.19) | .452 | 1.09 (0.74–1.60) | .663 | 1.12 (0.78–1.62) | 0.535 | 1.01 (0.69–1.48) | .948 |
| Age (years) | 1.04 (1.03–1.06) | <.001 | 1.03 (1.02–1.05) | <.001 | – | – | 1.04 (1.02–1.05) | <.001 |
| BMI (kg*m–2) | 0.92 (0.89–0.96) | <.001 | 0.93 (0.90–0.97) | <.001 | – | – | 0.93 (0.90–0.97) | <.001 |
| Smoking vs non-smoking | 1.31 (0.98–1.74) | .066 | 1.18 (0.80–1.73) | .401 | 1.21 (0.84–1.75) | 0.311 | 1.19 (0.82–1.74) | .355 |
| Haemoptysis | 0.69 (0.51–0.94) | .018 | 0.83 (0.60–1.14) | .251 | 0.77 (0.56–1.06) | 0.104 | 0.81 (0.59–1.12) | .198 |
| Exacerbations in the previous year | 1.03 (0.94–1.13) | .496 | – | – | – | – | – | – |
| MRC dyspnoea score | 0.95 (0.84–1.07) | .376 | – | – | – | – | – | – |
| Reiff score | 1.01 (0.98–1.03) | .675 | – | – | – | – | – | – |
| FEV1% predicted <50% versus ≥ 50% | 1.12 (0.84–1.50) | .427 | – | – | – | – | – | – |
| BACI score | 1.09 (1.06–1.12) | <.001 | 1.06 (1.03–1.10) | <.001 | 1.08(1.06–1.12) | <0.001 | – | – |
| Aetiology and associated diseases | – | – | ||||||
| Unknown aetiology | 1.00 (reference) | – | 1.00 (reference) | – | 1.00 (reference) | – | 1.00 (reference) | – |
| Associated with chronic respiratory disease | 1.51 (0.97–1.36) | .071 | 0.91 (0.56–1.46) | .683 | 0.88 (0.54–1.42) | 0.594 | 1.00 (0.63–1.60) | .996 |
| Associated with connected tissue disease | 1.19 (0.59–2.39) | .623 | 0.99 (0.49–2.03) | .993 | 0.83 (0.41–1.68) | 0.600 | 0.98 (0.48–2.02) | .960 |
| Post-infectious | 1.47 (0.95–2.27) | .085 | 1.34 (0.86–2.10) | .198 | 1.26 (0.81–1.96) | 0.313 | 1.50 (0.96–2.34) | .075 |
| Long-term oral macrolides | 0.74 (0.30–1.79) | .497 | – | – | – | – | – | – |
| Acinetobacter baumannii | 2.84 (1.77–4.57) | <.001 | 1.96 (1.21–3.18) | .006 | – | – | – | – |
| Klebsiella pneumoniae | 1.43 (0.76–2.70) | .271 | – | – | – | – | – | – |
| Escherichia coli | 0.84 (0.27–2.63) | .765 | – | – | – | – | – | – |
| Haemophilus influenzae | 0.713 (0.1–5.09) | .736 | – | – | – | – | – | – |
| Staphylococcus aureus | 2.55 (1.13–5.75) | .024 | – | – | – | – | – | – |
| Candida | 2.27 (1.54–3.33) | <.001 | 1.30 (0.85–1.98) | .226 | – | – | – | – |
| Aspergillus fumigatus | 1.33 (0.70–1.52) | .38 | – | – | – | – | – | – |
| BSI stage | ||||||||
| Mild | 1.00 (reference) | – | – | – | 1.00 (reference) | – | – | – |
| Moderate | 1.80 (1.07–3.03) | .026 | – | – | 1.75 (1.04–2.95) | 0.035 | – | – |
| Severe | 2.57 (1.53–4.33) | <.001 | – | – | 2.36 (1.40–3.98) | 0.001 | – | – |
| Status of PA and comorbidities | ||||||||
| Non-PA with low-risk comorbidities | 1.00 (reference) | – | – | – | – | – | 1.00 (reference) | – |
| Non-PA with moderate or high-risk comorbidities | 2.46(1.62–3.74) | <.001 | – | – | – | – | 1.93 (1.26–2.95) | .003 |
| PA with low-risk comorbidities | 1.55(0.70–3.40) | .28 | – | – | – | – | 1.56 (0.71–3.44) | .268 |
| PAwith moderate or high-risk comorbidities | 2.77(1.69–4.55) | <.001 | – | – | – | – | 2.11 (1.28–3.48) | .003 |
HR: Hazard ratio; CI: confidence interval; BMI: body mass index; PA: Pseudomonas aeruginosa; MRC: Medical Research Council; FEV1: forced expiratory volume in 1 s; BSI: Bronchiectasis Severity Index; BACI: Bronchiectasis Aetiology Comorbidity Index. Data are shown as estimated HRs (95% CIs) of the explanatory variables.
aInitial multivariable model comprised gender, age, BMI, smoking habit, haemoptysis, BACI score, aetiology and associated diseases, Acinetobacter baumanniiand Candida. Final multivariable model was adjusted for age, BMI, BACI score, Acinetobacter baumannii.
bInitial multivariable model comprised gender, smoking habit, haemoptysis, BACI score, aetiology and associated diseases and BSI stage. Final multivariable model was adjusted for BACI score and BSI stage.
cInitial multivariable model comprised gender, age, BMI, smoking habit, haemoptysis, aetiology and associated diseases and status of PA and comorbidities. Final multivariable model was adjusted for age, BMI and status of PA and comorbidities.