The interstitial lung disease spectrum under a uniform diagnostic algorithm: a retrospective study of 1,945 individuals

Rheumatoid arthritis development and survival in idiopathic interstitial pneumonia patients with anti-citrullinated protein antibodies

BACKGROUND

Some patients with idiopathic interstitial pneumonia (IIP) with anti-citrullinated protein antibodies (ACPA) develop rheumatoid arthritis (RA) during the early phase of ACPA positivity, whereas others develop RA either in the late phase or not at all; however, the clinical factors that predict RA development and survival outcome in these patients remain unknown.

METHODS

Retrospective clinical data from IIP patients without an RA diagnosis at the time of ACPA positivity were analysed. The chest high-resolution computed tomography (HRCT) score was calculated based on the extent of the lesions.

RESULTS

Of 78 patients enrolled, 46 (59.0 %) were diagnosed with RA during a median observation period of 49.3 months. The cumulative incidence of RA at 48 months was significantly higher in patients with high-positive ACPA than those with low-positive ACPA (67.5 %) vs. 36.3 % low-positive ACPA, p = 0.01). Multivariate analysis identified the high-positive ACPA and the high fibrosis score as significant predictors of RA development (hazard ratio [HR], 3.28, p < 0.01; and HR 1.57, p = 0.02, respectively). Additionally, Cox regression analysis revealed the fibrosis score and glucocorticoids and/or immunosuppressive agent treatment were associated with increased all-cause mortality (HR 1.76, p = 0.02; and HR 3.32, p < 0.01, respectively).

CONCLUSION

In ACPA-positive IIP patients, high-positive ACPA and high fibrosis scores might be the risk factors for imminent RA development. Furthermore, high fibrosis score was associated with poor survival outcomes. Pulmonologists should consider to enlist the help of rheumatologists for patients with high ACPA titres and extensive fibrotic changes.

Interstitial Lung Disease Epidemiology in the Past Three Decades: A Narrative Review

Current epidemiological data on interstitial lung disease (ILD) are still poor. The principal cause of the discordant data is associated with a heterogeneous group of respiratory diseases that includes a large number, about 200 families, with low frequency, distinct and sometimes unknown etiology, and different progression. In fact, some conditions spontaneously resolve, whereas others, such as IPF and most non-IPF ILDs, progress to respiratory failure and death despite treatment. Furthermore, epidemiological data are limited. The scope of the narrative review is to report ILD incidence and prevalence in registries from different countries in the last three decades. We identified 20 ILD registries (17 prospective and 3 retrospective) from major countries in Europe (n = 10), Asia (n = 7), North America (n = 2), and Oceania (n = 1). Significant discrepancies in ILD and ILD subtype prevalence and incidence among countries are reported in registries. These discrepancies could be determined by different ethnicities and socioeconomic conditions as well as by updates in disease diagnosis and classification. ILD epidemiological registries are progressively ameliorating through better adherence to updated guidelines and classification codes. An accurate and definite diagnosis and compilation of ILD epidemiological registries will be useful for a more precise monitoring of disease progression and treatment. Future research to identify the populations with the highest risk factors, including genetic and molecular studies, and implementation of disease progression scores are needed to improve ILD clinical assessment.

Relative incidence of interstitial lung diseases in Brazil

OBJECTIVE

To assess the relative frequency of incident cases of interstitial lung diseases (ILDs) in Brazil.

METHODS

This was a retrospective survey of new cases of ILD in six referral centers between January of 2013 and January of 2020. The diagnosis of ILD followed the criteria suggested by international bodies or was made through multidisciplinary discussion (MDD). The condition was characterized as unclassifiable ILD when there was no specific final diagnosis following MDD or when there was disagreement between clinical, radiological, or histological data.

