National Trends in Incidence, Mortality, and Clinical Outcomes of Patients Hospitalized for Thyrotoxicosis With and Without Thyroid Storm in the United States, 2004-2013

Background: Current evidence on the incidence and outcomes of patients with thyroid storm in the United States is limited to single-center case series. This study determined the national incidence of thyrotoxicosis with and without thyroid storm and clinical outcomes among hospitalized patients during a 10-year period in the United States. Methods: Retrospective longitudinal analysis was conducted of clinical characteristics, mortality, hospital length of stay, and costs from 2004 to 2013. Adults (>= 18 years of age) with a primary diagnosis of thyrotoxicosis with and without thyroid storm were included. To determine the incidence, outcomes, and cost of thyrotoxicosis with and without thyroid storm, the study used data from the National Inpatient Sample database, the largest public inpatient database, with a representative sample of all non-federal hospitals in the United States. Results: Among 121,384 discharges with thyrotoxicosis during the study period (M-age +/- standard error = 48.7 +/- 0.11 years; 51.9% Caucasian; 77.3% female), 19,723 (16.2%) were diagnosed with thyroid storm. During the past decade, the incidence of thyroid storm ranged between 0.57 and 0.76 cases/100,000 U.S. persons per year, and 4.8 and 5.6/100,000 hospitalized patients per year. Thyroid storm was associated with significantly higher hospital mortality (1.2-3.6% vs. 0.1-0.4%, p < 0.01) and longer length of stay (4.8-5.6 vs. 2.7-3.4 mean days, p < 0.001) compared to patients with thyrotoxicosis without storm. Inflation-adjusted hospitalization costs progressively increased in patients with thyroid storm from $9942 to $12,660 between 2004 and 2013 (p < 0.01). Conclusions: One of every six discharges for thyrotoxicosis was diagnosed with thyroid storm. Thyroid storm is associated with a 12-fold higher mortality rate compared to thyrotoxicosis without storm. The incidence and mortality of thyroid storm has not substantially changed in the past decade. However, hospitalization costs have significantly increased.