Amyloidosis and 30-Day Outcomes Among Patients With Heart Failure: A Nationwide Readmissions Database Study

Abstract

Background: The burden of amyloidosis among hospitalized patients is increasing over time. However, amyloidosis remains an underdiagnosed cause of heart failure (HF) hospitalization among older adults.

Objectives: We investigated the prevalence and prognostic implications of amyloidosis among patients hospitalized with HF.

Methods: All hospitalizations for primary diagnosis of HF between January 1, 2010, and August 31, 2015, identified in the Nationwide Readmissions Database were categorized into those with and without a secondary diagnosis of amyloidosis. HF hospitalizations with amyloidosis were then matched in a 3:1 fashion to HF hospitalizations without amyloidosis using the year of admission, discharge quarter, age, sex, and Charlson comorbidity index. Primary outcomes were inpatient mortality and 30-day readmission. Multivariable logistic regression was used to estimate the association between HF with amyloidosis and clinical outcomes.

Results: Of 1,593,360 HF hospitalizations that met inclusion criteria, 2,846 (0.18%) had HF with a secondary diagnosis of amyloidosis and were matched to 8,515 hospitalizations for HF without amyloidosis. Hospitalizations for HF with amyloidosis were associated with higher prevalence of kidney disease (56% vs. 45%), malignancy (20% vs. 4%), and higher inpatient mortality (6% vs. 3%) as compared with HF without amyloidosis. In adjusted analyses, HF with amyloidosis was associated with higher odds of in-hospital mortality (odds ratio: 1.46; 95% confidence interval [CI]: 1.17 to 1.82), 30-day readmission (odds ratio: 1.17; 95% CI: 1.05 to 1.31), and longer mean length of stay (least-squares mean difference: 1.46; 95% CI: 1.12 to 1.80).

Conclusions: In patients hospitalized with decompensated HF, presence of amyloidosis was associated with higher risk of inpatient mortality and 30-day readmission.

Keywords: ATTR, transthyretin amyloidosis; CCI, Charlson comorbidity index; CI, confidence interval; CV, cardiovascular; HF, heart failure; ICD-9-CM, International Classification of Diseases-9th Revision-Clinical Modification; LOS, length of stay; NRD, Nationwide Readmissions Database; OR, odds ratio; amyloidosis; heart failure; mortality; readmissions.