Cost analysis of the uninsured, indigent population of central Texas

The Indigent Care Collaboration (ICC) gathers data on hospital and clinic visits for uninsured patients in the greater Austin, Texas metropolitan area. While the ICC has patient and encounter information, no actual cost data exists. This study used the Diagnostic Cost Groups (DCG) diagnosis-based risk model to describe chronic disease prevalence and estimate patient yearly costs based on International Classification of Diseases System Ninth Revision (ICD-9) diagnosis codes. This study also evaluated the use of the ICC data and the DCG models to support disease and case management initiatives, following the methods of Zhao et al. (2002). A total of 163,729 patients had 471,194 inpatient, outpatient, or emergency room encounters during the study period of March 1, 2004, to February 28, 2005. The mean estimated patient yearly cost was $1,306.81, and the total estimated yearly population cost was $228,909,529. The most common chronic diseases and conditions included hypertension, diabetes, depression, substance abuse, pregnancy, asthma, chronic obstructive pulmonary disease (COPD), and congestive heart failure (CHF). The cohort of diabetic patients was further examined to test the data and model's ability to identify high-risk patient subgroups to target for disease or case management. The costliest comorbid conditions for diabetic patients included hypertension, renal failure, CHF, coronary atherosclerosis, COPD, polyneuropathy, and others. The DCG model provided cost estimates and a framework that facilitated analysis of the ICC data. The DCG model also allowed for identification of high risk patients and their characteristics.