@article {8271, title = {Development and demonstration of a state model for the estimation of incidence of partly undetected chronic diseases}, journal = {BMC MEDICAL RESEARCH METHODOLOGY}, volume = {15}, year = {2015}, pages = {98}, publisher = {15}, abstract = {Background: Estimation of incidence of the state of undiagnosed chronic disease provides a crucial missing link for the monitoring of chronic disease epidemics and determining the degree to which changes in prevalence are affected or biased by detection. Methods: We developed a four-part compartment model for undiagnosed cases of irreversible chronic diseases with a preclinical state that precedes the diagnosis. Applicability of the model is tested in a simulation study of a hypothetical chronic disease and using diabetes data from the Health and Retirement Study (HRS). Results: A two dimensional system of partial differential equations forms the basis for estimating incidence of the undiagnosed and diagnosed disease states from the prevalence of the associated states. In the simulation study we reach very good agreement between the estimates and the true values. Application to the HRS data demonstrates practical relevance of the methods. Discussion: We have demonstrated the applicability of the modeling framework in a simulation study and in the analysis of the Health and Retirement Study. The model provides insight into the epidemiology of undiagnosed chronic diseases.}, keywords = {Health Conditions and Status, Methodology}, author = {Ralph Brinks and Barbara H. Bardenheier and Annika Hoyer and Ji Lin and Sandra Landwehr and Edward W Gregg} } @article {6459, title = {Disability-Free Life-Years Lost Among Adults Aged >=50 Years, With and Without Diabetes}, journal = {Diabetes Care}, year = {2015}, abstract = {OBJECTIVE Quantify the impact of diabetes status on healthy and disabled years of life for older adults in the U.S. and provide a baseline from which to evaluate ongoing national public health efforts to prevent and control diabetes and disability.RESEARCH DESIGN AND METHODS Adults (n = 20,008) aged 50 years and older were followed from 1998 to 2012 in the Health and Retirement Study, a prospective biannual survey of a nationally representative sample of adults. Diabetes and disability status (defined by mobility loss, difficulty with instrumental activities of daily living IADL , and/or difficulty with activities of daily living ADL ) were self-reported. We estimated incidence of disability, remission to nondisability, and mortality. We developed a discrete-time Markov simulation model with a 1-year transition cycle to predict and compare lifetime disability-related outcomes between people with and without diabetes. Data represent the U.S. population in 1998.RESULTS From age 50, adults with diabetes died 4.6 years earlier, developed disability 6 7 years earlier, and spent about 1 2 more years in a disabled state than adults without diabetes. With increasing baseline age, diabetes was associated with significant (P 0.05) reductions in the number of total and disability-free life-years, but the absolute difference in years between those with and without diabetes was less than at younger baseline age. Men with diabetes spent about twice as much of their remaining years disabled (20 24 of remaining life across the three disability definitions) as men without diabetes (12 16 of remaining life across the three disability definitions). Similar associations between diabetes status and disability-free and disabled years were observed among women.CONCLUSIONS Diabetes is associated with a substantial reduction in nondisabled years, to a greater extent than the reduction of longevity.}, keywords = {Health Conditions and Status, Methodology}, doi = {10.2337/dc15-1095}, url = {http://care.diabetesjournals.org/content/early/2015/12/17/dc15-1095.abstract}, author = {Barbara H. Bardenheier and Ji Lin and Zhuo, Xiaohui and Mohammed K. Ali and Theodore J Thompson and Yiling J. Cheng and Edward W Gregg} }