Prognostic factors nullify positive link between race, survival in ALS
Black patients with ALS experienced a greater median survival than white patients in a large, single-center study, though researchers found no independent association between race and survival after adjusting for ALS prognostic factors.
The results suggested the presence of barriers related to access or referral to a tertiary care center, according to the researchers, who published the findings in Neurology.
“We found that Black patients with ALS had a longer diagnostic delay and a lower functional status at the time of the first visit to a tertiary clinic,” Christina Fournier, MD, MSc, of the Emory University department of neurology, told Healio. “While the reasons for this are unknown, it suggests that Black patients experience access barriers to tertiary care.”
Fournier and colleagues conducted a retrospective analysis of patients treated at the Emory ALS Center in Atlanta. Of 2,363 patients treated at the clinic between 1997 and 2020, researchers included 1,298 with self-reported race data in the analysis (Black, n = 203; white, n = 1,095). According to the researchers, white patients were “overrepresented” at the clinic compared with the national population, while the proportion of Black patients treated at the clinic was lower than population proportions in the general U.S. population, Georgia and the Atlanta metro area. The researchers compared baseline characteristics, frequency of invasive interventions, clinical phenotypes and survival between Black and white patients.
Black patients were younger than white patients at the time of symptom onset (mean difference, 2.59 years [95% CI, 0.69-4.5]), but experienced a longer time (mean difference, 8.04 months; 95% CI, –13.20 to –2.89) from symptom onset to ALS diagnosis, lower baseline Revised ALS Functional Rating Scale (ALSFRS-R) scores (mean difference, 4.73 points; 95% CI, 3.15-6.31) and lower baseline vital capacity predicted percentages (mean difference, 18.29%; 95% CI, 14.12-22.41) in their first visit to the clinic.
In addition, the researchers “confirmed that C9orf72 gene mutations were less common in Black patients with ALS compared to white patients,” Fournier said.
Among 128 Black patients and 927 white patients tested for the variant, C9orf72 was more common in white patients (8.31% vs. 3.13%). This finding was consistent with previous studies showing a relatively higher risk for the expansion mutation in predominantly white countries such as Finland and Sweden and with analyses of its origin, which “concluded that the founder was from northern Europe, a predominantly white population,” according to the study results.
“Understanding the underlying genetic causes of ALS is becoming increasingly important as targeted gene therapy treatments emerge,” Fournier told Healio.
A multivariate analysis controlling for the presence of C9orf72 and other factors known to predict prognosis in ALS, including age of symptom onset and bulbar site of symptom onset, found that “race was not an independent predictor of survival time,” the researchers wrote. Black patients also demonstrated lower baseline vital capacity and lower baseline functional scores compared with white patients at the first clinic visit, in addition to a greater delay to diagnosis, according to the study results.
”While the reasons for this are unknown, it suggests that black patients experience access barriers to tertiary care,” Fournier said. “We know that multidisciplinary care improves outcomes for patients with ALS, so this disparity needs to be studied and addressed through future research efforts.”