Patients on statins with elevated transaminases: Frequency of follow-up creatine kinase testing and gastroenterology...

To quantify how often creatine kinase (CK) is measured after newly elevated aminotransferases in statin users, and whether absent CK data are associated with gastroenterology (GI) referrals.

Retrospective chart review of adult outpatients on statins with a first alanine/aspartate aminotransferase (ALT/AST) elevation during a 5-year period at a large health system. The primary outcome was CK testing within 30 days; secondary outcomes included CK elevation rate and GI referral within 60 days.

Among 806 eligible patients, 22.8% (184/806) had CK measured within 30 days (median 9 days; IQR 5-17). Of those tested, 15.8% (29/184) had CK above the upper limit of normal (ULN); 3.6% (29/806) of the entire cohort therefore had unrecognized biochemical evidence of muscle injury. None had documented rhabdomyolysis, acute kidney injury or hospitalization. Among patients without timely CK testing (619/806), 4.7% (29/619) were referred to GI within 60 days; this proportion (3.6% of the total cohort) mirrored the fraction with CK elevation, suggesting potentially avoidable hepatic work-ups in the absence of muscle-specific testing.

In routine practice, CK is infrequently measured after new ALT/AST elevations in statin users, yet a non-trivial subset has biochemical myopathy. Reflex CK testing at the first abnormal transaminase could improve diagnostic accuracy and reduce unnecessary GI referrals while preserving effective lipid-lowering therapy. Prospective evaluation of reflex-testing pathways and tailored statin selection/dosing is warranted.