A Systematic Evidence Map of Renal Effects of Oral Exposure to Mercuric Chloride
Background and Purpose: We used systematic review methods to develop a systematic evidence map (SEM) for the renal effects as an example of how the data is handled, following oral exposure to mercuric chloride using Populations, Exposures, Comparators, and Outcomes (PECO) criteria.
Methods: In order to identify relevant studies, we conducted a comprehensive literature search involving PubMed, Web of Science, and Toxline. The literature was screened by two independent reviewers for title/abstract and full text initially using SWIFT-Review software and later using DistillerSR software. Studies meeting the PECO criteria were evaluated, extracted, and visualized using Health Assessment Workplace Collaborative (HAWC) tool. Study evaluations for studies with renal effects were performed in HAWC, and study confidence ratings (high, medium, low, uninformative) were assigned based on the evaluation of several domains including exposure measurement, chemical administration and characterization, confounding factors, observational bias, and sensitivity. We also identified studies containing potentially relevant supplemental mechanistic endpoints for renal outcomes to be used as supportive information.
Results: This approach did not identify and PECO relevant human studies. However, it has identified several animal studies with diverse study designs (chronic, subchronic, reproductive, and developmental) in male and female rats and mice, and in female goats which measured renal effects including absolute and/or relative kidney weight, histopathology, and clinical chemistry (blood and urinalysis).
Conclusions: Overall, this SEM provides an overview of the available evidence and helps to inform the usability of these data in the hazard identification and dose-response analysis to be conducted in the forthcoming Integrated Risk Information System (IRIS) assessment of inorganic mercury salts. Disclaimer: The views expressed in this abstract are those of the authors and do not necessarily represent the views or the policies of the U.S. Environmental Protection Agency.