MGC Score to Assess Severity in Myasthenia Gravis: A Prospective Observational Study
Ritu Shree1, Parminder Sharma2, Karthik Mahesh4, Manoj Goyal1, Manish Modi3, Vivek Lal3
1Neurology, 2Medicine, 3NEUROLOGY, PGIMER, 4Post Graduate institute of Medical Education and Research
Objective:
The data from Indian population is scarce regarding outcome measures of MG specially of the recently developed Myasthenia Gravis Composite (MGC). We aimed to assess the disease severity with MGC, and to find the correlation between MGC, Myasthenia Gravis Activity of Daily Living (MG-ADL) which is patient based score and Manual Muscle Testing (MMT) which is a physician based score.
Background:
The data from Indian population is scarce regarding outcome measures of MG specially of the recently developed Myasthenia Gravis Composite (MGC). We aimed to assess the disease severity with MGC, and to find the correlation between MGC, Myasthenia Gravis Activity of Daily Living (MG-ADL) and Manual Muscle Testing (MMT).
Design/Methods:
This was a prospective, single centre, observational study. We recruited all patients with MG >12 years of age with MGFA I-IV. A total of 36 patients were recruited over one year. MGC, MG-ADL and MMT were done at 0, 4, 8, and 12 weeks.
Results:
We noticed that MGC, MGADL and MMT scores have strong positive correlation among themselves at all visits. Logistic regression analysis showed that MGC could significantly predict the worsening with odd’s ratio (OR) =1.16 (CI 95%-1.03-1.3), however its subdomains had higher predictive value than the total score. Eye closure predicted highest worsening (OR= 3.8 ) followed by >neck weakness (OR=3.5)> hip flexion (OR=3.1) >shoulder abduction (OR=3.3) >talking (OR=1.8) >swallowing (OR=1.6). MGADL and MMT significantly predicted the worsening with OR of 1.3 and 1.1 respectively. Furthermore, linear negative correlation between MGC and single breath count (SBC) was observed.
Conclusions:
MGC score of >13 has good sensitivity and specificity of predicting worsening within 1 month (mean 18 days). Worsening in MGC scores of eye closure, neck weakness subdomains predicts highest chances of worsening. There was strong correlation between MGC, MGADL and MMT scores at all visits in our study.