Causes and prevalence of inadequate pulmonary function testing among patients with systemic sclerosis

Impulse Oscillometry as an Alternative Lung Function Test for Hospitalized Adults

BACKGROUND

Impulse oscillometry (IOS) is a noninvasive technique that measures lung physiology independently of patient effort. In the present study, we aimed to investigate the utility of IOS parameters in comparison with pulmonary function testing (PFT) among hospitalized subjects, with emphasis on obstructive and small airway diseases.

METHODS

Sixty-one subjects hospitalized either with unexplained dyspnea or for pre-surgery evaluation were included in the study. All subjects underwent PFTs and IOS test. The correlation between IOS results and PFTs was examined in different subgroups. The ability of IOS parameters to predict abnormal PFTs was evaluated using the area under the receiver operating characteristic (ROC) curve, and optimal cutoff values were calculated.

RESULTS

IOS results were found to correlate with PFT values. Subgroup analysis revealed that these correlations were higher in younger (age < 70) and non-obese (body mass index < 25kg/m2) subjects. The resonant frequency was an independent predictor and had the best predictive ability for abnormal FEV1/FVC (area under the ROC curve 0.732 [95% CI 0.57-0.90], optimal cutoff 17 Hz, 87% sensitivity, 62% specificity) and abnormal forced expiratory flow during the middle half of the FVC maneuver (area under the ROC curve 0.667 [95% CI 0.53-0.81], optimal cutoff 15 Hz, 77% sensitivity, 54% specificity). Area of reactance and the difference in respiratory resistance at 5 Hz and 20 Hz also showed a good predictive ability for abnormal FEV1/FVC (area under the ROC curve 0.716 and 0.730, respectively).

CONCLUSIONS

We found that the IOS performed well in diagnosing small airway and obstructive diseases among hospitalized subjects. IOS might serve as an alternative to standard PFTs in non-cooperative or dyspneic hospitalized patients.

Outcome measurement instrument selection for lung physiology in systemic sclerosis associated interstitial lung disease: A systematic review using the OMERACT filter 2.1 process

OBJECTIVE

The Outcome Measures in Rheumatology (OMERACT) is a research organization focused on improving health care outcomes for patients with autoimmune and musculoskeletal diseases. The Connective Tissue Disease-Interstitial Lung Disease (CTD-ILD) Working Group on Lung Physiology is a group within OMERACT charged with identifying outcome measures that should be implemented in studies of patients with CTD-ILD. The OMERACT Filter 2.1 is an evidence-based algorithm used to identify outcome measures that are truthful, feasible, and able to discriminate between groups of interest. Our objective was to summate evidence (published literature, key opinion leader input, patient perspectives) that would influence the CTD-ILD Working Group's vote to accept or reject the use of two measures of lung physiology, the forced vital capacity (FVC) and the diffusion capacity of carbon monoxide (DLco) for use in randomized controlled trials (RTCs) and longitudinal observational studies (LOSs) involving patients with systemic sclerosis associated ILD (SSc-ILD).

METHODS

Patient Research Partners (those afflicted with SSc-ILD) and the CTD-ILD Working Group on Lung Physiology were polled to assess their opinion on the FVC and DLco in terms of feasibility; the CTD-ILD Working Group was also queried on these instruments' face and content validity. We then conducted a systematic literature review to identify articles in the SSc-ILD population that assessed the following measurement properties of FVC and DLco: (1) construct validity, (2) test-retest reliability, (3) longitudinal construct validity, (4) clinical trial discrimination/sensitivity to detect change in clinical trials, and (5) thresholds of meaning. Results were summarized in a Summary of Measurement Properties (SOMP) table for each instrument. OMERACT CTD-ILD Working Group members discussed and voted on the strength of evidence supporting these two instruments and voted to endorse, provisionally endorse, or not endorse either instrument.

RESULTS

Forty Patient Research Partners reported these two measures are feasible (are not an unnecessary burden or represent an infeasible longitudinal assessment of their disease). A majority of the 18 CTD-ILD Working Group members voted that both the FVC and DLco are feasible and have face and content validity. The systematic literature review returned 1,447 non-duplicated articles, of which 177 met eligibility for full text review. Forty-eight studies (13 RCTs, 35 LOSs) were included in the qualitative analysis. The FVC SOMP table revealed high quality, consistent data with evidence of good performance for all five measurement properties, suggesting requisite published evidence to proceed with endorsement. The DLco SOMP table showed a lack of data to support test-retest reliability and inadequate evidence to support clinical trial discrimination. There was unanimous agreement (15 [100%]) among voting CTD-ILD Working Group members to endorse the FVC as an instrument for lung physiology in RCTs and LOSs in SSc-ILD. Based on currently available evidence, DLco did not meet the OMERACT criteria and is not recommended for use in RCTs to represent lung physiology of SSc-ILD. The OMERACT Technical Advisory Group agreed with these decisions.

CONCLUSION

The OMERACT Filter 2.1 was successfully applied to the domain of lung physiology in patients with SSc-ILD. The FVC was endorsed for use in RCTs and LOSs based on the Working Group's vote; DLco was not endorsed.

