1. Prevalence and clinical risk factors for interstitial lung disease in rheumatoid arthritis in a resource limited setting A Dasgupta, P Bhattacharyya, S Sengupta B R Singh Hospital for Medical Education and Research, Kolkata, West Bengal, India RISK FACTORS CONCLUSION AND RECOMMENDATIONS ABSTRACT PREVALENCE BACKGROUND METHODS OBJECTIVES STUDY DESIGN STATISTICAL ANALYSIS The prevalence of ILD is higher than most other reports. Although greater duration of disease had a greater risk of having ILD, there were 2 patients with early (<2 years) disease who also had ILD. 33.33% of patients had ILD despite being asymptomatic. Acknowledgements: Medical Department, Eastern Railways Pulmonary complications occur in 30% of rheumatoid arthritis patients and is an important cause of morbidity and mortality in these patients. The prevalence of ILD is grossly underestimated in resource limited settings mainly due to non availability of HRCT scans. It is important to recognise the presence of interstitial lung disease in these patients since the treatment of RA, especially choice of biologics, depends on the concomitant presence or absence of ILD. Further the risk factors for development of ILD in a similar group of patients and clinical setting has not been explored. Several factors such as smoking, erosive/destructive changes of joints, high disease disability, anti-cyclic citrullinated peptide antibodies (anti-CCP Abs), rheumatoid factor have been described, though these have remained the subject of debate. Baseline characteristics and demographic data were summarized using descriptive statistics. Between groups comparisons of normally distributed data were made using unpaired-t test and non-normally distributed data were made using non parametric tests. Analyses of categorical variables, levels of significance were determined by means of the chi-square test or Fisher’s exact probability test using contingency tables. Continuous variables were assessed using the independent t- test and Kruskal Wallis test. All tests were 2-sided and significance was accepted at 95% level. Screening for ILD should be considered in RA patients with longer duration (>10 years), deforming disease, those with high anti CCP titers (>90 IU/l) and female patients with rheumatoid factor positivity even if asymptomatic from a respiratory point of view. Annual screening with HRCT scans may be considered especially if treatment with biologics is being planned. To determine the prevalence of interstitial lung disease in rheumatoid arthitis. To examine the risk factors for development of interstitial lung disease in rheumatoid arthitis. Introduction: The prevalence of interstitial lung disease (ILD) in rheumatoid arthritis (RA) patients in resource limited countries is often under reported largely due to the absence of availability and affordability of High Resolution Computed Tomography scans (HRCT). The risk factors and therefore the necessity for screening such patients for ILD remain unknown. Objective: (1) To find out the prevalence of ILD in RA (2) To identify clinical risk factors for ILD in these patients in resource limited settings. Methods: HRCT images and clinical data were reviewed of 30 consecutive RA patients at their first visit to the rheumatology clinic of BR Singh Hospital, India. The diagnosis of ILD was based on abnormal HRCT findings while that of RA was based on ARA criteria. Results: The prevalence of ILD in RA was 60%. The main risk factors were duration of disease > 10 years (relative risk 2.05, p=0.02), high titer of anti-CCP (relative risk 1.85, p=0.05) and presence of deforming disease (relative risk 1.73, p=0.0014). Overall, i.e. when all patients were considered, age, gender or rheumatoid factor positivity were not predictive of the presence of ILD. However subgroup analysis showed that female patients with a positive rheumatoid factor had a greater prevalence of ILD. Despite being asymptomatic 33.33% of patients had HRCT evidence of ILD. Conclusion: The prevalence of ILD is RA is high. Screening for ILD should be considered in RA patients with longer duration, deforming disease, those with high anti CCP titers and female patients with rheumatoid factor positivity even if asymptomatic from a respiratory point of view. With ILD (n=18) No ILD (n=12) P value Age in years, median (25 th, 75 th percentiles) 48 (37.5,54)46 (42, 53.3)0.98 Male : Female3:152:100.61 RA duration,months, median (25 th, 75 th percentiles) 120 (75,144)84 (72, 96)0.24 Long Standing (> 10 years) RA, number of patients (%) 11(61.1)2 (16.67)0.006 Smoking history, number of patients (%) 1(5.6)0- Respiratory symptoms, numbers of patients (%) 9(50)0 - Positive anti-CCP, numbers of patients (%) 18(100)11(91.67) 0.33 High-titer anti-CCP (>90 U/ml), numbers of patients (%) 15(83.33)7(58.33) 0.15 Anti-CCP titer, U/ml, medians (25th, 75 th percentiles) 252 (164.5, 262.25) 232 (47.4, 258.5)0.19 Positive RF, Numbers of patients (%) 12(66.67)7(58.33)0.58 Table 1: Clinical characteristics of RA patients with or without Interstitial lung disease (n=30) Predictive factor (ILD vs no ILD) Relative Risk 95% Confidence Interval P value Anti CCP>90 (68% vs 32%) 1.831.3766 to 2.4535< 0.0001 Duration>10yrs (85% vs 41%) 2.051.1125 to 3.79580.022 Deforming ds (82% vs 47%) 1.730.9968 to 2.9932<0.0001 Age>65 (75% vs 58%) 1.30.6756 to 2.50170.01 Gender (M:F = 3:15 vs 2:10) 1.00.4566 to 2.19021.0 RA factor positivity (63% vs 55%) 1.160.6108 to 2.19490.65 Females with RA positivity (65% vs 35%) 1.31.0194 to 1.65780.03 Table 2 : Predictive Factors for ILD in RA This was an out patient department based cross sectional study. The records of 30 consecutive patients of rheumatoid arthritis who attended the rheumatology service of B R Singh Hospital, Kolkata, India were interviewed during their first consultation. Clinical data, pulmonary function tests and high resolution CT scan was reviewed systematically. The study was approved by the Institutional Ethics Committee and informed consent was obtained from all patients. The diagnosis of rheumatoid arthritis was based on the 2010 American College of Rheumatology/European League Against Rheumatism classification criteria. The diagnosis of the presence of interstitial lung disease in High Resolution CT scans (HRCT) was made independently by two radiologists in a blinded fashion to the patients’ clinical status. In case of differences in opinion, the patient was taken to have ILD even if only one radiologist thought so. Patients were included regardless of the absence or presence of respiratory symptoms. These patients were consecutively enrolled unless they met one of the following exclusion criteria: (1) a history of exposure to dust such as asbestos or silica, (2) a history of thoracic radiation for cancer therapy or (3) CREST / Overlap syndrome. The patients were not selected based on their reasons for visiting, which included evaluation of articular symptoms, treatment consultation, RA complications, and other reasons. All patients underwent the following investigations 1) Blood tests : Rheumatoid factor, anti-CCP 2) Chest X-ray PA view 3) Spirometry 4) HRCT of chest Figure 3: Radiological patterns of ILD Figure 2: ILD in females according to RF factor positivity