title: Variable course of disease of rheumatoid arthritis-associated usual interstitial pneumonia compared to other subtypes.
abstract: 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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Center of Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital, POB 100, 70029 KYS, Kuopio, Finland. hanna.nurmi@kuh.fi.|Division of Respiratory Medicine, Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland. hanna.nurmi@kuh.fi.
authors.forename: Hanna M
authors.initials: HM
authors.lastname: Nurmi
authors.affiliation: Center of Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital, POB 100, 70029 KYS, Kuopio, Finland.
authors.forename: Minna K
authors.initials: MK
authors.lastname: Purokivi
authors.affiliation: Division of Respiratory Medicine, Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland.|Harjula Hospital, the Municipal Hospital of Kuopio, Niuvantie 4, 70101, Kuopio, Finland.
authors.forename: Miia S
authors.initials: MS
authors.lastname: Kärkkäinen
authors.affiliation: Diagnostic Imaging Center, Division of Radiology, Kuopio University Hospital, POB 100, 70029, Kuopio, Finland.
authors.forename: Hannu-Pekka
authors.initials: HP
authors.lastname: Kettunen
authors.affiliation: Science Services Center, Kuopio University Hospital, POB 100, 70029, Kuopio, Finland.
authors.forename: Tuomas A
authors.initials: TA
authors.lastname: Selander
authors.affiliation: Center of Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital, POB 100, 70029 KYS, Kuopio, Finland.|Division of Respiratory Medicine, Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland.|Respiratory Medicine, Internal Medicine Research Unit, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, POB 20, 90029, Oulu, Finland.
authors.forename: Riitta L
authors.initials: RL
authors.lastname: Kaarteenaho
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications*; D002423:Cause of Death; D015897:Comorbidity; D005260:Female; D005387:Finland; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000145:classification* / Q000150:complications / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed
keywords: Cause of death; Comorbidity; High-resolution computed tomography