Background and aims: The accuracy of a diagnosis of heart failure (HF) in hospital discharge registers is largely unknown. We aimed to determine the validity of such a diagnosis in the Swedish hospital discharge register.
Methods and results: In a population-based study of 2322 middle-aged men (the ULSAM study), 321 participants were diagnosed with HF according to the Swedish hospital discharge register, during a median follow-up time of 29 years. A review board examined the validity of the diagnosis according to the European Society of Cardiology definition of HF. Eighty-two percent of the possible cases were classified as having definite HF. An echocardiographic examination increased the validity to 88%. For patients treated at an internal medicine or cardiology clinic the validity was 86% and 91%, respectively. If HF was the primary diagnosis, the validity was 95%, irrespective of clinic type.
Conclusion: The HF diagnosis in the Swedish hospital discharge register appears slightly less precise than for acute myocardial infarction and stroke. For population-based research, only those with a primary diagnosis of HF in the hospital discharge register should be regarded as definite HF cases, or alternatively the cases should be validated individually.