Prevalence and manifestations of diagnosed fibromuscular dysplasia by sex and race: Analysis of >4500 FMD cases in the United States

Objective: Fibromuscular Dysplasia (FMD) is a rare non-atherosclerotic non-inflammatory vascular disease associated with arterial aneurysms and dissections. The epidemiology of FMD is not well understood. We sought to characterize the epidemiology of FMD utilizing a large aggregated electronic medical record database. Methods: We used a commercial database (Explorys, IBM Watson), which aggregates data from electronic health records from 26 major integrated healthcare systems in the United States. Fibromuscular dysplasia cases were identified using a unique systemized nomenclature of medical terminology (SNOMED CT) term. We calculated the overall and age-, race-, and sex-based prevalence of FMD, and evaluated sex and race-specific differences in manifestations. Results: A total of 40,566,670 individuals were active in the database from January 2015 to January 2020. Of these, 4860 had a diagnosis of FMD with an overall prevalence of 12.0 cases per 100,000 individuals. The majority of patients with FMD were female (n=4130, 85.0%), Caucasian (n=3960, 80.5%) and adults aged 18 to 65 years (n=2610, 53.7%). FMD was more common in women (prevalence 18.4 per 100,000) than men (4.0 per 100,000) and among Caucasians (15.8 per 100,000) than African Americans (11.2 per 100,000). Men and African Americans with FMD were more likely to have traditional atherosclerotic risk factors (hypertension, diabetes mellitus type 2, smoking, obesity, hyperlipidemia, chronic kidney disease), and vascular manifestations (stroke, renal infarction, claudication), compared with women and Caucasians. Men with FMD were more likely to have dissection of aorta and renal artery as well as aneurysm of vertebral artery, coronary artery, aorta and iliac artery. African-Americans were more likely to have ruptured aortic aneurysms than Caucasians. Conclusions: The overall prevalence of FMD in this large aggregated electronic medical record study is estimated at 12.0 per 100,000 persons. FMD is more common in women and Caucasians, with variable characteristics and manifestations.