Table 1

Variation of patient characteristics with different methods of identifying cases

	GP	Hospital	Paired GP/hospital	Pooled GP/hospital	p Value
Myocardial infarction
N	145	171	105	209
Men (%)	65	59	60	64	0.68
Age, mean (SD)	68 (13.8)	67 (13)	68.4 (13.8)	68.8 (14.9)	0.51
Deprivation quintile (%)
1	19	11	10	12	0.55
2	15	25	26	17
3	26	17	29	31
4	15	23	21	22
5	24	24	14	17
Smokers (%)	33	34	45	28	0.028
Diabetes (%)	15	12	8	11	0.29
Hypertension (%)	39	44	38	44	0.52
Charlson Index, mean (SD)	2.5 (1.7)	2.2 (1.6)	1.8 (1.4)	2.0 (1.6)	<0.001

Ischaemic heart disease
N	362	529	270	585
Men (%)	56	55	61	56	0.38
Age, mean (SD)	66.2 (12.7)	65.8 (11.6)	66.9 (13.4)	68.4 (12.8)	0.007
Deprivation quintile (%)
1	17	13	11	13	0.25
2	18	20	20	21
3	29	23	27	26
4	17	22	24	20
5	20	23	19	19
Smokers (%)	27	27	35	24	0.011
Diabetes (%)	11	15	13	10	0.091
Hypertension (%)	42	47	44	45	0.51
Charlson Index, mean (SD)	1.5 (1.6)	1.7 (1.6)	1.3 (1.3)	1.5 (1.5)	0.002

Cerebrovascular disease
N	302	330	153	424
Men (%)	48	47	46	47	0.97
Age, mean (SD)	70.3 (14.1)	70.8 (13.6)	72 (12.9)	73 (13.6)	0.031
Deprivation quintile (%)
1	9	12	8	11.6	0.72
2	23	18	22	19.1
3	29	29	32	23.6
4	24	22	24	23.3
5	15	20	14	22.3
Smokers (%)	26	28	29	25	0.68
Diabetes (%)	13	16	13	13	0.47
Hypertension (%)	46	49	53	46	0.40
Charlson Index, mean (SD)	2 (1.7)	2.4 (1.7)	1.9 (1.6)	2.1 (1.7)	0.014

Patient characteristics for myocardial infarction, ischaemic heart disease and cerebrovascular disease, identified using GP, hospital, paired GP/hospital and pooled GP/hospital data. Deprivation quintile 1 is least deprived. Significant differences are calculated by χ² test or Kruskal-Wallis analysis of variance.
GP, general practitioner.