Assessment of pulmonary function in Rheumatoid arthritis patients attendin-g Rheumatology clinics in nairobi

Abstract

Background: Pulmonary involvement is frequent and among the most severe extra-articular manifestations of Rheumatoid arthritis (RA) ranking as the second cause of mortality in this patient population. Rheumatoid arthritis can affect the lung parenchyma, airways and pleura. Pulmonary complications are directly responsible for 10-20% of all mortality in RA patients. Spirometry is becoming increasingly available in Kenya and could be used in peripheral areas to screen and monitor for pulmonary function abnormalities in well characterized patient populations such as those with RA. Abnormalities detected by pulmonary function tests may precede symptoms by years and lead to early diagnosis of pulmonary fibrosis in rheumatoid arthritis and hence intervention. Objective: To determine the prevalence of pulmonary function abnormalities in Rheumatoid arthritis patients attending Rheumatology Clinics in Nairobi. Study Design: Cross sectional descriptive Study. Study population: Rheumatoid arthritis patients who have met the American College of Rheumatology Criteria (ACR) 2010 age 16 to 65 years. Study site: Rheumatology Clinics in Nairobi as follows; Kenyatta National Hospital, Aga Khan University hospital and Mater hospital. Methods: Rheumatoid arthritis patients who fulfilled the study inclusion criteria were recruited. Sociodemographic characterictics and respiratory symptoms were assessed using Lung Tissue Research Consortium questionnaire (LTRC) and RA disease activity was established by Disease Activity Score (DAS28). Pulmonary function tests were then done using Spirolab 111 according to the American thoracic society recommendations. Results: One hundred and sixty six RA patients were recruited; the male to female ratio was 1:9.3, with a median age of 47 years. The overall 6 month prevalence of pulmonary function abnormalities was 38.5% as measured by Spirometry and all our patients did not carry any prior pulmonary disease diagnosis. The predominant ventilatory defect was Obstructive pattern at 20.4%, followed by Restrictive pattern at 16.8% and least common being a mixed picture at 1.2%. Factors that were shown to be independently associated with pulmonary function abnormalities were age and RA disease activity. Respiratory symptoms that were predictive of PFTs abnormalities were cough, increased frequency of chest colds and illnesses and phlegm. - Conclusion: High prevalence of pulmonary function abnormalities was observed. Respiratory symptoms, older age and ongoing disease activity can identify patients in greatest need of further pulmonary evaluation.