Figure 1.

Design of a study to estimate numbers and trends of acute decompensated heart failure (ADHF) hospitalization in the United States by applying validation models derived from Atherosclerosis Risk in Communities (ARIC) Study ADHF surveillance (2005–2010) to the National Inpatient Sample (1998–2011). Eligible International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes had the potential to identify ADHF hospitalizations. Three separate models were developed for groups with eligible ICD-9-CM codes: code 428 primary, code 428 nonprimary, and code 428 absent.