Evolving concepts in the early and accurate diagnosis of idiopathic pulmonary fibrosis

Prevalence of Obstructive Lung Disease in Asymptomatic Gas Field Workers

Introduction Obstructive lung disease, if not managed appropriately and in a timely manner, increases morbidity and mortality. The aim of this study was to see an obstruction on spirometry reports of clinically asymptomatic oil and gas field workers. Methods In this retrospective observational study, spirometry reports performed at the pulmonary function laboratory of Ziauddin Hospital and University, Karachi, were reviewed. All reports were of the clinically asymptomatic employees of an oil and gas company in Pakistan, who presented for their routine assessment. Obstructive impairment was defined as a forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) ratio of less than 0.7. Results Of the total of 199 spirometry reports, 197 (99%) were of male employees. The mean age of the employees was 30.52 ± 8.24 years and 46 (23.1%) employee were smokers. Obstruction was observed in 48 (24.1%) of the reports of the employees with 13 (27.1%) smokers and 35 (72.9%) non-smokers. No statistically significant association between obstruction and gender, age, and smoking was observed. Conclusion In this study, we observed obstructive impairment in around one-fourth of the otherwise clinically asymptomatic oil and gas field workers with no apparent impact of baseline smoking behavior.

Voluntary pulmonary function screening identifies high rates of undiagnosed asymptomatic chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is projected to be the third leading cause of death by 2020. Early detection and screening may alter the course and prognosis associated with lung disease. We investigated the effectiveness of a voluntary public lung function screening program and factors that had a predictive value for asymptomatic COPD in Xi'an, China. Pulmonary function testing (PFT) was conducted on volunteers recruited from four community centers in Xi'an, China, between July and August 2012. Participants underwent three forced vital capacity maneuvers. The maneuver with the best forced expiratory volume in first second was retained. Participants filled out a medical history and environmental exposure survey before undergoing the PFT. Patients who self-reported lung disease on the health survey were excluded from the analysis. Logistical regression was used to determine associations with airway obstruction. A total of 803 volunteers participated in this study, and 33 subjects were excluded as the participants did not meet the requirements of PFT. Of the 770 volunteers, 44 participants had been diagnosed with chronic respiratory diseases previously, and 144 participants (18.7%) met COPD criteria. Four hundred forty-four participants did not self-report any respiratory symptoms, and the remaining 282 participants self-reported respiratory symptoms. Of the asymptomatic participants, 98 volunteers had PFT results that were consistent with COPD and 68.1% of asymptomatic participants were undiagnosed. A greater percentage of women than men had moderate or severe airway obstruction (p = 0.004).Only smoking status (odds ratio = 2.64, 95% confidence interval 1.20-6.04) was associated with asymptomatic COPD. Voluntary public lung function screening programs in China are likely to identify a large number of undiagnosed, asymptomatic COPD. Smoking status is associated with airway obstruction and a greater percentage of women than men had moderate or severe airway obstruction.

Idiopathic fibrotic lung disease at a university hospital setting: management and prognostic factors

Background

Idiopathic fibrosing interstitial pneumonia consists of many subtypes, most associated with a poor prognosis. The aim of the study was to evaluate diagnostic procedures and treatment as well as survival in patients with idiopathic fibrosing interstitial pneumonia.

Methods

This study comprised 175 patients with idiopathic fibrosing interstitial pneumonia (ICD 10 code J84) that had been diagnosed at Uppsala University Hospital, during 2005 to 2012. Patient records were reviewed concerning: gender, age, smoking, occupational exposure, comorbidities, procedures, lung function, and treatment. Information on survival and cause of death was collected.

Results

A total of 98% had been examined with computed tomography, 93% with spirometry, 49% with measurement of diffusion capacity, 48% with bronchoalveolar lavage, and 23% with lung biopsy. Prednisolone had been prescribed to 74% while N-acetylcysteine (NAC) and omeprazole were prescribed to 54%, respectively. Five-year survival was 46%. Mortality was associated with high age, low diffusion capacity, and the use of NAC.

Conclusion

High age and a low diffusion capacity are related to shorter survival in idiopathic fibrosing interstitial pneumonia. We also unexpectedly found that the use of NAC was related to shorter survival. A relatively low proportion of the patients were examined with diffusion capacity measurement. Thus, there is a possibility to improve diagnostic procedures and thereby improve estimation of prognosis in fibrotic lung disease.

