Lipid-Lowering Prescription Patterns in Patients With Diabetes Mellitus or Cardiovascular Disease

Abstract

The purpose of this study is to describe lipid-lowering therapy (LLT) prescriptions and low-density lipoprotein cholesterol (LDL-C) monitoring in patients with diabetes mellitus (DM) with or without concomitant cardiovascular disease (CVD). Olmsted County, Minnesota residents with a first-ever diagnosis of DM or CVD (ischemic stroke/transient ischemic attack, myocardial infarction, unstable angina pectoris, or revascularization procedure) between 2005 and 2012 were classified as having DM only, CVD only, or CVD + DM. All LLT prescriptions and LDL-C measurements were obtained for 2 years after diagnosis. A total of 4,186, 2,368, and 724 patients had DM, CVD, and CVD + DM, respectively. Rates of LDL-C measurement were 1.31, 1.66, and 1.88 per person-year and 14%, 32%, and 42% of LDL-C measurements were <70 mg/dl in those with DM, CVD, and CVD + DM. Within 3 months after diagnosis, 47%, 71%, and 78% of patients with DM, CVD, and CVD + DM were prescribed LLT. Most prescriptions were for moderate-intensity statins. Under one-fifth of patients with CVD and CVD + DM were prescribed high-intensity statins. Predictors of high-intensity statin prescriptions included male sex, having CVD or CVD + DM, increasing LDL-C, and LDL-C measured more recently (2012 to 2014 vs before 2012). In conclusion, a large proportion of patients at high CVD risk are not adequately treated with LLT. Despite often being considered a risk equivalent, patients with DM have substantially lower rates of LLT prescriptions and lesser controlled LDL-C than those with CVD or CVD + DM.

Figure 1.

Overall rates (95% confidence interval) of low-density lipoprotein cholesterol measurements before and after index event in patients with diabetes mellitus, cardiovascular disease, and cardiovascular disease with concomitant diabetes mellitus (panel A). Distribution of low-density lipoprotein cholesterol measurements before and after index event in patients with diabetes mellitus, cardiovascular disease, and cardiovascular disease with concomitant diabetes mellitus (panel B). CVD, cardiovascular disease; DM, diabetes mellitus.

Figure 2.

Proportion of patients on any lipid-lowering therapy before and after index event in patients with diabetes mellitus, cardiovascular disease, and cardiovascular disease with concomitant diabetes mellitus. CVD, cardiovascular disease; DM, diabetes mellitus.

Figure 3.

Daily rates of statin use in patients with diabetes mellitus (panel A), cardiovascular disease (panel B), and cardiovascular disease with concomitant diabetes mellitus (panel C). CVD, cardiovascular disease; DM, diabetes mellitus. The daily denominators were adjusted accordingly to account for deaths (n=167, 408, and 152 patients in the diabetes mellitus, cardiovascular disease, and cardiovascular disease + diabetes mellitus groups, respectively) and losses to follow-up (n=165, 41, and 6 patients in the diabetes mellitus, cardiovascular disease, and cardiovascular disease + diabetes mellitus groups, respectively).

Figure 4.

Predictors of high-intensity statin prescriptions among patients with an available baseline low-density lipoprotein cholesterol measurement (defined as a measure within 1 year prior to 30 days after index) and who were not on a high-intensity statin prior to the baseline low-density lipoprotein cholesterol measurement (n=5670). Hazard ratios are adjusted for all other variables in the figure. Low-density lipoprotein cholesterol and year of low-density lipoprotein cholesterol measurement were modeled as time-dependent variables. CHF, chronic heart failure; CI, confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; DM, diabetes mellitus; HR, hazard ratio; LDL-C, low-density lipoprotein cholesterol.