Table 1.

Baseline characteristics of Medicare beneficiaries with and without rheumatoid arthritis (RA) stratified by number of comorbid conditions in 2004 and 2008. All data percentages unless otherwise indicated.

		2004				2008
	RA	No. Comorbid Conditions in Those Without RA			RA	No. Comorbid Conditions in Those Without RA
		0	1–2	3+		0	1–2	3+
Unweighted, n	219	1180	6275	6824	184	1087	5620	6760
Age, yrs
< 55	8.2	7.1^*	8.4	7.6	8.3	10.5^*	8.8	7.6
55–64	6.9	2.2^*	4.7	9.9	9.9	2.6^*	5.6	10.5
65–74	38.8	57.9^*	46.8	36.4	45.6	57.3^*	48.3	36.5
75–84	36.5	25.3^*	31.0	34.4	27.9	23.0^*	27.6	32.4
85+	9.7	7.4^*	9.1	11.6	8.3	6.6^*	9.6	13.1
Female	76.2	49.9^*	53.6^*	58.1^*	76.8	51.9^*	54.1^*	55.4^*
Disabled	15.1	9.3	13.1	17.6	18.2	13.1	14.4	18.1
Income level
< US$25,000	62.3	51.4^*	54.8	63.7	48.4	46.7	47.7	55.8
US$25,000+	37.7	48.6^*	45.2	36.3	51.6	53.3	52.3	44.2
Race/ethnicity
Hispanic	10.1	8.0	8.3	7.3^*	13.9	7.6^*	7.6^*	8.3
Black/non-Hispanic	8.3	5.3	9.6	10.6^*	12.2	6.9^*	9.5^*	10.4
White	75.7	83.8	78.8	79.4^*	72.1	82.9^*	79.9^*	77.8
Residence
Rural	26.5	22.8	21.9	25.0	26.1	23.8	22.8	24.4
Metropolitan	73.5	77.2	78.1	75.0	73.9	76.2	77.2	75.6
Education level
> High school	40.0	45.3	42.2	39.3	41.2	48.4	47.2^*	41.6^*
High school	35.1	29.8	31.6	29.3	39.9	31.6	31.0^*	30.8^*
No high school	25.0	24.9	26.1	31.5	18.8	20.0	21.8^*	27.6^*
Prescription drug coverage
None	23.3	42.5^*	31.0^*	26.3^*	10.9	16.4	9.7	7.9
Partial	19.4	21.4^*	25.7^*	28.0^*	4.6	5.9	4.5	4.7
Full private	35.2	30.3^*	33.4^*	32.8^*	32.0	25.3	28.5	26.5
Full public	22.1	5.7^*	9.9^*	12.9^*	52.4	52.3	57.3	60.9
Self-reported health status
Excellent/good	57.6	93.9^*	83.1^*	60.8	46.8	93.9^*	84.2^*	61.7^*
Fair/poor	42.4	6.1^*	16.9^*	39.2	53.2	6.1^*	15.8^*	38.3^*

↵* p < 0.05 for comparisons between the RA and non-RA groups (0, 1–2, and 3+) for the study year of interest.