Session Information
Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: Clinically amyopathic dermatomyositis (CADM)
patients have the classic rash (es) of DM but no objective proximal muscle
weakness. Asian studies report a unique clinical phenotype in anti-MDA5 (+) CADM
which has not been well described in the U.S. Our goal was to determine the
clinical features associated with the anti-MDA5 autoantibody (autoAb) in CADM
as compared to classic DM in U.S. patients.
Methods: CADM patients
were selected consecutively from patients prospectively enrolled in a
computerized university Myositis Center database between January 1985 and July
2013. CADM was defined by a typical DM rash without objective muscle weakness
for at least 6 months after rash onset and no or minimal abnormalities of serum
muscle enzymes [< 3 x ULN], electromyography or muscle biopsy. Classic DM was defined as probable or definite by the
criteria of Bohan and Peter and 1:1 matched (gender and age +/- 5 years)
to CADM patients. Clinical features were extracted from the database and
supplemented with electronic medical record review when necessary.
Results: We identified 61
CADM patients (female 64%; mean age 44.8) and 61 matching classic DM controls
(female 62%;
mean age 48.2).
Anti-MDA5 frequency
was similar in both cohorts (13.1% [8/61] vs. 13.1% [8/61]). Anti-MDA5
positivity was associated with a higher likelihood of vasculitic rash and digital
tip ulceration and with a trend towards more abnormal capillary microscopy and a
lower frequency of Raynaud phenomenon compared to anti-MDA5
negative patients. The frequency of Gottron sign or papules, heliotrope rash and
mechanic hands were similar in both groups. However, puffy fingers and dysphagia
frequency were significantly higher in the anti-MDA5+ patients. Anti-MDA5
positivity was significantly associated with interstitial lung disease (ILD)
(p=0.043), rapidly progressive ILD (RPILD) (p<0.001), and poor survival (p=0.007).
Multivariate analysis suggested that anti-MDA5 positivity was predictive
of poor survival
even after controlling for diagnosis, age at diagnosis, gender, ethnicity,
smoking, and ILD (p=0.001). ILD frequency was similar in CADM and classic DM
(31.1% vs. 26.2%) as was RPILD (8.2% vs. 5%). CADM patients were more likely
to have heliotrope rash and dysphagia as compared to classic DM patients. The
remaining clinical features were similar for both CADM and classic DM cohorts
(Table 1).
Conclusion: Anti-MDA5
positivity has a similar frequency in CADM and classic DM patients in the U.S. Anti-MDA5
autoAb is associated with a unique clinical phenotype consisting of
ILD, RPILD, and a vasculitic
rash with digital tip ulceration. CADM patients had more dysphagia and
heliotrope rash as compared to classic DM, apart from obvious disease-defining
features of muscle weakness and muscle enzyme.
Table 1.
Clinical features of anti-MDA5 positive and CADM patients as compared to
anti-MDA5 negative and classic DM patients, respectively.
|
Clinical features |
MDA5 + (N = 16) |
MDA5 – (N = 106) |
p value |
CADM (N = 61) |
Classic DM (N = 61) |
p value |
|
ILD |
50% |
25.5% |
0.04 |
31% |
26% |
0.46 |
|
RPILD |
87.5% |
3.7% |
<0.001 |
8% |
5% |
0.55 |
|
Dyspnea at presentation |
37.5% |
27.3% |
0.4 |
32.7% |
24.5% |
0.31 |
|
Pulmonary HTN |
6.2% |
1.8% |
0.34 |
3.3% |
1.6% |
1 |
|
Cardiomyopathy |
0 |
0 |
1 |
0 |
0 |
1 |
|
Raynaud phenomenon |
12.5% |
26.4% |
0.35 |
22.9% |
26.2% |
0.67 |
|
Vasculitic rash |
18.7% |
1.8% |
0.01 |
3.2% |
4.9% |
1 |
|
Abnormal capillary microscopy |
43.7% |
26.4% |
0.15 |
29.5% |
27.8% |
0.8 |
|
Digital tip ulceration |
18.7% |
2.8% |
0.02 |
4.9% |
4.9% |
1 |
|
Heliotrope rash |
18.7% |
29.2% |
0.55 |
36% |
19.6% |
0.04 |
|
Gottron papules/sign |
37.5% |
32% |
0.66 |
32.7% |
32.7% |
1 |
|
Mechanic hands |
6.2% |
6.6% |
1 |
3.2% |
9.8% |
0.27 |
|
Arthralgia |
6.2% |
7.5% |
1 |
4.9% |
9.8% |
0.49 |
|
Arthritis |
0% |
1.8% |
1 |
1.6% |
1.6% |
1 |
|
Dysphagia |
31.2% |
10.3% |
0.03 |
24.5% |
1.6% |
<0.001 |
|
Sicca |
12.5% |
4.7% |
0.22 |
4.9% |
6.5% |
1 |
|
Puffy fingers |
25% |
4.7% |
0.01 |
9.8% |
4.9% |
0.49 |
|
Calcinosis |
0% |
0% |
1 |
0% |
0% |
1 |
|
Telangiectasia |
0% |
0.9% |
1 |
0% |
1.6% |
1 |
|
Myalgia |
18.7% |
29.2% |
0.55 |
34.4% |
21.3% |
0.1 |
To cite this abstract in AMA style:
Moghadam-Kia S, Oddis CV, Sato S, Kuwana M, Aggarwal R. Clinical Characteristics of Anti-MDA5 (+) Dermatomyositis Patients in North America [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/clinical-characteristics-of-anti-mda5-dermatomyositis-patients-in-north-america/. Accessed .« Back to 2015 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/clinical-characteristics-of-anti-mda5-dermatomyositis-patients-in-north-america/