Session Information
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose: Interstitial lung disease (ILD) is common in classic dermatomyositis (DM) and clinically amyopathic
dermatomyositis (CADM), in which rash is present without
weakness. Previous studies have shown increased mortality from ILD in CADM vs. DM
due to increased rates of acute-onset lung disease. This study aimed to 1) identify
the frequency of abnormal pulmonary function tests (PFTs) in patients with DM
and CADM and 2) assess frequency of ILD and changes in PFTs in patients with
abnormal PFTs.
Methods: Medical records of patients in an established single-center outpatient
dermatology cohort were screened to identify patients with possible, probable,
or definite DM based on Bohan and Peter criteria or CADM
based on Sontheimer criteria, excluding overlap
connective tissue disease. Charts of patients with any abnormal PFTs (FVC, TLC,
or DLCO < 80% predicted) were reviewed in detail. A radiologist blinded to clinical
characteristics reviewed chest CTs obtained within 1 year of the first available
abnormal PFTs to identify evidence of ILD. Follow-up PFTs were recorded, with
significant change defined as a 15% change in DLCO or 10% change in FVC or TLC
compared to the first abnormal PFTs.
Results: 128 patients met inclusion criteria, 76 with DM and 52 with CADM. 69
(91%) patients with DM and 47 (90%) with CADM had PFTs available. Abnormal PFTs
were present in 34 (46%) patients with DM and 20 (38%) with CADM (p =0.48).
Characteristics of these patients are shown (Table 1). A CT was available for
review in 39/54 (72%) of patients with abnormal PFTs. Among those with an available
CT, ILD was present in 9/23 (39%) patients with DM vs. 6/16 (38%) with CADM (p
= 0.92). Follow-up PFTs were available for review in 38/39 (97%) patients with
median follow-up of 3 years (range 0.5 to 9.5). 32/38 (84%) of patients received
immunosuppression during follow-up. At last follow-up, PFTs declined
significantly in 4/15 (27%) of patients with ILD and 7/23 (30%) of patients
without ILD. Among those with ILD, patients with a history of acute-onset ILD but
not CADM were more likely to have a decline in PFTs (Table 2). Anti-Jo-1
antibodies and inflammatory arthritis were more common in patients with PFT
decline although differences were not statistically significant.
Conclusion: PFT abnormalities are common and present at similar rates in
patients with DM and CADM. In patients with abnormal PFTs, CT evidence of ILD is
found at baseline in less than half of patients with either DM or CADM. History
of acute-onset ILD is associated with increased frequency of PFT decline.
Patients with CADM are not more likely than patients with DM to have a decline
in PFTs.
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Table 1: Characteristics of patients with classic DM vs CADM with abnormal pulmonary function tests
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Classic DM (n = 34)
|
CADM (n = 20)
|
p-value
|
|
Age, years |
52 [45, 62] |
59 [50, 68] |
0.11 |
|
Female |
25 (74%) |
18 (90%) |
0.15 |
|
Caucasian |
29 (85%) |
18 (90%) |
0.62 |
|
Disease duration, years |
1.5 [0.6, 7.2] |
1.8 [0.9, 4.0] |
0.94 |
|
Malignancy within 5 years of diagnosis |
6 (18%) |
2 (10%) |
0.44 |
|
Dyspnea at baseline* |
13 (38%) |
8 (40%) |
0.74 |
|
Cough at baseline |
6 (18%) |
6 (30%) |
0.35 |
|
History of acute onset ILD |
2 (6%) |
2 (10%) |
0.58 |
|
Fever associated with DM |
3 (9%) |
3 (15%) |
0.49 |
|
Raynaud’s phenomenon |
5 (15%) |
4 (20%) |
0.61 |
|
Inflammatory arthritis |
7 (21%) |
5 (25%) |
0.71 |
|
Mechanic’s hands |
9 (26%) |
10 (50%) |
0.08 |
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Echocardiogram with pulmonary hypertension (PASP ³ 35 mmHg)
|
0/20 (0%) |
3/12 (15%) |
0.06 |
|
Creatine kinase at baseline, units/L |
138 [70, 269] |
52 [29, 97] |
< 0.01 |
|
Peak creatine kinase, units/L |
395 [221, 2480] |
68 [41, 121] |
< 0.01 |
|
Aldolase at baseline, units/L |
4.4 [3.1, 5.9] |
4.8 [4.4, 6.3] |
0.30 |
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Peak aldolase, units/L |
6.2 [4.9, 9.7] |
4.8 [4.3, 6.5] |
0.06 |
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Hemoglobin at baseline, g/dL |
13.6 [12.2, 14.2] |
13.5 [12.6, 14.1] |
0.71 |
|
ANA ³ 1:160 |
14/29 (41%) |
6/18 (30%) |
0.53 |
|
Anti-Jo-1 antibodies |
4/21 (12%) |
2/13 (10%) |
0.94 |
|
Anti-SSA antibodies |
3/22 (9%) |
1/14 (5%) |
0.79 |
|
Anti-RNP antibodies |
1/10 (3%) |
0/9 (0%) |
0.53 |
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DLCO % predicted
|
74 [64, 79] |
67 [58, 72] |
0.08 |
