Spontaneous reporting of suspected adverse drug reactions (ADRs) has long been a cornerstone of pharmacovigilance. With the increasingly large volume of ADRs, regulatory agencies, scientific/academic organizations and marketing authorization holders have applied statistical tools to assist in signal detection by identifying disproportionate reporting relationships in spontaneous reporting databases. These tools have generated large numbers of signals defined as drug-ADR reporting associations that meet specified statistical criteria. The challenge is to identify which signals are most likely to be medically important and therefore warrant priority for further investigation. Decisions related to signal triage are often complex and are based on a combination of clinical, epidemiological, pharmacological and regulatory criteria. There are no specific regulations, guidelines or standards that provide an objective basis for these decisions. This paper describes preliminary work to identify and quantify the specific factors that contribute to a decision to prioritize a specific drug-ADR combination for further in-depth review. We applied a tool from the discipline of decision analysis to systematically assess the important attributes of spontaneously reported ADRs. A model was created that integrates these assessments and produces rankings for the signals generated from quantitative signalling methods. Although more research is necessary to evaluate the performance of this model fully, preliminary results suggest that the use of formal decision analysis approaches to support signal triage can provide potential benefit and will help meet an important need.

We measured sensitive indicators of renal damage in three different populations occupationally exposed to cadmium, and examined the degree of variation in damage and the relative sensitivity of different types of indicators. The three studies included (1) men exposed in a cadmium recovery plant, (2) men exposed in a nickel/cadmium battery plant, and (3) women exposed in the latter plant. The indicators of renal damage were urinary proteins in three categories: (1) the high molecular weight enzymes alanine aminopeptidase (AAP) and N-acetyl-beta-D-glucosaminidase (NAG), (2) the intermediate molecular weight protein albumin (ALB), and (3) the low molecular weight proteins retinol-binding protein (RBP) and beta 2-microglobulin (B2M). These tests indicate that exposed groups with higher urine cadmium levels had varying degrees of renal damage. All exposed groups showed evidence of renal damage when compared with their respective control groups. A higher percentage of elevated protein levels was noted in the exposed group of Study 1 than in the exposed groups of Studies 2 and 3. In Study 1, the means of all five protein levels and ALB, RBP, and B2M fractional clearances were significantly elevated in the group with higher urine cadmium concentrations when compared with the groups with lower urine cadmium concentrations. Highly significant dose-response relationships for all of the urinary protein tests, including fractional clearances, were found. All of the tests were more sensitive in detecting evidence of subclinical renal damage than serum creatinine, a commonly used indicator of renal function. The order of test sensitivity in men was determined by considering three factors: (1) the magnitude of the correlation coefficient between the test and the urine cadmium concentration in the study with the most advanced damage, (2) the relative cadmium level predicted by the dose-response model at which there is a 10% chance of observing an elevated test value, and (3) the ability of the tests to detect renal effects in the population with less advanced damage. The tests in order of decreasing sensitivity in men are ALB, AAP, NAG, RBP approximately B2M. The women with higher urine cadmium levels in Study 3 had a higher percentage of elevated AAP and NAG values when compared with the control group.

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