This study was performed to compare the assessments of drug–induced liver injury obtained with 2 methods, the Council for International Organizations of Medical Sciences (CIOMS) scale and the recently validated Maria & Victorino (M&V) clinical scale, in cases submitted to a registry of hepatotoxicity. A total of 215 cases of hepatotoxicity reported with a structured reporting form were evaluated by 3 independent experts. Because of the use of multiple drugs, 228 ratings were generated. The probability of the diagnosis was classified as definitive, probable, possible, unlikely, or excluded, and evaluated for consistency with a weighted κ statistical test. Absolute agreement between the 2 scales was observed in 42 cases (18%, weighted κ 0.28) with disagreement of 1 level in 108 cases (47%), and of 2 levels in 70 cases (31%). The best correlation between the 2 scales was obtained for drug–induced liver injury involving a suggested immunoallergic mechanism: the disagreement was 1 level or less in 72% of the cases (34 of 48), compared with 60% of the cases (85 of 141) that involved a presumed idiosyncratic metabolic mechanism. The lowest agreement (6%) was observed in cases with evidence of cholestasis. No agreement was found in cases of fulminant hepatitis or death. The CIOMS scale showed better discriminative power and produced assessments closer to those of specialists. The performance of the M&V scale was poor in reactions with long latency periods (i.e., amoxycillin/clavulanic acid), evolution to chronicity after withdrawal (cholestatic pattern), or death.
1 February 2015 in Reliability Engineering & System Safety
This paper analyses a condition-based maintenance for a system subject to different competing failure modes: internal degradation and external shocks. Internal degradation is the result of the arrival to the system of multiple cracks that grow according to stochastic deterioration processes. External shocks arrive to the system at random times and provoke the system failure. A condition-based maintenance model with periodic inspection times is developed for this competing failure model. Under this maintenance strategy, a preventive replacement is performed when the degradation level of a given crack in an inspection time exceeds a predetermined threshold. A corrective replacement is performed when the system is failed in an inspection time. Under this maintenance scheme, the expression of the expected cost rate is obtained. A numerical example illustrates the maintenance model.