Giant cell arteritis incidence similar among black, white patients
Contrary to widespread belief that biopsy-proven giant cell arteritis is comparatively rare among black patients, researchers found the condition occurs at a similar rate among black and white patients, according to data published in JAMA Ophthalmology.
“Most epidemiological data on GCA are derived from predominantly white populations in Europe and North America,” Anna M. Gruener, BMBS, MSc, FRCOphth, of Nottingham University Hospitals in the United Kingdom, and colleagues wrote. “In Olmsted County, Minnesota, where a large part of the population is of Scandinavian descent, the annual incidence of GCA is 19.8 per 100,000 population 50 years and older. Giant cell arteritis in black patients is thought to be comparatively rare.”
“In 1983, a 10-year study from Shelby County, Tennessee (in which the population at that time was 42% black) found the incidence of GCA in white patients to be seven times greater than in black patients,” they added. “Subsequent studies examining the frequency of GCA in other racial groups also suggest an almost negligible occurrence in black populations.”
To analyze the incidence of biopsy-confirmed giant cell arteritis among black and white patients, Gruener and colleagues conducted a retrospective review of all patients who underwent temporal artery biopsy at the Johns Hopkins Wilmer Eye Institute, in Baltimore, from July 1, 2007, through Sept. 30, 2017. The researchers used electronic medical records to tabulate biopsy results and demographic data, including age, sex and self-reported race. These characteristics were compared with all other patients attending the hospital during the same time period.
Among the 586 patients who underwent temporal artery biopsy, 423 were women, 167 were black and 382 were white. The primary outcome was the estimated incidence rates of biopsy-confirmed giant cell arteritis among black and white patients. The researchers analyzed data from Nov. 1, 2017, through July 31, 2018.
According to the researchers, of the 573 studied patients who were aged 50 years or older, 92 demonstrated a positive biopsy finding. Among these 92 positive cases, 14 were black, representing 8.4% of all black patients who underwent testing, and 75 were white, making up 19.6% of all white patients who underwent testing. Crude annual incidence rates for biopsy-confirmed giant cell arteritis were 2.9 (95% CI, 1.3-5.5) per 100,000 among black patients, compared with 4.2 (95% CI, 3.0-5.6) per 100,000 for white patients.
Population-adjusted age- and sex-standardized incidence rates were 3.1 (95% CI, 1-5.2) per 100,000 for black patients, and 3.6 (95% CI, 2.5-4.7) per 100,000 for white patients, for a difference of 0.5 (95% CI, –1.7 to 2.7).
Although the incidence rate ratio was not significant in white patients compared with black patients (1.2; 95% CI, 0.6-2.4), in women compared with men it was revealed to be 1.9 (95% CI, 1.1-3.4).
“This retrospective cohort study examined the incidence of [biopsy-proven] GCA in black compared with white patients,” Gruener and colleagues wrote. “Whereas previous reports have suggested that GCA is several times more common in white than in black patients, in our study a difference by race could not be identified. We therefore recommend that the same clinical thresholds for diagnosing and managing GCA be applied to black and white patients.” – by Jason Laday
Disclosure: The researchers report no relevant financial disclosures.