Sociodemographic Characteristics of Adverse Event Reporting in the USA: An Ecologic Study

The Food and Drug Administration Adverse Event Reporting System (FAERS) is a vital source of new drug safety information, but whether adverse event (AE) information collected from these systems adequately captures experiences of the overall United States (US) population is unknown.

To examine determinants of consumer AE reporting in the USA.

Five-year AE reporting rate per 100,000 residents per US county were calculated, mapped, and quartiled for AE reports received directly from consumers between 2011 and 2015. Associations between county-level sociodemographic factors obtained from County Health Rankings and AE reporting rates were evaluated using negative binomial regression.

Reporting rates were variable across US counties with > 17.6 reports versus ≤ 5.5 reports/100,000 residents in the highest and lowest reporting quartile, respectively. Controlling for drug utilization, counties with higher reporting rates had higher proportions of individuals age ≥ 65 years (e.g., 2.4% reporting increase per 1% increase in individuals age > 65, incidence rate ratio (IRR): 1.024, 95% confidence interval (CI): 1.017–1.030), higher proportions of females (IRR: 1.027, 95% CI 1.012–1.043), uninsured (IRR: 1.009, 95% CI 1.005–1.013), higher median log household incomes (IRR: 1.897, 95% CI 1.644–2.189) and more mental health providers per 100,000 residents (IRR: 1.003, 95% CI 1.001–1.004). Lower reporting was observed in counties with higher proportions of individuals age ≤ 18 years (IRR: 0.966, 95% CI 0.959–0.974), American Indian or Alaska Native individuals (IRR: 0.991, 95% CI 0.986–0.996), individuals not proficient in English (IRR: 0.978, 95% CI 0.965–0.991), and individuals residing in rural areas within a county (IRR: 0.998, 95% CI 0.997–0.998).

Observed variations in consumer AE reporting may be related to sociodemographic factors and healthcare access. Because these factors may also correspond to AE susceptibility, voluntary AE reporting systems may be suboptimal for capturing emerging drug safety concerns among more vulnerable populations.