A Blog by Jonathan Low


Apr 30, 2021

How Data Measure the Impact Of Victims' Years Lost To Covid

Scientists, public health officials and demographers are trying to figure out how to use data to most effectively measure the impact of lives lost to Covid. 

Years of lives lost calculates not just who died and how, which can become a political debate point, but also captures the opportunity cost of the decisions that failed to prevent those sickened by the virus. In so doing it better illustrates through data the impact as well as the social science implications of Covid and what was or wasnt done to mitigate it. JL

Kat Eschner reports in the New York Times:

To express what Covid-19 has taken health statisticians are increasingly using a calculation called years of life lost, which counts how much time the victims could have lived if they hadn’t died. It can help determine which communities lost the most. Lost years shifts the focus from death to life and reveals in 2020, the US lost four million years of potential life, a loss of opportunity to raise a family, build a house or a business. The largest contributors to lost years were the 55 to 75 group, which lost between 5.5 and 25 years. People 65 in 2020 live into their 80s, rather than 74.2, their life expectancy at birth in 1955. The effects of these losses carry on for generations. "It's not true people would have died anyway."

Anna Carter would be 14 if she were alive today. She would be finishing eighth grade and growing her savings account by babysitting for neighborhood kids. In a year, she would have started high school; in two, she would have been old enough to test for her driver’s license. That’s where her future starts to blur — after all, two years is a long time for a teenager.

But Anna died suddenly last July in the emergency room of the Comanche County Memorial Hospital in Lawton, Okla. “We checked in at like 6:15,” said her mother, Amber Carter, 42, “and by 8 o’clock, my husband and I were walking out without her.”

She was the first child to die of Covid-19 in Oklahoma. Most people lost to this pandemic in the United States have been much older, but, on average, each victim died about nine years early, according to a recently published study from the University of South Florida. Each death represented lost time.

Anna lost: three or four trips to Central Mall every month with her 18-year-old sister, Sophia; countless hours practicing tap and hip-hop and the opportunity to start jazz dance; and eventually, she hoped, a big family like the one she grew up in with her four siblings.

“There’s a whole life that’s not going to be able to be finished,” Ms. Carter said from her home in Fort Sill, Okla.

For the past year, experts and journalists have struggled to express what Covid-19 has taken. But health statisticians are increasingly using a calculation called years of life lost, which counts how much time the victims could have lived if they hadn’t died. They say it can help us determine which communities have lost the most and prioritize how to recover.

“In a pandemic situation, everybody’s gone to the lowest common denominator, which is the number of deaths,” said Andrew Briggs, a professor of health economics at the London School of Hygiene and Tropical Medicine.

Looking at lost years shifts the focus from death to life and reveals the depth of this pandemic’s impact crater: In 2020, the United States lost around four million years of potential life, a sweeping international study published in February found.

“It’s such a big number that if I’m truly honest, we don’t have the mental capacity to process it,” said one study author, Mikko Myrskyla, the executive director of the Max Planck Institute for Demographic Research.

The life insurance industry would translate those years — particularly before retirement — into dollars. Public health experts refer to them as a burden of disease. But they are also a loss of opportunity — to raise a family, build a house or a business or be part of a community.

“Life has stages,” said Mary Bassett, director of the FXB Center for Health and Human Rights at Harvard University, “and we all hope to experience all of them.”

Many public health researchers have pushed agencies to use lost years as well as deaths to create a fuller picture of the toll on communities and allow policymakers and the public to see the effectiveness of safety measures like social distancing and mask-wearing.

Dr. Briggs said that by centering the Covid-19 conversation around deaths, it makes it easier to discount some who have died. “We moved from a situation where everyone was concerned about flattening the curve,” he said, “to people starting to talk about, well, these are old people who would have died anyway.”

That’s the problem with the death statistic: It’s easy to spin, because it doesn’t contain very much information.

Dr. Briggs’s study compared years of life lost during the pandemic’s first wave in the United States, Britain and several other countries. It showed that even older people with comorbidities lost a tremendous number of years — more than a year per person even among those between 90 and 100. The February study found that the largest contributors to lost years were in the 55 to 75 group, which Dr. Briggs’s study found to have lost between 5.5 and 25 years each, depending on their age and health.

