Accepted answer
Answer first: mild transaminase elevation is common in this population before any drug is involved, and the usual cause is hepatic steatosis rather than anything acute.
Alanine aminotransferase is relatively liver-specific; aspartate aminotransferase is also present in muscle, heart and red cells. A raised AST with a normal ALT after heavy resistance training is usually muscle, and creatine kinase settles the question.
Relative to absolute, worked
| 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.
Hy's law describes the combination that matters: transaminases above three times the upper limit together with bilirubin above twice the upper limit and no cholestatic explanation. That combination is a signal; isolated mild transaminase elevation is not.
Hy's law and its variants are the standard framework for identifying drug-induced liver injury in trials and are why bilirubin is measured alongside transaminases rather than instead.
Attributing an enzyme change to a compound requires a baseline, and most people asking have not got one.
Get a baseline before you start anything, because it converts an uninterpretable result into an interpretable one for the cost of one blood draw.