Temporal Trends in Hospitalization for Acute Decompensated Heart Failure in the United States, 1998-2011

Abstract

Estimates of the numbers and rates of acute decompensated heart failure (ADHF) hospitalization are central to understanding health-care utilization and efforts to improve patient care. We comprehensively estimated the frequency, rate, and trends of ADHF hospitalization in the United States. Based on Atherosclerosis Risk in Communities (ARIC) Study surveillance adjudicating 12,450 eligible hospitalizations during 2005-2010, we developed prediction models for ADHF separately for 3 International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 428 discharge diagnosis groups: 428 primary, 428 nonprimary, or 428 absent. We applied the models to data from the National Inpatient Sample (11.5 million hospitalizations of persons aged ≥55 years with eligible ICD-9-CM codes), an all-payer, 20% probability sample of US community hospitals. The average estimated number of ADHF hospitalizations per year was 1.76 million (428 primary, 0.80 million; 428 nonprimary, 0.83 million; 428 absent, 0.13 million). During 1998-2004, the rate of ADHF hospitalization increased by 2.0%/year (95% confidence interval (CI): 1.8, 2.5) versus a 1.4%/year (95% CI: 0.8, 2.1) increase in code 428 primary hospitalizations (P < 0.001). In contrast, during 2005-2011, numbers of ADHF hospitalizations were stable (-0.5%/year; 95% CI: -1.4, 0.3), while the numbers of 428-primary hospitalizations decreased by -1.5%/year (95% CI: -2.2, -0.8) (P for contrast = 0.03). In conclusion, the estimated number of hospitalizations with ADHF is approximately 2 times higher than the number of hospitalizations with ICD-9-CM code 428 in the primary position. The trend increased more steeply prior to 2005 and was relatively flat after 2005.

Keywords: International Classification of Diseases codes; United States; acute decompensated heart failure; adjudicated heart failure; community surveillance; hospitalizations; national inpatient sample; secular trends.

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.

Figure 2.

Temporal trends in estimated numbers of US hospitalizations with acute decompensated heart failure (ADHF) and International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) discharge code 428 in the primary position among persons aged ≥55 years, 1998–2011. Data were obtained from the Atherosclerosis Risk in Communities Study and the National Inpatient Sample. Estimates of ADHF hospitalization were obtained using various models (Web Table 14). PPV, positive predictive value.

Figure 3.

A) Temporal trends in numbers of US hospitalizations with International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) discharge code 428 primary, nonprimary, and absent among persons aged ≥55 years, 1998–2011. B) Estimated (Est.) number of acute decompensated heart failure (ADHF) hospitalizations contributed by each ICD-9-CM code group and their total. C) Rates of hospitalization per 1,000 persons based on panel A and the US Census. D) Estimated rates of ADHF hospitalization based on panel B. Data were obtained from the Atherosclerosis Risk in Communities Study and the National Inpatient Sample. Corresponding annual percentage change in estimates is shown in Web Table 12.