Table 1.

Characteristics of patients with severe mental illness and the controls

Characteristic	Mental illness		Control		P valuea
	N	%	N	%
Gender
Male	8606	43.9	294,036	47.2	<0.001
Female	11,003	56.1	329,139	52.8
Age group
18–34	3256	16.6	220,215	35.3	<0.001
35–49	5131	26.2	190,390	30.6
50–64	4168	21.3	133,643	21.4
65+	7054	36	78,927	12.7
Insurance premium
Less than US$ 528	11,631	59.3	207,414	33.3	<0.001
US$ 528–833	5830	29.7	220,778	35.4
US$ 834 or more	2148	11	194,983	31.3
Dentist no. per 10,000 residents
Less than 3.43	4968	25.3	153,061	24.6	<0.001
3.43–6.50	7494	38.2	293,535	47.1
6.61 or more	7147	36.4	176,579	28.3
Hospitalization bed days
Less than 30 days	17,746	90.5	618,760	99.3	<0.001
30 days or more	1863	9.5	4415	0.7
Low income
Yes	1196	6.1	5368	0.9	<0.001
No	18,413	93.9	617,807	99.1
Outpatient visit no.
0–6	889	4.5	158,353	25.4	<0.001
7–23	6083	31.1	315,280	50.6
24 or more	12,637	64.4	149,542	24

^aChi-square test