TABLE 4.

Predictors for first anaphylactic events following IvIg administrations, calendar period 2009–18

	Anaphylactic events	IvIg administrations	IR per 10 000 IvIg administrations (0.95 CI)	Crude IRR 1 (0.95 CI)	Adjusted IRR 1 , 2 (0.95 CI)
Total IvIg administrations	128	174 413	7.34 (6.12–8.73)
Predictors
Age (years)
<18	39	18 504	21.08 (14.98–28.82)	3.69 (2.52–5.41)	2.94 (1.91–4.52)
≥18 or unknown	89	155 909	5.71 (4.58–7.03)	1	1
Sequence of IvIg treatment
First IvIg administration	57	24 919	22.87 (17.32–29.64)	1	1
Effectively IvIg‐naive administration 3	20	18 551	10.78 (6.58–16.66)	0.47 (0.28–0.78)	0.76 (0.44–1.32)
Subsequent administration 4	51	130 943	3.89 (2.89–5.13)	0.17 (0.12–0.25)	0.27 (0.17–0.42)
Non‐predictors
Sex
Male	58	77 451	7.49 (5.68–9.69)	1	1
Female	70	96 962	7.22 (5.62–9.13)	0.96 (0.68–1.37)	1.07 (0.75–1.52)
Transfusion of blood component
No transfusion	116	168 122	6.90 (5.70–8.28)	1	1
Red blood cells ± other blood products	11	5615	19.59 (9.77–35.06)	2.84 (1.53–5.27)	1.53 (0.79–2.95)
Other blood products only	1	676	NA	NA	NA
IvIg Indication
Low‐dose indication 5	36	68 045	5.29 (3.70–7.33)	1	1
High‐dose indication 6	78	95 335	8.18 (6.46–10.22)	1.55 (1.04–2.31)	1.20 (0.76–1.88)

CI = confidence interval; IR = incidence rate; IRR = incidence rate ratio; IvIg = intravenous immunoglobulin; NA = not applicable due to cell counts ≤3.

¹ Estimated from Poisson regression models clustering for patients.

² IRR estimates adjusted for age (<18, 18+), sex, race, sequence of IvIg treatment, hospital setting, transfusion of blood components, IvIg indication dose group and calendar period.

³ No IvIg administration in the previous 42 days except the first IvIg administration.

⁴ IvIg administration in the previous 42 days.

⁵ Including neurological, hematological and autoimmune diseases.

⁶ Including immunodeficiency, malignant lymphoid or hematopoietic neoplasm, anti‐cancer treatment and sepsis/septicemia.