Investigation of the chronic pulmonary effects of low-dose oral methotrexate in patients with rheumatoid arthritis: a prospective study incorporating HRCT scanning and pulmonary function tests

Rheumatoid arthritis treatment and the risk of severe interstitial lung disease

OBJECTIVES

Interstitial lung disease (ILD) is an important complication of rheumatoid arthritis (RA) or its treatment, and is associated with substantially increased mortality. Reports have suggested that infliximab with or without azathioprine might lead to rapidly progressive or fatal ILD. We used an RA data bank to assess the associations of treatments for RA and severe ILD.

METHODS

ILD was identified in hospitalisations and death records in 100 of 17,598 RA patients and studied in relation to RA therapy with Cox regression analyses.

RESULTS

The incidence of hospitalisation for ILD (HILD) was 260 per 100,000 patient years. Among those hospitalised for ILD, 27.0% died. In multivariable models of current and past RA treatment, the only current treatment associated with HILD was prednisone: hazard ratio (HR) 2.5 [95% confidence interval (CI) 1.5-4.1]. Among past therapies, prednisone (HR 3.0, 95% CI 1.0-8.9), infliximab (HR 2.1, 95% CI 1.1-3.8), etanercept (HR 1.7, 95% CI 1.0-3.0), and cyclophosphamide (HR 3.7, 95% CI 0.9-15.5) were associated with HILD. Pre-existing lung problems were identified in 67% of HILD. Only one case of HILD in the 100 hospitalisations suggested a possible temporal relationship between infliximab and HILD.

CONCLUSIONS

Associations between RA treatment and HILD are confounded by the prescription of treatments for ILD such as prednisone, infliximab, etanercept, and cyclophosphamide. There is no clear pattern of causal association of treatment and ILD, and there is no clear evidence to support a causal relationship between infliximab, azathioprine, and HILD.

Lymphocyte transformation test is not helpful for the diagnosis of methotrexate-induced pneumonitis in patients with rheumatoid arthritis

BACKGROUND

The pathophysiology underlying methotrexate (MTX)-induced pneumonitis has been considered as a hypersensitive reaction. The lymphocyte transformation test (LTT) is frequently used to detect hypersensitivity. Whereas previous reports have proposed that the LTT is not ideal to detect hypersensitivity to MTX, it has not been directly confirmed.

METHODS

Forty rheumatoid arthritis (RA) patients (24 patients currently taking MTX and 16 patients with a past history of MTX administration) and 13 healthy subjects were recruited. LTT with MTX was used to assess thymidine incorporation. An MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) assay was also performed. The mitogenic activity was expressed as the Stimulatory Index (SI). The activity of RA was assessed by the disease activity score 28 (DAS28).

RESULTS

In the presence of MTX, the SI measured by the LTT and by the MTS assay showed an inverse correlation. The presence of MTX significantly elevated the SI values measured by the LTT. However, the SI values were significantly lower in RA patients currently taking MTX than those of patients not currently taking MTX, although DAS28 was not different. Furthermore, a past history of MTX-induced pneumonitis did not affect the SI values.

CONCLUSION

LTT with MTX in RA patients is not appropriate to detect MTX-induced pneumonitis.

Lung disease in rheumatoid arthritis

PURPOSE OF REVIEW

To examine the role of lung disease in rheumatoid arthritis from a clinical, epidemiologic, pathophysiologic, and therapeutic perspective.

RECENT FINDINGS

Lung disease in rheumatoid arthritis is pleomorphic and has a marked adverse impact on the morbidity and premature mortality of patients with this disease. Recent advances in the understanding of the pathophysiology of lung disease associated with rheumatoid arthritis reveal it to be characterized by more active cellular infiltrates of both T cells and B cells, as well as other immunologically active cells, including mast cells, than many of the other forms of interstitial lung disease. Satisfactory treatment is lacking; available biologic response modifiers have been reported to have both beneficial and adverse effects on the lung. Newer approaches targeting cellular immunologic dysfunction including T-cell-directed and B-cell-directed therapies hold the promise of reducing lung damage related to the underlying disease.

SUMMARY

Lung disease in rheumatoid arthritis is a heterogeneous and oftentimes serious condition, with a profound impact on patient wellbeing and survival. Advances in the understanding of its etiology and targeted application of available, as well as development of new, more specific therapeutics will be of benefit to patients with rheumatoid arthritis who are suffering from lung disease.

