Editor’s Note: H. Gilbert Welch is a general internist in the Center for Surgery and Public Health at Brigham and Women’s Hospital and author of “Less Medicine, More Health.” Vinay Prasad is an oncologist, associate professor of medicine at Oregon Health and Science University and author of “Malignant: How Bad Policy and Bad Medicine Harm People With Cancer.” The opinions expressed in this commentary are those of the authors; view more opinion articles on CNN.

CNN  — 

The concern was that Covid-19 would overwhelm the medical care system with patients. While that has happened in some hot spots, the broader picture is just the opposite: Covid-19 has deprived the system of patients.

H. Gilbert Welch
Vinay Prasad

Some of these would-be patients have surely been hurt: having either shied away or been told to stay away from interventions that would have helped them live longer and/or live better. For others the delay may not matter; they will do equally well with intervention at a later date. But it is important to consider another possible outcome: some do better with less medical care.

No one has national data yet, but the turn of events is remarkable.

In mid-March hospitals began to cancel elective surgeries both to protect patients and to provide surge capacity, following guidance from the American College of Surgeons. This not only halted hernia repairs and joint replacements, but also surgeries for low-risk cancers – specifically, early stage breast and prostate cancer.

Next, emergency care unexpectedly plummeted. Emergency rooms in Boston, Detroit and Minneapolis/St. Paul saw substantial drops in volume, and ER doctors are experiencing cuts to both their hours and pay. The decline in volume doesn’t appear to be confined to fewer minor injuries and self-limited illnesses, it also includes fewer heart attacks and strokes.

But the impact of Covid-19 goes well beyond the hospital to include all physician/patient encounters. Despite the advent of telehealth, primary care practices are seeing fewer patients and laying off staff. The American Academy of Family Physicians estimates that about 40% of family medicine clinics are at risk of closing by the end of June – more than doubling the number of US counties with a significant shortfall in health care providers at the end of March.

Given fewer outpatient visits, one downstream effect is wholly expected: fewer lab tests and X-rays. This limits efforts to find disease early in asymptomatic individuals. Most notably, cancer screening has been effectively shut down.

What can we learn from this cataclysmic disruption in medical intervention?

Previous research on the global effects of doctor strikes suggests that overall mortality either remains stable – or, in fact, declines. Clearly, it will be important to carefully study 2020 mortality trends and disentangle Covid-related deaths from other causes of death. It will be equally important to distinguish the well-off from the poor: we may find that medical care disruption decreases mortality among the well-off, yet increases mortality among the poor.

While analysis of overall mortality is important, so, too, is looking into more granular topics. The disruption in elective surgeries should lead us to reevaluate the necessity of those surgeries and their associated risks. There are opportunities to look at still finer detail: In our hospitals (Brigham and OHSU), for example, women with early-stage breast cancer are having their surgeries delayed and are instead being started on hormonal therapy. Maybe we will learn that some women don’t need surgery.

Suspending cancer screening is another important area to study. There is little doubt, for example, that the decline in mammography will lead to fewer breast cancers diagnosed. But is that a bad thing or good thing?

One opportunity is to study what happens to US cancer statistics when screening is resumed. One of two observations are possible. Rates of breast cancer might catch up: meaning the deficit in cancers during the pandemic would be matched by a surplus of cancers in subsequent years. In other words, all the cancers that sat undetected in patients during the pandemic would be eventually found. The alternative would be that breast cancer diagnoses never catch up.

Years ago, researchers observed this phenomenon in Norway. Women, ages 50-64, who underwent three mammograms over six years had more invasive breast cancers found compared to similar women who had a single mammogram at the end of six years. Delayed mammography led to less breast cancer diagnoses and the deficit never caught up – despite a mammogram at the end of six years. These findings suggest that some small cancers regress on their own. Might this be happening right now during the Covid-19 pandemic?

The decline in heart attack and strokes raises equally important questions in cardiovascular disease. Some patients may have been reluctant to come to the hospital and suffered, perhaps even died, at home. However, what “counts” as a heart attack or stroke has expanded over the years. An alternative explanation may be that doctors are no longer diagnosing patients with very mild cardiac or neurologic abnormalities. Perhaps what is being missed are painless, minor events for which treatment is unneeded – or even harmful.

It’s also possible that there are genuinely fewer heart attacks and strokes occurring right now. Smog is disappearing in Los Angeles and, in India, people can see the Himalayas from miles away for the first time in 30 years. Air pollution has been consistently linked to heart attacks. And “hunkering down” has meant slowing down for many. Has better air and lifestyle helped our hearts?

After Covid-19, if we dare imagine the day, it will be important to ask who was harmed by delayed and forgone medical care. But the severe financial strains on individuals and public budgets make it just as essential to ask who benefited from avoiding interventions with no salutatory effect.

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    But we won’t find the benefits unless we look for them. We need physician researchers willing to ask hard questions about services they deliver – questions that may threaten their own professional/financial self-interests.

    Covid-19 provides a once in a lifetime opportunity to study what happens when the well-oiled machine of medical care downshifts from high to low volume in order to focus on acutely ill patients. It will be comfortable for physician researchers to study what was lost. It will be courageous for them to study what was gained.