Effect of rK39 testing in guiding treatment initiation and outcome in patients with visceral leishmaniasis in Ethiopia: A prospective cohort study.

Autor: Hagos DG; Mekelle University College of Health Sciences, Mekelle, Ethiopia.; Department of Medical Microbiology, Parasitology Unit, Amsterdam University Medical Center, Amsterdam, The Netherlands., Kebede Y; Mekelle University College of Health Sciences, Mekelle, Ethiopia., Abdulkader M; Mekelle University College of Health Sciences, Mekelle, Ethiopia., Nigus E; Mekelle University College of Health Sciences, Mekelle, Ethiopia., Gessesse Arefaine Z; Mekelle University College of Health Sciences, Mekelle, Ethiopia., Nega G; Mekelle University College of Health Sciences, Mekelle, Ethiopia., Schallig HDF; Department of Medical Microbiology, Parasitology Unit, Amsterdam University Medical Center, Amsterdam, The Netherlands., Wolday D; Mekelle University College of Health Sciences, Mekelle, Ethiopia.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2021 Jun 14; Vol. 16 (6), pp. e0253303. Date of Electronic Publication: 2021 Jun 14 (Print Publication: 2021).
DOI: 10.1371/journal.pone.0253303
Abstrakt: Background: The rapid diagnostic test (RDT) rK39 is currently being used for routine diagnosis of visceral leishmaniasis (VL) in East Africa. However, continuous monitoring of the performance of the assay, in particular its impact on the clinical decision in initiating anti-leishmanial treatment and outcomes remains needed as there are concerns about the diagnostic performance of this test.
Methods: VL patients prospectively enrolled in a diagnostic trial and with rK39 RDT were included. We evaluated the effect of rK39 testing in guiding treatment initiation and outcome. On the basis of rK39 RDT test result as well as clinical case definition for VL and microscopy examination, the clinicians decide whether to initiate VL therapy or not. Poisson regression models were used to identify factors associated with a decision to initiate VL therapy. In addition, treatment outcomes of those who received VL therapy were compared to those who received non-VL treatment.
Results: Of 324 VL suspects enrolled, 184 (56.8%) were rK39+ and 140 (43.2%) were rK39‒. In addition, microscopy exam was done on tissue aspirates from a sub-population (140 individuals), which is 43.2% of the suspected cases, comprising of 117 (63.6%) rK39+ and only 23 (16.4%) rK39‒ cases. Of those with microscopy examination, only 87 (62.1%) were found positive. Among 184 (56.8%) patients without microscopy, 67 (36.4%) were rK39+, of whom 83 (65.9%) were positive by microscopy, 21 (16.7%) were negative by microscopy and 22 (17.5%) had no microscopy results. On the other hand, of those who did not receive VL treatment 58/189 (30.7%) were rK39+ and 131 (69.3%) were rK39‒. Of the rK39+ cases who did not receive VL therapy, only 1 (1.7%) patient was microscopy positive, 12 (20.7%) were negative and 45 (77.6%) patients had no microscopy result. Of the rK39‒ cases (n = 131) who did not receive VL treatment, 16 were microscopy negative and 115 without microscopy exams. Whereas positive rK39 result [adjusted Relative Risk (aRR) 0.69; 95% CI: 0.49-0.96, p = 0.029] and positive microscopy results (aRR 0.03; 95% CI: 0.00-0.24, p = 0.001) were independently associated with VL treatment, having confirmed diagnosis other than VL (aRR 1.64; 95% CI: 1.09-2.46, p = 0.018) was independently associated with initiation of non-VL therapy. The proportion of rK39+ patients who received non-VL treatment with no improvement outcome was significantly higher when compared to those who received VL treatment (24.1%, 95% CI: 14.62-37.16 vs. 11.9%, 95%CI: 7.26-18.93; p<0.0001).
Conclusion: The study shows that a significant proportion of patients with rK39+ results were undertreated. Failure to do microscopy was associated with lack of improved clinical outcome. Including an additional simple point-of-care assay in the diagnostic work-up is urgently needed to correctly identify VL cases and to prevent morbidity and mortality associated with the disease.
Competing Interests: The authors declare that they have no competing interests. The funding organization had no role in the study design, data collection, analysis, or interpretation, or the decision to submit the study for publication.
Databáze: MEDLINE
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