Polymyositis/dermatomyositis is a potential risk factor for acute respiratory failure: a pulmonary heart disease

Polymyositis: A Rare Cause of Acute Respiratory Failure and a Diagnostic Dilemma

Polymyositis is an autoimmune multisystemic disorder that affects the body's muscular system. It usually affects the proximal muscles of the shoulder, pelvis, neck flexor muscles, and sometimes, the hip extensor muscles. However, it can also affect the diaphragm causing acute respiratory failure. This case report educates clinicians about the atypical presentation of polymyositis, diagnosis, and treatment of this disease. It also emphasizes the importance of looking for an alternative diagnosis such as polymyositis when the treatment for the more common diagnoses such as community-acquired pneumonia does not improve the patient's respiratory status.

Clinical and Radiological Features of Interstitial Lung Diseases Associated with Polymyositis and Dermatomyositis

Polymyositis and dermatomyositis are autoimmune idiopathic systemic inflammatory diseases, characterized by various degrees of muscle inflammation and typical cutaneous lesions-the latter found in dermatomyositis. The underlying pathogenesis is characterized by a high level of uncertainty, and recent studies suggest diseases may have different immunopathological mechanisms. In polymyositis, components of the cellular immune system are involved, whereas in dermatomyositis, the pathogenesis is mainly mediated by the humoral immune response. The interstitial lung disease occurs in one-third of polymyositis and dermatomyositis patients associated with worse outcomes, showing an estimated excess mortality rate of around 40%. Lung involvement may also appear, such as a complication of muscle weakness, mainly represented by aspiration pneumonia or respiratory insufficiency. The clinical picture is characterized, in most cases, by progressive dyspnea and non-productive cough. In some cases, hemoptysis and chest pain are found. Onset can be acute, sub-acute, or chronic. Pulmonary involvement could be assessed by High Resolution Computed Tomography (HRCT), which may identify early manifestations of diseases. Moreover, Computed Tomography (CT) appearances can be highly variable depending on the positivity of myositis-specific autoantibodies. The most common pathological patterns include fibrotic and cellular nonspecific interstitial pneumonia or organizing pneumonia; major findings observed on HRCT images are represented by consolidations, ground-glass opacities, and reticulations. Other findings include honeycombing, subpleural bands, and traction bronchiectasis. In patients having Anti-ARS Abs, HRCT features may develop with consolidations, ground glass opacities (GGOs), and reticular opacities in the peripheral portions; nonspecific interstitial pneumonia or nonspecific interstitial pneumonia mixed with organizing pneumonia have been reported as the most frequently encountered patterns. In patients with anti-MDA5 Abs, mixed or unclassifiable patterns are frequently observed at imaging. HRCT is a sensitive method that allows one not only to identify disease, but also to monitor the effectiveness of treatment and detect disease progression and/or complications; however, radiological findings are not specific. Therefore, aim of this pictorial essay is to describe clinical and radiological features of interstitial lung diseases associated with polymyositis and dermatomyositis, emphasizing the concept that gold standard for diagnosis and classification-should be based on a multidisciplinary approach.

Hydroxychloroquine on the Pulmonary Vascular Diseases in Interstitial Lung Disease: Immunologic Effects, and Virus Interplay

To investigate the effects of hydroxychloroquine (HCQ) drug use on the risk of pulmonary vascular disease (PVD) in an interstitial lung disease cohort (ILD cohort, ILD+ virus infection), we retrospectively enrolled the ILD cohort with HCQ (HCQ users, N = 4703) and the ILD cohort without HCQ (non-HCQ users, N = 4703) by time-dependence after propensity score matching. Cox models were used to analyze the risk of PVD. We calculated the adjusted hazard ratios (aHRs) and their 95% confidence intervals (CIs) for PVD after adjusting for sex, age, comorbidities, index date and immunosuppressants, such as steroids, etc. Compared with the HCQ nonusers, in HCQ users, the aHRs (95% CIs) for PVD were (2.24 (1.42, 3.54)), and the women’s aHRs for PVD were (2.54, (1.49, 4.35)). The aHRs based on the days of HCQ use for PVD of 28−30 days, 31−120 days, and >120 days were (1.27 (0.81, 1.99)), (3.00 (1.81, 4.87)) and (3.83 (2.46, 5.97)), respectively. The medium or long-term use of HCQ or young women receiving HCQ were associated with a higher aHR for PVD in the ILD cohort. These findings indicated interplay of the primary immunologic effect of ILD, comorbidities, women, age and virus in the HCQ users.

Disease burden and treatment sequence of polymyositis and dermatomyositis patients in Japan: a real-world evidence study

INTRODUCTION/OBJECTIVES

Since new consensus on polymyositis (PM) and dermatomyositis (DM) were released in Japan, an updated evidence on treatment landscape and PM/DM burden was essential. This study evaluates treatment burden and overall treatment cost of PM/DM-related inpatient and outpatient visits, treatments, and procedures/patient/year.

METHOD

This retrospective, observational study analyzed insurance claims from Japan Medical Data Center (JMDC) database. Patients with at least one PM/DM diagnosis/one dispensation of treatment between 1 January 2009 and 31 December 2019 were enrolled. Patient characteristics, treatment patterns and sequence, treatment choices, healthcare resource utilization (HCRU), and related costs were assessed. Chi-square test and linear regression model were used to assess impact of patient characteristics on treatment choice.

RESULTS

Patients (836/4,961) receiving a relevant treatment were analyzed. Heart disease (35%), interstitial lung disease (27%), and diabetes mellitus (26%) were frequently identified as comorbidities. Concomitant dispensation of immunosuppressants and systemic steroids was largely found in first and second line of treatment (LoT) while systemic steroids remained as single dominant treatment across all LoTs. HCRU was very low for inpatient visits (0.68 [1.43]) or rehabilitation (4.74 [14.57]). The mean (SD) number of inpatient visits decreased from first (1.23 [2.32]) to third year (0.11 [0.54]). Total mean (SD) healthcare cost per patients per year was ¥ 3,815,912 (7,412,241), with overall drug dispensation compounding to 80% of total cost.

CONCLUSIONS

High concomitant immunosuppressant and systemic steroid prescriptions in first LoT recommend early optimal treatment to manage PM/DM. Although inpatient costs are low, outpatient dispensation costs increase overall economic burden.