ImportanceRace and ethnicity are routinely used to inform pulmonary function test (PFT) interpretation. However, there is no biological justification for such use, and it may reinforce health disparities.ObjectiveTo compare the PFT interpretations produced with race-neutral and race-specific equations.Design, Setting, and ParticipantsIn this cross-sectional study, race-neutral reference equations recently developed by the Global Lung Function Initiative (GLI) were used to interpret PFTs performed at an academic medical center between January 2010 and December 2020. The interpretations produced with these race-neutral reference equations were compared with those produced using the race and ethnicity–specific reference equations produced by GLI in 2012. The analysis was conducted from April to October 2022.Main Outcomes and MeasuresThe primary outcomes were differences in the percentage of obstructive, restrictive, mixed, and nonspecific lung function impairments identified using the 2 sets of reference equations. Secondary outcomes were differences in severity of these impairments.ResultsPFTs were interpreted from 2722 Black (686 men [25.4%]; mean [SD] age, 51.8 [13.9] years) and 5709 White (2654 men [46.5%]; mean [SD] age, 56.4 [14.3] years) individuals. Among Black individuals, replacing the race-specific reference equations with the race-neutral reference equations was associated with an increase in the prevalence of restriction from 26.8% (95% CI, 25.2%-28.5%) to 37.5% (95% CI, 35.7%-39.3%) and of a nonspecific pattern of impairment from 3.2% (95% CI, 2.5%- 3.8%) to 6.5% (95% CI, 5.6%-7.4%) and no significant change in the prevalence of obstruction (19.9% [95% CI, 18.4%-21.4%] vs 19.5% [95% CI, 18.0%-21.0%]). Among White individuals, replacing the race-specific reference equations with the race-neutral reference equations was associated with a decrease in the prevalence of restriction from 22.6% (95% CI, 21.5%-23.6%) to 18.0% (95% CI, 17.0%-19.0%), a decrease in the prevalence of a nonspecific pattern of impairment from 8.7% (95% CI, 7.9%-9.4%) to 4.0% (95% CI, 3.5%-4.5%), and no significant change in the percentage with obstruction from 23.9% (95% CI, 22.8%-25.1%) to 25.1% (95% CI, 23.9%- 26.2%). The race-neutral reference equations were associated with an increase in severity in 22.8% (95% CI, 21.2%-24.4%) of Black individuals and a decrease in severity in 19.3% (95% CI, 18.2%-20.3%) of White individuals vs the race-specific reference equations.Conclusions and RelevanceIn this cross-sectional study, the use of race-neutral reference equations to interpret PFTs resulted in a significant increase in the number of Black individuals with respiratory impairments along with a significant increase in the severity of the identified impairments. More work is needed to quantify the effect these reference equations would have on diagnosis, referral, and treatment patterns.

A 38-year-old woman presented to her primary care clinic with 3 weeks of progressive numbness and tingling sensation, which began in both hands and then progressed to involve both feet, ascending from the legs to the chest while sparing her buttocks. She also noted weakness of her left leg, but no other motor symptoms were reported. She had no fevers, chills, weight loss, bladder dysfunction, nausea, vomiting, or diarrhea.As with all neurological complaints, localization of the process will often inform a more specific differential diagnosis. If both sensory and motor findings are present, both central and peripheral nerve processes deserve consideration. The onset of paresthesia in the hands, rapid progression to the trunk, and unilateral leg weakness would be inconsistent with a length-dependent peripheral neuropathy. The distribution of complaints and the sacral sparing suggests a myelopathic process involving the cervical region rather than a cauda equina or conus lesions. In an otherwise healthy person of this age and gender, an inflammatory demyelinating disease affecting the cord including multiple sclerosis (MS) would be a strong consideration, although metabolic, vascular, infectious, compressive, or neoplastic disease of the spinal cord could also present with similar subacute onset and pattern of deficits.Her medical history included morbid obesity, dry eyes, depression, iron deficiency anemia requiring recurrent intravenous replenishment, and abnormal uterine bleeding. Her surgical history included gastric band placement 7 years earlier with removal 5 years later due to persistent gastroesophageal reflux disease, dysphagia, nausea, and vomiting. The gastric band removal was complicated by chronic abdominal pain. Her medications consisted of duloxetine, intermittent iron infusions, artificial tears, loratadine, and pregabalin. She was sexually active with her husband. She consumed alcohol occasionally but did not smoke tobacco or use illicit drugs.On exam, her temperature was 36.6°C (97.8°F), blood pressure 132/84 mm Hg, and heart rate 85 beats per minute. Body mass index was 39.5 kg/m 2 . The cardiac, pulmonary, and skin examinations were normal. The abdomen was soft with diffuse tenderness to palpation without rebound or guarding. Examination of cranial nerves 2-12 was normal. Cognition, strength, proprioception, deep tendon reflexes, and light touch were all normal. Her gait was normal, and the Romberg test was negative.The normal neurologic exam is reassuring but imperfectly sensitive and does not eliminate the possibility of underlying neuropathology. Bariatric surgery may result in an array of nutritional deficiencies such as vitamin E, B 12 , and copper, which can cause myelopathy and/or neuropathy. However, these abnormalities occur less frequently with gastric banding procedures. If her dry eyes are part of the sicca syndrome, an underlying autoimmune diathesis may be present. Her unexplained chronic abdominal pain prompts considering nonmenstrual causes of iron deficiency anemia, such as celi...