Abstract #1408299: National Trends in Incidence, Mortality, and Costs of Hypothyroidism in Patients Hospitalized with and Without Myxedema Coma in the United States

Abstract

Myxedema coma (MC) is a syndrome of decompensated hypothyroidism with high mortality risk. But, because of its rarity, data regarding the demographics and outcomes of patients with MC are very limited. To address this gap, we perform an analysis of national data to determine the characteristics, mortality, and costs associated with MC or hypothyroidism without MC in hospitalization patients. A retrospective analysis using National Inpatient Sample database, a large public database of inpatient admissions to non-federal hospitals in the United States from 2016-2018, including patients ≥18 years of age with primary diagnosis of MC (ICD-10 E03.5) or hypothyroidism (E03.0-E03.9, E98.0) evaluating patient demographics, mortality, length of stay (LOS), and costs. Of 18,635 hospitalized patients with hypothyroidism, 2,495 (13.4%) had diagnosis of MC. Diagnosis with MC was associated with older patient age (p=0.02), public insurance (p=0.01), and unhoused status (p=0.04) vs patients without MC, while distribution of sex and ethnicity/race were similar between groups. More admissions with MC occurred in Winter compared to other seasons (p=0.01). Potential precipitating diagnoses associated with MC included septicemia, acute myocardial infarction, and adrenal insufficiency (p<0.001 for all), while medication nonadherence was not. During the years of 2016-2018, mean LOS ranged from 8.28-10.4 days for MC vs 4.36-4.86 days for patients without MC. Annual mortality rate for MC was 5.1-9.3% vs only 0.5%-0.9% for patients with hypothyroidism without MC. Finally, mean hospitalization costs during 2016-2018 varied from $86,511-$92,415 vs %34,025-%42,730 per admission for hypothyroid patients with and without MC, respectively. Myxedema coma diagnosis was significantly associated with cardiogenic shock, vasopressor use, acute heart failure, and acute respiratory failure (p<0.001 for all). National hospitalization data show that while only 13.5% of discharges with hypothyroidism had diagnosis of MC, patients hospitalized with diagnosis of myxedema coma have substantially higher mortality, LOS and costs. The diagnoses associated with myxedema coma may help clinicians identify patients with hypothyroidism at risk for MC and/or poor hospitalization outcomes.