Copeptin does not accurately predict disease severity in imported malaria.
BACKGROUND
Copeptin has recently been identified to be a stable surrogate marker for the unstable hormone arginine vasopressin (AVP). Copeptin has been shown to correlate with disease severity in leptospirosis and bacterial sepsis. Hyponatraemia is common in severe imported malaria and dysregulation of AVP release has been hypothesized as an underlying pathophysiological mechanism. The aim of the present study was to evaluate the performance of copeptin as a predictor of disease severity in imported malaria.


METHODS
Copeptin was measured in stored serum samples of 204 patients with imported malaria that were admitted to our Institute for Tropical Diseases in Rotterdam in the period 1999-2010. The occurrence of WHO defined severe malaria was the primary end-point. The diagnostic performance of copeptin was compared to that of previously evaluated biomarkers C-reactive protein, procalcitonin, lactate and sodium.


RESULTS
Of the 204 patients (141 Plasmodium falciparum, 63 non-falciparum infection), 25 had severe malaria. The Area Under the ROC curve of copeptin for severe disease (0.66 [95% confidence interval 0.59-0.72]) was comparable to that of lactate, sodium and procalcitonin. C-reactive protein (0.84 [95% CI 0.79-0.89]) had a significantly better performance as a biomarker for severe malaria than the other biomarkers.


CONCLUSIONS
C-reactive protein but not copeptin was found to be an accurate predictor for disease severity in imported malaria. The applicability of copeptin as a marker for severe malaria in clinical practice is limited to exclusion of severe malaria.
Department of Internal Medicine, Harbour Hospital and Institute for Tropical Diseases, Haringvliet 2, 3011 TD Rotterdam, The Netherlands.
Marlies E
ME
van Wolfswinkel
Dennis A
DA
Hesselink
Ewout J
EJ
Hoorn
Yolanda B
YB
de Rijke
Rob
R
Koelewijn
Jaap J
JJ
van Hellemond
Perry J J
PJ
van Genderen
D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002648:Child; D005260:Female; D006020:Glycopeptides / Q000097:blood*; D006801:Humans; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D044967:Serum / Q000737:chemistry; D012720:Severity of Illness Index; D055815:Young Adult
D015415:Biomarkers; D006020:Glycopeptides; C048197:copeptins; D002097:C-Reactive Protein