Systemic Sclerosis in Zimbabwe: Autoantibody Biomarkers, Clinical, and Laboratory Correlates

Introduction

Systemic sclerosis (SScl) is an autoimmune disease whose prevalence is rarely reported in Africa. Autoantibodies are the biomarkers of the condition, precede overt disease and determine disease phenotypes. SSc specific autoantibodies also vary between racial groupings. Objective: To investigate the clinical and laboratory characteristics of Zimbabwean patients who were reactive SSc specific autoantibodies.

Materials and Method

240 patients, 173 of them female with SSc specific autoantibodies were included. Autoantibodies were detected by indirect immunofluorescence microscopy and immunoblotting using a panel of 13 SScl (Euroimmun Ag., Germany). Demographic, clinical and laboratory parameters relevant to the monitoring of SScl were captured. These included pulmonary function tests, hematology, clinical chemistry, serology and thyroid function tests. Allergy skin prick tests (SPT) to inhalant and food allergen sources were conducted when indicated.

Results

All the 240 patients (median age was 36 years) expressed SSc specific autoantibodies. 86% were Black, 11% White and 3% Asian and a fifth (20%) were younger than 16 years. Eleven (4.6%) fulfilled the ACR/EULAR classification of SSc. Clinically they had limited cutaneous (n=6), diffuse cutaneous (n=3) and SScl/inflammatory myopathy overlap (n=2). The most frequently detected antibodies anti-RNA polymerase III (RNAP) 55%, anti-Th/To (28%) anti-RNAP 11 (22%), anti-CENPB (18%) and anti-Scl-70/ATA (13%). Racial variations in the expression of these antibodies were apparent between Black, White and Asian patients. The majority (95%), who did not fulfil the ARA/EULAR criteria were symptomatic. Raynaud's Phenomenon was documented in 24%. Respiratory symptoms included coughing, dyspnea and wheezing. There was a restrictive ventilatory defect with increased FEV1/FVC ratio. Pruritus, urticaria and skin depigmentation were the main cutaneous features while constipation, bloating, Gastroesophageal reflux disease (GERD) and abdominal pain dominated GI symptoms. Mean blood pressure readings while normal varied with biomarkers. Haematology and biochemistry parameters were within normal reference ranges.

Conclusion

The expression of SSc specific autoantibodies is common and associated with known SSc symptoms. The types and frequency of autoantibodies varied with racial groupings. A fifth of the patients were children below the age of 16 years.

Standardization of Spirometry 2019 Update. An Official American Thoracic Society and European Respiratory Society Technical Statement

Background: Spirometry is the most common pulmonary function test. It is widely used in the assessment of lung function to provide objective information used in the diagnosis of lung diseases and monitoring lung health. In 2005, the American Thoracic Society and the European Respiratory Society jointly adopted technical standards for conducting spirometry. Improvements in instrumentation and computational capabilities, together with new research studies and enhanced quality assurance approaches, have led to the need to update the 2005 technical standards for spirometry to take full advantage of current technical capabilities.Methods: This spirometry technical standards document was developed by an international joint task force, appointed by the American Thoracic Society and the European Respiratory Society, with expertise in conducting and analyzing pulmonary function tests, laboratory quality assurance, and developing international standards. A comprehensive review of published evidence was performed. A patient survey was developed to capture patients' experiences.Results: Revisions to the 2005 technical standards for spirometry were made, including the addition of factors that were not previously considered. Evidence to support the revisions was cited when applicable. The experience and expertise of task force members were used to develop recommended best practices.Conclusions: Standards and consensus recommendations are presented for manufacturers, clinicians, operators, and researchers with the aims of increasing the accuracy, precision, and quality of spirometric measurements and improving the patient experience. A comprehensive guide to aid in the implementation of these standards was developed as an online supplement.

Quantitative computed tomography detects interstitial lung diseases proven by biopsy

Background: The Quantitative chest CT (QCT) is emerging as a promising tool in the assessment of interstitial lung disease (ILD). However, the precise relationship between QCT parameters and the fibrosis detectable in lung tissue, remains to be established. Objectives: The aim of this study was to compare QCT and histopathological features in patients with ILD. Moreover we verified if the QCT assessment is similar in patients with or without a ILD diagnosis proven by a biopsy. Methods: Twenty patients affected by ILD who underwent a chest CT and, later, a lung biopsy, were enrolled. Patients were divided according to the histopathological findings (IPF vs sarcoidosis) in two groups (respectively bIPF and bSarc). Other 20 patients with a radiological diagnosis of IPF were included in a control group (rIPF). All CTs were post-processed with a free software (Horos) in order to obtain an ILD quantitative assessment. Results: There were no differences in terms of gender, smoking habit and spirometric values between patients' groups. rIPF subjects were older than the other: 70 vs 59 and 47 years (p<0.001). A different distribution of QCT parameters was observed between bIPF and bSarc (p<0.01) while it was comparable within bIPF and rIPF. Conclusions: QCT parameters were similar in subjects affected by the same type of ILD detected with biopsy and with CT alone. These findings make stronger the assumption that QCT can identify the presence of pulmonary fibrosis and, ultimately, that it can represent an useful and effective tool to assess ILD. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 16-20).