Race Adjustments for Spirometers Could Exacerbate Racial Disparities in COVID Recovery

By Megan Brooks

December 21, 2020

NEW YORK (Reuters Health) - Racial biases built into spirometers have the potential to exacerbate racial disparities in recovery from COVID-19, caution the authors of a comment in The Lancet Respiratory Medicine.

Minority populations suffer disproportionately from the effects of COVID-19, Dr. Amy Non and coauthors with the University of California, San Diego, note in their article.

Spirometers use a race-based correction or "ethnic adjustment," which assumes a 10% to 15% smaller lung capacity for Blacks and 4% to 6% smaller lung capacity for Asians compared with whites.

"These corrections are automatically applied in the spirometry output (as percentage of predicted values), with many physicians unaware of the adjustment," the authors point out.

With the COVID-19 pandemic, these race adjustments could lead clinicians to miss important diagnoses, they add.

One example is restrictive ventilatory dysfunction, an emerging problem in COVID-19 patients that may be apparent for at least two weeks after hospital discharge. This defect is indicated by a spirometry measure of forced vital capacity (FVC) below the lower limits of normal for the appropriate reference population.

"Clinicians might miss this diagnosis if lower lung capacity measures are considered normal for minority populations," Dr. Non and colleagues caution.

Spirometers are also used to determine severity of ventilatory defects with forced expiratory volume in one second (FEV1), and these results can influence treatment plans. For example, in patients with pulmonary fibrosis caused by COVID-19 induced pneumonia, pulmonary rehabilitation might be needed, including breathing exercises and ongoing lung function monitoring.

"These treatments might not be undertaken if the racial adjustment leads to misdiagnosis," the authors say.

Dr. Non told Reuters Health by email, "Clinicians should consider using the raw volume of lung capacity directly from the spirometer, rather than relying on race-adjusted calculations in making any clinical decisions."

"If they get more accurate estimates of lung damage, it could change the treatment and follow-up plans they recommend, particularly if the race adjustments were leading to under estimates of lung damage in minority patients," she noted.

Dr. Non said further research on the factors that affect lung capacity is needed and "we should consider not using race anymore in these adjustments. There is strong evidence that lifetime exposures influence lung capacity, such as exposure to smoking, prenatal exposures, childhood respiratory infections, housing conditions, diet, and occupational exposures. Clinicians could ask about these exposures directly, rather than rely on race as a shortcut."

SOURCE: https://bit.ly/34qMsFL The Lancet Respiratory Medicine, online December 10, 2020.