Reference: Ann Intern Med. 2022 Aug;175(8):1118-1125
Race is a social construct most often built on the classification of groups based on certain physical traits. Race has no biological basis, and there are tremendous variations in genetics within any given racial classification group. We have just recently gotten to the point of rejecting formulas for estimating glomerular filtration rate (GFR) with an adjustment for race which resulted in underdiagnosis and delayed treatment of kidney disease in Black patients. The most recent area to be scrutinized for the use of race-based norms is pulmonary function testing, which takes into account age, sex, and race.
Researchers used data from a large ongoing longitudinal study to determine how many people with normal lung function actually have emphysema. Emphysematous changes can be seen on CT before there are obstructive changes on PFTs, and these changes increase the risk of both progression to COPD as well as mortality. These study investigators looked at patients who had CTs of the chest and then PFTs five years later, the presumption being that any prior emphysema seen would still be present. They took a close look at the 6.4% of patients with PFTs in the normal range but who had emphysema identified on CT scans. They found that the use of race-based PFT criteria classified about 1-2% more patients who self-identified as Black as having PFTs in the normal range than if race-neutral criteria had been applied.
This study provides more evidence that using race-based norms is harmful to Black patients. The difference of 1-2% that was found in this study may not seem like a big deal, but 1-2% of a very large number is still a large number. Continuing to use race-based criteria is treating some degree of impairment as “normal” in Black people, and can cause delays in timely diagnosis and initiation of treatment. At this point, it seems reasonable to be skeptical of any clinical criteria that use race. They are clearly doing more harm than good.
Clinical Take-Home Point: Stop using race-based norms for pulmonary function testing.
EBM Pearl: Many older accepted “facts” are based on assumptions that themselves stand on shaky ground.
For more information, see the topic Pulmonary Function Tests in DynaMed.
DynaMed EBM Focus Editorial Team
This EBM Focus was written by Alan Ehrlich, MD, Executive Editor at DynaMed and Associate Professor in Family Medicine at the University of Massachusetts Medical School. Edited by Katharine DeGeorge, MD, MS, Deputy Editor at DynaMed and Associate Professor of Family Medicine at the University of Virginia; Dan Randall, MD, Deputy Editor at DynaMed; Carina Brown, MD, Assistant Professor at Cone Health Family Medicine Residency; Nicole Jensen, MD, Family Physician at WholeHealth Medical; Vincent Lemaitre, PhD, Senior Medical Writer at DynaMed; and Sarah Hill, MSc, Associate Editor at DynaMed.