RESULTS

The sample comprised 1,406 patients (mean age = 61 ± 14 years), and 764 (54%) were female. Of the 747 cases exposed to hypersensitivity pneumonitis (HP)-related antigens, 327 (44%) had a final diagnosis of HP. A family history of ILD was reported in 8% of cases. HRCT findings were indicative of fibrosis in 74% of cases, including honeycombing, in 21%. Relevant autoantibodies were detected in 33% of cases. Transbronchial biopsy was performed in 23% of patients, and surgical lung biopsy, in 17%. The final diagnoses were: connective tissue disease-associated ILD (in 27%), HP (in 23%), idiopathic pulmonary fibrosis (in 14%), unclassifiable ILD (in 10%), and sarcoidosis (in 6%). Diagnoses varied significantly among centers (c2 = 312.4; p < 0.001).

CONCLUSIONS

Our findings show that connective tissue disease-associated ILD is the most common ILD in Brazil, followed by HP. These results highlight the need for close collaboration between pulmonologists and rheumatologists, the importance of detailed questioning of patients in regard with potential exposure to antigens, and the need for public health campaigns to stress the importance of avoiding such exposure.

Incidence and prevalence of interstitial lung diseases worldwide: a systematic literature review

Interstitial lung disease (ILD) is a collective term representing a diverse group of pulmonary fibrotic and inflammatory conditions. Due to the diversity of ILD conditions, paucity of guidance and updates to diagnostic criteria over time, it has been challenging to precisely determine ILD incidence and prevalence. This systematic review provides a synthesis of published data at a global level and highlights gaps in the current knowledge base. Medline and Embase databases were searched systematically for studies reporting incidence and prevalence of various ILDs. Randomised controlled trials, case reports and conference abstracts were excluded. 80 studies were included, the most described subgroup was autoimmune-related ILD, and the most studied conditions were rheumatoid arthritis (RA)-associated ILD, systemic sclerosis associated (SSc) ILD and idiopathic pulmonary fibrosis (IPF). The prevalence of IPF was mostly established using healthcare datasets, whereas the prevalence of autoimmune ILD tended to be reported in smaller autoimmune cohorts. The prevalence of IPF ranged from 7 to 1650 per 100 000 persons. Prevalence of SSc ILD and RA ILD ranged from 26.1% to 88.1% and 0.6% to 63.7%, respectively. Significant heterogeneity was observed in the reported incidence of various ILD subtypes. This review demonstrates the challenges in establishing trends over time across regions and highlights a need to standardise ILD diagnostic criteria.PROSPERO registration number: CRD42020203035.

Analysis of Clinical Characteristics of Connective Tissue Disease-Associated Interstitial Lung Disease in 161 Patients: A Retrospective Study

Objective

This study was conducted to retrospectively analyze the clinical characteristics of CTD-ILD patients to provide strategies for clinical management.

Methods

This study collected and analyzed the clinical data and relevant examination results of 161 patients diagnosed with CTD-ILD between 01 January 2018 and 01 January 2021.

Results

A total of 161 CTD-ILD patients, 74.53% were females and 25.47% were males, 32.92% were elderly and 67.08% were non-elderly. The main clinical symptoms of CTD-ILD patients were cough (44.72%), decreased activity tolerance (40.37%). RA-ILD was the most common one in the non-elderly and the elderly CTD-ILD patients (48.15% and 50.94%, respectively). Compared with non-elderly, elderly patients with CTD-ILD had a longer duration of CTD (p=0.04). However, fatigue (p=0.005), activity tolerance (p=0.029), the incidence of pulmonary diffusion dysfunction (p=0.047), and systemic immunoinflammatory index (SII, p=0.014) (platelet × NLR) were all decreased. The standard deviation of red blood cell distribution width (RDW) (p=0.024) and immunoglobulin (IgA) (p=0.033) was significantly increased. The smoking index was significantly higher in men than in women with CTD-ILD (p=0.000), but symptoms of reduced activity tolerance were less pronounced than in women (p<0.05). Elderly CTD-ILD patients (p=0.003) and women from non-elderly patients were prone to lower hemoglobin (p=0.000). Among the elderly, the lymphocyte ratio was more significantly elevated in female CTD-ILD patients than in males (p=0.018). In contrast, neutrophil to lymphocyte ratio (NLR) and SII were lower in female (p=0.038) than in male CTD-ILD patients (p=0.043).

