170 likes | 655 Views
8. Causality assessment: scales and methods. Multi-partner training package on active TB drug safety monitoring and management ( aDSM ) July 2016. Objectives of the presentation By the end of this presentation, the participant is expected to be able to:.
E N D
8. Causality assessment: scales and methods Multi-partner training package on active TB drug safety monitoring and management (aDSM) July 2016
Objectives of the presentationBy the end of this presentation, the participant is expected to be able to: describe the main principles of causality assessment identify the different levels of certainty when attributing an event to a suspected exposure
Causality assessment (1) one of the main reasons we collect aDSM data • Programme indicators • Causality assessment • Signal detection • Drug-safety profiles
Causality assessment (2) an integral part of clinical management • Evaluating the likelihood that a TB medicine was the causative agent of an observed adverse reaction forms part of clinical evaluation. • While the details of the systematic method of conducting causality assessment may not be familiar to the practitioner, the overall approach is not too different from the clinical practice followed when evaluating any patient on treatment.
Causality assessment (3) attribution • The attribution (relationship or causality or drug related assessment) must be made • A physician or any other health care professional who has the right expertise describes the relationship between the adverse event and an exposure • This determination must be recorded both in the medical record as well as in the case report form • For aDSM, causality assessment should be made primarily at the country level and by consulting the relevant data sources close to where the event occurred
Causality assessment (4) • Is there a convincing relationship between the medicine and the event ? • Did the medicine actually cause the event ? • OR • Other TB medicines ? • Medicines for otherdiseases ? • Effect of the TB diseaseitself or co-morbidities?
Causality assessment (5) reaction versus event Adverse drug reactions (ADR): a response to a medicine which is noxious and unintended, and which occurs at doses normally used in humans Adverse events (AE): Any untoward medical occurrence that may present during treatment with a pharmaceutical product, but which does not necessarily have a causal relationship with this treatment
Causality assessment (6)main things to look out for • Is the time to onset of the event compatible with the suspected cause (plausible time-frame) ? • Did the event occur after the start of some other medicine or new illness? • Is the event plausible given what is known about the drug? • Is there any other possible cause for the event? • What is the response to withdrawal of the medicine • (dechallenge)? • What is the response to rechallenge, if applicable?
Causality assessment (7)keydata elements for causality assessment • Medical history (incl. concomitant disease) • Other risk factors (social factors, alcohol use, substance abuse, etc.) • Details of drugs taken : names, doses, routes • Start and stop dates and indications for use • Description of adverse event, including clinical description, laboratory results, and date of onset / end • Evolution of event, severity, seriousness, outcome
Causality assessment (8)classification of level of relationship
Causality assessment (9)inference on the grade of the relationship • Definite – Clearly caused by the exposure • Probable – Likely to be related to the exposure • Possible – May be related to the exposure • Unlikely – Doubtfully related to the exposure • Unrelated – Clearly not related to the exposure
Causality assessment (10)inference on the grade of the relationship
Causality assessment (11)Naranjo ADR probability scale (items and score) Source: Naranjo CA et al. A method for estimating the probability of adverse drug reactions. Clin Pharmacol Ther 1981; 30: 239 - 245.
Causality assessment (12)WHO-UMC system • Practical tool for the assessment of case reports • Combined assessment taking into account • clinical-pharmacological aspects of the case history • the quality of the documentation • Other criteria such as previous knowledge and statistical chance play a less prominent role as to facilitate detection of unknown and unexpected adverse drug reactions Source: http://who-umc.org/Graphics/24734.pdf
Causality assessment (13)approaches to test hypotheses Adapted from R Benkirane (WHO-CC Morocco; 2014)
Causality assessment (14) who does the causality assessment ?
Conclusion • An attempt to attribute an event to a cause is a basic principle of monitoring and clinical management in aDSM • Attributing a relationship requires a systematic process and is one of the main reasons why data are collected in aDSM. The exercise is done by experts who are competent in therapeutics and toxicity • The causality assessment once done attributes a level of certainty between the event and the exposure, ranging from certain to unrelated