When should we perform lipid screening in low-risk women?
There are conflicting guidelines and opinions about at what age lipid screening should be routinely performed in adults. The United States Preventive Services Task Force (USPSTF) 2016 guidelines found “insufficient evidence that screening for dyslipidemia before age 40 years has an effect on either short- or longer-term cardiovascular outcomes.”6 Therefore, the USPSTF “recommends neither for nor against screening for dyslipidemia in this age group,” and instead encourages “clinicians to use their clinical judgment for [these] patients.”6
A common practice is to obtain a baseline lipid profile at the time of initiation of care with an adult primary care practitioner, if the patient was not previously screened, and to then determine subsequent testing based on these results and the patient’s risk factors for cardiovascular disease. For patients with normal lipid screening results and lower cardiovascular risk factors (no hypertension, diabetes mellitus, cigarette smoking, family history of premature coronary heart disease), experts suggest follow-up lipid screening be performed in men at age 35 and in women at age 45.7 Therefore, for this patient who had essentially a normal lipid panel a year prior, she should not have required repeat lipid testing until she is age 45.
As for how frequently subsequent lipid testing should be performed, the Centers for Disease Control and Prevention states, “most healthy adults should have their cholesterol checked every 4 to 6 years.”8 Those taking lipid-lowering medications or those with risk factors such as heart disease, diabetes, or concerning family history should have their cholesterol checked more frequently. If patients are near a threshold for treatment, some experts suggest repeating measurements every 3 years, but even in these settings, annual testing would be considered excessive.7
A standard lipid panel screen includes total cholesterol, LDL, HDL, and triglycerides. While a variety of assays have been developed that subfractionate lipoprotein particles based on size, density, or charge, these tests do not add value for low-risk patient screening and should only be used on an individualized basis for selected intermediate to high-risk patients. The American Society for Clinical Pathology released a Choosing Wisely recommendation that advises, “Do not routinely order expanded lipid panels (particle sizing, nuclear magnetic resonance) as screening tests for cardiovascular disease.”9
Do lipid panels need to be fasting?
For adults who are not taking lipid-lowering therapy, measurement of either a fasting or a nonfasting plasma lipid profile is effective for documenting baseline LDL and estimating cardiovascular risk.1 In other words, nonfasting lipid testing is appropriate for most low-risk screening. Nonfasting testing generally is more convenient for patients; however, nonfasting lipid panels could result in elevated triglyceride levels. If an initial nonfasting lipid profile reveals a triglyceride level of 400 mg/dL or higher, then a repeat lipid profile in the fasting state should be performed for assessment of fasting triglyceride levels and baseline LDL.1 Some patients may prefer to simply get a fasting lipid panel initially so that they do not run the risk of having to return for a second test, especially if they are at increased risk for high triglyceride levels (ie, if they are obese, have diabetes, or are taking medications such as steroids, which can increase triglyceride levels).
The bottom line
Some patients receive primary care directly from their gynecologist, and thus it is important for women’s health clinicians to be aware of appropriate cholesterol screening practices. While lipid panels may commonly be ordered routinely as part of annual health check-ups, the evidence suggests that this is an unnecessary practice that contributes to wasteful health spending at both individual and system levels; it also is an avoidable inconvenience for patients. It is unclear when lipid screening should be initiated for adult patients, but it seems reasonable to check baseline levels for a new patient who has not previously been screened. In low-risk patients with normal lipid panel levels, experts recommend initiating retesting at age 45 for women and obtaining repeat lipid levels no more than every 4 to 6 years. For most patients, nonfasting lipid levels will suffice for screening. Avoiding common unnecessary testing is an effective way to improve value for patients. ●