Rheumatoid lung disease

Rheumatoid arthritis (RA) is a common, functionally disabling disease with genetic and environmental contributors. It occurs in approximately 1% of the population and adversely affects quality of life, functional status, and survival. Beyond its impact on the joints, pulmonary involvement occurs regularly and is responsible for a significant portion of the morbidity and mortality. Although pulmonary infection and/or drug toxicity are frequent complications, lung disease directly associated with the underlying RA is more common. The airways, vasculature, parenchyma, and pleura can all be involved, with variable amounts of pathologic inflammation and fibrosis. The true adverse clinical impact of the most important of these directly associated disorders, RA-associated interstitial lung disease (RA-ILD), has only recently begun to reveal itself. Our knowledge of the underlying pathobiology and the impact of our current immunomodulatory and biologic therapies on the lung disease are less than incomplete. However, what is clear is the importance of progressive lung fibrosis in shortening survival and impairing quality of life in RA as well as in other connective tissue diseases. The impact of historically available and newer biologic therapies in altering the outcome of RA-ILD is unknown; translational studies focused on the pathobiology and clinical studies focused on the treatment of RA-ILD are needed.

Interstitial lung disease in rheumatoid arthritis: recent advances

PURPOSE OF REVIEW

Subsequent to the ATS/ERS consensus classification of idiopathic interstitial pneumonia, non-specific interstitial pneumonia pattern was the dominant pattern in many collagen vascular diseases, which may explain the better prognosis of interstitial pneumonia associated with collagen disease than idiopathic pulmonary fibrosis. Recent papers on rheumatoid arthritis suggest that this is not the same in all collagen diseases, and this paper will review previous data and discuss recent papers.

RECENT FINDINGS

In contrast to other collagen diseases, the usual interstitial pneumonia pattern seems to be more common, or at least as common in rheumatoid arthritis. This pathological observation was supported by high-resolution computed tomography findings. In addition to the usual interstitial pneumonia pattern, several types of small airway involvements were frequently observed in rheumatoid arthritis-associated interstitial pneumonia, the prognosis of which is also variable.

SUMMARY

Because the usual interstitial pneumonia pattern may be more frequent in rheumatoid arthritis and some data suggest a poor prognosis for rheumatoid arthritis-associated interstitial pneumonia, further studies are required on the prognosis of collagen vascular disease-associated interstitial pneumonia, especially in relation to the pathological pattern. Drug-related interstitial pneumonia should also be considered in rheumatoid arthritis patients on methotrexate or newer drugs such as leflunomide.

Pulmonary involvement in lifelong non-smoking patients with rheumatoid arthritis and ankylosing spondylitis without respiratory symptoms

Pulmonary involvement seen in rheumatoid arthritis (RA) and ankylosing spondylitis (AS) has been detected increasingly by using highly sensitive diagnostic techniques such as high-resolution computed tomography (HRCT). However, HRCT findings in healthy controls and the effects of smoking and drugs have not been well studied. The aim of this controlled study was to evaluate the relationships between disease-specific clinical, laboratory, HRCT and pulmonary function test (PFT) findings in 20 RA patients using methotrexate (MTX) and 20 AS patients using sulphasalazine who were non-smokers and exhibited asymptomatic respiratory signs. For this purpose, a total of 60 persons (40 patients and 20 healthy controls) were included in this study. A restrictive pattern on PFT was detected in four patients (20%) with AS, one patient with RA and one control (p<0.05). Fourteen patients (70%) with RA and ten patients (50%) with AS had positive HRCT findings. Only one patient (5%) in the control group had abnormal HRCT findings (p<0.05). Interstitial lung disease (ILD) was the most frequently seen HRCT finding in both the RA (35%) and AS (20%) groups. The chest expansion measurement, the score of the visual analogue scale (VAS) for pain and C-reactive protein (CRP) levels were statistically significantly better in patients with AS having normal HRCT than in those with abnormal findings (p<0.05). There was no correlation detected between HRCT and duration of disease, disease activity markers, functional indexes and PFT in patients with RA and AS. HRCT is a sensitive tool in detecting ILD in patients with RA and AS with no signs and symptoms of pulmonary involvement and may be an integral part of such work-up. However, future prospective studies are needed to better determine if HRCT is in fact a predictor of subsequent MTX toxicity.

