Table 5

Associations between characteristics at diagnosis of COPD in primary care and times to 2nd to 10th hospital admissions for AECOPD

Characteristic at diagnosis of COPD in primary careLevelRisk of readmission (2nd to 10th)*
Unadjusted HR (95% CI)p ValueFully adjusted HR (95% CI)†p Value
Age (years)Increase of 1 SD (11.4 years)1.02 (0.97 to 1.07)0.491.02 (0.97 to 1.08)0.42
SexFemale0.95 (0.87 to 1.04)0.270.97 (0.89 to 1.07)0.57
DeprivationQuintile 11.000.231.000.27
Quintile 20.92 (0.83 to 1.03)0.94 (0.84 to 1.04)
Quintile 30.91 (0.80 to 1.04)0.94 (0.82 to 1.08)
Quintile 40.94 (0.81 to 1.09)0.97 (0.84 to 1.13)
Quintile 50.81 (0.67 to 0.99)0.80 (0.65 to 0.98)
COPD severity (% predicted forced expiratory volume)Mild1.00<0.00011.00<0.0001
Moderate1.19 (0.96 to 1.47)1.19 (0.95 to 1.47)
Severe1.42 (1.15 to 1.76)1.39 (1.12 to 1.72)
Very severe1.78 (1.42 to 2.22)1.75 (1.39 to 2.19)
Unknown1.59 (1.26 to 2.01)1.44 (1.14 to 1.83)
Body mass index (kg/m2)Normal1.000.0031.000.021
Low1.10 (0.94 to 1.29)1.10 (0.93 to 1.30)
High0.86 (0.75 to 0.98)0.87 (0.76 to 0.99)
Unknown1.03 (0.92 to 1.16)1.01 (0.89 to 1.13)
Smoking statusCurrent1.000.231.000.46
Not current1.02 (0.93 to 1.12)0.99 (0.90 to 1.10)
Never smoked0.79 (0.51 to 1.23)0.78 (0.50 to 1.23)
Unknown1.25 (0.97 to 1.61)1.17 (0.89 to 1.53)
Asthma comorbidity1.10 (0.98 to 1.23)0.111.11 (0.98 to 1.26)0.087
Other respiratory comorbidity1.21 (1.06 to 1.37)0.0041.12 (0.98 to 1.28)0.11
Non-respiratory comorbidity0.99 (0.90 to 1.09)0.850.99 (0.89 to 1.09)0.79
Prior admission with COPD1.34 (1.23 to 1.47)<0.00011.32 (1.20 to 1.45)<0.0001
Prior intervention for COPD1.09 (1.00 to 1.19)0.0531.06 (0.96 to 1.16)0.23
  • The HRs are from Prentice-Williams-Peterson models for time to admission since start of at risk period for admission with common regression coefficient(s) across the admission strata.

  • *Patients were deemed ‘at risk’ of further AECOPD admission from 14 days after the date of discharge of the Continuous Inpatient Stay in which the previous exacerbation occurred.

  • †Adjusted for all variables in the table.

  • AECOPD, acute exacerbation of COPD; COPD, chronic obstructive pulmonary disease.