Background Surveys and retrospective studies of patients with idiopathic pulmonary fibrosis (IPF) have shown a significant diagnostic delay. However, the causes and risk factors for this delay are not known. Methods Dates at six time points before the IPF diagnosis (onset of symptoms, first contact to a general practitioner, first hospital contact, referral to an interstitial lung disease (ILD) centre, first visit at an ILD centre, and final diagnosis) were recorded in a multicentre cohort of 204 incident IPF patients. Based on these dates, the delay was divided into specific patient-related and healthcare-related delays. Demographic and clinical data were used to determine risk factors for a prolonged delay, using multivariate negative binomial regression analysis. Results The median diagnostic delay was 2.1 years (IQR: 0.9–5.0), mainly attributable to the patients, general practitioners and community hospitals. Male sex was a risk factor for patient delay (IRR: 3.84, 95% CI: 1.17–11.36, p = 0.006) and old age was a risk factor for healthcare delay (IRR: 1.03, 95% CI: 1.01–1.06, p = 0.004). The total delay was prolonged in previous users of inhalation therapy (IRR: 1.99, 95% CI: 1.40–2.88, p <  0.0001) but not in patients with airway obstruction. Misdiagnosis of respiratory symptoms was reported by 41% of all patients. Conclusion Despite increased awareness of IPF, the diagnostic delay is still 2.1 years. Male sex, older age and treatment attempts for alternative diagnoses are risk factors for a delayed diagnosis of IPF. Efforts to reduce the diagnostic delay should focus on these risk factors. Trial registration This study was registered at http://clinicaltrials.gov (NCT02772549) on May 10, 2016. Electronic supplementary material The online version of this article (10.1186/s12931-019-1076-0) contains supplementary material, which is available to authorized users.

Highlights Anecdotal reports of asymptomatic ‘silent hypoxia’ in COVID-19 are emerging A minimal increase in dyspnea was seen with worsening hypoxia during exercise The 6-minute walking test is a potential tool in discharge assessment

Background Patients with idiopathic pulmonary fibrosis (IPF) have impaired health-related quality of life (HRQL). To measure HRQL, an IPF-specific version of the St. George’s Respiratory Questionnaire (SGRQ-I) was developed, but not sufficiently validated. This study aimed to assess the validity (i.a. known-groups validity and concurrent validity) and test-retest reliability of SGRQ-I in IPF patients with different disease durations. Methods Patients with IPF were consecutively recruited and completed SGRQ, SGRQ-I, King’s Brief Interstitial Lung Disease questionnaire (K-BILD), University of California, San Diego Shortness of Breath Questionnaire (SOBQ) and Short Form-36 (SF-36) along with pulmonary function tests and a 6-min walk test (6MWT) at baseline. After two weeks, SGRQ-I and Global Rating of Change Scales (GRCS) were completed. Results At baseline and after two weeks, 150 and 134 patients completed the questionnaires, respectively. The internal consistency of SGRQ-I was high (Cronbach’s α = 0.92). Good concurrent validity was demonstrated by high intraclass correlation coefficients (ICC = 0.97), Bland-Altman plots and moderate to strong correlations to K-BILD, SOBQ and SF-36 (r = − 0.46 to 0.80). High ICC (0.92) and a Bland-Altman plot indicated good test-retest reliability. SGRQ-I was good at discriminating between patients with different stages of disease (Δscore > 18.1, effect sizes > 0.10). Validity was similar across groups of different disease duration. Conclusions SGRQ-I proved to be valid at distinguishing between different disease severities, valid compared to other HRQL instruments, applicable across different disease durations and reliable upon repetition. SGRQ-I is a valid option for measuring HRQL in patients with IPF. Trial registration The study was registered at clinicaltrials.org ( NCT02818712 ) on 15 June 2016. Electronic supplementary material The online version of this article (10.1186/s12931-019-1169-9) contains supplementary material, which is available to authorized users.

