From the Guidelines
CK-MB levels do not need to be routinely checked after initiating statin therapy, and instead, creatine kinase (CK) levels should be measured if a patient on statins develops muscle symptoms, as recommended by the 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults 1.
Rationale for CK Measurement
The 2013 ACC/AHA guideline suggests that baseline measurement of CK is reasonable for individuals believed to be at increased risk for adverse muscle events because of a personal or family history of statin intolerance or muscle disease, clinical presentation, or concomitant drug therapy that might increase the risk of myopathy 1. However, for the general population starting statin therapy, routine CK measurement is not recommended.
CK-MB vs. Total CK
CK-MB is a cardiac-specific isoenzyme of CK that is primarily used to diagnose myocardial infarction, not statin-induced myopathy. For monitoring statin side effects, total CK is the appropriate test, along with liver function tests which should be checked before starting therapy and as clinically indicated thereafter, as stated in the guideline 1. The reason for monitoring CK rather than CK-MB is that statin-induced myopathy affects skeletal muscle, causing elevation in total CK, while CK-MB is more specific to cardiac muscle damage.
Clinical Approach
If a patient develops symptoms suggestive of myopathy, such as muscle pain, tenderness, or weakness, CK levels should be measured promptly. The guideline recommends measuring CK in individuals with muscle symptoms during statin therapy 1. If CK levels are significantly elevated, the statin should be temporarily discontinued to assess whether the symptoms and elevated CK levels resolve. This approach prioritizes the patient's safety and minimizes the risk of severe muscle injury.
From the Research
Checking CKMB Levels After Initiating Statin
- There is no specific guideline on when to check CKMB levels after initiating statin therapy, as the provided studies do not directly address this question.
- However, it is known that statin therapy can cause muscle damage, and CKMB is a marker of muscle damage 2, 3.
- The studies suggest that statin therapy can be safely initiated in patients with high CK levels, and that CK levels may actually decrease after starting statin therapy 3.
- The frequency of checking CKMB levels may depend on the individual patient's risk factors and medical history, as well as the specific statin being used 4, 5.
- It is also important to note that CKMB is not the only marker of muscle damage, and other markers such as creatine kinase (CK) may also be used to monitor muscle damage 2, 3.
- In general, the decision to check CKMB levels after initiating statin therapy should be made on a case-by-case basis, taking into account the individual patient's needs and medical history 5, 6.