Table 1.

Baseline characteristics, diagnoses, and immunosuppressant medications among included patients, by prophylaxis use.

	Total Cohort (N=316)		Yes prophylaxis (N=124)		No prophylaxis (N=192)
	N	%	N	%	N	%	p-value*
Female	252	80%	93	75%	159	83%	0.12
Age (mean (SD))	43.3 (17.3)		44.7 (16.6)		42.3 (17.7)		0.13
<18	12	4%	2	2%	10	5%
18–50	184	58%	68	55%	116	60%
51–75	110	35%	51	41%	59	31%
>75	10	3%	3	2%	7	4%
Race							0.25
White	118	37%	54	44%	64	33%
African American	39	12%	16	13%	23	12%
Asian	61	19%	19	15%	42	22%
Hispanic	60	19%	19	15%	41	21%
Other/multiple	38	12%	16	13%	22	11%
Comorbid conditions and clinical parameters
Charlson score (mean (SD))	3.3 (2.9)		3.6 (3.1)		3.2 (2.7)		0.22
Lung disease*	44	14%	31	16%	13	10%	0.21
White blood cell count (1000/mL, mean (SD))	7.4 (3.6)		8.5 (4.0)		6.7 (3.1)		<0.001
Lymphocyte count (1000/mL, mean (SD))†	1.2 (0.7)		1.2 (0.7)		1.3 (0.7)		0.08
Neutrophil count (1000/mL, mean (SD))‡	5.6 (3.4)		6.7 (3.7)		4.8 (3.0)		<0.001
Diagnosis requiring immunosuppression							<0.001
High Risk
Granulomatosis with polyangiitis	47	15%	30	24%	17	9%
Microscopic polyangiitis	21	7%	13	10%	8	4%
Intermediate Risk
Dermatomyositis	55	17%	30	24%	25	13%
Polymyositis	17	5%	6	5%	11	6%
Systemic Lupus Erythematosus	176	56%	45	36%	131	68%
Anchor immunosuppressant drug in drug bundle, among patients with an index drug							<0.001
Highest Risk
Cyclophosphamide	30	9%	23	19%	7	4%
Intermediate Risk
Rituximab	41	13%	28	23%	13	7%
High-dose glucocorticoids	94	30%	37	30%	57	30%
Lower Risk
Mycophenolate	71	22%	15	12%	56	29%
Azathioprine	33	10%	11	9%	22	11%
Methotrexate	47	15%	10	8%	37	19%

^*p-value for chi square or t-test, as appropriate

^*Lung disease: defined as any code for 416.8, 416.9, 490.x-505.x, 506.4, 508.1, or 508.8 prior to the index date

^**: N = 296

^†: N=296

^‡: N=296