Interstitial lung abnormalities were common in this lung cancer screening population of relatively healthy smokers and were associated with mortality regardless of the interstitial morphological phenotype. The increased mortality was partly due to an association with lung cancer and non-pulmonary malignancies.

BackgroundHealth-related quality of life (HRQL) is impaired in patients with idiopathic pulmonary fibrosis (IPF). The King’s Brief Interstitial Lung Disease questionnaire (K-BILD) is a validated measure of HRQL, but no previous studies have focused on the validity of K-BILD in IPF. Moreover, the relationship between K-BILD and dyspnoea or the 6-min walk test (6MWT) has not been assessed. The aim of this study was to validate K-BILD in the largest cohort of patients with IPF to date and assess how K-BILD correlates to dyspnoea and 6MWT.MethodsFirstly, K-BILD was translated into Danish using validated translation procedures. Consecutive patients with IPF were recruited. At baseline, patients completed K-BILD, the IPF-specific version of St. Georges Respiratory Questionnaire, University of California, San Diego Shortness of Breath Questionnaire (SOBQ) Short Form-36, and pulmonary function tests and 6MWT were performed. After 14 days, K-BILD and Global Rating of Change Scales were completed. Internal consistency, concurrent validity, test-retest reliability and known groups validity were assessed. Analyses were also performed in subgroups of patients with different time since diagnosis.ResultsAt baseline, 150 patients with IPF completed the questionnaires, and 139 patients completed the questionnaires after 14 days. K-BILD had a high internal consistency (Cronbach’s α = 0.92). The concurrent validity was strong compared to SOBQ (r = − 0.66) and moderate compared to 6MWT (r = 0.43). Intraclass correlation coefficients (ICC = 0.91) and a Bland Altman plot demonstrated a good reliability. K-BILD was also able to discriminate between patients with different stages of disease (p < 0.002, Δscore > 7.4) and most results were comparable in patients with different time since diagnosis.ConclusionK-BILD is a valid and reliable instrument in patients with IPF and in patients with different time since diagnosis. To a major extent, K-BILD scores reflected the impact of dyspnoea on HRQL and the impact of physical functional capacity measured by the 6MWT to a moderate degree. Compared to PFTs alone, K-BILD provides additional information on the burden of living with IPF, and importantly, K-BILD is simple to implement in both research and clinical contexts.Trial registrationClinicaltrials.org (NCT02818712) on 30 June 2016.

Background: Interstitial lung abnormalities (ILA) are common in participants of lung cancer screening trials and broad population-based cohorts. They are associated with increased mortality, but less is known about disease specific morbidity and healthcare utilisation in individuals with ILA. Methods: We included all participants from the screening arm of the Danish Lung Cancer Screening Trial with available baseline CT scan data (n = 1990) in this cohort study. The baseline scan was scored for the presence of ILA and patients were followed for up to 12 years. Data about all hospital admissions, primary healthcare visits and medicine prescriptions were collected from the Danish National Health Registries and used to determine the participants' disease specific morbidity and healthcare utilisation using Cox proportional hazards models. Results: The 332 (16.7%) participants with ILA were more likely to be diagnosed with one of several respiratory diseases, including interstitial lung disease (HR: 4.9, 95% CI: 1.8-13.3, p = 0.008), COPD (HR: 1.7, 95% CI: 1.2-2.3, p = 0.01), pneumonia (HR: 2.0, 95% CI: 1.4-2.7, p < 0.001), lung cancer (HR: 2.7, 95% CI: 1.8-4.0, p < 0.001) and respiratory failure (HR: 1.8, 95% CI: 1.1-3.0, p = 0.03) compared with participants without ILA. These findings were confirmed by increased hospital admission rates with these diagnoses and more frequent prescriptions for inhalation medicine and antibiotics in participants with ILA. Conclusions: Individuals with ILA are more likely to receive a diagnosis and treatment for several respiratory diseases, including interstitial lung disease, COPD, pneumonia, lung cancer and respiratory failure during long-term follow-up.

