Title : Validation of the normandy score- Predictive of abnormal echocardiography- in the management of bacterial native joint and bone infections
Introduction. Native joint and bone infections (NJBI) are frequently associated with infective endocarditis (IE). Normandy score, based on the patient's valvular assessment, the bacterial species and the hematogenous mechanism of NJBI was published to guide the prescription of an echocardiography during NJBI management (1). The aim of this study is to validate the Normandie score in a new multicenter cohort.
Methods. This is a multicenter retrospective study covering 3 French regions between 2008 and 2020. Inclusion criteria are adult NJBI documented by blood culture and/or joint puncture. Exclusion criteria were fungal and mycobacterial infections, and prosthetic material. The primary endpoint was the discovery of a major abnormality of IE on echocardiography, ie valvular vegetation, abscess, perforation, dehiscence of a vascular prosthesis. The Normandy score was applied: high risk valvopathy of IE (+1.5), unknown heart murmur (+1.25), direct joint or spinal inoculation (-0.75), multifocal infection (+0.5), positive blood culture (+1 if only 1 positive blood culture, +2 if ≥ 2 positive blood cultures), S. bovis (+1), Enterococcus sp (+0.5), bacteria not associated with IE (-1.5). A score greater than 0 should perform an echocardiography because of risk of associated IE.
Results. A total of 450 patients were included. The mean age was 64.1 years old. The causative germs were : Staphylococcus aureus 43.5%, Streptococcus sp. or Enterococcus sp. 18.7%. Sixty-nine (15.3%) patients had an echocardiography suggestive of IE. Normandy score recommends echocardiography for 259 (57.6%) patients in whom 67 (25.8%) valvular anomalies were found, and echocardiographic abstention for 186 (41.3%) patients with 2 (1.1%) false-negative. The sensitivity of the Normandy score was 97% (CI95% 90.7;99.7), its negative predictive value 98.9% (CI95% 96.2;99.9) and its positive predictive value 23.4% (CI95% 18.8;28.5).
Conclusion. Normandy score appears to be robust in detecting patients at risk of IE in the specific population of NJBI. This reinforces the need to take into account the bacterial species, but also the valvular risk and the mechanism of hematogenous dissemination during NJBI.
(1). Beaufrère M, et al. Valvular and infection-associated risk factors as criteria to guide the use of echocardiography in patients with native joint infections. Semin Arthritis Rheum. 2021 51(6):1274-1281