Trends in Outcomes and Hospitalization Charges among Mechanically Ventilated Patients with Myasthenia Gravis in the United States

Abstract

Introduction: To assess the impact of new therapeutic strategies on outcome and cost of hospitalization among patients with myasthenia gravis (MG) who are mechanically ventilated in United States.

Methods: Using a retrospective analysis of cross sectional survey, we determined the rates of occurrence, in-hospital outcomes, and mean hospital charges for patients hospitalized with MG requiring mechanical ventilation in 1991-1992 using the Nationwide Inpatient Survey (NIS) and compared these outcomes with homologous data from 2001-2002. NIS is the largest all-payer inpatient care database in the United States.

Results: When comparing data from 2001-2002 with data from 1991-1992, we found a higher number of admissions for MG that required mechanical ventilation (994 vs. 652). The proportion of women was similar (53% vs. 60%). The average age (in years ± standard deviation) was significantly higher (65 ± 17 vs. 58 ± 18, p=0.0002). The length of hospitalization (in days ± standard deviation) was not different (22 ± 19 vs. 21 ± 16). Discharge to home occurred less frequently (29% vs. 60%, p=0.0001) and in hospital mortality minimally lower (13% vs. 15%). There was a significant increase in mean hospital charges ($118,000 vs. $84,100 adjusted for inflation, p=0.0001). In hospital mortality was higher among urban teaching hospitals compared with urban non teaching hospitals in 2001-2002.

Conclusions: Despite improvement in therapeutic strategies from 1991 to 2002, there was only a modest reduction in mortality and no substantial reduction of length of hospitalization for patients with MG requiring mechanical ventilation.

Keywords: cost; length of stay; mechanical ventilation; mortality; myasthenia crisis; myasthenia gravis; outcome.