Table 2.

Self-controlled case series analysis results for Guillain-Barré syndrome (GBS) and negative controls following herpes zoster (HZ) using MarketScan Commercial Claims and Encounters (CCAE) and Centers for Medicare and Medicaid Services (CMS) Medicare data, United States, 2010–2018^a

		Risk Window	Control Windows
	Number of HZ cases	Cases 1–42 days after HZ	Primary (Cases 100–365 days after HZ)		Secondary (Cases 43–99 days after HZ)
Group	#	#	#	Rate Ratio	#	Rate Ratio
MarketScan CCAE, 2010–2018, 18–64 years (N = 489,516 HZ cases)
GBS	11	5	5	6.3 (1.8–21.9); p = .0035	1	6.8 (0.8–58.1); p = .0805
Negative controls
Appendicitis	281	38	202	1.2 (0.8–1.7); p = .3219	41	1.3 (0.8–2.0); p = .3083
Nephrolithiasis	214	26	159	1.0 (0.7–1.6); p = .8685	29	1.2 (0.7–2.1); p = .4676
Cholecystitis	443	49	332	0.9 (0.7–1.3); p = .6592	62	1.1 (0.7–1.6); p = .7139
Fractures upper limb	3,994	463	2,898	1.0 (0.9–1.1); p = .8140	633	1.0 (0.9–1.1); p = .9042
CMS Medicare, 2014–2018, ≥65 years (N = 650,229 HZ Cases)
GBS	41	11	17	4.1 (1.9–8.7); p = .0003	13	1.1 (0.5–2.6); p = .7356
Negative controls
Appendicitis	316	37	225	1.0 (0.7–1.5); p = .8188	54	0.9 (0.6–1.4); p = .7334
Nephrolithiasis	279	44	194	1.4 (1.0–2.0); p = .0301	41	1.5 (1.0–2.2); p = .0832
Cholecystitis	1,496	221	1,054	1.3 (1.1–1.5); p = .0001	221	1.4 (1.1–1.6); p = .0013
Fractures upper limb	12,375	1,560	8,959	1.1 (1.0–1.2); p = .0004	1,856	1.1 (1.1–1.2); p = .0001

^aMarketScan CCAE data from 2010–2018; CMS Medicare data from 2014–2018.