Objective:

To define the epidemiology and demographics of seropositive neuromyelitis optica spectrum disorder (NMOSD) in a large health system in the United States.

Background:

Epidemiological studies of NMOSD have been limited by several factors. Challenges include disease rarity and identification, a heterogenous composition of individuals diagnosed with seronegative disease, and inconsistent capture of the lab-based biomarker, aquaporin-4 antibodies, in large datasets. Health Data Compass (HDC), a health data warehouse at a large academic healthcare system, combines health system data with claims from the Colorado All Payer Claims Database (2011-present). Notably, HDC curates all forms of aquaporin-4 testing since database inception.

Design/Methods:

This is a retrospective cohort study comprising all adult patients that had any contact with a single academic healthcare system from 1/1/2011 to 12/31/2020. Through HDC, we extracted salient demographic information for the constituent population including our cohort of NMOSD patients. All database lab entries for aquaporin-4 were reviewed with HDC analysts to ensure complete capture of seropositive patients. Prevalence was calculated as of 12/31/2020. Complete validation of diagnosis will be confirmed by chart review using the IPND 2015 criteria. Statistical analysis was completed using SAS version 9.4.

Results:

Our population consisted of 2,474,871 individuals, contributing 11,079,341 person-years of observation for forthcoming incidence calculations. 80 seropositive NMOSD patients were identified. Female patients comprised 86.2% (6.3 F:M) of patients. Mean age was 46.9 years at first positive aquaporin-4 test. Of NMOSD patients, 22.5% (N = 18) identified as Hispanic (identified separately from race), 17.5% as Black (N = 14), 8.8% (N = 7) as Asian, 61.3% (N = 49) as White, and 12.5% (N = 10) as Other race. Prevalence was 3.23 per 100,000 (95% CI 2.52 - 3.94).

Conclusions:

Prevalence is consistent with existing studies. We confirm a high female predominance in NMOSD. Epidemiological data will be slightly adjusted as diagnostic confirmation is completed.