A study shows more aggressive treatment may be needed for a large number of patients taking statin medications, and that treatment could help reduce cases of cardiovascular disease, the leading cause of death in the US.
High levels of low-density lipoprotein cholesterol (LDL-C), sometimes called “bad” cholesterol, are associated with cardiovascular disease. The new research finds a third of people in Indiana are not reaching a safe level of LDL-C while taking statin medications.
The collaboration by researchers at Merck, known as MSD outside the US and Canada, Regenstrief Institute, Indiana University School of Medicine and the University of North Carolina at Chapel Hill looked at electronic health records in the state of Indiana and found that about a third of people taking statins did not reach a therapeutic level of LDL-C. The researchers say these patients seem to be at an increased risk for cardiovascular disease events like heart attack and stroke and may represent an important and potentially preventable burden on health care costs.
Principal investigator and cardiologist from the University of North Carolina, Dr Ross Simpson, Jr, says this study adds to the body of evidence that many people are not getting adequate treatment for high cholesterol. “This provides an opportunity for improving care, whether it’s with higher doses, more aggressive treatments or new therapies.”
The study set out to determine how many patients on statins achieved the therapeutic threshold of LDL-C, estimate the number of potentially avoidable cardiovascular disease events if that threshold were reached, and forecast potential health care cost savings.
The team examined electronic health records from the Indiana Network for Patient Care for 86,000 patients who started taking statins. They found 33.7% of those people did not reach therapeutic levels of LDL-C (< 100 mg per dL) after six to 18 months on therapy. In a high-risk subgroup, 58% did not reach a more stringent LDL-C standard (< 70 mg per dL) commonly applied to them. Among patients who regularly took their statin therapy as directed, 24% of the full population and 51% of the high-risk subgroup did not meet their respective thresholds.
“Statins are first-line therapy in patients with hyperlipidemia because they clearly prevent cardiovascular events,” said Dr Robert Boggs, director of outcomes research, Centre for Observational and Real-world Evidence (CORE) at Merck. “This study demonstrates not only the value of helping patients adhere to their statin therapy but, in some cases, the need for additional treatments to get their LDL-cholesterol down to reasonable thresholds.”
Researchers estimated that reducing the LDL-C levels of the subgroup who were above the threshold could avoid 1,173 cardiovascular disease events. If those patients were given the necessary treatments to lower their bad cholesterol levels to the recommended threshold, the reduced risk would save about $1,455 per person.
This study is fairly unique because researchers were able to analyse the records of patients from the entire state of Indiana. Therefore, the results are more representative of the state’s population and may have greater public health implications than studies conducted with, for instance, patients of a single health system.
“The presence of the health information exchange in Indiana was a crucial factor in being able to do this study,” said Dr Titus Schleyer, the first author on the paper and a research scientist at Regenstrief Institute. “The Indiana Network for Patient Care allows us to gather health data from large numbers of people on an ongoing basis. While that information is a by-product of going to the doctor, it is tremendously useful for research.”
This study provides evidence to health insurance agencies and physicians that there are opportunities to improve care and reduce the cost of treating cardiovascular events with more aggressive therapy for bad cholesterol. Schleyer hopes information from studies like these could eventually be used to identify populations at risk and help prevent negative outcomes.
In addition to his appointment as a Regenstrief Institute investigator, Schleyer is a faculty member of Indiana University School of Medicine. The study team also included Dr Siu Hui, Dr Jane Wang, Dr Zuoyi Zhang and Dr Jarod Baker from Regenstrief Institute.
Funding support for this study was provided by Merck.
Background: Statins are effective in helping prevent cardiovascular disease (CVD). However, studies suggest that only 20%-64% of patients taking statins achieve reasonable low-density lipoprotein cholesterol (LDL-C) thresholds. On-treatment levels of LDL-C remain a key predictor of residual CVD event risk.
Objectives: To (a) determine how many patients on statins achieved the therapeutic threshold of LDL-C < 100 mg per dL (general cohort) and < 70 mg per dL (secondary prevention cohort, or subcohort, with preexisting CVD); (b) estimate the number of potentially avoidable CVD events if the threshold were reached; and (c) forecast potential cost savings. Methods: A retrospective, longitudinal cohort study using electronic health record data from the Indiana Network for Patient Care (INPC) was conducted. The INPC provides comprehensive information about patients in Indiana across health care organizations and care settings. Patients were aged > 45 years and seen between January 1, 2012, and October 31, 2016 (ensuring study of contemporary practice), were statin-naive for 12 months before the index date of initiating statin therapy, and had an LDL-C value recorded 6-18 months after the index date. Subsequent to descriptive cohort analysis, the theoretical CVD risk reduction achievable by reaching the threshold was calculated using Framingham Risk Score and Cholesterol Treatment Trialists’ Collaboration formulas. Estimated potential cost savings used published first-year costs of CVD events, adjusted for inflation and discounted to the present day.
Results: Of the 89,267 patients initiating statins, 30,083 (33.7%) did not achieve the LDL-C threshold (subcohort: 58.1%). In both groups, not achieving the threshold was associated with patients who were female, black, and those who had reduced medication adherence. Higher levels of preventive aspirin use and antihypertensive treatment were associated with threshold achievement. In both cohorts, approximately 64% of patients above the threshold were within 30 mg per dL of the respective threshold. Adherence to statin therapy regimen, judged by a medication possession ratio of ≥ 80%, was 57.4% in the general cohort and 56.7% in the subcohort. Of the patients who adhered to therapy, 23.7% of the general cohort and 50.5% of the subcohort had LDL-C levels that did not meet the threshold. 10-year CVD event risk in the at-or-above threshold group was 22.78% (SD = 17.24%) in the general cohort and 29.56% (SD = 18.19%) in the subcohort. By reducing LDL-C to the threshold, a potential relative risk reduction of 14.8% in the general cohort could avoid 1,173 CVD events over 10 years (subcohort: 15.7% and 454 events). Given first-year inpatient and follow-up costs of $37,300 per CVD event, this risk reduction could save about $1,455 per patient treated to reach the threshold (subcohort: $1,902; 2017 U.S. dollars) over a 10-year period.
Conclusions: Across multiple health care systems in Indiana, between 34% (general cohort) and 58% (secondary prevention cohort) of patients treated with statins did not achieve therapeutic LDL-C thresholds. Based on current CVD event risk and cost projections, such patients seem to be at increased risk and may represent an important and potentially preventable burden on health care costs.
Titus Schleyer, Siu Hui, Jane Wang, Zuoyi Zhang, Kristina Knapp, Jarod Baker, Monica Chase, Robert Boggs, Ross J Simpson