Asymptomatic Obstructive Ventilatory Defect is common among Rheumatoid Arthritis Patients

Abstract

Background Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting about 0.5–2% of the population worldwide. Extra-articular involvement in RA is a common condition and can occur in up to 40% of patients. Pulmonary involvement is a common extra-articular manifestation and may affect parenchyma, pleura, airway, and vasculature. It occurs in 20 to 67% of RA patients and it is responsible for about 10–20% of mortality in RA patients. So evaluation of the patients with rheumatoid arthritis for any deterioration in their lung functions is essential to treat appropriately, improve their mobility and quality of life. Objectives The study aimed to evaluate the effect of RA on the pulmonary function tests (PFTs) among Sudanese RA patients attending Rheumatology clinics in Omdurman Military hospital. Methods This is an analytical cross-sectional hospital -based study conducted among Sudanese RA patients. The study included 32 RA patients who were not known to have any respiratory illnesses or chronic diseases. An interview questionnaire with personal data and brief medical history was filled by the investigator. Height and weight were measured and BMI was calculated. Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), and Peak Expiratory flow Rate (PEFR) were measure for each participant by digital spirometer. Matching from control group with similar age and height was performed and the results were compared with normal reference values for Sudanese subjects.. The tested data was analyzed using SPSS version 25, t-test was used to compare the statistical significant (P-value ≤ 0.05 was considered statistical significant). Results In this study, all the measured parameters of the PFTs in RA patients were lower than the published reference normal values for Sudanese subjects with significant P values. The mean of FEV1, FVC, FEV1/FVC ratio and PRFR in RA patients was found to be 1.8 ± ,3 L/min, 2,1 ± ,4 L/min, 87.1 ± 12,2% and 223.6 ± 86.2 L/min respectively in compared to 2,4 ± ,1 L/min, 2,7 ± ,1 L/min,90.81 ± 2.6% and 345.4 ± 86.2 L/min respectively in the control group (P Value 0.001, 0.001,0.05, and 0.001 respectively). There was no statistical significance correlation between PFT and duration of age, disease, and BMI. Obstructive ventilatory defect was seen in 78.1% (25) of patients. Restrictive ventilatory defect was seen in only 6.3% (2) of patients and 15.6% (5) showed normal pattern. Conclusion Pulmonary function abnormalities are common in asymptomatic rheumatoid patients which were found to be obstructive defect. Different pattern of pulmonary function abnormalities had a manifested in RA patients and the obstructive pattern represents the most common feature. Spirometry is indicated as a baseline assessment and for follow up of RA patient to enhance early detection and management of the pulmonary involvement.