Random coefficient for SLS COPD placed in distribution of random coefficients of local authorities from CPRD (self-controlled comparison within the trial before and during the trial period)
| Variable | CPRD-xGM 2.5th percentile | CPRD-xGM median value | CPRD-xGM 97.5th percentile | SLS COPD value | SLS COPD percentile | Unusual flag |
| Count of AECOPD*† | 0.88 | 1.00 | 1.15 | 1.02 | 64.17 | No |
| Count of strict definitionn of AECOPD*‡ | 0.81 | 0.96 | 1.21 | 1.34 | 100 | Yes |
| Number of days contact with primary care* | 0.97 | 1.07 | 1.19 | 1.08 | 57.06 | No |
| Count of trial-related prescriptions§ | 0.95 | 1.03 | 1.08 | 0.63 | 0 | Yes |
| Treatment switching¶** | 0.60 | 0.63 | 0.65 | 0.59 | 0.27 | Yes |
For full definitions of above outcomes, see online supplementary appendix 1.
For Poisson models, the random intercepts represent relative rates; for logistic models, they represent ORs. SLS COPD is deemed unusual with respect to a particular variable if the random intercept for the SLS lies outside of the 2.5th–97.5th percentile range of the distribution of random intercepts of the local authorities in CPRD.
*Poisson model.
†AECOPD events were those that met any criteria from the validated algorithm.16
‡The strict definition of AECOPD events was strictly codes for acute exacerbation of COPD.
§Prescription of any treatment counted as usual care in SLS COPD.
¶Logistic model.
**Switching from one treatment class to another during follow-up.
AECOPD, acute exacerbations of COPD; COPD, chronic obstructive pulmonary disease; COPD, Salford Lung Study in chronic obstructive pulmonary disease; CPRD-xGM, Clinical Practice Research Datalink outside of Greater Manchester.