Primary and secondary outcomes at 1 year: results from intention-to-treat analyses
| Intervention (N=14 pracs, n=457 px) | Control (N=15 pracs, n=454 px) | Unadjusted OR* (95% CI) unless indicated | p | Adjusted OR† (95% CI) unless indicated | p Value | |
| Mean (range) cluster size, comprising number of high risk patients on register per practice | 32.6 (3; 82) | 30.3 (4; 90) | ||||
| Mean (SD) days per person post-intervention observation time | 352 (54) | 358 (36) | ||||
| Primary outcome | ||||||
| Moderate-severe asthma exacerbation | 245 (53.6%) | 211 (46.5%) | 1.30 (0.93 to 1.80) | 0.120 | 1.27 (0.95 to 1.70) | 0.105 |
| Secondary outcomes: exacerbation-related events | ||||||
| Hospitalisation for asthma exacerbation‡ | 15 (3.3%) | 29 (6.4%) | 0.50 (0.26 to 0.94) | 0.031 | 0.51 (0.26 to 1.00) | 0.051 |
| A&E attendance for asthma exacerbation‡ | 29 (6.4%) | 37 (8.2%) | 0.74 (0.42 to 1.31) | 0.303 | 0.70 (0.37 to 1.34) | 0.284 |
| Out-of-hours contact for asthma exacerbation‡ | 26 (5.7%) | 32 (7.1%) | 0.79 (0.45 to 1.37) | 0.396 | 0.75 (0.41 to 1.37) | 0.350 |
| Oral prednisolone course for asthma exacerbation‡ | 247 (54.1%) | 213 (46.9%) | 1.31 (0.92 to 1.85) | 0.136 | 1.28 (0.95 to 1.73) | 0.112 |
| Ambulance call for asthma exacerbation | 13 (2.8%) | 12 (2.6%) | 1.03 (0.42 to 2.51) | 0.950 | 1.02 (0.45 to 2.35) | 0.954 |
| Nebulised short-acting β-agonist for asthma exacerbation | 36 (7.9%) | 63 (13.9%) | 0.51 (0.29 to 0.88) | 0.016 | 0.61 (0.36 to 1.02) | 0.061 |
| Secondary outcomes: other healthcare attendances | ||||||
| Secondary care outpatient consultations for asthma | 81 (17.7%) | 71 (15.6%) | 1.14 (0.76 to 1.70) | 0.532 | 1.27 (0.82 to 1.98) | 0.283 |
| Median (IQR) rate of primary care consultations for any reason | 9 (11) | 8 (11) | 1.09§ (0.95 to 1.26) | 0.234 | 1.06¶ (0.97 to 1.16) | 0.190 |
| ‘Did not attend’ (DNAs) at primary care consultation for any reason | 82 (17.9%) | 105 (23.1%) | 0.64 (0.29 to 1.42) | 0.270 | 0.73 (0.35 to 1.52) | 0.396 |
| Secondary outcomes: other asthma medications | ||||||
| Median (IQR) rate of short-acting β-agonist inhalers prescribed | 6 (10) | 7 (12) | 1.03§ (0.89 to 1.19) | 0.666 | 1.03¶ (0.91 to 1.17) | 0.600 |
| Median (IQR) BDP-equivalent μg/day dose of inhaled corticosteroids prescribed | 658 (1036) | 658 (1036) | 1.10§ (0.97 to 1.25) | 0.152 | 1.07¶ (0.96 to 1.18) | 0.223 |
| Median (IQR) rate of long-acting β-agonist inhalers prescribed | 8 (9) | 6 (9) | 1.24§ (1.08 to 1.43) | 0.002 | 1.08¶ (0.99 to 1.17) | 0.085 |
| Leukotreine receptor antagonists prescribed | 111 (24.3%) | 131 (28.9%) | 0.85 (0.55 to 1.31) | 0.459 | 0.96 (0.49 to 1.86) | 0.895 |
| Theophyllines prescribed | 23 (5.0%) | 40 (8.8%) | 0.56 (0.29 to 1.07) | 0.079 | 0.53 (0.21 to 1.34) | 0.179 |
Data are at patient-level, showing N (%) experiencing event per year and ORs unless otherwise indicated.
↵* OR estimated using ‘univariate’ analysis of proportions in random-effects logistic regression model, adjusted for clustering and stratification only.
↵† OR estimated using multivariable analysis of proportions in random-effects logistic regression model, adjusted for clustering and stratification plus baseline values of outcome variable, exacerbation count, age (continuous), asthma severity (no. classes of meds), Charlson co-morbidity index (in 3 categories), and rhinitis.
↵‡ Event included in count of exacerbations (see methods for full definition).
↵§ Rate ratio estimated using ‘univariate’ analysis of counts in random-effects negative binomial regression model, adjusted for clustering and stratification only.
↵¶ Rate ratio estimated using multivariable analysis of counts in random-effects negative binomial regression model adjusted for clustering and stratification plus baseline values of outcome variable, exacerbations count, age (continuous), asthma severity (#classes of meds), Charlson co-morbidity index (in 3 categories), and rhinitis.
A&E, accident and emergency.