Multiple regression analyses
| PCT level* | Regression coefficient | 95% CIs | p Value |
| Observed prevalence | 1.325 | 1.204 to 1.459 | <0.001 |
| IMD (deprivation) score | 1.023 | 1.018 to 1.028 | <0.001 |
| GPs/100000 population | 0.995 | 0.991 to 1.000 | 0.052 |
| Practice nurses/100000 population | 0.992 | 0.987 to 0.996 | 0.001 |
| Smoking prevalence | 1.023 (Ed) | 1.012 to 1.033 | <0.001 |
| QOF PE7 | 0.678 | 0.466 to 0.985 | 0.042 |
| Practice level† | Incidence rate ratio | 95% CIs | p Value |
| Observed prevalence | 1.224 | 1.206 to 1.243 | <0.001 |
| Undiagnosed prevalence | 1.045 | 1.032 to 1.059 | <0.001 |
| IMD (deprivation) score | 1.009 | 1.006 to 1.012 | <0.001 |
| Smoking prevalence | 1.036 | 1.031 to 1.042 | <0.001 |
| GPs/100000 population | 0.998 | 0.998 to 0.999 | <0.001 |
| QOF PE7 | 0.790 | 0.730 to 0.855 | <0.001 |
| QOF PE8 | 0.902 | 0.850 to 0.957 | 0.001 |
| COPD clinical quality 8 (influenza immunisation) (Ed) | 0.825 | 0.690 to 0.987 | 0.036 |
↵* Stepwise linear regression. Adjusted R-squared=0.75. Dependent variable: admission rates for COPD.
↵† Stepwise Poisson regression, Dependent variable: observed admission count.
COPD, chronic obstructive pulmonary disease; COPD 8, the percentage of patients with COPD who have had influenza immunisation in the preceding 1 September to 31 March; GP, general practitioner; IMD, Index of Multiple Deprivation; PCT, primary care trust; PE7, score for ability to obtain a consultation within two working days; PE8, score for ability to book an appointment with a GP more than 2 days ahead; QOF, Quality and Outcomes Framework.