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Objectives: Fibrotic interstitial lung disease (ILD) includes a large group of conditions that lead to scarring of the lungs. The lack of available 5-level EuroQol 5D (EQ5D) data has limited the ability to conduct economic evaluations in ILD. The purpose of this study was to develop and validate a mapping algorithm that predicts EQ5D utilities from commonly collected pulmonary function measurements (forced vital capacity [FVC] and diffusing capacity of the lung for carbon monoxide [DLCO]) in fibrotic ILDs. Methods: EQ5D utility and pulmonary function measurements from the Canadian Registry for Pulmonary Fibrosis were included. Ordinary least squares (OLS), beta regression, two-part, and tobit models were used to map EQ5D utilities from FVC or DLCO. Model performance was assessed by comparing the predicted and observed utilities. Subgroup analyses were also conducted to test how well models performed across different patient characteristics. The models were then externally validated in the Australian Idiopathic Pulmonary Fibrosis Registry. Results: The OLS model performed as well as other more complex models (root mean squared error: 0.17 for FVC and 0.16 for DLCO). As with the other models, the OLS algorithm performed well across the different subgroups (except for EQ5D utilities < 0.5) and in the external validation cohort. Conclusion: We developed a mapping algorithm that predicts EQ5D utilities from FVC and DLCO, with the intent that this algorithm can be applied to clinical trial populations and real-world cohorts that have not prioritized collection of health-related utilities. The mapping algorithm can be used in future economic evaluations of potential ILD therapies. [ABSTRACT FROM AUTHOR]

ABSTRACT Background and objective Studies analysing the effect of worsening pulmonary physiological impairment in idiopathic pulmonary fibrosis ( IPF) with respect to quality of life have been limited to single centres or highly selected trial populations. The aim of this study was to determine the principal determinants of baseline and longitudinal health-related quality of life ( HRQoL) in a large unselected IPF population. Methods We used the Australian IPF Registry to examine the relationship between HRQoL, measured using the St George Respiratory Questionnaire ( SGRQ), and demographic features, physiological features, co-morbidities and symptoms. Linear regression analysis was performed to identify predictors of baseline HRQoL, linear mixed model analysis to determine the effect of time and forced vital capacity ( FVC) on SGRQ and Cox proportional hazards regression to examine the relationship between HRQoL and all-cause mortality. Results Baseline data from 516 patients were available (347 males; mean ( SD) age: 71.3 ± 8.6 years). Univariate analysis showed significant associations between HRQoL and demographic, clinical and physiological features. However, multivariate analysis demonstrated independent associations only between SGRQ and dyspnoea (University of California San Diego Shortness of Breathlessness Questionnaire ( UCSD-SOBQ); R2 = 0.71, P < 0.0001), cough severity (visual analogue scale; R2 = 0.06, P < 0.0001) and depression (Hospital Anxiety and Depression Scale; R2 = 0.04, P < 0.0001). Linear mixed-effects modelling of combined baseline and longitudinal data confirmed these associations, as well as for FVC% predicted ( P = 0.005). Multivariate Cox proportionate-proportional hazards regression analysis demonstrated no association between HRQoL and risk of mortality. Conclusion Cough, dyspnoea and depression are major symptomatic determinants of HRQoL in IPF. FVC decline is associated with worsening HRQoL. [ABSTRACT FROM AUTHOR]

There is little Australian epidemiologic data on idiopathic pulmonary fibrosis ( IPF), a relatively uncommon but devastating disease. The vast geographic distances in Australia have been a major impediment for collaborative research into IPF. A collaborative national effort, the Australian IPF Registry, has been formed, launched and is recruiting successfully ( n = 359, January 2014). Our experience provides unique insights for others wishing to set up IPF registries and in time for a global IPF registry. [ABSTRACT FROM AUTHOR]