1. ObstructiveSleep Apnea (OSA) The prevalence of OSA in IPF wasreported to be 60% to 90%, but OSA therapy reduces the clinical symptomsassociated with OSA in IPF patients. Studies shown that outcomes get worse inIPF patients who do not comply with CPAP. 12 Oxygensupplementation alone may alleviate the severity of desaturation in the casesof patients with worsened PH, occurred due to failure to treat OSA.
2. DepressionDepressionand anxiety show high prevalence of >20% in patients with ILD. Depressioncan be alone independently predicted based on the severity of dyspnea, sleepquality, reduced FVC, and pain. Recent studies suggest that ILD patients shouldbe referred early in the stages to pulmonary rehabilitation based on fatigue,functional capacity, and improvements in symptoms of depression and anxiety. 13 3.
Rheumatoid Arthritis (RA)Alongwith some drug therapies or infectious precipitants, chronic immune activationand inflammation occurs in RA that promotes aberrant fibro-proliferation, whichgives rise to RA-associated ILD (RA-ILD). 14 It has been shownthat RA-ILD significantly decreased the quality of life with high utilizationof healthcare resources and poorer mortality. 15 Treatments of RA includemethotrexate, leflunomide (LEF), and anti-tumor necrosis factor ? (anti-TNF?). 16Immunomodulators such as mycophenolate and rituximab and newly studiedantifibrotic agents have shown promising effects. Prevalence of RA-ILD has beenreported from 3.6% to 60%. CONCLUSION Comorbidities in ILD have shown tosignificantly impair the quality of life and to reduce life expectancy.
Due todifferent nature of each comorbidity or the adverse effects on each other, thetreatments for each of them can be further complicated. For example,antifibrotic therapy is less likely to prolong life in IPF patients withadvanced lung cancer or severe PH. In some cases, immunosuppression may help toalleviate the symptoms itself, however, it may further cause the worsening ofpre-existing or triggers the development of ILD. It is essential to study the comorbiditiesin ILD because an early detection and its accurate management may have the potentialbenefits in reducing morbidity and mortality in the future.