Abstract Background Blood culture-negative infective endocarditis (CNE), pose a significant clinical challenge and have been associated with increased morbidity and mortality compared with culture-positive infective endocarditis (CPE). However, data among this subset of patients are sparse and originates from studies on small sample sizes or from tertiary centers. Therefore, detailed information from a nationwide cohort of unselected patients is warranted to elucidate potential areas for intervention. Purpose This study aimed to describe patient characteristics and clinical practice patterns among patients with CNE compared with culture-positive IE. Methods Using data from the novel National Danish endocarditis studies (NIDUS) registry, we examined all patients admitted with IE in Denmark from 2016 to 2021. The study included all patients with first-time left-sided IE and categorized them into those with CNE and those with CPE. Patients were categorized as CNE if no bacterial pathogen was identified by blood cultures, heart valve tissue cultures, and polymerase chain reaction (PCR). We reported the pre-existing comorbidities, clinical presentation at admission, in-hospital treatment and mortality. Results We identified 2,889 patients with first-time left-sided IE: 201 (7%) had CNE (60% male, median age 72) and 2,688 (93%) had CPE (67% male, median age 74). In CPE, bacterial etiology was confirmed via blood cultures (97%), valve tissue cultures (2%), and PCR (1%). A definite Duke diagnosis was made in 20% of CNE and 85% of CPE cases, with possible diagnoses in 80% and 15%, respectively. Compared to CPE, CNE patients had lower rates of diabetes (19% vs. 23%) and prior cancer (8% vs. 15%) but higher rates of prior stroke (20% vs. 14%), native valve disease (14% vs. 11%), and congenital heart disease (9% vs. 3%). An equal proportion of patients had prosthetic valve IE (23%), while fewer CNE patients had a CIED (8% vs. 13%). At admission, sepsis was less common in CNE patients (7% vs 25%), and their median vegetation size was slightly smaller (8 mm vs 10 mm). However, they had higher rates of emboli (25% vs 10%) and conduction disturbances (7% vs 5%). PET-CT was performed at similar rates in both groups (66% vs. 67%) but more frequently confirmed IE in CNE patients (14% vs10%). CNE patients had longer median hospital stays (39 vs 35 days) and were less likely to undergo heart valve surgery (15% vs 21%). In-hospital mortality rates were comparable (20% vs 18%). Conclusion These findings highlight a heterogeneous subgroup of patients with CNE who may require alternative treatment approaches due to distinct clinical characteristics. Despite differences in comorbidities, presentation, and surgical interventions, CNE patients had comparable in-hospital mortality and length of stay to CPE patients. In contrary to the existing data, these results suggest that prognosis may be similar between groups.
Petersen et al. (Sat,) studied this question.