Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose: Interstitial lung disease (ILD) is a common manifestation in systemic sclerosis (SSc) and the leading cause of morbidity and mortality. Serial pulmonary function tests are useful for monitoring SSc-ILD, and total decline in forced vital capacity (FVC) above 10% predicts mortality. Moderate FVC decline (5-10%) was recently shown to predict poor outcome in idiopathic pulmonary fibrosis, but it is not known if moderate FVC decline has any impact on the outcome of SSc-ILD.
Methods: The study cohort included 305 SSc patients enrolled in the prospective SSc cohort (Norwegian Systemic Connective Tissue Disease and Vasculitis Registry [NOSVAR]) at the Department of Rheumatology, Oslo University Hospital (OUH). Serial pulmonary function test (PFT), lung fibrosis measured on high resolution computed tomography (HRCT) and clinical data were registered at baseline and then prospectively at annual follow-up visits. Patients were segregated in three groups according to annual FVC decline rates; (A) stable or minimal decline (<5%), (B) moderate decline (5-10%) and (C) major decline (>10%). Mortality and disease progression (fibrosis progression, DLCO and total FVC decline) quantified from baseline data were defined as poor outcome. Descriptive statistics and t-tests were applied; Kaplan-Meyer and Cox proportional hazard models were used to analyse survival.
Results: 305 SSc patients were followed for mean 3.8 years (range 1-15) from the baseline FVC. Altogether, 241 patients (79%) had stable FVC, 43 (14 %) had moderate FVC decline and 21 (7%) had major decline (Table 1). Sixty-seven deaths occurred during the observation period. Moderate decline in FVC was significantly associated with mortality (HR 2.5 (95% CI 1.4, 4.6, p-value 0.003). The 1-year survival rates for the three FVC groups were 100%, 100%, 86%, 5-year survival rates were 97%, 85% and 76% and 10-year survival rates were 85%, 66% and 54%, respectively. Compared to the stable FVC group, the moderate FVC decline group were older at disease onset, had more lung fibrosis at baseline and at follow up, higher total decline in DLCO and lower FVC% at follow up (table 1).
Conclusion: In this prospective SSc cohort, annual moderate FVC decline was associated with high total DLCO decline, high lung fibrosis scores and increased mortality. These results highlight the importance of regular PFT measurements in daily clinical practice.
Table 1: Clinical and lung characteristics of 305 SSc patients stratified by FVC decline
|
|
Annual decline in FVC |
|
||
|
|
<5% |
5-10% |
>10% |
p-val* |
|
Demographics |
|
|
|
|
|
Number of patients (%) |
241 (79) |
43 (14) |
21 (7) |
|
|
Age at diagnoses, yrs (SD) |
46.6 (15.1) |
53.2 (13.6) |
53.3 (13.1) |
0.007 |
|
Disease duration¹, yrs (SD) |
5.2 (6.9) |
4.9 (7.1) |
6.0 (8.0) |
0.862 |
|
Deceased, n (%) |
41 (17) |
14 (33) |
12 (57) |
<0.001 |
|
Time to death², yrs (SD) |
9.6 (9.5) |
10.6 (7.4) |
9.1 (8.7) |
0.328 |
|
Male gender, n (%) |
49 (20) |
11 (26) |
3 (14) |
0.437 |
|
Ever smoker, n (%) |
100 (42) |
14 (33) |
10 (48) |
0.436 |
|
dcSSc, n (%) |
60 (25) |
17 (40) |
9 (43) |
0.056 |
|
ATA positive, n (%) |
36 (15) |
11 (26) |
52 (17) |
0.161 |
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|
|
|
|
|
|
Lung function and imaging |
|
|
|
|
|
Baseline FVC, % (SD) |
93.0 (23.4) |
91.7 (21.0) |
91.4 (22.5) |
0.712 |
|
FVC at follow up, % (SD) |
91.7 (22.9) |
77.0 (24.8) |
66.9 (19.9) |
<0.001 |
|
Baseline DLCO, % (SD) |
67.3 (20.9) |
68.4 (19.7) |
52.9 (17.4) |
0.759 |
|
DLCO at follow up, % (SD) |
60.2 (20.2) |
55.4 (19.9) |
42.5 (18.5) |
0.154 |
|
Total DLCO decline, % (SD) |
6.9 (13.4) |
13.0 (12.8) |
10.0 (15.4) |
0.006 |
|
Baseline lung fibrosis, % (SD) |
6.0 (12.9) |
11.3 (18.3) |
6.4 (10.8) |
0.015 |
|
Fibrosis at follow up, % (SD) |
7.6 (13.9) |
13.1 (19.2) |
7.8 (13.3) |
0.026 |
|
>20% fibrosis, follow up, n (%) |
36 (15) |
11 (26) |
4 (19) |
0.084 |
Yrs: years; n: number; dcSSc: diffuse cutaneous systemic sclerosis; ATA: anti-topoisomerase antibody, FVC: forced vital capacity; DLCO: diffusing factor for carbon monoxide; * p-value between <5% and 5-10% decline in FVC; ¹ time from first non-Raynaud symptom to baseline FVC, ² time from disease onset to death
Disclosure:
A. M. Hoffmann-Vold,
None;
O. Midtvedt,
None;
T. Garen,
None;
M. B. Lund,
None;
T. M. Aalokken,
None;
J. T. Gran,
None;
O. Molberg,
None.
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