Positive predictive value and impact of misdiagnosis of a heart failure diagnosis in administrative registers among patients admitted to a University Hospital cardiac care unit

OBJECTIVE To evaluate the positive predictive value (PPV) of a diagnosis of heart failure (HF) in the Danish National Registry of Patients (NRP) among patients admitted to a University Hospital cardiac care unit, and to evaluate the impact of misdiagnosing HF. DESIGN The NRP was used to identify patients with heart failure from July 1, 2005 to June 30, 2007. Heart failure was defined in accordance with European Society of Cardiology (ESC) guidelines. The recorded diagnoses from the NRP were compared with clinical data from the medical records. RESULTS We identified 758 patients with a diagnosis of heart failure in the NRP. The PPV of a heart failure discharge diagnosis was 84.0% (95% confidence interval: 81.2-86.6). Patients with a discharge diagnosis of HF in the NRP without fulfilling the ESC criteria for HF had a better survival rate, a lower rate of rehospitalization, none were followed in the outpatient clinic, and they had a lower consumption of anticongestive medicine after discharge. CONCLUSION We found a relatively high PPV of the HF diagnosis in the NRP, and the NRP can therefore be a valuable tool for identification of patients with HF. However, using the NRP alone will not give a true picture of the cost and total burden of the disease.