Estimating the US pericarditis prevalence using national health encounter surveillance databases

Objective To obtain a nationally representative annualized estimate of the prevalence of pericarditis (inflammation of the pericardium) in the United States (US) in order to better understand the potential burden on the health care system. Methods Three nationally representative datasets were used to estimate the annualized period prevalence and prevalence rate of pericarditis from 2007 to 2016: the National Ambulatory Medical Care Survey (NAMCS), the National Hospital Ambulatory Medical Care Survey (NHAMCS), and the Nationwide Inpatient Sample (NIS). Across all data sources, ICD-9/10 codes were used to identify healthcare encounters with >= 1 primary or secondary diagnosis related to pericarditis irrespective of duration or etiology. The prevalence of pericarditis in 2020 was extrapolated by multiplying the average annualized prevalence rate from 2007 to 2016 by the total US population as of March 2020. Results Data from NAMCS/NHAMCS (2007-2016) yielded an average annualized estimate of 125,209 patients with pericarditis, resulting in a pooled average annualized prevalence estimate of 40 patients with pericarditis per 100,000 persons. Data from NIS (2007-2016) yielded an average annualized estimate of 34,441 patients with pericarditis, resulting in a pooled average annualized prevalence estimate of 11 hospitalized patients with pericarditis per 100,000 persons. Extrapolation of these results based on the March 2020 population estimates from the US Census Bureau of 329,436,928 resulted in an estimated US prevalence of pericarditis to be approximately160,000. Conclusion Despite certain methodologic limitations, our analysis of data from nationally representative sources support that pericarditis is a rare disease affecting substantially fewer than 200,000 persons in the US.