Rheumatoid Arthritis-related ILD
OVERVIEW
Rheumatoid arthritis (RA) is a condition in which patients may develop interstitial lung disease. In this chapter, we’ll first address RA, and then RA-ILD.
Rheumatoid arthritis is a systemic disease that causes pain and inflammation, tendon and ligament stretching, and erosion of cartilage and bone.1,2 RA-induced inflammation that does not respond to therapy or is not treated results in joint destruction that reduces physical function and interferes with tasks of daily living and the ability to maintain employment.2,3
RA has the highest prevalence of all connective tissue diseases.4
EPIDEMIOLOGY
An estimated 1.3-1.5 million people in the United States are living with RA, and around 130,000 will receive a new diagnosis this year.5,6
Onset of disease typically occurs in adults in their 60s.3
RISK FACTORS3,7
- Women are 2-3 times more likely to develop the disease than men
- Most common in women 60 years of age or older
- Not having children (females only)
- Male sex (tend to have later onset, more aggressive disease)
- Smoking
- Obesity
RA DIAGNOSTICS
SYMPTOMS
- Patients with early disease may have joint manifestations that are difficult to distinguish from other forms of inflammatory polyarthritis.1,8
- The more distinctive signs of RA, such as joint erosions, rheumatoid nodules, and other extra-articular manifestations, are seen primarily in patients with long-standing, poorly controlled disease but are frequently absent on initial presentation.1,8,9
- Lung tissue is often affected in the way of10-12
- Parenchymal disease (ILD, nodules)
- Airway disease
- Pleural disease
- 20% of RA mortality is due to pulmonary manifestations4
DIAGNOSTICS
Established diagnosis of RA OR comprehensive medical history + synovitis + number of joints involved + serologies (RF, ACPA) + erythrocyte sedimentation rate (ESR) + C-reactive protein (CRP).1
RHEUMATOID ARTHRITIS-ILD OVERVIEW
- Around 10% of patients with RA will have clinically significant ILD10
- Higher numbers of patients will have asymptomatic pulmonary changes that can be found on HRCT10
- Mostly associated with erosive joint disease13
- Although ILD can occur any time before or after RA diagnosis, 34% of ILD occurs within the first year10
| ILD Lifetime Risk (%)10 | |||
|---|---|---|---|
| RA | General Population | ||
| 7.7 | 0.9 | ||
- ILD risk increases with duration of the disease10
- Patients who develop RA-ILD have a 3-fold greater risk of death than RA patients without ILD10
- While RA is more common in females, RA-ILD occurs more frequently in males (approximately 2:1)14
RISK FACTORS
Risk Factors for developing RA-ILD:10
- Male
- Older age at onset
- Smoking
- High titer of rheumatoid factor/anti-citrullinated protein antibodies (ACPA)
There is a high variability in the RA-ILD clinical course – asymptomatic disease can become rapidly progressive.10
RA-ILD COMORBIDITIES
- Many standard treatments for RA can lead to drug-induced ILD, which is often difficult to differentiate from RA-ILD4
- Drug-induced ILD is relatively rare but should be suspected when clinical, functional, or radiologic abnormalities appear in the first 6 months of treatment18
- Other complicating factors include pulmonary infections, which can also occur in this population due to immunosuppression from standard RA therapies4
