Indicators for serious kidney complications associated with toxic exposures: an analysis of the National Poison Data System

Abstract

Context. Over two million poisoning exposures are reported to U.S. poison control centers annually. A broad population-based survey of toxic exposures and the correlated patterns of reported kidney injury (acute or chronic) have not been systematically characterized. Objective. Our objective was to study the demographic and exposure patterns associated with indicators for serious kidney complications (ISKC), as defined by the variables in the NPDS. Materials and methods. This was a retrospective, case-control study using the data elements available in the NPDS. We assessed data related to patient characteristics, substance exposure, and management. Cases and controls were derived from adult and pediatric exposures documented in NPDS (2001–2007) as having “renal effects.” For substance-specific analyses, cases were restricted to those involving single substances or single entity pharmaceutical preparations. ISKC cases presented with one or more of the following NPDS codes: increased creatinine, and/or oliguria/anuria, and/or renal failure. Controls were subjects with “renal effects” but did not have increased creatinine, nor anuria/oliguria, nor renal failure. Univariate and multivariate logistic regression analyses identified factors associated with ISKC and determined the relationship between these factors. Results. From the approximate 16.8 million exposures reported to the NPDS within the study timeframe, there were 16,444 single substance exposures with renal effects of which 9,074 cases experienced ISKC (55.2%) compared to 7,370 controls without ISKC. Cases with ISKC tended to be males, adults, and reported to involve intentional exposures. Cases with ISKC had higher rates of reported hemodialysis/hemofiltration (27.7%; N = 2,517) and death (10.9%; N = 990) compared to controls, respectively, (2.1%; N = 155) and (0.8%; N = 60), p < 0.001. Substances considered a priori to be nephrotoxic were associated with a higher risk of ISKC. Discussion and conclusion. The NPDS provided insight into the subjects and types of exposures that associate with ISKC. Subjects with ISKC experienced higher rates of morbidity and mortality compared to subjects without ISKC. We identified subject characteristics and classes of compounds associated with ISKC. We hope that the hypotheses generated from this study of the NPDS will raise awareness of the possible risk factors and complications associated with ISKC.

Keywords:

• Nephrotoxicity
• Poisoning; Poison control center; Toxicity

Declaration of interest

The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.

Disclaimer

The American Association of Poison Control Centers (AAPCC) maintains the national database of information logged by the country's 57 poison control centers. Case records in this database are from self-reported calls: they reflect only information provided when the public or healthcare professionals report an actual or potential exposure to a substance (e.g., an ingestion, an inhalation, or a topical exposure, etc.), or request information/educational materials. Exposures do not necessarily represent a poisoning or overdose. The AAPCC is not able to completely verify the accuracy of every report made to member centers. Additional exposures may go unreported to PCCs and data referenced from the AAPCC should not be construed to represent the complete incidence of national exposures to any substance(s).

NOTE: All data produced from the American Association of Poison Control Centers databases during the year in which the exposures occur are considered preliminary. Changes occur in only a small number of cases each year. This is because it is possible that a poison center may update a case anytime during that year if new data are obtained. In the fall of each year the data for the previous year are locked and no changes are permitted. At that time the data for a year are considered closed.

Support

This project was supported in full by the National Institutes of Health grant DHHS/NIH/NCRR 1UL1RR031977-01 University New Mexico Clinical and Translational Science Center and the National Center for Research Resources and the National Center for Advancing Translational Sciences of the National Institutes of Health through Grant Number 8UL1TR000041, The University of New Mexico Clinical and Translational Science Center.

Previous Publications

This work has been presented as a platform presentation (Vilay AM, Wong CS, Schrader RM, Mercier RC, Seifert SA. Acute kidney injury related to toxic exposures. Pediatr Nephrol 25(9): 52, 2010) at the 15th Congress of the International Pediatric Nephrology Association, New York, NY, USA and as a poster presentation (Seifert SA, Vilay AM, Wong CS, Schrader RM, Mercier RC. Characterization of acute kidney injury in toxic exposures. Clin Toxicol (Phila) 48 (6): 615, 2010) at the 2010 North American Congress of Clinical Toxicology Annual Meeting Denver, CO, USA.