Table 1.

Demographic and clinical characteristics of cancer cases and controls with rheumatoid arthritis

Characteristic	SEER Cases n = 10,263		NMSC n=501		SCC n=150		BCC n=161		Controls n = 30,475
	N	%	N	%	N	%	N	%	N	%
Age at selection/diagnosis (years)
65–69	1,369	13.3	78	15.6	20	13.3	29	18.0	4,536	14.9
70–74	2,783	27.1	122	24.4	36	24.0	48	29.8	8,223	27.0
75–79	2,509	24.4	96	19.2	37	24.7	27	16.8	6,861	22.5
80–84	1922	18.7	102	20.4	29	19.3	28	17.4	5,571	18.3
85+	1680	16.4	103	20.6	28	18.7	29	18.0	5,284	17.3
Sex
Male	3,140	30.6	144	28.7	54	36.0	69	42.9	6,111	20.1
Female	7,123	69.4	357	71.3	96	64.0	92	57.1	24,364	79.9
Race
White	8,389	81.7	501	100.0	150	100.0	161	100.0	23,860	78.3
Black	1,136	11.1	.	.	.	.	.	.	3,389	11.1
Other	738	7.2	.	.	.	.	.	.	3,226	10.6
Year of diagnosis/selection
2007–2009	2,878	28.0	212	42.3	.	.	.	.	8,080	26.5
2010–2012	3,268	31.8	188	37.5	72	48.0	70	43.5	9,684	31.8
2013–2015	4,117	40.1	101	20.2	78	52.0	91	56.5	12,711	41.7
Smoking
No	4,152	40.5	255	50.9	66	44.0	81	50.3	15,360	50.4
Yes	6,111	59.5	246	49.1	84	56.0	80	49.7	15,115	49.6
Complications of rheumatoid arthritis a
No	8,787	85.6	421	84.0	123	82.0	141	87.6	26,248	86.1
Yes	1,476	14.4	80	16.0	27	18.0	20	12.4	4,227	13.9
Opioid use
None	2,988	29.1	183	36.5	43	28.7	42	26.1	9,639	31.6
1–3 prescriptions	2,802	27.3	169	33.7	49	32.7	53	32.9	7,902	25.9
4+ prescriptions	4,473	43.6	149	29.7	58	38.7	66	41.0	12,934	42.4
Any treatment b
No	4,237	41.3	204	40.7	54	36.0	51	31.7	13,564	44.5
Yes	6,026	58.7	297	59.3	96	64.0	110	68.3	16,911	55.5
Corticosteroid use
No	4,065	39.6	232	44.8	48	32.0	56	34.8	223	44.5
Yes	6,198	60.4	286	55.2	102	68.0	105	65.2	278	55.5
Methotrexate use
No	6,145	59.9	310	61.9	89	59.3	90	55.9	19,100	62.7
Yes	4,118	40.1	191	38.1	61	40.7	71	44.1	11,375	37.3
Other DMARD use c
No	7,130	69.5	349	69.7	92	61.3	103	64.0	21,546	70.7
Yes	3,133	30.5	152	30.3	58	38.7	58	36.0	8,929	29.3
TNFi use
No	8,571	83.5	396	79.0	127	84.7	119	73.9	25,544	83.8
Yes	1,692	16.5	105	21.0	23	15.3	42	26.1	4,931	16.2
TNFi medication
Etanercept	508	5.0	30	6.0	NR	NR	14	8.7	1,681	5.5
Infliximab	907	8.8	64	12.8	13	8.7	21	13.0	2,384	7.8
Adalimumab	368	3.6	16	3.2	NR	NR	NR	NR	1,199	3.9
Golimumab	52	0.5	NR	NR	NR	NR	NR	NR	130	0.4
Certolizumab	65	0.6	NR	NR	NR	NR	NR	NR	226	0.7

Abbreviations: NMSC, non-melanoma skin cancer; BCC, basal cell carcinoma; SCC, squamous cell carcinoma; TNFi, tumor necrosis factor inhibitor; MTX, methotrexate; DMARD, disease modifying antirheumatic drug; NR, not reported because cell size < 12.

^aA person is classified as having complications of RA if an RA diagnosis occurs in the first position of a hospitalization claims or if there is a diagnosis for any of the following conditions prior to cancer diagnosis/control selection: Sjogren syndrome, interstitial lung disease, Felty syndrome, or vasculitis. See Supplemental Table 2 for diagnosis codes.

^bAny treatment is defined as methotrexate, other DMARD, or TNFi use.

^cOther DMARDs include hydroxychloroquine, leflunomide, sulfasalazine, azathioprine, cyclophosphamide, cyclosporine, penicillamine, and minocycline. See Supplemental Table 1.