Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [number-needed-to-treat]

NNT is a common measure of effect size in the biomedical sciences. It is the number of patients that you expect to have to treat in order to cure one patient. Also use this tag for questions about the number needed to harm.

The number needed to treat (abreviated NNT) is a common measure of effect size in the biomedical sciences. The NNT is the number of patients that you expect to have to treat in order to cure one patient. For example, if a drug cures 10% of patients with a certain disease, you expect to have to administer the drug to ten patients before one of them will be cured.

There is an analogous measure called the number needed to harm, which is the number of patients you can give the treatment to before you expect one of the patients to have a specified side effect.

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What are the problems with number needed to treat (or harm) in observational studies?

I have been asked to comment on the use of NNT (number needed to treat) and NNH (number needed to harm) in observational studies. My intuition doesn't give me any reasons these would be problematic and a brief Google search did not find any,…
Peter Flom
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Two methods to calculate the confidence interval for number needed to treat yield different results

Assume that two drugs were tested. The risk of death for drug 1 is $p_1$ and the risk for drug 2 is $p_2$. We define: Risk difference (RD) $RD=p_1-p_2$ The number needed to treat (NNT) $NNT=1/|RD|$ If we know the estimated RD as RD* and its…
fiona
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Risk difference with patient-years incidence rates

I am aware that you can compute risk differences as the difference of risk between two treatment arms $( (\text{No. events}_1/ N_1) - (\text{No. events}_2 / N_2))$. However, can I estimate the same using patient-years incidence rather than just…
Claudio Laudani
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Reporting significance values for relative risk (RR) and number needed to treat (NNT)

I have calculated the relative risk & number needed to treat using the log-binomial regression model. NNT is calculated as the reciprocal of the marginal difference. Does it make sense to report different p-values for the RR and the NNT?
Megan Moreton
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Absolute risk and NNT from logistic regression

I fitted a Logistic regression with a number of variables, and was asked about the absolute risk (AR) and number needed to treat (NNT) for one of the variable with the outcome. I understand how to calculate them in a 2x2 table, but I am wondering if…
Inji
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Deciding Optimal Cutoff for a Prognostic Index derived from Cox Proportional Hazards

I am planning to develop a prognostic model that would identify a particular group of head neck cancer patients who will do better if chemotherapy is added to standard radiation therapy. The data for the patients in question is derived from a…
Santam
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How to calculate number needed to treat for case-crossover study design?

I'm relatively new to epidemiological methods. I'm trying to assess a program where I have access to administrative data that can be put into a case-crossover study design. I'm trying to assess the financial effectiveness of the program, and came…
Scott White
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How to calculate NNT when it's NOT a clinical trial?

I am working on a revise and resubmit for a journal article. This is an observational, cross-sectional study. We compared endorsements of different behaviors across groups (e.g., 30.1% of Group 1 members endorsed this behavior, a significantly…
Blair Burnette
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Is this NNT calculation correct? Using odds ratio of an RCT study for Remdesivir

In an analysis that used a proportional-odds model with an eight-category ordinal scale, the patients who received remdesivir were found to be more likely than those who received placebo to have clinical improvement at day 15 (odds ratio (OR), 1.5;…
KKW
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How to incorporate the customers leaving (addition of new ones) in the measurement of treatment effectiveness?

Consider I have taken a random sample for forming control group in month of January with sample size 5k and treatment group size being 95k. I am Sending offers to treatment group which are intend to increase the purchasing capacity of the…
Artiga
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