Variable course of disease of rheumatoid arthritis-associated usual interstitial pneumonia compared to other subtypes
Nurmi et al. BMC Pulmonary Medicine
Variable course of disease of rheumatoid arthritis-associated usual interstitial pneumonia compared to other subtypes
Hanna M. Nurmi 0 1
Minna K. Purokivi 1
Miia S. Kärkkäinen 0 5
Hannu-Pekka Kettunen 4
Tuomas A. Selander 3
Riitta L. Kaarteenaho 0 1 2
0 Division of Respiratory Medicine, Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland , POB 1627, 70211 Kuopio , Finland
1 Center of Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital , POB 100, 70029 KYS Kuopio , Finland
2 Respiratory Medicine, Internal Medicine Research Unit, Medical Research Center Oulu, Oulu University Hospital and University of Oulu , POB 20, 90029 Oulu , Finland
3 Science Services Center, Kuopio University Hospital , POB 100, 70029 Kuopio , Finland
4 Diagnostic Imaging Center, Division of Radiology, Kuopio University Hospital , POB 100, 70029 Kuopio , Finland
5 Harjula Hospital, the Municipal Hospital of Kuopio , Niuvantie 4, 70101 Kuopio , Finland
Background: In rheumatoid arthritis-associated interstitial lung disease (RA-ILD), occurring in 10 % of patients with patients with RA, usual interstitial pattern (UIP) has shown to associate with poor prognosis but more detailed data about the course of the disease in different subtypes is limited. Our aim was to compare the disease course of patients with RA-ILD categorized into either UIP or other types of ILDs. Methods: Clinical and radiological information of 59 patients with RA-ILD were re-assessed and re-classified into UIP or non-UIP groups, followed by a between-group comparison of demographic data, lung function, survival, cause of death and comorbidities. Results: The majority of patients (n = 35/59.3 %) showed a radiological UIP-like pattern in high resolution computed tomography. The median survival was 92 months (95 % CI 62.8-121.2) in the UIP-group and 137 months (95 % CI 31.0-243.0) in the non-UIP-group (p = 0.417). Differences in course of disease were found in the number of hospitalizations for respiratory reasons (mean 1.9 ± 2.6 in UIP vs. 0.5 ± 0.9 in non-UIP group, p = 0.004), the use of oxygen therapy (8/22.9 % UIP patients vs. 0 non-UIP patients, p = 0.016), number of deaths (23/65.7 % vs. 10/41.7 %, p = 0.046) and decline in diffusion capacity (56 ± 20.6 vs. 69 ± 20.2, p = 0.021). Dyspnea and inspiratory crackles were detected more often in the UIP group. RA-ILD was the most common primary cause of death (39.4 % of cases). Hypertension, coronary artery disease, chronic obstructive pulmonary disease, heart insufficiency, diabetes and asthma were common comorbidities. ILD preceded RA diagnosis in 13.6 % of patients. Conclusions: The course of the disease in RA-UIP patients is different from the other RA-ILD subtypes. Several comorbidities associated commonly with RA-ILD, although ILD was the predominant primary cause of death.
High-resolution computed tomography; Cause of death; Comorbidity
Background
Interstitial lung disease (ILD) is a rather common
extraarticular manifestation of rheumatoid arthritis (RA) and
a major cause of morbidity and mortality in RA patients
[
1, 2
]. Approximately 10 % of patients with RA may
develop clinically evident ILD with respiratory symptoms
and/or a decline in pulmonary function tests [3]. In
asymptomatic RA patients, high-resolution computed
tomography (HRCT) scans commonly reveal evidence
of interstitial lung involvement, and a large proportion
of those with subclinical disease deteriorate with time
[
4, 5
]. However, the clinical course of RA-ILD is highly
heterogenic, as some patients remain stable for years,
even decades, while others develop an insidious
progressive disease [6].
While the overall mortality in RA has declined, the
numbers of deaths due to RA-ILD have increased [
7
],
although the results of studies investigating survival have
been variable. Some studies have reported survival of
3 years, similar to that of idiopathic pulmonary fibrosis
(IPF) [
8, 9
], whereas in others the prognosis of RA-ILD
has been significantly better, with median survival of
approximately 6–8 years [
10, 11
].
Since it lacks its own distinctive classification, the
subtypes of RA-ILD have been categorized according
to the subdivisions of the idiopathic interstitial
pneumonias (IIP) [
12
]. Unlike the situation in other
connective tissue diseases (CTD), the most common
radiologic and histopathologic pattern of RA-ILD is
usual interstitial pneumonia (UIP), whereas
nonspecific interstitial pneumonia (NSIP) and other subtypes
also exist to a lesser extent [
13
]. The clinical
significance of these different histological and radiological
patterns has become nowadays more important since
the RA-ILD patient with the UIP pattern (RA-UIP)
seems to have a significantly worse prognosis and
reduced survival compared to other types such as NSIP
and organizing pneumonia (OP) [
11, 14–16
]. Other
diff (...truncated)