IJCS | Volume 33, Nº2, March / April 2020

176 Sarteschi et al. Predictors of post-discharge 30-day readmission Int J Cardiovasc Sci. 2020; 33(2):175-184 Original Article hospitalization alone of around BRL 334 million. In same year, in the Northeast of Brazil, hospitalizations for HF were around 48,000, includingmore than 8,000 in the state of Pernambuco, with 13.7% mortality. 3 In First Brazilian Registry of Heart Failure — BREATHE — in-hospital mortality was 12.6% of 1,263 patients distributed in 51 urban centers in Brazil. 4 One of the greatest problems related to the outcome of HF refers to high rates of hospital admissions caused by clinical decompensation, generating intense stress to patients and relatives, with high economic cost and great impact on the health system, in addition to worsening of ventricular function. 5 Studies have demonstrated that each event of clinical decompensation results in additional worsening of ventricular remodeling in HF, resulting in worse heart function and clinical manifestations of heart failure. 6 The objective of this study is to calculate hospital readmission rate within 30 days of discharge, as well as to identify the main predictors of re-hospitalization of patients with acute decompensated heart failure (ADHF), in order to assist the development of public health policies, with positive impact on the reduction of morbimortality among those patients. Methods Retrospective study with historic cohort of patients assisted at a private hospital fromRecife/PE (Brazil), who were in hospital for over 24 hours, from January 2008 to February 2016. Admitted patients had primary diagnosis of decompensated heart failure, were 18 years of age or older, Functional Class III and IV according to the Classification of the New York Heart Association – NYHA. Decompensated heart failure was diagnosed according to the Framingham Study. 7 Patients with incomplete or unavailable data on their electronic charts, patients submitted to transplantation and minors of 18 years of age were excluded. Datacollectionincludedhospital admissioninformation from the date of admission to medical discharge or in- hospital death, and hospital readmission within 30 days of discharge. Information was obtained from medical records, then complemented, when necessary, by consultation with the medical assistant. Data collection instrument was a structured questionnaire, including demographic and clinical variables, complementary tests and the therapy used, besides information about clinical outcomes and post-discharge outcome. The outcome of interest was hospital readmission within 30 days of discharge. Only hospital readmissions due to cardiac causes were considered in this study. HF etiologies were defined as: a) ischemic heart disease due to previous heart attack, chest angina, previous coronary artery bypass grafting surgery or percutaneous angioplasty, or coronary angiography showing major artery obstructions (> 70%) in epicardial branches; b) hypertension heart disease, defined as long-term history of systemic hypertensionwithout adequate blood pressure control or long-term use of anti-hypertensive medication associatedwith the presence of left ventricular hypertrophy on electrocardiogram or echocardiogram; c) valvular heart disease defined as history of previous valvular disease or based on echocardiogram results; d) idiopathic cardiomyopathy in the presence of dilatation and ventricular dysfunction, in the absence of any other evident cause. Left ventricular ejection fraction (LVEF) was measured by echocardiogram, using the Teichholz formula for records on mode M or modified Simpson’s rule for final left ventricular systolic and diastolic diameter measurements on apical four-chamber view, according to the regulations applicable. All tests were conducted at the echocardiography section of the hospital. 8 The variable hospital-acquired complication was made by the composition of in-hospital events (dialysis procedure, ventricular arrhythmia, infection, pulmonary embolism and cardiogenic shock), that is to say, if the patient had at least one of the described events, it was considered hospital-acquired complication. Some of the continuous variables were changed to categorical variables for analytical purposes: 9 age (< 65 and ≥ 65 years), systolic blood pressure (< 115 mmHg and ≥ 115 mmHg), heart rate (≤ 80 bpm and > 80 bpm), hospitalization period (≤ 7 days and > 7 days), creatinine (abnormal: > 1.3 mg/dl men and > 1.1 mg/dl women), plasma sodium (altered — hyponatremia: < 130 mEq/L), blood urea nitrogen (abnormal: ≥ 92 mg/dL) and LVEF (< 40% and ≥ 40%). Presence of anemia was based on the World Health Organization (hemoglobin < 13 g/dl men and hemoglobin < 12 g/dl women). Statistical analysis Demographic and clinical characteristics of patients were analyzed using descriptive statistics: mean and