Conclusion

CTD-ILD mainly affects non-elderly and women. Age may not be involved with decreased activity tolerance and increased lung function impairment in CTD-ILD patients. However, the elderly patients with CTD-ILD, especially the elderly female patients with low inflammation levels and high immune disorders, have a poor prognosis.

Enhancing Imagistic Interstitial Lung Disease Diagnosis by Using Complex Networks

Background and Objectives: Diffuse interstitial lung diseases (DILD) are a heterogeneous group of over 200 entities, some with dramatical evolution and poor prognostic. Because of their overlapping clinical, physiopathological and imagistic nature, successful management requires early detection and proper progression evaluation. This paper tests a complex networks (CN) algorithm for imagistic aided diagnosis fitness for the possibility of achieving relevant and novel DILD management data. Materials and Methods: 65 DILD and 31 normal high resolution computer tomography (HRCT) scans were selected and analyzed with the CN model. Results: The algorithm is showcased in two case reports and then statistical analysis on the entire lot shows that a CN algorithm quantifies progression evaluation with a very fine accuracy, surpassing functional parameters' variations. The CN algorithm can also be successfully used for early detection, mainly on the ground glass opacity Hounsfield Units band of the scan. Conclusions: A CN based computer aided diagnosis could provide the much-required data needed to successfully manage DILDs.

Anti-melanoma Differentiation-Associated Gene 5 (Anti-MDA5) Dermatomyositis: A Case Presentation

We present a case of anti-melanoma differentiation-associated gene 5 (Anti-MDA5) dermatomyositis (DM) in a 30-year-old female. Anti-MDA5 dermatomyositis, previously termed clinically amyopathic dermatomyositis, was first recognized in 2005. Most cases present with varying combinations of cutaneous and oral ulcerations, palmar papules, respiratory symptoms, and minor muscle involvement (most commonly in the shoulders, upper arms, hips, thighs, and neck). This subtype of disease is most notable for its association with an increased risk of rapidly progressive interstitial lung disease. Our patient presented initially with only complaints of cutaneous ulcerations on the dorsal aspect of her hands. Following several months of no true diagnosis, she developed muscle weakness and joint pain. This led to retrieval of a punch biopsy which suggested anti-MDA5 DM at the top of the differential diagnoses. Immunoprecipitation revealed the presence of melanoma differentiation-associated gene 5 (MDA5) antibodies, confirming the diagnosis of anti-MDA5 dermatomyositis. This case demonstrates the importance of pinpointing the diagnosis of this rare disease subtype in a timely manner to prevent a fatal course, and we hope to inform dermatologists, rheumatologists, pulmonologists, and internists alike of the uncommon presentation of anti-MDA5 in an unsuspected, young patient.

