Can you calculate NNT with hazard ratio?

Asked by: Juan Heredia

How do you calculate hazard ratio NNT?

NNT is simply calculated as the reciprocal of the ARR, which is the difference between the absolute risk of an event in the intervention group (treatment A) and the absolute risk in the control group (B).

How do you calculate the number needed to harm a hazard ratio?

The reported hazard ratio was h=0.72 with 95% confidence interval 0.55 to 0.92. The number needed to treat at 2 years is thus estimated as 1/(0.33^0.72–0.33)=8.32. The 95% confidence interval for the number needed to treat is obtained from equation 1 setting h to 0.55 and then 0.92, giving 4.7 to 32.7.

How do you interpret the hazard ratio for overall survival?

If the hazard ratio is > 1, it indicates that the treatment group has a shorter survival than the control referenced group, and if it is < 1, it indicates that the group of interest is less likely to have a shorter time to the event than the reference group. The ratio does not quantify the magnitude of the difference.

How do you calculate relative risk reduction from hazard ratio?

Relative Risk Reduction = |EER-CER|/CER



For example, say the disease A occurs in 1 in 100,000 people but taking drug X reduces the incidence to 1 in 10,000,000. The absolute risk of disease is 0.001%. The relative risk is 0.00001/0.001 = 0.1 and the relative risk reduction is 1- 0.1 = .

Are hazard ratio and relative risk the same?

Hazard ratio is frequently interpreted as risk ratio (or relative risk), but they are not technically the same.

What is NNT and ADR?

Every doctor needs to give his/her patients just two bits of important information before they embark on any drug treatment. The drug’s NNT and ADR (adverse drug reaction) risk. None of the drugs that we prescribe helps every patient. It is a lottery. ‘number needed to treat’ (NNT) is a statistical term.

Can NNT and NNH be the same?

NNT and NNH



Number needed to harm is similar to number Number needed to treat (NNT); While NNH is a measure of harm or adverse effects, NNT is a measure of how many patients needed to be treated in order for one to benefit. Together, these statistics help physicians decide on courses of treatment.

How do you calculate number needed to harm NNH?

From this the value known as the number needed to harm (NNH) can be calculated by dividing 1 by the absolute risk increase, and again multiplying by 100 when the ARI is expressed as a percentage. NNH shows how many individuals would need to be treated with the drug in order for 1 to show the harmful effect.

What is a good NNT number?

As a general rule of thumb, an NNT of 5 or under for treating a symptomatic condition is usually considered to be acceptable and in some cases even NNTs below 10. Below are some NNTs for routine medical interventions. Note that the various tables below offer additional context to the numbers.

What does a hazard ratio of 0.6 mean?

If an effective treatment reduces the hazard of death by 40% (i.e., results in an HR of 0.60), the hazard is only 0.6% per day, meaning the chances of surviving 1 day with this diagnosis are 99.4%, the chances of surviving 2 days are 0.994 × 0.994 = 0.988, and so forth.

What does a hazard ratio of 0.33 mean?

A hazard ratio of 1 means that both groups (treatment and control) are experiencing an equal number of events at any point in time. A hazard ratio of 0.333 tells you that the hazard rate in the treatment group is one third of that in the control group.

What does a hazard ratio of 1.2 mean?

This would be described in what researchers call a “hazard ratio.” The magic number would be 1.2, meaning that patients do 20% better on remdesivir than placebo. If the median time to event can be calculated, it is also straight forward to list the median time to event.

What does a hazard ratio of 0.05 mean?

Conventionally it is accepted that if this probability is less than 0.05 (p<0.05) then the differences are statistically significant and the null hypothesis can be rejected – the treatments are not the same.

What does a hazard ratio of 0.25 mean?

Interpretation of a Hazard Ratio. HR (E vs C) = 0.75 for an overall survival end point. This means on average, under an exponential distribution, approximately • a 25% lower risk of death (25% as 1 − 0.75 = 0.25)

What does a hazard ratio of 1.6 mean?

It means that the probability. That an individual at a small period of time will call T has an event at that particular time.

Do hazard ratios have P values?

Haz- ard ratios are obtained as point estimates for the measure of increased or decreased risk of the outcome associated with each predictor variable. Each estimated hazard ratio will have a corresponding confidence interval and P value.

What does p-value with hazard ratio mean?

A P-value is a ratio between the effect size (in this case, the hazard ratio) and the precision with which it has been measured. A small effect, measured precisely, is likely to be statistically significant, while a large effect measured imprecisely is likely not to be.

What does a hazard ratio of 0.48 mean?

A hazard ratio of 0.48 means that patients in the experimental group had half the risk of experiencing a bad outcome (progression) than patients in the comparison group did. The hazard ratio includes a confidence interval (CI) at the end of the value because it is an estimate.

What does a hazard ratio of 1.1 mean?

Broadly speaking, a hazard ratio of 1.1 indicates that one group has 1.1 times the risk of the event of the group it is being compared against.

What does a hazard ratio of 2 mean?

The hazard ratio and survival



Hazard ratios are often treated as a ratio of death probabilities. For example, a hazard ratio of 2 is thought to mean that a group has twice the chance of dying than a comparison group.

How do you convert hazard ratio to odds ratio?

OR = ((1 – p) * RR) / (1 – RR * p). Thus, for instance, a RR of 2.0 with a p of 0.1 would lead to an OR of 2.25, whereas if p increases to 0.2 it would lead to an OR of 2.67. But RR ≠ hazard ratio.

How do I calculate hazard ratio in Excel?

For two survival distributions, the ratio of the failure rates is called the hazard ratio (aka the relative risk or risk ratio), i.e. For Example 1 of Log-Rank Test, the failure rates of trials A and B are 12/9.828 = 1.221 and 8/10.172 = . 786. Thus the hazard ratio h (of A to B) is 1.55.