The "Buruli Score": Development of a Multivariable Prediction Model for Diagnosis of Mycobacterium ulcerans Infection in Individuals with Ulcerative Skin Lesions, Akonolinga, Cameroon

Mueller, Yolanda K.; Bastard, Mathieu; Nkemenang, Patrick; Comte, Eric; Ehounou, Geneviève; Eyangoh, Sara; Rusch, Barbara; Tabah, Earnest Njih; Trellu, Laurence Toutous; Etard, Jean-Francois
Abstract:
BACKGROUND: Access to laboratory diagnosis can be a challenge for individuals suspected of Buruli Ulcer (BU). Our objective was to develop a clinical score to assist clinicians working in resource-limited settings for BU diagnosis. METHODODOLOGY/PRINCIPAL FINDINGS: Between 2011 and 2013, individuals presenting at Akonolinga District Hospital, Cameroon, were enrolled consecutively. Clinical data were collected prospectively. Based on a latent class model using laboratory test results (ZN, PCR, culture), patients were categorized into high, or low BU likelihood. Variables associated with a high BU likelihood in a multivariate logistic model were included in the Buruli score. Score cut-offs were chosen based on calculated predictive values. Of 325 patients with an ulcerative lesion, 51 (15.7\%) had a high BU likelihood. The variables identified for the Buruli score were: characteristic smell (+3 points), yellow color (+2), female gender (+2), undermining (+1), green color (+1), lesion hyposensitivity (+1), pain at rest (-1), size {\textgreater}5cm (-1), locoregional adenopathy (-2), age above 20 up to 40 years (-3), or above 40 (-5). This score had AUC of 0.86 (95\%CI 0.82-0.89), indicating good discrimination between infected and non-infected individuals. The cut-off to reasonably exclude BU was set at scores {\textless}0 (NPV 96.5\%; 95\%CI 93.0-98.6). The treatment threshold was set at a cut-off ≥4 (PPV 69.0\%; 95\%CI 49.2-84.7). Patients with intermediate BU probability needed to be tested by PCR. CONCLUSIONS/SIGNIFICANCE: We developed a decisional algorithm based on a clinical score assessing BU probability. The Buruli score still requires further validation before it can be recommended for wide use.
Research areas:
Year:
2016
Type of Publication:
Article with Review Committee
Keywords:
Adolescent; Adult; Aged; 80 and over; Buruli Ulcer; Cameroon; Child; Preschool; Decision Support Techniques; Female; Humans; Infant; Newborn; Male; Middle Aged; Prospective Studies; Sensitivity and Specificity; Skin; Young Adult
Journal:
PLoS Negl Trop Dis
Volume:
10
Number:
4
Pages:
e0004593
Month:
April
ISSN:
1935-2735
DOI:
10.1371/journal.pntd.0004593
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