Table 1

Descriptive statistics on the 7521 general practices included in the analysis

Rates of ED attendance per 1000 population	Mean	SD	25th percentile	Median	75th percentile
Total ED attendances	256.5	89.8	195.1	247.6	311.4
Definition 1: self-referred discharged (Tammes et al) 5 6	93.6	50.4	56.7	86.9	124.0
Definition 2: GP treatable (NHS Digital)15	33.7	23.6	17.2	28.2	44.0
Definition 3: no treatment and no-follow up (McHale et al)16	15.5	12.8	6.8	12.5	20.5
Primary care quality measures
Proportion of clinical Quality and Outcomes Framework points achieved	0.954	0.070	0.943	0.977	0.994
Proportion of patients who would recommend the practice	0.774	0.124	0.701	0.793	0.869
Proportion of patients reporting good overall experience of GP surgery	0.852	0.092	0.803	0.870	0.921
Proportion of patients who could see their preferred GP	0.620	0.173	0.500	0.630	0.750
Proportion of patients reporting easy phone access	0.731	0.168	0.625	0.761	0.865
Proportion of patients able to get an appointment to see or speak to someone	0.847	0.081	0.801	0.860	0.906
Proportion of patients who were able to get same day appointment	0.367	0.145	0.258	0.350	0.458
Control variables
Size of the registered population	7459	4444	4086	6629	9965
Proportion of registered population aged 0–4 years	0.060	0.016	0.049	0.058	0.069
Proportion of registered population aged 5–15 years	0.126	0.027	0.112	0.124	0.139
Proportion of registered population aged 16–44 years	0.388	0.086	0.333	0.373	0.426
Proportion of registered population aged 45–54 years	0.143	0.021	0.134	0.146	0.156
Proportion of registered population aged 55–64 years	0.113	0.026	0.097	0.116	0.130
Proportion of registered population aged 65–74 years	0.093	0.035	0.068	0.094	0.117
Proportion of registered population aged 75–85 years	0.055	0.022	0.039	0.055	0.069
Proportion of registered population aged 85+ years	0.022	0.012	0.014	0.021	0.029
Income deprivation score	0.176	0.110	0.087	0.150	0.245
Proportion of registered patients of UK white ethnicity	0.764	0.254	0.649	0.879	0.949
Proportion of registered patients unemployed	0.051	0.047	0.017	0.039	0.072
Response rate to General Practitioner Patient Survey	0.412	0.110	0.330	0.419	0.496
Atrial fibrillation prevalence (proportion of registered patients)	0.020	0.254	0.011	0.017	0.021
COPD prevalence (proportion of registered patients)	0.027	0.669	0.013	0.018	0.024
Asthma prevalence (proportion of registered patients)	0.078	1.660	0.051	0.059	0.067
Heart failure prevalence (proportion of registered patients)	0.009	0.138	0.005	0.007	0.009
Coronary heart disease prevalence (proportion of registered patients)	0.042	0.853	0.025	0.032	0.040
Distance from GP practice to nearest type one ED (km)	6.858	6.677	2.503	4.497	9.014
Rate of attendance at type 1–3 EDs (per 10 patients)	0.830	1.012	0.105	0.388	1.253
Number of GPs	5.349	3.388	3.000	4.915	7.099
Variables included in sensitivity analyses
Rated good or outstanding by CQC on first inspection	0.828	0.378	1.000	1.000	1.000
Weighted proportion of patients who could see their preferred GP	0.590	0.171	0.469	0.595	0.715

COPD, chronic obstructive pulmonary disease; CQC, Care Quality Commission; ED, emergency department; GP, general practitioner.