Cystatin C in a composite risk score for mortality in patients with infective endocarditis: a cohort study

Abstract

Objective: To develop a multimarker prognostic score for infective endocarditis (IE).

Design: Retrospective case-control.

Setting: Secondary care. Single centre.

Participants: 125 patients with definite IE.

Primary outcome measures: 90-day and 5-year mortality.

Results: Mean age was 62.7±17 years. The 90-day and 5-year mortality was 10.4% and 33.6%, respectively. CysC levels at admission and over 20% increases in CysC levels during 2 weeks of treatment were prognostic for 90-day and 5-year mortality independent of creatinine estimated glomerular filtration rate. In multivariate analyses, CysC (OR 5.42, 95% CI 1.90 to 15.5, p=0.002) and age (OR 1.06, 95% CI 1.02 to 1.10, p=0.002) remained prognostic for 5-year mortality. NT-proBNP, TnT, C reactive protein and interleukin 6 were also linked to prognosis. A composite risk scoring system using levels of CysC, NT-proBNP, age and presence of mitral valve insufficiency was able to separate a high-risk and a low-risk group.

Conclusions: CysC levels at admission and increase in CysC after 2 weeks of treatment were independent prognostic markers for both 90-day and 5-year mortality in patients with IE. A multimarker composite risk scoring system including CysC identified a high-risk group.

Figure 1

Kaplan–Meier survival plot by quartiles of admission levels of CysC.

Figure 2

Kaplan–Meier survival plot by risk score for death within 5 years among patients with IE. Patients with 0–2 points were compared with patients with 3–4 points (p<0.001). The presence of these risk factors adds 1 point each: any grade of MI, CysC >1. 2 mg/l, NT-proBNP >2000 ng/l, aged >70 years.