Disclosures: Andrew K. Dang, BS: Nothing to disclose

Objective: Myasthenia gravis (MG) is an autoimmune neuromuscular disease caused by auto-antibodies binding to post-synaptic nicotinic acetylcholine receptors. Standard therapy for MG includes plasma exchange (PLEX), known as plasmapheresis, and intravenous immunoglobulin (IVIG). To date, neither PLEX nor IVIG has established superior clinical benefit. Obesity has significant impact on decision making among patients undergoing either type of treatment. This study aims to compare PLEX vs. IVIG in obese patients with MG.

Design: This retrospective cohort study utilized the Nationwide Inpatient Sample to identify patients (18+) from 2012-2015 with a primary diagnosis of MG undergoing PLEX or IVIG. ICD-9 codes identified patients with a diagnosis of obesity and excluded patients missing identifiers (age, gender, death). Patients who received both PLEX and IVIG during the same hospitalization were excluded as combined treatment may affect outcomes. Data analyses assessed length of stay (LOS), total charges, mortality and age of admission.

Setting: Nationwide Inpatient Sample Administrative Database, 2011-2015.

Participants: Patient encounters documented in the Nationwide Inpatient Sample Administrative Database.

Interventions: Not applicable.

Main Outcome Measures: Mortality, total in-hospital charges, length of stay, age of admission.

Results: Of the 2,604 who received either PLEX or IVIG, 655 patients had a diagnosis of obesity (359 underwent PLEX, 296 underwent IVIG). In comparison to patients who received IVIG, significant increases were observed in the PLEX group: • LOS (7.40 vs. 9.15 days, P=.003) • Total charges ($109,904.10 vs. $125,087.51, P<.0001) • Mortality (2.5% vs. 4.3%, P=.007) There were no significant differences between IVIG vs. PLEX for age of admission (55.75 vs. 57.22 years, P=.135).

Conclusions: Obese patients who underwent PLEX suffer from increased LOS, mortality, and total charges when compared to IVIG. The results of this study can aid clinicians in making treatment decisions within this population. Limitations include inability to determine severity of obesity or MG. Peri-procedural optimization of symptomatic patients is one avenue to reduce LOS, total charges, mortality and improve patient outcomes.

Level of Evidence: Level I

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/impact-of-obesity-on-short-term-in-hospital-outcomes-in-patients-with-myasthenia-gravis-undergoing-plasma-exchange-vs-intravenous-immunoglobulin-treatment/