Bayesian probit regression model for the diagnosis of pulmonary fibrosis: proof-of-principle

Background

The accurate diagnosis of idiopathic pulmonary fibrosis (IPF) is a major clinical challenge. We developed a model to diagnose IPF by applying Bayesian probit regression (BPR) modelling to gene expression profiles of whole lung tissue.

Methods

Whole lung tissue was obtained from patients with idiopathic pulmonary fibrosis (IPF) undergoing surgical lung biopsy or lung transplantation. Controls were obtained from normal organ donors. We performed cluster analyses to explore differences in our dataset. No significant difference was found between samples obtained from different lobes of the same patient. A significant difference was found between samples obtained at biopsy versus explant. Following preliminary analysis of the complete dataset, we selected three subsets for the development of diagnostic gene signatures: the first signature was developed from all IPF samples (as compared to controls); the second signature was developed from the subset of IPF samples obtained at biopsy; the third signature was developed from IPF explants. To assess the validity of each signature, we used an independent cohort of IPF and normal samples. Each signature was used to predict phenotype (IPF versus normal) in samples from the validation cohort. We compared the models' predictions to the true phenotype of each validation sample, and then calculated sensitivity, specificity and accuracy.

Results

Surprisingly, we found that all three signatures were reasonably valid predictors of diagnosis, with small differences in test sensitivity, specificity and overall accuracy.

Conclusions

This study represents the first use of BPR on whole lung tissue; previously, BPR was primarily used to develop predictive models for cancer. This also represents the first report of an independently validated IPF gene expression signature. In summary, BPR is a promising tool for the development of gene expression signatures from non-neoplastic lung tissue. In the future, BPR might be used to develop definitive diagnostic gene signatures for IPF, prognostic gene signatures for IPF or gene signatures for other non-neoplastic lung disorders such as bronchiolitis obliterans.

Strategies for treating idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common and most lethal diffuse fibrosing lung disease, with a mortality rate that exceeds that of many cancers. Recently, there have been many clinical trials of novel therapies for IPF. The results have mostly been disappointing, although two treatment approaches have shown some efficacy. This Review describes the difficulties of treating IPF and the approaches that have been tried or are in development, and concludes with suggestions of future therapeutic targets and strategies.

Is there a uniform approach to the management of diffuse parenchymal lung disease (DPLD) in the UK? A national benchmarking exercise

Background

Benchmarking is the comparison of a process to the work or results of others. We conducted a national benchmarking exercise to determine how UK pulmonologists manage common clinical scenarios in diffuse parenchymal lung disease (DPLD), and to determine current use and availability of investigative resources. We compared management decisions to existing international guidelines.

Methods

Consultant members of the British Thoracic Society were mailed a questionnaire seeking their views on the management of three common scenarios in DPLD. They were asked to choose from various management options for each case. Information was also obtained from the respondents on time served as a consultant, type of institution in which they worked and the availability of a local radiologist and histopathologist with an interest/expertise in thoracic medicine.

Results

370 out of 689 consultants replied (54% response rate). There were many differences in the approach to the management of all three cases. Given a scenario of relapsing pulmonary sarcoidosis in a lady with multiple co-morbidities, half of respondents would institute treatment with a variety of immunosuppressants while a half would simply observe. 42% would refer a 57-year old lady with new onset DPLD for a surgical lung biopsy, while a similar number would not. 80% would have referred her for transplantation, but a fifth would not. 50% of consultants from district general hospitals would have opted for a surgical biopsy compared to 24% from cardiothoracic centres: this may reflect greater availability of a radiologist with special interest in thoracic imaging in cardiothoracic centres, obviating the need for tissue diagnosis. Faced with an elderly male with high resolution CT thorax (HRCT) evidence of usual interstitial pneumonia (UIP), three quarters would observe, while a quarter would start immunosuppressants. 11% would refer for a surgical biopsy. 14% of UK pulmonologists responding to the survey revealed they had no access to a radiologist with an interest in thoracic radiology.

Conclusion

From our survey, it appears there is a lack of consensus in the management of DPLD. This may reflect lack of evidence, lack of resources or a failure to implement current guidelines.