220-Dictionary of Pharmaceutical Medicine, 2nd Edition-Gerhard Nahler Annette Mollet-3211898352-S

14bento calculate the posterior odds in favor of a particular drug beingthe cause of the adverse event; the posterior odds are calculatedby considering 6 assessment subsets: “prior odds” as backgroundepidemiological and clinical trials information, and 5 other dealingwith case-specific information of possible differential diagnosticvalue (“likelihood ratios”); → see also adverse drug reaction,standardized assessment of causality (SAC).benefit-risk analysis → see decision analysis.Berkson’s bias There is an increased chance that hospitalised patientswill have other comorbid conditions in addition to the diseaseof interest, compared with the decreased chance that nonhospitalisedpatients will have more than one condition; → seealso bias.beta error syn. type II error; “missed difference”; statistical riskof saying there is no difference between two treatments A and Bwhen actually there is one (error of falsely accepting the null hypothesisHo; truth (one-sided): A > or < B, false judgment: A = B);therefore β is the probability of failing to detect, by mere chance, atreatment difference at least as large as the degree specified (deltavalue) by the alternative hypothesis Ha; 1-b is usually referredto as the power of the statistical test, the probability of detectingthe specified difference and, therefore, the probability of rejectingHo when Ha is true; the probability for a β-error increases with alower delta, smaller sample size and larger variance of the measured(continuous) variables; → see also alpha error, gammaerror.between-subject design opp. within-patient d.; → see design.bias Errors due to incorrect assumptions (ICH E9: “systematic tendencyof any aspect of the design, conduct, analysis, and interpretationof the results of clinical trials to make the estimate of a treatmenteffect to deviate from its true value”; frequent examples for bias are:recall b. = the more often a subject is asked the same question, themore likely are differences in the answer due to more intensive reflectionsor due to a better memory for findings which were importantfor the subject (which is not necessarily the case for controls,e.g. diagnosis or treatments in cancer); allocation b. = even drugsof the same substance class and being nearly identical may not be“allocated” by prescribing physicians in exactly the same way, newdrugs are more likely to find their principle first uses in patientswho have not responded satisfactorily to previously availabledrugs; attrition b. = biased occurrence and handling of protocoldeviations and losses to follow-up; changing pattern b. = methodsof diagnosis, techniques, treatments a.s.o. may change over time;confounding b. = one or more variable associated, independently