Background: Idiopathic pulmonary fibrosis (IPF) specific version of St. George's Respiratory Questionnaire (SGRQ-I) and King's Brief Interstitial Lung Disease questionnaire (K-BILD) are validated health-related quality of life (HRQL) instruments, but no or limited data exist on their responsiveness and minimal clinically important difference (MCID). The objectives of this study were to assess responsiveness of SGRQ-I and K-BILD and determine MCID separately for deterioration and improvement in a large, prospective cohort of patients with IPF in a real-world setting. Methods: Consecutive patients with IPF were recruited. SGRQ-I, K-BILD, SGRQ, Shortness of Breath Questionnaire, pulmonary function tests and 6-min walk test measurements were obtained at baseline and at six and 12 months; at six and 12 months, patients also completed Global Rating of Change Scales. Responsiveness was assessed using correlation coefficients and linear regression. Cox regression was used for mortality analyses. MCID was estimated using receiver operating characteristic curves with separate analyses for improvement and deterioration.Results: A total of 150 IPF patients were included and 124 completed the 12-month follow-up. Based on all HRQL anchors and most physiological anchors, responsiveness analyses supported the evidence pointing towards SGRQ-I and K-BILD as responsive instruments. Multivariate analyses showed an association between SGRQ-I and mortality (HR: 1.18, 95% CI: 1.02 to 1.36, p = 0.03) and a trend was found for K-BILD (HR: 0.82, 95% CI: 0.64 to 1.05, p = 0.12). MCID was estimated for all domains of SGRQ-I and K-BILD. MCID for improvement differed from deterioration for both SGRQ-I Total (3.9 and 4.9) and K-BILD Total (4.7 and 2.7).Conclusions: SGRQ-I and K-BILD were responsive to change concerning both HRQL and most physiological anchors. MCID was determined separately for improvement and deterioration, resulting in different estimates; especially a smaller estimate for deterioration compared to improvement in K-BILD. Trial registration: Clinicaltrials.gov, no. NCT02818712. Registered 30 June 2016.

Background Idiopathic pulmonary fibrosis (IPF) is characterized by the accumulation of fibrillar collagens in the alveolar space resulting in reduced pulmonary function and a high mortality rate. Biomarkers measuring the turnover of type I and III collagen could provide valuable information for prognosis and treatment decisions in IPF. Methods Serological biomarkers reflecting the formation of type III collagen (PRO-C3) and degradation of type I (C1M) and III collagen (C3M) were evaluated in a real-world cohort of 178 newly diagnosed IPF patients. Blood samples and clinical data were collected at baseline, six, and 12 months. Baseline and longitudinal biomarker levels were related to disease progression of IPF (defined as ≥ 5% decline in forced vital capacity (FVC) and/or ≥ 10% decline in diffusing capacity for carbon monoxide (DLco) and/or all-cause mortality at 12 months). Furthermore, we analysed differences in percentage change of biomarker levels from baseline between patients receiving antifibrotic treatment or not. Results Increased baseline levels of type I and III collagen turnover biomarkers were associated with a greater risk of disease progression within 12 months compared to patients with a low baseline type I and III collagen turnover. Patients with progressive disease had higher serum levels of C1M (P = 0.038) and PRO-C3 (P = 0.0022) compared to those with stable disease over one year. There were no differences in biomarker levels between patients receiving pirfenidone, nintedanib, or no antifibrotics. Conclusion Baseline levels of type I and III collagen turnover were associated with disease progression within 12 months in a real-world cohort of IPF patients. Longitudinal biomarker levels of type I and III collagen turnover were related to progressive disease. Moreover, antifibrotic therapy did not affect type I and III collagen turnover biomarkers in these patients. PRO-C3 and C1M may be potential biomarkers for a progressive disease behavior in IPF.