News Release

Large spikes in handgun acquisitions seen in aftermath of mass shootings

Peer-Reviewed Publication

American College of Physicians

1. Large spikes in handgun acquisitions seen in aftermath of mass shootings
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Large increases in handgun acquisitions occurred in California immediately following the mass shootings in Newtown, Connecticut in 2012 and San Bernardino, California in 2015. The spikes were short-lived and accounted for less than 10 percent of annual handgun acquisitions statewide, but researchers express concern about whether repeated shocks of this kind could lead to substantial increases in the prevalence of firearm ownership. The findings are published in Annals of Internal Medicine.

Each year in the United States, more than 32,000 people die of gunshot wounds. While mass shootings account for less than 1 percent of those deaths, they are the most visible form of firearm violence. Mass shootings may boost firearm sales among people who are concerned about personal protection or among those who fear that the government will react to the mass shooting with increased gun control measures. News stories and two studies have reported sharp increases in handgun acquisition after several mass shootings, but the size and nature of these increases have not been well-described. Moreover, those reports rely on statistics from the National Instant Criminal Background Check System (NICS), which does not retain purchase-level information.

Using detailed individual-level information on firearm transactions in California between 2007 and 2016, researchers at Stanford University analyzed acquisition patterns after two of the highest-profile mass shootings in U.S. history. Overall, the number of handguns acquired in California increased sharply in the first 12 weeks following Newtown and San Bernardino mass shootings. Large and significant spikes occurred among white and Hispanic persons, but not among black persons. Increases in acquisitions were also larger among those who had no record of having previously acquired a handgun. After San Bernardino, a much larger increase in acquisitions occurred in neighborhoods in and around that city than in other parts of the state.

The researchers suggest that these findings may have implications for public health, as firearm ownership is a risk factor for firearm-related suicide and homicide. Further research is needed to explore both cumulative effects and lasting shifts in acquisition patterns; their causes; and their implications for public health, crime, and social cohesion.

Media contacts: For an embargoed PDF, please contact Cara Graeff. To reach the lead author David Studdert, LLB, ScD, please contact Beth Duff-Brown at or 650-736-6064.

2. A routine invasive strategy may significantly reduce death risk in unstable angina
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The absolute cumulative probability of death at 12 months was 5 percent lower for patients who received routine invasive coronary angiography and revascularization as indicated during an unstable angina admission compared to those who did not. The survival benefit persisted when angiography was delayed up to 2 months after the first unstable angina episode. Results of a comparative effectiveness analysis are published in Annals of Internal Medicine.

Non-ST-segment elevation acute coronary syndromes consist of non-ST-segment elevation myocardial infarction (MI) and unstable angina. Reported rates of unstable angina have declined with the introduction of high-sensitivity troponin testing, which identifies patients with non-ST-segment elevation MI, yet patients with unstable angina still account for one-quarter to one-half of all those with acute coronary syndromes who present to the hospital. In general, current guidelines recommend routine invasive coronary angiography for patients with non-ST-segment elevation MI, but not for those with unstable angina. Meta-analyses of previous trials have shown conflicting results with regard to routine invasive management of unstable angina, potentially due to the high crossover from control to intervention groups in the randomized controlled trials.

Researchers at St. Vincent's Hospital, University of Melbourne, Victoria, Australia used hospital discharge data to assess the effect of angiography on mortality in 33,901 patients admitted to the hospital with an initial episode of unstable angina. The investigators compared outcomes of patients who had angiography during their first hospitalization with those of other patients by using advanced statistical methods to adjust for differences in individual patient characteristics and to account for crossovers from control to intervention groups. The data showed that routine angiography, with or without subsequent revascularization, was associated with a 52 percent relative decrease in 12-month mortality. Revascularization offered no additional statistical mortality benefit compared with diagnostic angiography alone. The authors conclude that routine invasive diagnostic angiography up to 2 months after an emergent admission for unstable angina in association with optimum medical therapy might prevent up to 5 deaths per 100 hospital admissions for unstable angina during the 12 months after hospitalization for the initial episode.

Media contacts: For an embargoed PDF, please contact Cara Graeff. To speak with the lead author, Dr. Vijaya Sundararajan, please contact Elizabeth Lopez at or +61 3 8344 2704.

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