Socioeconomic and demographic disparities of moyamoya disease in the United States

Abstract

Objectives: Although stroke incidence is inversely associated with socioeconomic status, whether similar disparities exist with moyamoya disease (MMD) is unknown. Determining the socioeconomic and demographic factors involved in MMD will provide better direction in elucidating the etiology or addressing healthcare inequalities.

Patients and methods: To investigate MMD incidence with respect to sex, age, income, residence, and race/ethnicity, we examined the largest American administrative dataset, the National (Nationwide) Inpatient Sample (NIS), which surveys 20 % of United States discharges irrespective of payor. We then determined median annual incidence per 100,000 people and trends between 2008-2015.

Results: Overall MMD incidence (with 25th and 75th quartiles) was 0.293 (0.283, 0.324) and annually increasing (τ = 0.857, p = 0.004). Females had an incidence of 0.398 (0.371, 0.464), larger (p = 0.008) than the male incidence of 0.185 (0.165, 0.195). Amongst age groups incidence varied (χ² = 8.857, p = 0.012) as follows: 1-17 years old group, 0.298 (0.259, 0.346); 18-44 group, 0.380 (0.346, 0.412); 45-64 group, 0.308 (0.280, 0.328). Those 18-44 ha d a significantly larger incidence relative to the 1-17 (p = 0.039) and 45-64 (p = 0.008) groups. Individuals with low income had an incidence of 0.514, larger (p = 0.008) than the 0.239 of middle/high income patients. Depending on whether the patients lived in an urban, suburban, or rural community, incidence differed (χ² = 7.6, p = 0.022) as follows, respectively: 0.344 (0.293, 0.371); 0.269 (0.258, 0.294); 0.283 (0.273, 0.293). Living in an urban community resulted in a significantly greater incidence, relative to suburban (p = 0.016) or rural (p = 0.032). Amongst race/ethnicity (χ² = 7.6, p = 0.022), incidence for Asian/Pacific Islanders, Blacks, Whites, and Hispanics between 2008-2013 was as follows, respectively: 0.509 (0.429, 0.595); 0.292 (0.219, 0.356); 0.148 (0.137, 0.157); 0.121 (0.075, 0.153). Other than comparisons between Whites and Blacks/Hispanics, incidence significantly varied between all groups. Annually incidence was significantly increasing for females (τ = 0.929, p = 0.002), ages 18-44 (τ = 0.786, p = 0.009), ages 45-64 (τ = 0.714, p = 0.019), middle/high income (τ = 0.786, p = 0.009), and urban (τ = 0.714, p = 0.019) or suburban (τ = 0.714, p = 0.035) dwelling patients.

Conclusion: MMD diagnoses between 2008-2015 have been significantly increasing in the United States, with disparities growing between socioeconomic and demographic strata. Disproportionately, incidence was greatest for patients who were low income, urban living, female, aged 18-44, and Asian/Pacific Islanders. This data highlights a growing healthcare inequality amongst MMD and provides direction in etiology elucidation.

Keywords: Demographics; Disparities; Incidence; Moyamoya disease; Socioeconomic.