Risk ratio

As a general rule, clinical data are required as evidence to support conformity with the requirements of the Active Implantable Medical Devices (AIMD) and the Medical Device (MD) directives with regards to safety and effectiveness under the normal conditions of use, evaluation of undesirable side effects, and the acceptability of the benefit/risk ratio. Risk analysis should be used to establish key objectives that need to be addressed by clinical data, or alternatively to justify why clinical data are not required (mainly for Class I devices). The risk analysis process should help the manufacturer to identify known (or reasonably foreseeable) hazards associated with the use of the device, and decide how best to investigate and estimate the risks associated with each hazard. The clinical data should then be used to establish the safety and effectiveness of the device under the intended use conditions, and to demonstrate that any of the residual risks are acceptable, when weighed against the benefits derived from use of the device. 

Using the PECs from section 6 and the above PNECs (Table 28), both based on the organotin chlorides, risk ratios (PEC/PNEC) can be derived for each of the identified uses of organotins these are summarized in Table 29. Regional PEC/PNEC ratios are given in Table 30. 

Risk Ratio—The ratio of the risk among persons with specific risk factors compared to the risk among persons without risk factors. A risk ratio greater than 1 indicates greater risk of disease in the exposed group compared to the unexposed. 

Epinephrine has a narrow benefit-to-risk ratio. Along with its therapeutic effects, when administered in recommended doses by any route, it potentially causes transient anxiety, fear, restlessness, palpitations, pallor, tremor, and headache. Although usually perceived as adverse effects, such symptoms indicate that a pharmacologically active dose of the medication has been absorbed. The desirable pharmacologic effects of epinephrine cannot be separated from the undesirable pharmacologic effects [10]. 

In anaphylaxis, epinephrine appears to have an optimal benefit-to-risk ratio when it is administered promptly by intramuscular injection [1-6]. 

The European/Australian Stroke Prevention in Reversible Ischaemia Trial (ESPRIT) confirmed the finding of ESPS 2, showing that the combination of aspirin and dipyridamole is more effective than aspirin alone in the prevention of new vascular events in patients with nondisabling cerebral ischaemia of presumed arterial origin. Adding the ESPRIT data to the meta-analysis of previous trials resulted in an overall risk ratio for the composite of vascular death, stroke, or MI of 0.82 (95% Cl 0.74-0.91). 

Table 13.1. Comparison of selected adverse event risk ratios during treatment (all patients who received levormeloxifene are combined vs. placebo) (from Goldstein and Nanavati 2002)...

Usually, the main purpose of meta-analysis is quantitative. The goal is to develop better overall estimates of the degree of benefit achieved by specific exposure and dosing techniques, based on the combining (pooling) of estimates found in the existing studies of the interventions. This type of meta-analysis is sometimes called a pooled analysis (Gerbarg and Horwitz, 1988) because the analysts pool the observations of many studies and then calculate parameters such as risk ratios or odds ratios from the pooled data. 

It is insufficient to define the MAP simply in terms of the drug works and seems to be safe. The acceptable benefit risk ratio will depend greatly on the seriousness of the target disease and the availability of other treatments. 

The proposed review of PER in the United Kingdom, already considered necessary, was to correspond to the requirements under European Directives. These Directives required that throughout the Community proprietary medicinal products granted licences before 22 November 1976 should be reviewed by 20 May 1990. Indeed, the United Kingdom was among the first to complete this review on time. This review eliminated from the market all medicinal products that were released for clinical use previously without scrutiny and that were ineffective, imsafe or that had an unacceptable benefit to risk ratio. 

In contrast, FDA officials have contended that the agency is more willing to admit (and leave) drugs on the market than other national authorities. They assert that the FDA can do so because it has been proactive in developing programmes to manage the known risks, when a drug with a narrow benefit/risk ratio comes up for approval. 

Risk ratio greater than 1.0 among hits at all hit levels. Risk ratio equals the percent of hits listing the ADR divided by the baseline percentage. 

The prolonged administration often leads to the development of a positive antinuclear antibody (ANA) test, with or without symptoms of a lupus erythematosus-like syndrome. If a positive ANA titer develops, assess the benefit/risk ratio related to continued procainamide therapy. 

Evidence-based pharmacotherapy provides a succinct appreciation of the benefits of a drug, but rarely takes into account the patient s quality of life. Eor instance, intensive statin therapy is recommended because it reduces the incidence of cardiovascular death (odds ratio 0.86), myocardial infarction (odds ratio 0.84), and stroke (odds ratio 0.82) however, the increased risks for any adverse event (odds ratio 1.44), for abnormalities on liver function testing (odds ratio 4.48), for elevations in CK (odds ratio 9.97) and for adverse events requiring discontinuation of therapy (odds ratio 1.28) are less often taken into account by the prescriber. This example emphasises that individualisation is of the utmost importance to keep an acceptable benefit/risk ratio (Clin Ther 2007 29 253-60). The benefits of evidence-based pharmacotherapy may be obtained whenever concordance/compliance of the patient is adequate. However, concordance rate is slightly higher than 30% for chronic conditions, such as hypertension (Curr Hypertens Rep 2007 9 184-9), indicating that the patient has to be educated about the use of drugs, and therapy has to be individualised. 

El-Khayat R, Baldwin DS (1998) Antipsychotic drugs for non-psychotic patients assessment of the benefit/risk ratio in generalized anxiety disorder. J Psychopharmacol 12 323-329 Elman MJ, Sugar J, Fiscella R, Deutsch TA, Noth J, Nyberg M, Packo K, Anderson RJ (1998) The effect of propranolol versus placebo on resident surgical performance. Trans Am... 

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