PURPOSE: To describe the characteristics of the pulmonary function tests (PFTs) in a cohort of patients with diagnosis of rheumatoid arthritis (RA).
METHODS: we prospectively evaluated, with forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), total lung capacity (TLC), residual volume (RV) and diffusing capacity for carbon monoxide (DLCO) a cohort of 36 patients with diagnosis of RA. The results were expressed in absolute values and as percentages of predicted values.
RESULTS: we include 36 consecutive patients with RA (25 females and 11 males, mean age: 56±11.2 years). The mean values were for FVC 2.7 l ± 0.76 (82% ± 19), FEV1 2.2 l ± 0.61 (91% ± 22) and for FEV1 /FVC 82 ±4.6, for lung volumes were: total lung capacity (TLC) 4.7 l ± 0.8 (93 % ± 35.5), functional residual capacity (FRC) 0.5 l ± 0.18 (48% ± 13), residual volume (RV) 1.06 ± 0.4, VER 45± 44.7 and RV/TLC 42± 9.9. The mean diffusing capacity for carbon monoxide (DLCO) measured by single breath expressed in percentage was 69.7% ± 28, adjusted by hemoglobin 71.9% ± 31 and the kCO (DLCO/AV) 99% ± 19.The 38.8% of the patients showed a decrease in the FVC (< 80%), and of these, only 35% manifested dyspnea. Only in one patient (2.7%) we founded airway obstruction measured by the spirometry and in no case we evidenced hyperinsuflaction (TLC<120%), 63.8% showed DLCO < 80% and only 9 (39%) refered dyspnea and 11 (47%), declined of FVC. Of the total of 17 patients without dyspnea, 8 had abnormal DLCO (47%).
CONCLUSION: Obstructive and restrictive defects in the spirometry and a decrease of the DLCO are frequently seen in patients with RA, even in asymptomatic patients.
CLINICAL IMPLICATIONS: Nearly 50% of the patients with RA present extra-articular manifestations. Although cardiovascular disease is responsible for the majority of RA-related deaths, pulmonary complications can cause 10-20% of overall mortality.Functionally, are described restrictive and obstructive ventilatory defects, the lasts, related with airway involvement.
DISCLOSURE: Gabriela Tabaj, No Financial Disclosure Information; No Product/Research Disclosure Information