Abstract Details

Title Analysis of Serious Infections and Malignancy Risk in Myasthenia Gravis: A US Claims Database Study

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P10 - Poster Session 10 (11:45 AM-12:45 PM)

Poster/Presentation
Number 11-007

Background

N/A

Objective To characterize the incidence risk of serious infections and malignancies among adult myasthenia gravis (MG) patients compared to matched controls in the general population.

Design/Methods This retrospective cohort study using Optum’s de-identified Market Clarity claims dataset (2015-2018) assessed incidence rate (IR) per 1,000 person-years and incidence rate ratio (IRR) for infections and malignancies between MG patients and propensity score-matched non-MG controls. Patients with malignancies (including malignant thymoma) within the 1-year lookback period were excluded.

Results

The cohort consisted of 5,004 MG patients and 3,818 control patients. Most confounders were well-balanced between groups. MG patients were more likely to experience serious infections compared to controls (IRR = 1.83, 95% CI [1.54, 2.16]), especially sepsis (IRR = 1.84, 95% CI [1.38, 2.46]), pneumonia (IRR = 1.48, 95% CI [1.08, 2.02]), cellulitis (IRR = 1.84, 95% CI [1.12, 3.04]), and urinary tract infections (IRR = 1.79, 95% CI [1.17, 2.72]). They were also more likely to experience fatal infection (IRR = 2.57, 95% CI [1.29, 5.10]). Among opportunistic pathogens, the incidence risk of Candida (IRR = 1.52, 95% CI [1.26, 1.82]), Herpes zoster (IRR = 1.66, 95% CI [1.27, 2.17]), Klebsiella (IRR = 2.93, 95% CI [1.65, 5.22]), and Pseudomonas (IRR = 2.53, 95% CI [1.41, 4.54]) was also higher.

MG patients had an increased rate of some malignancies including thymic (IRR = 79.5, 95% CI [4.91, 1287.63]), skin (IRR = 1.46, 95% CI [1.19, 1.79]), male genital organs (IRR = 1.54, 95% CI [1.01, 2.33]), and CNS malignancies (IRR = 5.76, 95% CI [1.54, 21.51]). Malignancy-related death rate was not different between the groups.

Conclusions This study supports an increased risk for serious infections, opportunistic infections, and infection-related death in patients with MG. Besides the expected increased risk for thymic malignancies, MG patients had an increased risk of certain solid malignancies.

Authors/Disclosures
Jana Podhorna (argenx) PRESENTER	No disclosure on file
Charlotte Ward	No disclosure on file
Ikjae Lee, MD (Columbia University)	Dr. Lee has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Alexion. Dr. Lee has received personal compensation in the range of $0-$499 for serving as a Consultant for Amylyx. Dr. Lee has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Regeneron. The institution of Dr. Lee has received research support from CReATe consortium/American Brain Foundation. The institution of Dr. Lee has received research support from NIH.
Yuebing Li, MD, PhD, FAAN (Cleveland Clinic)	Dr. Li has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Argenx. Dr. Li has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Catalyst. Dr. Li has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Immunovant. Dr. Li has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Alexion. The institution of Dr. Li has received research support from Argenx.
Tobias Ruck (Heinrich-Heine-University Düsseldorf, Department of Neurology)	No disclosure on file
Elizabeth Teperov (argenx)	No disclosure on file
Ami Shah (Argenx)	No disclosure on file
Jeff Guptill, MD, FAAN (argenx US)	Dr. Guptill has received personal compensation for serving as an employee of argenx. Dr. Guptill has stock in argenx.