Self-controlled assessment of thromboembolic event (TEE) risk following intravenous immune globulin (IGIV) in the U.S. (2006–2012)

Since 2013, the U.S. Food and Drug administration (FDA) has required that intravenous immune globulin (IGIV) products carry a boxed warning concerning the risk of thromboembolic events (TEEs). This study assessed the incidence of TEEs attributable to IGIV in a large population-based cohort. A self-controlled risk interval design was used to quantify the transient increase in TEE risk during the risk interval (days 0–2 and 0–13 following IGIV for arterial and venous TEEs, respectively) relative to a later control interval (days 14–27 following IGIV). Potential IGIV-exposed TEE cases from 2006 to 2012 were identified from the FDA-sponsored Sentinel Distributed Database and confirmed through medical record review. Inpatient IGIV exposures were not included in the venous TEE analysis due to concerns about time-varying confounding. 19,069 new users of IGIV who received 93,555 treatment episodes were included. Charts were retrieved for 62% and 70% of potential venous and arterial cases, respectively. There was a transient increase in the risk of arterial TEEs during days 0–2 following IGIV treatment (RR = 4.69; 95% CI 1.87, 11.90; absolute increase in risk = 8.86 events per 10,000 patients, 95% CI 3.25, 14.6), but no significant increase in venous TEE risk during days 0–13 following outpatient IGIV treatments (RR = 1.07, 95% CI 0.34, 3.48). Our results suggest there is a small increase in the absolute risk of arterial TEEs following IGIV. However, lower-than-expected chart retrieval rates and the possibility of time-varying confounding mean that our results should be interpreted cautiously. Continued pharmacovigilance efforts are warranted.