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

Abstract

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.

Randomized trial evaluating an mHealth intervention for the early community-based detection and follow-up of cutaneous leishmaniasis in rural Colombia

“…Another potential limitation is that the intervention arm was evaluated via photographs, while the control arm was evaluated in person. However, we have recently shown that evaluation by photographs is highly accurate [ 12 ].…”

“…It has three main functions: i) promoting adherence to pharmacologic treatment, ii) measurement of adverse events associated with treatment, via periodic follow-up, and iii) assessment of therapeutic response via photographic evaluation. This evaluation strategy has been found to be sensitive and specific, relative to in-person assessment [ 12 ]. The intended users are community health volunteers and other healthcare workers.…”

mHealth Monitoring of Treatment of Cutaneous Leishmaniasis Patients: A Community-Based Implementation Study

“…Based on efficacy results of a previous study using the Guaral app for presumptive diagnosis and the Guaral+ST app by CHLs, 14 – 16 expert consensus, 29 , 30 and recommendations of the national guidelines, 6 a community-based strategy utilizing the Guaral+ST app was undertaken to monitor the treatment and follow the therapeutic response of CL patients.…”

“…The high accuracy of the remote evaluation of therapeutic response using the photographs taken with the app was previously demonstrated. 16 …”