Effects of the US Food and Drug Administration Boxed Warning of Erythropoietin-Stimulating Agents on Utilization and Adverse Outcome.

Purpose In March 2007, a US Food and Drug Administration boxed warning was issued for erythropoietin-stimulating agents (ESAs) regarding serious adverse events, such as venous thromboembolism (VTE). We evaluated the US Food and Drug Administration's boxed warning of ESAs used to treat chemotherapy-induced anemia because evidence on the effectiveness of boxed warnings remains inconclusive. Patients and Methods Using 2004 to 2009 SEER-Medicare data, we exploited a natural experiment to examine the effects of ESA boxed warnings on utilization and risk of VTE. The intervention group included Medicare fee-for-services patients diagnosed with colorectal, breast, or lung cancers targeted by this warning and undergoing chemotherapy; the control group included patients with myelodysplastic syndromes not targeted by this warning. The period from January 2004 to September 2006 was used as the prewarning period; the period from April 2007 to September 2009 was used as the postwarning period. The two binary dependent variables included ESA use and hospitalized VTE. Linear probability models with a difference-in-differences specification were used for estimation. Results Our sample consisted of 45,319 unique patients between 2004 and 2009. The trends in ESA use remained similar between the intervention and control groups before the warning, but started declining sharply in the intervention group only after the warning. The trends in hospitalized VTE were relatively stable. Regressions showed that the ESA boxed warning was associated with a 20.2-percentage-point reduction ( P < .001) in the likelihood of ESAs being used to treat cancers targeted by the warning, but not significantly associated with the likelihood of hospitalized VTE. Conclusion Our study showed that the warning was effective in reducing ESA utilization. Future studies should examine other regulatory drug safety actions, such as the Risk Evaluation and Mitigation Strategy initiative, whose effectiveness remains unknown.

Participatory surveillance of diabetes device safety: a social media-based complement to traditional FDA reporting.

BACKGROUND AND OBJECTIVE: Malfunctions or poor usability of devices measuring glucose or delivering insulin are reportable to the FDA. Manufacturers submit 99.9% of these reports. We test online social networks as a complementary source to traditional FDA reporting of device-related adverse events. METHODS: Participatory surveillance of members of a non-profit online social network, TuDiabetes.org, from October 2011 to September 2012. Subjects were volunteers from a group within TuDiabetes, actively engaged online in participatory surveillance. They used the free TuAnalyze app, a privacy-preserving method to report detailed clinical information, available through the network. Network members were polled about finger-stick blood glucose monitors, continuous glucose monitors, and insulin delivery devices, including insulin pumps and insulin pens. RESULTS: Of 549 participants, 75 reported device-related adverse events, nearly half (48.0%) requiring intervention from another person to manage the event. Only three (4.0%) of these were reported by participants to the FDA. All TuAnalyze reports contained outcome information compared with 22% of reports to the FDA. Hypoglycemia and hyperglycemia were experienced by 48.0% and 49.3% of participants, respectively. DISCUSSION: Members of an online community readily engaged in participatory surveillance. While polling distributed online populations does not yield generalizable, denominator-based rates, this approach can characterize risk within online communities using a bidirectional communication channel that enables reach-back and intervention. CONCLUSIONS: Engagement of distributed communities in social networks is a viable complementary approach to traditional public health surveillance for adverse events related to medical devices.