Regression analyses results from negative binomial regression for locum use at general practice level, Model A: over time (2018–2019), Model B: cross-sectionally (2019)a
| Characteristic | Model A IRR (95% CI) | Standard error | P-value | Model B IRR (95% CI) | Standard error | P-value |
|---|---|---|---|---|---|---|
| Rurality (0 = urban, 1 = rural) | 1.250 (1.095 to 1.428) | 0.085 | <0.001 | 1.300 (1.085 to 1.559) | 0.120 | <0.004 |
| IMD 2019 | 1.002 (0.999 to 1.006) | 0.002 | <0.096 | 1.005 (1.000 to 1.009) | 0.002 | <0.046 |
| QOF practice performance | 1.005 (0.991 to 1.017) | 0.007 | <0.479 | 1.009 (0.991 to 1.026) | 0.009 | <0.298 |
| Single-handed practice | 4.611 (4.101 to 5.184) | 0.276 | <0.001 | 4.618 (3.928 to 5.428) | 0.381 | <0.001 |
| QOF morbidity burden | 1.384 (0.963 to 1.991) | 0.257 | <0.079 | 1.255 (0.801 to 1.996) | 0.287 | <0.320 |
| Percentage of female population | 0.967 (0.959 to 0.981) | 0.006 | <0.001 | 0.970 (0.946 to 0.994) | 0.012 | <0.015 |
| Proportion of practice population aged ≥65 years | 0.970 (0.950 to 0.984) | 0.009 | <0.001 | 0.971 (0.958 to 0.988) | 0.007 | <0.001 |
| Practice workload (total GP FTE/list size) | 1.001 (1.001 to 1.002) | 0.001 | <0.001 | 1.001 (1.001 to 1.002) | 0.001 | <0.003 |
| CQC ratings (reference group is outstanding services) | Reference group | Reference group | ||||
| Inadequate | 2.108 (1.370 to 3.246) | 0.464 | <0.001 | 2.687 (1.451 to 4.974) | 0.844 | <0.001 |
| Requires improvement | 1.229 (0.949 to 1.592) | 0.163 | <0.118 | 1.198 (0.822 to 1.744) | 0.229 | <0.346 |
| Good | 1.343 (1.103 to 1.637) | 0.136 | <0.003 | 1.267 (0.947 to 1.696) | 0.188 | <0.111 |
| Year (reference year is 2018) | Reference year | — | ||||
| 2019 | 1.055 (0.970 to 1.148) | 0.045 | <0.210 | — | ||
| Constant | 0.041 (0.011 to 0.142) | 0.026 | <0.001 | 0.020 (0.004 to 0.111) | 0.018 | <0.001 |
↵a Locum use is defined as practice aggregate FTE of locum doctors. QOF performance is measured as % achievement of the population across all QOF indicators. Coefficients can be interpreted as percentage change, for example, adjusted locum use in London was 0.45% lower than the East of England (Model A). CI = confidence interval. CQC = Care Quality Commission. FTE = full-time equivalent. IMD = Index of Multiple Deprivation. IRR = incidence rate ratio. QOF = Quality and Outcomes Framework.