Contrasting diagnosis performance of forced oscillation and spirometry in patients with rheumatoid arthritis and respiratory symptoms

Abstract

OBJECTIVES:Pulmonary involvement in rheumatoid arthritis is directly responsible for 10% to 20% of all mortality. The best way to improve the prognosis is early detection and treatment. The forced oscillation technique is easy to perform and offers a detailed exam, which may be helpful in the early detection of respiratory changes. This study was undertaken to (1) evaluate the clinical potential of the forced oscillation technique in the detection of early respiratory alterations in rheumatoid arthritis patients with respiratory complaints and (2) to compare the sensitivity of forced oscillation technique and spirometric parameters.METHODS:A total of 40 individuals were analyzed: 20 healthy and 20 with rheumatoid arthritis (90% with respiratory complaints). The clinical usefulness of the parameters was evaluated by investigating the sensibility, the specificity and the area under the receiver operating characteristic curve. ClinicalTrials.gov: NCT01641705.RESULTS:The early adverse respiratory effects of rheumatoid arthritis were adequately detected by the forced oscillation technique parameters, and a high accuracy for clinical use was obtained (AUC>0.9, Se = 80%, Sp = 95%). The use of spirometric parameters did not obtain an appropriate accuracy for clinical use. The diagnostic performance of the forced oscillation technique parameters was significantly higher than that of spirometry.CONCLUSIONS:The results of the present study provide substantial evidence that the forced oscillation technique can contribute to the easy identification of initial respiratory abnormalities in rheumatoid arthritis patients that are not detectable by spirometric exams. Therefore, we believe that the forced oscillation technique can be used as a complementary exam that may help to improve the treatment of breathing disorders in rheumatoid arthritis patients.

Oscillation mechanics of the respiratory system in never-smoking patients with silicosis: pathophysiological study and evaluation of diagnostic accuracy

“…Several authors have argued that the FOT has the potential to improve diagnosis and the tracking of treatments and that further studies are necessary in this area (7,13,14). Previous studies from our group suggest that this technique may contribute to the detection of respiratory changes in smokers (15,16) and in patients suffering from sarcoidosis (17) and rheumatoid arthritis (18). Therefore, the FOT may facilitate the diagnosis of patients with occupational diseases (8) and enable simple, routine evaluations in these patients.…”

Respiratory mechanics measured by forced oscillation technique in rheumatoid arthritis-related pulmonary abnormalities: frequency-dependence, heterogeneity and effects of smoking

“…Although the origin of ΔXrs is still uncertain, high ΔXrs values at low frequencies may derive from the presence of airway abnormalities, including expiratory flow limitations and decreases in lung volume in our cohort. It has been reported that small airway abnormalities are involved in RA patients even when the CT findings show IP dominant patterns or normal shadow (Mori et al 2011 ; Faria et al 2012 ) different from idiopathic IP and other collagen vascular diseases-related IP.…”

“…Xrs is determined by the elastic properties of the respiratory system at the lowest frequency and the inertive properties at higher frequencies (Oostveen et al 2003 ). It is expected that FOT will be able to identify respiratory abnormalities in patients with RA that are not detectable by spirometric examinations (Faria et al 2012 ). However, the Zrs assessed by this technique has not been fully evaluated in patients with RA-related pulmonary diseases yet.…”

Espirometria em pacientes portadores de artrite reumatoide e sua associação com aspectos epidemiológicos, clínicos, radiológicos e tratamento

“…7,37,45 Por outro lado, estudo recente conduzido na população brasileira mostrou que em pacientes com AR referenciados por sintomas respiratórios mas com espirometria normal, uma técnica mais sensível (técnica oscilatória forçada) mostrou sinais de aumento de resistência em vias aéreas, sugerindo acometimento precoce dessas estruturas. 46 Um outro teste capaz de medir a heterogeneidade da ventilação alveolar, focado principalmente nas pequenas vias aéreas, é o teste de washout de gás inerte, realizado através de duas possíveis técnicas, de respiração única ou respirações múltiplas. 47 No nosso meio a técnica disponível é a de respiração única com washout de nitrogênio, que já foi utilizada previamente em pacientes com AR e, interessantemente, mostrou valores consistentes com maior heterogeneidade das pequenas vias aéreas em pacientes sem história de tabagismo.…”

“…Há poucos estudos sobre doença pulmonar associada à AR, sendo importante a caracterização desta população. 46,75 Além do mais, há uma recomendação de realização anual de RX de tórax para tais pacientes. 17 Os estudos que avaliaram a performance dos RX de tórax utilizaram aparelhos antigos, cujas imagens ainda eram impressas e não passíveis de ajuste.…”