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2020 May 20

Traffic deaths: up or down?

Filed under: Uncategorized — gasstationwithoutpumps @ 21:02
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I saw two NPR headlines today:

As States Locked Down In March, Motor Vehicle Fatality Rate Spiked By 14%

and

Organ Transplants Down As Stay-At-Home Rules Reduce Fatal Traffic Collisions

So which is it? Are fatalities up or down?

Closer reading reveals that the crucial word here is “rate”—both the number of fatalities and the amount of driving are down, but the ratio of them (fatalities per million miles driven) is up, because idiots are driving faster on nearly empty roads.

The first article says “for every 100 million miles driven in March [2020] there were 1.22 deaths on the road, compared to 1.07 in March 2019.”  The article also says “The total number of motor-vehicle-related deaths dropped by 8% in March of this year compared to March 2019, but the number of miles driven dropped by over 18%, due to myriad COVID-19 related impacts.”

The impact on organ transplants has been bigger than the 8% drop in traffic fatalities—from the second article: “From March 8 to April 11, the number of organ donors who died in traffic collisions was down 23% nationwide compared with the same period last year, while donors who died in all other types of accidents were down 21%, according to data from UNOS.”

The fatalities were down 8%, but the organ donations resulting from those fatalities were down 23%—something other than the reduction in crashes is at play.  The article also mentions that other major sources of donated organs are down: “At Kaiser Permanente medical centers in Northern California, where 4.4 million patients get care, weekly hospital admissions for heart attacks have dropped almost 50% since the region’s first COVID-19 death was reported in early March.  Strokes and heart attacks are the second and third most common sources of organ donations, accounting for 27% and 20% of organs, respectively.”

Organ transplants were way down because it takes a lot of hospital resources to maintain a brain-dead body to keep the organs alive—”Earlier in the pandemic, as medical centers braced for a wave of COVID-19 patients, they wanted to free up as many ventilators as possible. In addition to donors needing to die on ventilators to keep their organs viable, doctors often keep them on ventilators for two or three days while transplant teams and recipients are lined up. Then the recipients need to be on ventilators during surgery.”

So the combination of fewer donor deaths in hospital, fewer hospitals willing to dedicate ventilators to organ transplant donors, deferral of elective surgery, fear that donor organs may be infected with SARS-CoV-2, and general reluctance to have immunosuppressed transplant patients exposed to SARS-CoV-2 in hospitals has resulted in massive decreases in transplants: “Transplant surgeries across the country plummeted 52% from March 8 to April 11, according to UNOS data.”  (I think that they mean that the March 8–April 11 period is 52% lower than the corresponding period last year, though that is not the literal meaning of their sentence.)

My main takeaways from this pair of articles:

  • traffic dropped (though not as much as I had thought)
  • traffic fatalities dropped (though not as much as traffic did)
  • the organ transplant market was massively disrupted—way more than the drop in donor deaths would have suggested.

2 Comments »

  1. This is how statistics are being reported these days. Conflicting and confusing. My husband is a biostatistician and he won’t read any of this stuff. I still try to make some sense of it.

    Comment by cindy knoke — 2020 May 20 @ 21:13 | Reply

    • In defense of NPR, the articles themselves were well-written and explained the concepts clearly—it was just the juxtaposition of the two headlines that confused me for a moment.

      Comment by gasstationwithoutpumps — 2020 May 20 @ 21:36 | Reply


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