Measures of treatment effect

In Table 8.5, we compare the response rates for the two primary endpoints - disease deterioration and mortality for the Flindle et al. study. What is interesting is that for the mortality endpoint ARR shows less deviation from the null than in the case of disease deterioration, while the converse holds for the RR. This is often regarded as a major defect of the RR as a measure of treatment effect, in that it does... 

Laupacis et al. introduced the number needed to treat (NNT) into the medical literature" as an easily imderstood and useful measure of treatment effect for clinical trials in which the main outcome variable is binary. It has been argued that the NNT is more easily... 

Each trial that is to be included in the meta-analysis will provide a measure of treatment effect (difference). For continuous data this could be the mean response on the active treatment minus the mean response in the placebo arm. Alternatively, for binary data the treatment effect could be captured by the difference in the cure rates, for example, or by the odds ratio. For survival data, the hazard ratio would often be the measure of treatment difference, but equally well it could be the difference in the two-year survival rates. 

Cook RJ, Sackett DL. The number needed to treat. A clinically useful measure of treatment effect. BMJ 1995 310 452-4... 

Mini L, Wang-Weigand S, Zhang J. Ramelteon 8 mg/d versus placebo in patients with chronic insomnia post hoc analysis of a 5-week trial using 50% or greater reduction in latency to persistent sleep as a measure of treatment effect. Clin Ther 2008 30(7) 1316-23. 

Although increases in bone mineral density have been reported at other sites, most of the clinically significant fractures occur in the hip or spine, and these sites have become clinically important measures in the trials. These increases in bone mineral density are an important marker of treatment effects and are related to the benefits found in larger trials of decreased fracture risk. 

Abstract In this chapter we discuss practical techniques and instrumentation used in experimental measurements of kinetic and equilibrium isotope effects. After describing methods to determine IE s on rate constants, brief treatments of mass spectrometry and isotope ratio mass spectrometry, NMR measurements of isotope effects, the use of radio-isotopes, techniques to determine vapor pressure and other equilibrium IE s, and IE s in small angle neutron scattering are presented. 

Patients receiving IFN experience side effects similar to influenza symptoms headache, nausea and tiredness. IFN also decreases red blood cells, white blood cells and platelet counts. A measure of the effectiveness of IFN treatment is the marker called alanine aminotransferase in blood. The normal range is 10-70 U/L. 

It is important when choosing a particular measurement scale to answer a number of questions. Is the choice that is made of clinical relevance How is the endpoint to be measured Can we measure the clinical endpoint directly, or must we choose an indirect approach Is the choice that is made sensitive enough to measure real treatment effects Having collected the information how are we to analyse it Some of these issues are illustrated in the following sections. 

Quantitative Treatment. To obtain a more quantitative measure of the effectiveness, if any, of micelles within the membrane, we recall that for any given concentration of micelles the solubilizate distributes itself in a constant ratio between the micelles and the water. Further, as shown by the straight line of Figure 3, the amount dissolved per unit micellized material is also constant so that the ratio of the concentration of dye in water and in the micelles is a constant, r, that is... 

Reduction of male trap catch is a measure of the effect of pheromone treatment, but the efficacy of the treatment will be influenced by population density. Therefore, it was suggested that not only trap-catch reduction but also a measurement of population based on larval counts be taken into account to obtain an indication of the potential effect of pheromone treatment (11). 

The Doppler shifts of positron annihilations in the sample provide a more sensitive measure of this effect. The plasma treatment oxidizes the rather open structure of HSSQ. Oxygen atoms are included in the network. These have high momentum electrons in p-orbitals, which lower the sharpness of the annihilation line [22],... 

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