I have three data points across nine months, which I hope is enough to see a trend.
I would like the arithmetic checked rather than the conclusion asserted.
I have deliberately not used an online calculator because I want to be able to check the result.
Can someone walk through the arithmetic step by step?
A hazard ratio from STEP 5 cannot be converted into an absolute risk reduction without the control-arm event rate, and that rate is the number people forget to carry across. The arithmetic: absolute reduction equals the control event rate minus the treated event rate, and the treated rate is approximately the control rate multiplied by the ratio. A hazard ratio of 0.80 against a 10 per cent control rate is a 2-point absolute reduction and a number needed to treat of 50; the same 0.80 against a 2 per cent control rate is 0.4 points and a number needed to treat of 250. Identical ratio, six-fold difference in what it is worth. Take the control-arm rate and the follow-up duration from the STEP 5 paper, not from the abstract, and do the subtraction yourself.
Answer first: the cardiovascular signal in this class is a reduction in major adverse cardiovascular events in populations already at elevated risk, not a general cardioprotective claim for everyone.
SELECT randomised people with established cardiovascular disease and overweight or obesity but without diabetes to semaglutide 2.4 mg, and reported roughly a twenty per cent relative reduction in the primary composite. The absolute difference over about three years was on the order of one and a half percentage points.
| Quantity | Value | Derivation |
|---|---|---|
| Control-arm event rate | 8.0 % | From the trial table, not the abstract |
| Hazard ratio | 0.80 | Reported |
| Treated event rate | 6.4 % | 8.0 × 0.80 |
| Absolute risk reduction | 1.6 pp | 8.0 − 6.4 |
| Number needed to treat | 63 | 1 ÷ 0.016 |
| Relative risk reduction | 20 % | 1 − 0.80 |
The last two rows describe the same finding. Only one of them is used in headlines.
To be exact about it, cardiovascular composites in this programme are typically cardiovascular death, non-fatal myocardial infarction and non-fatal stroke. When one component drives the result, that is worth knowing, because the components differ in how much they matter.
Population, baseline risk, endpoint definition. In that order, then the effect size.
Aggregated, published test results and vendor ratings built from submitted batches. Methodology stated, dataset browsable, no listing fees.
Browse resultsHeart-rate increase and blood-pressure reduction both occur in this class, in opposite directions, and both are modest. Reading one without the other gives a misleading picture.
A twenty per cent relative reduction on a baseline three-year event rate of eight per cent is an absolute reduction of about one and a half points, which is a number-needed-to-treat somewhere in the region of sixty to seventy. Both framings are true and they read very differently.
Baseline risk decides how much the relative reduction is worth. The same twenty per cent applied to a one per cent annual risk and a five per cent annual risk produce very different absolute numbers.
The caveat that matters: none of this is a reason for anyone to alter cardiovascular medication, and I am not in a position to advise on that.
Read SELECT for the without-diabetes population and the earlier outcome trials for the with-diabetes one. They are not the same result.
Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.