Table 2.

12-month pre-index comorbidities and utilization of study sample, by cohort. Data are percentages, except where indicated.

Characteristic	RA Alone,	RA + CVD,		RA + Depression,		RA + CVD + Depression,
	n = 8,916	n = 608	p^*	n = 716	p^*	n = 58	p^*
No. of comorbidities, mean (SD)	1.3 (1.3)	2.8 (1.5)	< 0.001	1.9 (1.6)	< 0.001	3.9 (1.9)	< 0.001
Comorbidities
Crohn’s	0.8	0.7	0.730	0.8	0.878	3.4	0.023
Ankylosing spondylitis	1.0	1.3	0.397	2.1	0.004	6.9	< 0.001
SLE	3.1	4.9	0.012	5.0	0.004	8.6	0.015
Psoriasis	1.6	1.6	0.869	2.0	0.414	1.7	0.919
Fibromyalgia	6.8	8.4	0.143	16.9	< 0.001	27.6	< 0.001
Diabetes	9.0	24.0	< 0.001	11.0	0.067	27.6	< 0.001
Hypertension	27.1	66.1	< 0.001	31.8	0.006	65.5	< 0.001
Hyperlipidemia	19.9	61.2	< 0.001	24.0	0.008	62.1	< 0.001
Asthma and COPD	11.1	22.5	< 0.001	20.0	< 0.001	37.9	< 0.001
Osteoporosis	11.9	14.3	0.072	11.7	0.922	20.7	0.038
Osteoarthritis	23.4	35.5	< 0.001	28.5	0.002	48.3	< 0.001
Pneumonia/influenza	3.5	10.2	< 0.001	7.1	< 0.001	13.8	< 0.001
Epilepsy	0.3	0.5	0.524	0.7	0.122	5.2	< 0.001
Cancer	5.7	10.0	< 0.001	6.7	0.272	13.8	0.008
Respiratory disease	1.0	2.8	< 0.001	1.0	0.935	8.6	< 0.001
Migraine	2.4	2.6	0.746	8.1	< 0.001	10.3	< 0.001
CHF	0.7	13.3	< 0.001	2.1	< 0.001	19.0	< 0.001
Generalized anxiety disorder	0.4	0.7	0.270	5.0	< 0.001	5.2	< 0.001
Panic disorder	0.2	0.3	0.603	2.0	< 0.001	1.7	0.018
Evidence of hospitalization	7.9	34.9	< 0.001	18.6	< 0.001	60.3	< 0.001
RA-related severity covariates
RA-related surgery	4.9	6.3	0.155	8.4	< 0.001	17.2	< 0.001
Inflammation markers	57.1	55.9	0.555	61.3	0.030	56.9	0.97
Tendon injections	5.4	7.6	0.026	7.1	0.057	5.2	0.932
Arthrocentesis (small/intermediate/major)	21.9	28.0	< 0.001	26.7	0.003	34.5	0.021
Extraarticular manifestations	3.2	4.3	0.157	5.9	< 0.001	6.9	0.115
Difficulty walking	0.1	0.5	0.005	0.0	0.423	0.0	0.819
Pain in joint	0.7	1.2	0.200	1.0	0.389	1.7	0.35
NSAID	39.0	29.1	< 0.001	40.4	0.479	36.2	0.662
COX-2 inhibitors	24.2	23.4	0.650	25.8	0.317	27.6	0.545
Narcotic analgesics	44.7	58.9	< 0.001	67.6	< 0.001	74.1	< 0.001
Corticosteroids	64.4	71.4	< 0.001	70.8	< 0.001	86.2	< 0.001
MTX	73.7	67.9	0.002	75.4	0.314	58.6	0.009
Cytotoxic DMARD	3.5	5.4	0.016	2.7	0.216	13.8	< 0.001
Noncytotoxic DMARD	22.4	21.1	0.430	23.3	0.582	24.1	0.756
Etanercept	20.9	19.4	0.386	20.3	0.689	25.9	0.353
Adalimumab	4.9	3.9	0.305	4.7	0.887	6.9	0.475
Infliximab	11.9	14.6	0.041	13.7	0.147	17.2	0.206
Anakinra	1.0	1.3	0.488	1.1	0.805	3.4	0.069
Charlson Comorbidity Index, mean (SD)	1.4 (0.9)	2.6 (1.8)	< 0.001	1.7 (1.2)	< 0.001	3.3 (2.1)	< 0.001
Total pre-index cost of care, mean (SD) US$	11,091 (14,082)	24,667 (29,358)	< 0.001	16,313 (17,315)	< 0.001	38,094 (40,578)	< 0.001

↵* Reference group is RA Alone. CVD: cardiovascular disease, SLE: systemic lupus erythematosus, COPD: chronic obstructive pulmonary disease, CHF: congestive heart failure, MTX: methotrexate, DMARD: disease modifying antirheumatic drug.