Co-morbidities and cause of death in patients with rheumatoid arthritis associated interstitial lung disease

Abstract

Various types of interstitial lung diseases (ILD) are relatively common in patients with rheumatoid arthritis (RA). Since little is known about morbidity of the RA-ILD patients, we have evaluated co-morbidities and cause of death in patients with RA-ILD. The patients with RA (n=444) and patients with ICD-10 code J84 (n=610) were treated in Kuopio University Hospital out-patient clinic of respiratory medicine in the years 2002-2012 due to respiratory symptoms. After re-evaluation, we selected 61 patients (23 men and 38 women) with RA-ILD into this study. Radiological and clinical information of the patients was collected on specially designed forms and re-analyzed. Concomitant diseases and both primary and immediate causes of death were gathered. Fifty-one percent of patients were non-smokers. The mean age at the time of diagnosis of RA-ILD was 70 years and mean survival after diagnosis was similar (5.6 years) in both genders and in smokers and non-smokers. The most common concomitant diseases were cardio vascular disease (CVD) (37%) and hypertension (35%), followed by diabetes (15%), asthma (15%) and chronic obstructive pulmonary disease (COPD) (12%). Forty-nine percent of the subjects had died. The most common causes of death were ILD (38%) and CVD (35%). The most common immediate causes of death were pneumonia and CVD (both 32% of cases). We conclude that although CVD and hypertension were the most common co-morbidities in the patients with RA-ILD, obstructive lung diseases also co-existed rather often. The most prevalent cause of death was ILD, and acute respiratory infection was frequently present in conjunction with the chronic lung disease.