Table 3

Associations between patient characteristics at diagnosis of COPD in primary care and time to first hospital admission for acute exacerbation of COPD

Characteristic at diagnosis of COPD in primary careLevelRisk of first admission
Unadjusted HR (95% CI)p ValueFully adjusted HR (95% CI)*p Value
Age (years)Increase of 1 SD (11.4 years)1.42 (1.35 to 1.49)<0.00011.31 (1.23 to 1.39)<0.0001
SexFemale1.06 (0.97 to 1.17)0.210.99 (0.90 to 1.09)0.82
DeprivationQuintile 1 (most deprived)1.000.0031.000.0002
Quintile 20.96 (0.85 to 1.08)0.89 (0.79 to 1.01)
Quintile 30.80 (0.70 to 0.92)0.76 (0.66 to 0.87)
Quintile 40.80 (0.68 to 0.93)0.80 (0.68 to 0.93)
Quintile 5 (least deprived)0.84 (0.71 to 1.01)0.74 (0.62 to 0.89)
COPD severity (% predicted forced expiratory volume)Mild1.00<0.00011.00<0.0001
Moderate1.43 (1.17 to 1.75)1.44 (1.18 to 1.76)
Severe2.89 (2.37 to 3.54)2.44 (1.99 to 2.99)
Very severe4.55 (3.60 to 5.75)3.33 (2.63 to 4.22)
Unknown2.41 (1.93 to 3.01)1.64 (1.30 to 2.06)
Body mass index (kg/m2)Normal1.00<0.00011.00<0.0001
Low1.61 (1.37 to 1.89)1.47 (1.25 to 1.73)
High0.79 (0.69 to 0.89)0.83 (0.73 to 0.94)
Unknown2.32 (2.04 to 2.64)2.39 (2.09 to 2.74)
Smoking statusCurrent1.000.0111.00<0.0001
Not current1.11 (1.00 to 1.22)0.86 (0.78 to 0.96)
Never smoked0.71 (0.52 to 0.96)0.47 (0.35 to 0.65)
Unknown1.18 (0.89 to 1.55)0.70 (0.52 to 0.94)
Asthma comorbidity1.11 (0.97 to 1.26)0.121.12 (0.97 to 1.28)0.11
Other respiratory comorbidity2.28 (1.96 to 2.64)<0.00011.47 (1.26 to 1.72)<0.0001
Non-respiratory comorbidity1.53 (1.39 to 1.68)<0.00011.39 (1.24 to 1.55)<0.0001
Prior admission with COPD2.67 (2.42 to 2.95)<0.00011.94 (1.75 to 2.17)<0.0001
Prior intervention for COPD1.38 (1.26 to 1.52)<0.00011.22 (1.10 to 1.36)0.0002
  • The HRs are from Cox proportional hazards models for time to admission since diagnosis of COPD in primary care.

  • *Adjusted for all variables in the table.

  • COPD, chronic obstructive pulmonary disease.