Race-neutral equations for COPD trial eligibility may lead to more Black patients enrolled

Key takeaways:

• Race-neutral vs. -adjusted reference equations are recommended for spirometry interpretation.
• When using race-neutral equations, 8.3% of Black patients gained eligibility compared with 1.6% of white patients.

SAN DIEGO — Using race-neutral equations to determine eligibility for COPD clinical trials may lead to higher percentages of Black patients enrolled, according to a poster presented at the American Thoracic Society International Conference.

“In our study, we saw a discernible pattern in which race-neutral equations tend to decrease the severity level for self-identified white subjects, while concurrently increasing severity for self-identified Black subjects,” Chad Karoleski, BA, a research IT specialist at University of Pittsburgh Emphysema COPD Research Center, said in a press release from ATS. “This resulted in a GOLD stage shift which led to more Black subjects and fewer white subjects meeting typical spirometric inclusion criteria for COPD clinical trials.”

In a recent statement, the ATS recommended the use of race-neutral vs. race-adjusted reference equations for interpreting the results of spirometry.

To evaluate the influence of this recommendation on eligibility for COPD clinical trials, Karoleski and colleagues identified 3,716 patients (white, n = 3,474; Black, n = 242) from the Combined Pittsburgh Lung Cohort. All patients had a baseline spirometry evaluation demonstrating an FEV₁/FVC ratio less than 0.7.

The researchers calculated predicted values for both Global Lung Initiative (GLI) ethnic-adjusted and GLI race-neutral equations to identify the FEV₁ percent predicted and resulting Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage for each patient. They also conducted a descriptive analysis of the shift in GOLD category overall and by self-reported race.

Using the traditional GLI race-adjusted equation, 64.7% of the patients were GOLD II or GOLD III (FEV₁ 30% to ≤ 80%), meeting the typical entry criteria for enrollment in COPD clinical trials (FEV₁/FVC < 0.7; FEV₁ percent predicted 30% to ≤ 80%).

When using the race-neutral reference equations instead, researchers found that 5.8% of patients became ineligible for trial enrollment, including 5.6% who shifted from GOLD II to GOLD I, and 0.2% who shifted from GOLD III to GOLD IV. Further, 2.1% of patients became eligible, including 0.6% who shifted from GOLD I to GOLD II, and 1.5% who shifted from GOLD IV to GOLD III.

The researchers noted that all cases of decreasing GOLD stage occurred among white individuals and all cases of increasing GOLD stage occurred among Black individuals.

Additionally, 1.6% of white and 8.3% of Black patients gained eligibility, whereas 6% of white and 2.9% of Black patients lost trial eligibility.

“We anticipate that our findings will stimulate further discussion and investigation into the development of appropriate inclusion criteria, guided by the ATS recommendation of using race-neutral spirometry reference equations,” Karoleski said in the release. “Future research will be needed to determine the implication of these shifts on appropriate clinical trial selection, while the role of the race-independent classification STAR [Staging of Airflow obstruction by Ratio] staging in clinical trial selection, based exclusively on FEV₁/FVC ratio, also warrants evaluation.”

Reference:

• Spirometry clinical trial eligibility may differ with race-neutral equations. https://site.thoracic.org/about-us/news/2024-international-conference-press-release/spirometry-clinical-trial-eligibility-may-differ-with-race-neutral-equations. Published May 19, 2024. Accessed May 19, 2024.