Sensitivity and Specificity of the Remote Evaluation of Therapeutic Response in Cutaneous Leishmaniasis Using Photographs from a Mobile Application

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  • 1 Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia;
  • | 2 Universidad Icesi, Cali, Colombia;
  • | 3 Grupo i2t, Universidad Icesi, Cali, Colombia
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Cutaneous leishmaniasis (CL) primarily affects people in remote settings with limited access to health services. mHealth tools offer an opportunity to overcome knowledge gaps about clinical response to treatment. We evaluated the validity of the Guaral+ST mobile application for the remote assessment of therapeutic response in patients with CL, through photographs of lesions captured with the app by community health volunteers. Patients with confirmed CL were followed at weeks 13 and 26 after completion of treatment to assess therapeutic response in two clinical settings in southwest Colombia. Direct evaluation of lesions performed by an experienced physician was considered the reference standard. Photographs of lesions taken by CHV or nurse assistants with the mobile app, were independently evaluated by three physicians to define clinical response. A summary measure of clinical outcome defined by the three physicians was considered the index test. Sensitivity, specificity, and positive and negative predictive values were estimated. Interrater reliability (kappa) was calculated. Among 53 participants with CL who had at least one follow-up visit, the sensitivity of therapeutic response evaluation through photographs taken with the Guaral+ST app, compared with direct evaluation by an expert physician, had high validity with sensitivity of 100% (95% confidence interval: 80.5–100%) and specificity of 97.2% (95% confidence interval: 85.5–99.9%). The chance-adjusted agreement (κ) was > 0.8, which is conventionally characterized as almost perfect. The high accuracy of the remote evaluation of photographs for the assessment of therapeutic response supports the use of mHealth tools for improving access to treatment follow-up for CL.

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Author Notes

Address correspondence to Neal Alexander, Centro Internacional de Entrenamiento e Investigaciones Médicas, Cali, Colombia. E-mail:

Financial support: This study was supported by the Fogarty International Center of the National Institutes of Health (NIH), under award nos. D43 TW006589 and R21 TW009907; the National Institutes of Allergy and Infectious Diseases of the National Institutes of Health under award no. U19AI129910; and an International Master’s Fellowship from the Wellcome Trust awarded to J. A. G. (reference number 214641/Z/18/Z). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Authors’ addresses: Alejandra Maria Del Castillo and David Esteban Rebellón-Sánchez, Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia, E-mails: and Maria del Mar Castro, Alexandra Cossio, Jonny Alejandro García Luna, and Ruth Mabel Castillo, CIDEIM, Cali, Colombia, and Universidad Icesi, Cali, Colombia, E-mails:,,, and Domiciano Rincón and Andrés Navarro, Universidad Icesi, Cali, Colombia, and Grupo i2t, Universidad Icesi, Cali, Colombia, E-mails: and