Clinical events leading to the progression of heart failure: insights from a national database of hospital discharges

AIMS: To describe the sequence of clinically apparent events causing readmission and antedating death, subsequent to a first-time hospital admission for heart failure, in order to give insights into the natural history and mechanisms of progression of heart failure. METHODS: A national database of linked hospital discharge and mortality data for Scotland (population 5.1 million) was used. Patients with a first-time admission to hospital with heart failure in 1992 (index population) were identified and, using a record linkage system, hospital readmissions and their cause according to the hospital physician and deaths were recorded over the subsequent 3 years. A flowchart showing the sequence of events leading to death or recurrent admission was constructed. RESULTS: 12 640 patients had first-time admissions with heart failure in 1992; their mean age was 74 years and 46.2% were men. A cohort of 2922 (23%) patients died on their first admission. Among the remaining 9718 patients there were 22 747 readmissions and 4877 deaths over the subsequent 3 years; only 15% had neither event reported. Nine per cent of patients died without any readmission and a further 6% without a further readmission for cardiovascular reasons. A cohort of 5992 (61% of patients at risk) had at least one cardiovascular readmission and half of these had occurred within 6 months. Heart failure without a report of any cardiovascular precipitating event was responsible for 37% (2188 patients) of first cardiovascular readmissions and of these patients approximately 12% had evidence of renal failure or acute respiratory infection as possible triggers for readmission. Acute ischaemic events including myocardial infarction (19%), myocardial infarction alone (8%) and atrial fibrillation (11%) were associated with a substantial number of first readmissions. First readmission precipitated by acute myocardial infarction was associated with a particularly poor prognosis (40% inpatient mortality). CONCLUSIONS: Recurrent ischaemic events and atrial fibrillation may be the predominant mechanisms leading to exacerbation of and progression of heart failure and death. A substantial proportion of readmissions appear related to heart failure alone. Whether this reflects progressive ventricular remodelling leading to worsening heart failure or other unidentified mechanisms cannot be discerned from this data.