Poster Session B
Myopathic rheumatic diseases (polymyositis, dermatomyositis, inclusion body myositis)
Asim Mohamed, MD, MBA
PGY5
Aurora, Colorado, United States
No financial relationships with ineligible companies to disclose
We studied 24 patients. For demographics of our population, the mean age was 59.3 years with approximately 33% male and 67% White. The antibodies were divided as follows; HMG-CoA reductase antibody positivity in 62.5%, SRP antibody positivity in 29.2%, and 12.5% were seronegative. IVIG was administered in 18 patients (75%) and rituximab in (45.8%), with a variety in use of disease modifying antirheumatic drugs (DMARDs). Aldolase concentrations trended with statin use (Atorvastatin P=0.086, Simvastatin P=0.097). No similar trend was observed with CPK values.
Of note, a vacuolar muscle pathology was observed in 3 patients (12%). All were females with HMG-CoA reductase antibody, while two out of the three were African American (p=0.03) with a positive antinuclear antibody. Two had protracted courses despite high-dose glucocorticoids and IVIG use. All three required rituximab and all achieved remission.
Among the IVIG treated patients (18), the mean IVIG duration was 15.6 months (SD 25.9). Remission was achieved in about 77% (mean time: 11.2 months). Flares occurred in 39% (mean onset approximately 20 months from IVIG initiation). IVIG duration correlated with time to remission and flare likelihood (P=0.03 for each).