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

contextOver 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.

objectiveOur 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

methodsThis 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.

resultsFrom 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

conclusionThe 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.