TABLE 2

Multivariate, multilevel analysis of factors associated with length of stay longer than the median

VariableCategoryOR (95% CI)
Patient-related variables
 Age years1.01 (1.01–1.02)
 Smoking statusEx-smoker1
Active0.85 (0.78–0.93)
Never-smoker0.94 (0.80–1.12)
Missing1.08 (0.92–1.28)
 Charlson Comorbidity Index score1.04 (1.01–1.06)
 Body mass index kg·m−2<19.51.13 (0.97–1.33)
19.5–24.991
25–29.990.89 (0.79–1.00)
>29.990.88 (0.78–1.00)
Missing0.83 (0.74–0.93)
Disease-related variables
 Previous admissionsNo1
Yes1.15 (1.07–1.24)
Missing1.11 (0.96–1.28)
 GOLD stage11
21.10 (0.79–1.55)
31.20 (0.86–1.67)
41.77 (1.25–2.49)
Missing1.36 (0.97–1.90)
Exacerbation severity-related variables
 pH<7.351.25 (1.12–1.40)
≥7.351
Missing1.04 (0.93–1.16)
 Purulent sputumNo1
Yes1.11 (1.03–1.20)
Missing1.05 (0.91–1.20)
 ConsolidationNo1
Yes1.27 (1.16–1.40)
Treatment-related variables
 Invasive mechanical ventilationNo1
Yes2.15 (1.25–3.72)
 In-hospital antibioticsNo1
Yes1.46 (1.30–1.64)
 In-hospital methylxanthinesNo1
Yes1.22 (1.07–1.40)
 In-hospital inhaled corticosteroidsNo1
Yes1.10 (1.01–1.20)
 In-hospital diureticsNo1
Yes1.36 (1.25–1.49)
 Radiography performedNo1
Yes1.42 (1.03–1.95)
Resources-related variables
 Respiratory wardYes1
No1.33 (1.22–1.45)
Missing0.38 (0.11–1.32)
 Number of respiratory specialists in unit<61
≥61.19 (1.00–1.40)
Missing0.68 (0.38–1.24)
LevelEmpty modelFinal model
CountryHospitalCountryHospital
Intra-class correlation coefficient0.110.190.120.21
Median odds ratio0.192.311.942.42
  • GOLD: Global Initiative for Chronic Obstructive Lung Disease. Wald χ2 (35) 1006.00; log likelihood −9562.0768; probability that χ2>0.0000.