Interstitial lung disease in the patient who has connective tissue disease

Interstitial lung disease is a common complication of many of the connective tissue diseases. Because the prognosis, degree of reversibility, and optimal therapy differs for each disease presentation, a thorough knowledge of the pulmonary presentations of each connective tissue disease is important. Additionally, the challenge of finding the patient who has occult connective tissue disease in an interstitial lung disease clinic is discussed.

Understanding the mechanisms of drug-associated interstitial lung disease

Drugs have been implicated in lung injury as a result of direct pharmacological action, persistence or metabolism in the tissue, or via the production of a reactive metabolite or metabolites. The result of this apparent drug-associated injury ranges from cellular dysfunction through to cell death (apoptosis) and alteration of repair mechanisms that are essential in replacing critical tissue elements and function. There is limited knowledge on how timing of drug administration or drug interactions may interfere with the repair mechanisms or modulate the expression of pulmonary toxicity. Chemotherapeutic drugs and novel agents, such as those targeting the epidermal growth factor receptor (EGFR), appear to affect both normal and neoplastic cells. However, unlike chemotherapy, where the actions are systemic and directly as a result of biotransformation or cell injury, it has been postulated that effects of EGFR-targeting agents are more likely to be focused on epithelia via a pharmacological effect. Furthermore, risk factors for the development of adverse pulmonary reactions, as well as biological markers indicating incipient toxicity, need to be prospectively identified. Proteomics, through the identification of ⩾1000 proteins or peptides in blood samples, will hopefully identify candidates for this role.

Management of extra-articular disease manifestations in rheumatoid arthritis

PURPOSE OF REVIEW

To discuss the rationale for various treatment strategies in rheumatoid arthritis with extra-articular manifestations, and to review advances in understanding the impact of extra-articular rheumatoid arthritis and its management.

RECENT FINDINGS

Recent epidemiologic studies of extra-articular rheumatoid arthritis manifestations have emphasized their major role as predictors of premature mortality in patients with rheumatoid arthritis, and provide a rationale for aggressive ant-rheumatic treatment of extra-articular rheumatoid arthritis. Previous uncontrolled or nonrandomized studies favor the use of cyclophosphamide in patients with systemic rheumatoid vasculitis, and methotrexate in the case of other manifestations of extra-articular rheumatoid arthritis. Recent case reports indicate that patients with rheumatoid lung disease may respond to cyclosporine or tumor necrosis factor inhibitors, and that tumor necrosis factor blocking therapy also may be successful in cases of treatment-resistant vasculitis. By contrast, it has been suggested that tumor necrosis factor inhibitors may induce some manifestations of extra-articular rheumatoid arthritis. Data indicating a high risk of serious infections and cardiovascular disease in patients with extra-articular rheumatoid arthritis underline the importance of carefully monitoring such patients.

SUMMARY

Extra-articular rheumatoid arthritis is a serious condition, and rheumatoid arthritis patients with extra-articular manifestations should be aggressively treated and monitored. Advances in the understanding of the pathogenesis of rheumatoid arthritis and developments of new, more specific drugs may be of particular benefit to patients with extra-articular disease.

Pulmonary involvement in rheumatoid arthritis

The primary objective of this investigation was to assess the relationships between clinical characteristics, lung involvement, and frequency of pulmonary involvement in rheumatoid arthritis (RA). Using high-resolution computed tomography (HRCT) and pulmonary function tests (PFT), we prospectively evaluated 52 patients with RA (eight males and 44 females, mean age 53.6 years). The HRCT was abnormal in 35 patients (67.3%), the most frequent abnormalities being reticulonodular patterns, which were found in 22 patients (62.9%), ground-glass attenuation (20%), and bronchiectasis (17%). In this group of patients, PFT results were normal in 13 patients (37%). Titers of rheumatoid factor and erythrocyte sedimentation rate were significantly higher in abnormal HRCT presence. Higher Larsen's score, advanced age, and severe disease were significant risk factors for lung involvement (p<0.001, p<0.01, and p<0.01, respectively) and are suggested by our data to be statistically significant predictors of lung involvement in RA.