What is an acceptable non-inferiority margin?
In order to demonstrate non-inferiority, the recommended approach is to pre-specify a margin of non- inferiority in the protocol. After study completion, a two-sided 95% confidence interval (or one-sided 97.5% interval) for the true difference between the two agents will be constructed.
What is non-inferiority clinical trial?
in-FEER-ee-OR-ih-tee TRY-ul) A study that tests whether a new treatment is not worse than an active treatment it is being compared to. Non-inferiority trials are sometimes done when a placebo (an inactive treatment) cannot be used.
What is a non-inferiority p value?
In non-inferiority trials, investigators are interested in whether new treatment is non-inferior to standard treatment. Only the non-inferior margin to the right side of unity on the forest plot is specified. Therefore, the significance level is usually set as a one-sided p value of 0.025.
How do you calculate sample size for non-inferiority trials?
To calculate the sample size, we can use Table 5, which gives calculated sample sizes for various standardised non-inferiority limits (δNI = dNI/σ). The percentage mean differences are given for the case where it is anticipated that there may be a non-zero difference between treatments, that is, µA−µB = 0.
How do you analyze non-inferiority?
Noninferiority trials are used to assess whether the effect of a new drug is not worse than an active comparator by more than a noninferiority margin. If the difference between the new drug and the active comparator does not exceed this prespecified margin, noninferiority can be concluded.
How do you interpret non-inferiority results?
If the upper bound of the 95% CI falls below the noninferiority margin, ƒ, then the trial has failed to demonstrate noninferiority and has in fact demonstrated inferiority (Figure 3). If the 95% CI crosses ƒ, then the study result is indeterminate.
How do you prove non-inferiority?
Traditional statistical methods were designed to demonstrate differences and cannot easily show that a new treatment is similar to an older one. Non-inferiority can be shown if the difference between two treatments does not cross a predefined inferiority margin.
Can you show superiority in a non-inferiority trial?
In a non-inferiority trial, the focus is on the lower bound margin, what happens at the upper end is not of primary concern in this type of trial design. One can also declare superiority in a non-inferiority trial if the lower limit of CI of the new treatment is above the non-inferiority margin and above zero.
How can I calculate sample size?
How to Calculate Sample Size
- Determine the population size (if known).
- Determine the confidence interval.
- Determine the confidence level.
- Determine the standard deviation (a standard deviation of 0.5 is a safe choice where the figure is unknown)
- Convert the confidence level into a Z-Score.
How do you calculate sample size for an intervention study?
The following simple formula would be used for calculating the adequate sample size in prevalence study (4); n = Z 2 P ( 1 – P ) d 2 Where n is the sample size, Z is the statistic corresponding to level of confidence, P is expected prevalence (that can be obtained from same studies or a pilot study conducted by the …
What is the main advantage of non-inferiority trials when testing a new drug?
Non-inferiority clinical trials are being performed with an increasing frequency now-a-days, because it helps in finding a new treatment that have approximately the same efficacy, but may offer other benefits such as better safety profile.
Can you determine superiority from a non-inferiority trial?
What is the benefit of a non-inferiority trial?
Can a non-inferiority trial show superiority?
How do you demonstrate non-inferiority?
Non-inferiority can be shown if the difference between two treatments does not cross a predefined inferiority margin. Non-inferiority studies need to be carefully planned; failings in the design of the study may make accepting an inferior treatment more likely.
How can you differentiate between superiority and non-inferiority clinical trial?
In comparison studies with a current therapy, non-inferiority is used to demonstrate that the new therapy provides at least the same benefit to the patient. Superiority trials are always used when comparisons are made to placebo or vehicle treatments.
What are 3 factors that determine sample size?
In general, three or four factors must be known or estimated to calculate sample size: (1) the effect size (usually the difference between 2 groups); (2) the population standard deviation (for continuous data); (3) the desired power of the experiment to detect the postulated effect; and (4) the significance level.
What is a good sample size?
A good maximum sample size is usually 10% as long as it does not exceed 1000. A good maximum sample size is usually around 10% of the population, as long as this does not exceed 1000. For example, in a population of 5000, 10% would be 500. In a population of 200,000, 10% would be 20,000.
What is the formula for determining sample size?
How to Find a Sample Size Given a Confidence Level and Width (unknown population standard deviation)
- za/2: Divide the confidence level by two, and look that area up in the z-table: .95 / 2 = 0.475.
- E (margin of error): Divide the given width by 2. 6% / 2.
- : use the given percentage. 41% = 0.41.
- : subtract. from 1.
What is a good sample size for a medical study?
Initial trials might require a total of around 20-80 patients. In phase II trials that investigate the treatment effects, seldom require more than 100-200 patients (8).
Is non-inferiority the same as equivalence?
Non-inferiority trials aim to show that the new drug is no worse than standard treatment. Equivalence trials aim to show the new treatment is no better and no worse. An equivalence boundary should be set before the trial. This is the definition of what would be the minimum important difference between the treatments.
Can you claim superiority in a non-inferiority trial?
What are the 5 factors affecting sample selection?
Healthcare and patient satisfaction surveys – 5 factors to consider when selecting patient sample size
- Diversity of Target Population.
- Degree of Precision.
- Sample Design & Method.
- Budget.
- Number of Break Variables for Analysis.
What are the 4 ways to determine the sample size?
How to Calculate Sample Size
- Determine the population size (if known).
- Determine the confidence interval.
- Determine the confidence level.
- Determine the standard deviation (a standard deviation of 0.5 is a safe choice where the figure is unknown)
- Convert the confidence level into a Z-Score.
Why is 30 the minimum sample size?
A sample size of 30 often increases the confidence interval of your population data set enough to warrant assertions against your findings. 4 The higher your sample size, the more likely the sample will be representative of your population set.