“It’s not true that people would have died anyway,” he said. Other research has built on this concept, concluding that prioritizing the oldest and frailest people for vaccines saved not only the most lives, but also the most years of potential life.

One reason for findings like these is that life expectancy usually increases the longer one lives, Dr. Briggs said. For instance, people who were 65 in 2020 can now be expected to live into their 80s, rather than dying at 74.2 years of age, which was their life expectancy at birth in 1955.

Who dies of Covid-19 is “unbelievably strongly correlated with age,” said Dr. Christopher Murray, director of the University of Washington’s Institute for Health Metrics and Evaluation. For most diseases, the likelihood of death after infection goes up by about 3 percent per year of life lived, he said, whereas Covid-19 raises it by 9 percent to 10 percent per year.

But you can’t get Covid-19 if you aren’t exposed to the pathogen. And in the United States, the likelihood of exposure is directly related to race. Recent data from the Centers for Disease Control and Prevention shows that deaths of Black and Latino people are occurring at a rate 1.9 and 2.3 times higher than that of white people.

But those figures hide the true toll, according to a research team led by Dr. Bassett. They found that between March and June of 2020, Black Americans under the age of 65 lost 4.6 times as many years of life as white Americans. For Hispanic Americans the number was 3.2 times as high. Preliminary analysis of the same data through March 2021 shows the trend continuing.

The losses among younger people in these groups, ages 25 to 54, were even more lopsided — as much as nine times higher than those of white Americans.

“Not only were people of color dying at higher rates,” she said, “they were dying at younger ages.”

These deaths can’t be accounted for by a higher rate of comorbidities alone. Exposure played a key role, she said, “driven by who was still working, who was on public transit, who was going home to crowded apartments.”

The loss of high numbers of young people is also a hallmark of Covid-19’s impacts in low- and middle-income countries, according to the February study. In the United States, it found people 55 to 75 bore the greatest proportion of lost years, but those younger than that bore about one-fifth — less than the global average but far more than in Britain, Canada or Israel. The effects of these kinds of losses will carry on for generations.

“It matters how old you are when you die,” said Dr. Bassett. People value the presence of elders in their lives, she said, “But when someone dies too young,” she said, “a family may lose a breadwinner. They may leave children without a parent.”

“We get more call to think about years of life lost in low-income and middle-income settings,” Dr. Murray said. In the early 1990s the World Bank used it as the basis of its Global Burdens of Disease study, which is now produced annually.

In the United States, it continues to be used in the insurance industry, where it originated, to calculate premiums and for other purposes. It isn’t often used to talk about public health, although there’s a movement to use it in drug pricing.

There’s good reason to use it, Dr. Murray and others said. “We’ve had clear difficulties figuring out what works best, when, and in what contexts,” said Adeline Lo, a political scientist at the University of Wisconsin who was an author on the international study. “This at least puts another fact on the table that may be helpful.”

Choosing to prioritize demographics that are losing the greatest number of overall years would be one way to lessen the pandemic’s toll. Even so, no number can truly capture human loss.

“We don’t live our lives statistically,” said Dan Bouk, a historian of demography from Colgate University. When they think of this pandemic, most people will remember those they took care of, the illnesses they suffered or the loved ones they lost, he said. “Neither aggregate death totals nor years of life lost will accurately capture that experience.”

Before her death last summer, Anna Carter lived 13 years, eight months and eight days. In that time, she hiked Mount Fuji, went to church, played with her baby brother, David, and coveted fake nails. She aspired to become an entertainer or maybe go into medicine and try to make the world better for others with scleroderma, the autoimmune disease she lived with.

Her life expectancy at birth was 77.9 years. You could measure the loss of her time in years she might have spent with her family or the degrees she might have earned. Perhaps it’s the dances she won’t perform or the cures she won’t find. Or just the years her family expected to have with her as a daughter and sister. “I just have her smiling face in my head all the time,” Amber Carter said.

The Carters, a military family, were planning to move to the East Coast in a few years, when Anna’s father retired. After her death, their plans changed. They will stay in Fort Sill, near her grave in the National Cemetery. Her parents plan to be buried alongside her when the time comes. “God changed our lives with hers,” her marker reads.


Post a Comment