Variability in Global Prevalence of Interstitial Lung Disease

There are limited epidemiologic studies describing the global burden and geographic heterogeneity of interstitial lung disease (ILD) subtypes. We found that among seventeen methodologically heterogenous studies that examined the incidence, prevalence and relative frequencies of ILDs, the incidence of ILD ranged from 1 to 31.5 per 100,000 person-years and prevalence ranged from 6.3 to 71 per 100,000 people. In North America and Europe, idiopathic pulmonary fibrosis and sarcoidosis were the most prevalent ILDs while the relative frequency of hypersensitivity pneumonitis was higher in Asia, particularly in India (10.7–47.3%) and Pakistan (12.6%). The relative frequency of connective tissue disease ILD demonstrated the greatest geographic variability, ranging from 7.5% of cases in Belgium to 33.3% of cases in Canada and 34.8% of cases in Saudi Arabia. These differences may represent true differences based on underlying characteristics of the source populations or methodological differences in disease classification and patient recruitment (registry vs. population-based cohorts). There are three areas where we feel addition work is needed to better understand the global burden of ILD. First, a standard ontology with diagnostic confidence thresholds for comparative epidemiology studies of ILD is needed. Second, more globally representative data should be published in English language journals as current literature has largely focused on Europe and North America with little data from South America, Africa and Asia. Third, the inclusion of community-based cohorts that leverage the strength of large databases can help better estimate population burden of disease. These large, community-based longitudinal cohorts would also allow for tracking of global trends and be a valuable resource for collective study. We believe the ILD research community should organize to define a shared ontology for disease classification and commit to conducting global claims and electronic health record based epidemiologic studies in a standardized fashion. Aggregating and sharing this type of data would provide a unique opportunity for international collaboration as our understanding of ILD continues to grow and evolve. Better understanding the geographic and temporal patterns of disease prevalence and identifying clusters of ILD subtypes will facilitate improved understanding of emerging risk factors and help identify targets for future intervention.

Unclassifiable, or simply unclassified interstitial lung disease?

PURPOSE OF REVIEW

Unclassifiable interstitial lung disease (ILD) comprises a subset of ILDs which cannot be classified according to the current diagnostic framework. This is a likely a heterogeneous group of diseases rather than a single entity and it is poorly defined and hence problematic for prognosis and therapy.

RECENT FINDINGS

With increased treatment options for progressive fibrosing ILD it is increasingly relevant to correctly categorise ILD.

SUMMARY

This review article will summarise the definition and reasons for a diagnosis of unclassifiable ILD, the current management options and possible future approaches to improve diagnosis and differentiation within this broad subset. Finally, we will describe the implications of the labelling of unclassifiable ILD in clinical practice and research and whether the term 'unclassified' should be used, implying a less definitive diagnosis.

Transbronchial lung cryobiopsy for connective tissue disease-related interstitial lung disease and interstitial pneumonia with autoimmune features: a single center retrospective case series

OBJECTIVE

Transbronchial lung cryobiopsy (TBLC) has been recently introduced for diagnosing interstitial lung diseases. We aimed to assess the effectiveness and safety of TBLC by identifying the specific patterns of histology in the diagnosis of connective tissue disease-related interstitial lung disease (CTD-ILD) and interstitial pneumonia with autoimmune features (IPAF).

METHODS

The clinical-radiological-pathological data from the Affiliated Hospital of Guilin Medical University between July 1, 2017, and October 31, 2020, of patients whose clinical-radiological or clinical-radiological-pathological diagnosis was CTD-ILD or IPAF and who underwent TBLC, transbronchial lung biopsy (TBLB), or surgical lung biopsy were retrospectively analyzed and summarized with review. The size of biopsy samples, complications, and diagnostic yield were compared.

RESULTS

Fourteen patients met the inclusion criteria, of whom 12 underwent TBLC, 1 underwent TBLB, and 1 underwent each procedure at different times. Compared to the size of TBLB specimens (5.625 ± 0.479 mm²), the size of TBLC specimens (12.00 (12.00, 15.00) mm²) was much larger (Z = - 3.262, P = 0.001). The diagnostic yields of TBLC and TBLB were 100.00% (13/13) and 0.00% (2/2), respectively (P = 0.0095). The most frequent complication was mild bleeding. The risk of bleeding between TBLB (1/2, 50.00%) and TBLC (10/13, 76.92%) did not differ significantly (P = 0.469).

CONCLUSION

TBLC can add extra diagnostic value by effectively identifying specific types of histology for patients with suspected CTD-ILD or IPAF, with a procedure that is safe from adverse events. Key Points • Transbronchial lung cryobiopsy has been introduced recently for diagnosing interstitial lung disease. • Transbronchial lung cryobiopsy was found to be effective and safe in the diagnosis for patients with suspected interstitial lung disease. It can be used as a preferred method for biopsy when the clinical-radiological diagnosis is uncertain.