Lipid Testing Trends in the US Before and After the Release of the 2013 Cholesterol Treatment Guidelines

Abstract

Background

The 2013 ACC/AHA cholesterol treatment guidelines removed the recommendation to treat adults at risk of cardiovascular disease to goal levels of low-density lipoprotein cholesterol (LDL-C). We anticipated that the frequency of LDL-C testing in clinical practice would decline as a result. To test this hypothesis, we evaluated the frequency of LDL-C testing before and after the guideline release.

Methods

We used the MarketScan^® Commercial and Medicare Supplemental claims data (1/1/2007–12/31/2016) to identify four cohorts: 1) statin initiators (any intensity), 2) high-intensity statin initiators, 3) ezetimibe initiators, and 4) patients at very high cardiovascular risk (≥2 hospitalizations for myocardial infarction or ischemic stroke, with prevalent statin use). Rates of LDL-C testing by calendar year quarter were estimated for each cohort. To estimate rates in the absence of a guideline change, we fit a time-series model to the pre-guideline rates and extrapolated to the post-guideline period, adjusting for covariates, seasonality, and time trend.

Results

Pre- and post-guideline rates (LDL-C tests per 1,000 persons per quarter) were 248 and 235, respectively, for 3.9 million statin initiators; 263 and 246 for 1.3 million high-intensity statin initiators; 277 and 261 for 323,544 ezetimibe initiators; and 180 and 158 for 42,108 very high-risk patients. For all cohorts, observed post-guideline rates were similar to model-predicted rates. On average, the difference between observed and predicted rates was 8.5 for patients initiating any statin; 2.6 for patients initiating a high-intensity statin; 11.4 for patients initiating ezetimibe, and −0.5 for high-risk patients.

Conclusion

We observed no discernible impact of the release of the 2013 ACC/AHA guidelines on LDL-C testing rates. Rather, there was a gradual decline in testing rates starting prior to the guideline change and continuing throughout the study period. Our findings suggest that the guidelines had little to no impact on use of LDL-C testing.

Keywords:

• low-density lipoprotein cholesterol
• statin
• ezetimibe
• cardiovascular disease
• guideline adherence
• database
• epidemiology

Acknowledgments

Portions of this study were presented at the 2019 American Heart Association Scientific Sessions as a poster presentation with interim findings. The poster’s abstract was published in “Abstracts from the American Heart Association’s 2019 Scientific Sessions” in Circulation: https://www.ahajournals.org/doi/abs/10.1161/circ.140.suppl_1.13025.

Data Sharing Statement

Study data are available for purchase from IBM Corp. Readers can request R code from the corresponding author.

Ethics Approval

This study was approved by the Chesapeake Institutional Review Board.

Author Contributions

All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; agreed to submit to the current journal; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.

Disclosure

S.N. Levintow is an employee and owns stock in NoviSci, Inc. and received doctoral training support from the National Institute on Drug Abuse (R36 DA045569), National Institute of Allergy and Infectious Disease (T32 AI070114-10), and ViiV Healthcare (pre-doctoral fellowship). S.R. Reading is an employee and owns stock in Amgen, Inc. B.C. Saul is an employee and owns stock in NoviSci, Inc. Y. Yu is an employee and owns stock in NoviSci, Inc. D. Reams is an employee and owns stock in NoviSci, Inc. L.J. McGrath is an employee and owns stock in NoviSci, Inc. K. Philip is an employee and owns stock in Amgen, Inc. P.J. Dluzniewski is an employee and owns stock in Amgen, Inc. M.A. Brookhart is an employee and owns stock in NoviSci, Inc and in the last three years has served as a scientific advisor to AbbVie, Amgen, the Brigham and Women’s Hospital, Genentech, Gilead, Merck, Rockwell Medical and Vertex. He also reports grants from BlueCross BlueShield of North Carolina and North Carolina Department of Health and Human Services. The authors report no other conflicts of interest in this work.

Additional information

Funding

This work was funded by Amgen.