The validity of heart failure diagnoses at hospital-discharge and ambulatory evaluation visits: insights from two Norwegian local hospitals

Background The validity of heart failure (HF) diagnoses made in hospitals has been debated and low positive predictive values (PPV) may represent a bias in epidemiological research. Purpose To validate primary and secondary HF diagnoses at discharge or during ambulatory evaluation in general hospitals aiming to obtain confirmed HF diagnoses to develop a HF-prediction risk score. Methods We extracted data on all patients with a HF diagnosis by ICD-10 codes (I50 HF, I42 cardiomyopathy and I11 hypertension with HF) in any position from the hospitals' electronic medical records from Oct. 2006 to Dec. 2018. One experienced cardiologist scrutinized all journals for events being either a valid HF event, unlikely, or uncertain due to lacking information, according to the 2016 ESC HF guidelines. In cases where first event was unlikely or uncertain subsequent events were judged for valid HF. Results A total of 3411 patients with at least one HF diagnosis were assessed (mean age 79.7±10.6 yrs, 49.1% men); 3089 after in-hospital stays and 322 after ambulatory consultations. Overall, 2174 were deemed as valid HF diagnosis with a PPV of 63.7%; PPV was higher when HF diagnosis was based on in-hospital diagnoses and when HF was the primary diagnosis (Table). Conclusions Only 64% of all HF diagnoses were likely HF according to present guidelines, with higher precision for in-hospital diagnoses and HF in the primary position. This underscores the importance to use validated HF-diagnoses for HF prediction risk score development. FUNDunding Acknowledgement Type of funding sources: Other. Main funding source(s): Boehringer Ingelheim Norway KS