(309) Race and sex differences in healthcare resource utilization among patients with myasthenia gravis in the United States

Background: Myasthenia gravis (MG), is a rare, neuromuscular disorder that affects muscle strength and movement. Patients are known to develop MG at different ages depending on their sex and males and females may receive different treatments as a result, but fewer studies have quantified the relationship between race and sex.

Objectives: To characterize the differences in healthcare utilization stratified by sex and race for patients with MG.

Methods: Patients with MG enrolled in the PicnicHealth Research Platform and consented to collection of their medical records across U.S. health systems, with visit dates ranging from 1962 - 2023. Patients self-reported demographics, including sex, race, and ethnicity. Data were abstracted from structured and unstructured medical records using human-validated machine learning. Patients with at least one visit each in the two years before and after diagnosis were included in the study. Demographics were evaluated quantitatively using Wilcoxon rank sum tests for continuous variables and Chi-squared tests for descriptive variables to examine the associations of demographics with healthcare utilization around diagnosis.

Results: 478 patients qualified for this analysis; of those, 66% (N = 317) were female. 12% (N = 59) of females were non-white (including Black, Asian, American Indian or Alaska Native, Native Hawaiian or Other Pacific Islander, or more than 1 race), and 54% (N = 258) were white. 4% (N = 20) males were non-white, and 29% (N = 141) males were white. Median age at diagnosis for non-white females was approximately 10 years earlier 34 (28-44) than white females 47 (35-61; p < 0.001), and white and non-white females were diagnosed earlier than white 62 (54-69) and non-white males 52 (39-62; p = 0.007). Of the four groups, non-white males had the fewest total years of visits 6 (4-9), followed by white males 9 (5-13; p = 0.21). Non-white females had fewer total visits 7 (4-10) than white females 9 (6-13; p < 0.001). They also had more neurology visits per year (3.53 vs. 2.53; p = 0.042), more ophthalmology visits per year (1.34 vs. 0.71; p = 0.049), and more emergency visits per year (1.26 vs. 0.81; p = 0.02) than white females. Males had no difference in emergency or specialist visits per year.

Conclusions: Non-white females had fewer total visits than white females, but visited specialists more frequently than white females. Males had fewer differences in healthcare utilization between races. Race and sex differences in MG patients at or near diagnosis may contribute to disparities in health outcomes and accessing care, and it is important for future research to determine the effects of these disparities.