Association of Frequency of Lipid Testing With Changes in Lipid-Lowering Therapy

Statins are among the most commonly prescribed medications in the United States and are effective for prevention of cardiovascular events.¹ Recent lipid management guidelines no longer recommend treating to a target low-density lipoprotein (LDL) level and instead favor a risk-assessment approach.² Though there is insufficient data to show that monitoring lipids leads to meaningful improvements in clinical outcomes or adherence to pharmacologic treatment,³ US guidelines recommend lipid monitoring every 3 to 12 months, whereas European guidelines advise annual lipid monitoring among patients receiving therapy.^2,4,5 This study aimed to understand clinician rationale for ordering monitoring lipid panels among patients on statin therapy and to determine how often treatment changes occur as a result of testing.

The study protocol was approved by the Colorado Multiple institutional review board, and informed consent waiver was granted because all data were collected as part of usual patient care. We identified 4945 patients aged 40 to 79 years at the University of Colorado Hospital, who had been seen by a primary care physician in the past 12 months and had been recieving statin therapy for longer than 3 years. We reviewed all medical records between November 1, 2012, and November 1, 2015, from a random sample of 210 of these patients. Clinician rationale for ordering lipid testing and changes to lipid lowering therapy in the following 12 months were assessed.

Of 634 monitoring lipid panels performed over the 3-year study period, the mean (SD) number of lipid panels per patient was 3.01 (1.60) (range, 0-11). Mean age of the participant population was 64.7 years; 137 (65%) patients were white; mean 10-year atherosclerotic cardiovascular disease (ASCVD) risk was 14.2%; and all patients were on statin therapy. Comorbidities included diabetes (77 [37%]), hypertension (150 [71%]), and current tobacco use (22 [11%]). Primary prevention of cardiovascular events was the indication for statin therapy in 165 (79%) patients. Rationale for ordering lipid tests was available in 183 (87%) of the medical charts reviewed. The most commonly reported indications were monitoring (146 [70%]), follow-up of statin dosage change (17 [8%]), and patient request (9 [4%]). Other rationale for lipid testing and representative quotes from ordering clinicians are reported in Table 1.

Most monitoring of lipid profiles did not result in a change in therapy (548 of 634 lipid tests [86%]). Changes following a lipid test are shown in Table 2 and were uncommon irrespective of lipid-lowering indication.

Our data indicate that most monitoring lipid tests result in no change in lipid-lowering therapy. The high frequency of testing may reflect adherence to current guidelines, practice habits stemming from the historic treat-to-target approach, patient expectations, and a perception that lipid testing may allow for monitoring adherence to therapy.

We suspect that the rarity of treatment changes was owing to the dearth of data supporting LDL or triglyceride targets, as well as guidelines that now advocate a risk-stratification approach though still recommend routine lipid monitoring.^2,4-6 Because the key clinical decision has shifted from treatment to an LDL goal to mitigating cardiovascular risk, the utility of lipid monitoring may be diminished.

An important strength of our study is the rigorous review of patient medical charts, which permitted insights into clinician rationale for ordering monitoring lipid panels in patients already recieving treatment. Study limitations include its single center design and data collection was limited to the data available via medical chart review. In addition, our sample had a high proportion of patients recieving statins for primary prevention, and may not be applicable to populations with higher rates of known atherosclerotic cardiovascular disease or use of nonstatin medications, such as PCSK9 inhibitors.

Our study raises the question of the utility of routine lipid monitoring. The appropriate frequency of lipid testing is uncertain. As attention to value-based care increases nationally, this may be a target for cost savings and warrants further study.

Corresponding Author: Karen Stenehjem, MD, Division of General Internal Medicine, University of Colorado School of Medicine, 3162 S Metropolitan Way, Salt Lake City, UT 84019 (karen.stenehjem@gmail.com).

Accepted for Publication: June 23, 2017.

Published Online: August 28, 2017. doi:10.1001/jamainternmed.2017.3954

Author Contributions: Dr Stenehjem had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Stenehjem, Combs.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Stenehjem, Combs.

Critical revision of the manuscript for important intellectual content: Heeren, Pulver, Combs.

Statistical analysis: Stenehjem, Heeren.

Administrative, technical, or material support: Stenehjem, Pulver, Combs.

Study supervision: Combs.

Conflict of Interest Disclosures: None reported.