Bioclinical Test to Predict Nephropathia Epidemica Severity at Hospital Admission

Abstract

We conducted a multicenter, retrospective cohort study of hospitalized patients with serologically proven nephropathia epidemica (NE) living in Ardennes Department, France, during 2000-2014 to develop a bioclinical test predictive of severe disease. Among 205 patients, 45 (22.0%) had severe NE. We found the following factors predictive of severe NE: nephrotoxic drug exposure (p = 0.005, point value 10); visual disorders (p = 0.02, point value 8); microscopic or macroscopic hematuria (p = 0.04, point value 7); leukocyte count >10 × 10⁹ cells/L (p = 0.01, point value 9); and thrombocytopenia <90 × 10⁹/L (p = 0.003, point value 11). When point values for each factor were summed, we found a score of <10 identified low-risk patients (3.3% had severe disease), and a score >20 identified high-risk patients (45.3% had severe disease). If validated in future studies, this test could be used to stratify patients by severity in research studies and in clinical practice.

Keywords: Europe; France; Puumala virus; acute kidney injury; cohort studies; disease severity; hantavirus; hematuria; hemorrhagic disease; hospital admission; leukocytosis; nephropathia epidemica; nephrotoxic drug exposure; prognosis; risk factors; thrombocytopenia; viruses; visual disorder.

Figure 1

Determination of study population used to derive a bioclinical score that enables identification of patients more likely to develop severe NE. Patients were those living in Ardennes Department, France, who were hospitalized for serologically proven NE during January 2000–December 2014. NE, nephropathia epidemica.

Figure 2

Peak creatinine plasma levels in patients hospitalized for nephropathia epidemica by nephrotoxic drug exposure, Ardennes Department, France, January 2000–December 2014. Top and bottom borders of boxes indicate interquartile ranges (IQRs), horizontal lines within boxes indicate medians, diamonds indicate means, and circles represent outliers. A whisker is drawn from the upper edge of the box to the largest observed value within the upper fence (located at 1.5 × IQR above the 75th percentile), and another is drawn from the lower edge of the box to the smallest observed value within the lower fence (located at 1.5 × IQR below the 25th percentile). Peak plasma creatinine levels were higher in the patients exposed to nephrotoxic drugs (p = 0.002).

Figure 3

Receiver operating characteristic curve of test to predict development of severe nephropathia epidemica among patients hospitalized for nephropathia epidemica, Ardennes Department, January 2000–December 2014. Severe nephropathia epidemica was defined as the occurrence of >1 of the following criteria: hypovolemic, hemorrhagic, or septic shock; plasma creatinine level >353.6 µmol/L; anuria (urine output <300 mL/d); acute kidney injury or hydroelectrolytic disorders requiring dialysis; hemorrhage requiring blood transfusion; admission to the intensive care unit; or death. Area under the curve is 0.80.