The prevalence and burden of interstitial lung diseases in the USA

The prevalence, DALYs and mortality rates are presented as crude rates per 100 000 people with corresponding 95% uncertainty intervals (UIs). These were based on 1000 runs of the models for each quantity of interest, with the mean considered as the point estimate, and the 2.5th and 97.5th percentiles considered as the 95% UI. All ages were included for the overall rates, and male and female rates. Non-fatal estimates were obtained from systematic reviews, surveys, administrative health records, registries and disease surveillance systems. The specific data sources used for quantifying non-fatal outcomes are available online in the Global Burden of Disease Results Tool [6]. Non-fatal data were analysed using DisMod-MR version 2.1, a Bayesian meta-regression tool that adjusts data points for variations in study methods among different data sources. Fatal estimates were obtained from vital registration data (death records from the National Center for Health Statistics and population counts from the US Census Bureau). The single cause of death was determined using the International Classification of Diseases, Ninth and Tenth Revision, Clinical Modification. Causes of death data were analysed using the Cause of Death Ensemble Model with corrections for changes in coding practices for underlying causes of death [7]. DALYs were calculated as the sum of years of life lost (YLL) and years of healthy life lost due to disability (YLD) for each cause. For each disease, the YLD is derived from the multiplication of the incidence by the duration of disability and a weight factor. To account for the co-occurrence of disease and injury outcomes, the YLD was corrected for comorbidity, assuming a multiplicative rather than additive function of disability weights. The YLL due to premature death was estimated by multiplying the death number for a given age and sex by the standard life expectancy. One DALY is equal to the loss of 1 year of healthy life from the combined impacts of death and disability. Since our study utilised existing data without patient identifiers, it did not require institutional review board approval. The Global Burden of Disease study complies with the Guidelines for Accurate and Transparent Health Estimates Reporting recommendations.