The Lung in a Cohort of Rheumatoid Arthritis Patients

An Overview of Different Types of Involvement and Treatment

Ana C. Duarte; Joanna C. Porter; Maria J. Leandro


Rheumatology. 2019;58(11):2031-2038. 

In This Article


Patients and Design

A retrospective study including all RA patients that attended the Rheumatology Department of University College London Hospital from 2002 to March 2018 was conducted. Data were collected as part of a Service Evaluation exercise as defined by the National Health Service Health Research Authority and the Medical Research Council, and therefore did not require research ethics committee approval. All patients' data were anonymized and therefore no informed consent was required. Lung involvement was based on high resolution CT (HRCT) results and histopathological data. Demographics and clinical data, including smoking history, RA disease duration, presence of secondary Sjögren's syndrome, cutaneous rheumatoid nodules (RN) and/or cutaneous vasculitis at any time, were analyzed from electronic records of all RA patients until last follow-up appointment. Laboratory results included RF, ACPA, ANA, ENA, ESR and CRP. The presence of erosive disease was based on skeletal X-rays performed either at baseline or during follow-up.

Types of lung involvement were based on HRCT, with the date of the exam being considered the date of lung disease diagnosis. Subsequent HRCT results were also recorded. Pulmonary function test results (PFTs), including gas transfer (transfer factor for carbon monoxide), were collected for patients with lung involvement. Patients with ILD had their Gender Age Physiology (GAP) index calculated at time of lung disease diagnosis.[15–18]

Regarding treatment, current and previous synthetic and biologic DMARDs were recorded. A sub-analysis of patients with ILD who had been treated with RTX was performed in order to evaluate treatment response at 6, 12, 24 and 36 months. We considered disease progression as: a decline of 15% in gas transfer from baseline; and/or decline of 10% in forced vital capacity; and/or imaging worsening in follow-up HRCT.

Safety analysis included severe adverse events and infections. Severe adverse events were defined as those requiring hospital admission, life-threatening conditions or death. Possible relation of severe adverse events to lung disease and/or therapy was also evaluated. The use of prophylactic antibiotics was reported.

Statistical Analysis

A descriptive analysis was performed. Continuous variables were expressed as mean ± S.D., if they had a normal distribution, or median with interquartile range if not normally distributed. Categorical variables were presented as absolute values and frequencies (expressed as percentages). Groups were compared using χ2 and Mann–Whitney U tests. Logistic regression analysis was used to assess the association between disease duration/interval between articular and respiratory manifestations, disease outcomes and lung disease patterns. A significance level of 5% was used in all analyses. Statistical analyses were performed using SPSS, version 22.0. (IBM Corp, Armonk, NY, USA).