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FVC % predicted
|
81 [71, 91]
|
88 [78, 97]
|
0.18
|
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TLC % predicted
|
86 [77, 98]
|
87 [70, 98]
|
0.60
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Pulmonary function test pattern
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– Isolated low DLCO
|
14 (41%) |
12 (60%) |
0.26 |
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– Restriction
|
8 (24%) |
3 (15%) |
0.51 |
|
– Obstruction
|
10 (29%) |
2 (10%) |
0.17 |
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– Mixed or Undetermined**
|
2 (6%) |
2 (10%) |
0.62 |
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– Nonspecific FVC reduction
|
0 (0%) |
1 (5%) |
0.37 |
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Median [IQR] compared with Wilcoxon rank-sum. Number (%) compared with Chi-squared or Fisher’s exact test if expected values ² 5 * Baseline defined as time of the first available abnormal PFTs ** Undetermined if TLC not available and unable to distinguish obstruction from restriction DM: dermatomyositis, CADM: clinically amyopathic dermatomyositis, ILD: interstitial lung disease, PASP: pulmonary artery systolic pressure, DLCO: diffusion capacity for carbon monoxide, FVC: forced vital capacity, TLC: total lung capacity |
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Table 2: Characteristics associated with decline in pulmonary function tests* among patients with dermatomyositis with interstitial lung disease on chest CT
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PFT Decline (n = 4)
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No PFT decline (n = 11)
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p-value
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Female
|
3 (75%) |
5 (45%) |
0.57 |
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Age, years
|
54 [45, 63] |
59 [48, 64] |
0.51 |
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Classic Dermatomyositis
|
2 (50%) |
7 (64%) |
1.0 |
|
Clinically Amyopathic Dermatomyositis
|
2 (50%) |
4 (36%) |
1.0 |
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Disease duration at baseline
|
1.5 [0.5, 3.1] |
0.8 [0.3, 1.4] |
0.60 |
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Duration of follow-up
|
4.6 [2.3, 5.7] |
3.5 [1.4, 6.8] |
0.90 |
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History of acute-onset lung disease
|
3 (75%) |
1 (9%) |
0.03 |
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Arthritis
|
3 (75%) |
2 (18%) |
0.08 |
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Raynaud’s phenomenon
|
1 (25%) |
0 (0%) |
0.27 |
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Fever
|
2 (50%) |
2 (18%) |
0.52 |
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Never smoker
|
4 (100%) |
6 (55%) |
0.23 |
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Non-specific interstitial pneumonia
|
3 (75%) |
9 (82%) |
1.0 |
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Cryptogenic organizing pneumonia
|
1 (25%) |
2 (18%) |
1.0 |
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Anti-Jo-1 antibodies
|
3/4 (75%) |
1/7 (8%) |
0.07 |
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Anti-SSA antibodies
|
1/3 (25%) |
0/7 (0%) |
0.09 |
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Immunosuppression during follow-up
|
4 (100%) |
9 (92%) |
1.0 |
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Lost to follow-up
|
0 (0%) |
1 (9%) |
1.0 |
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Died
|
1 (25%) |
0 (0%) |
0.27 |
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Median [IQR] compared with Wilcoxon rank-sum. Number (%) compared with Fisher’s exact *PFT decline defined as 15% reduction in DLCO or 10% reduction in FVC or TLC based on American Thoracic Society guidelines |
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To cite this abstract in AMA style:
George M, Kreider M, Shah R, Miller W Jr., Merkel PA, Werth V. Abnormal Pulmonary Function Tests, Interstitial Lung Disease, and Lung Function Decline in Patients with Classic and Clinically Amyopathic Dermatomyositis [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/abnormal-pulmonary-function-tests-interstitial-lung-disease-and-lung-function-decline-in-patients-with-classic-and-clinically-amyopathic-dermatomyositis/. Accessed .« Back to 2015 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/abnormal-pulmonary-function-tests-interstitial-lung-disease-and-lung-function-decline-in-patients-with-classic-and-clinically-amyopathic-dermatomyositis/