LDL-C goal attainment among patients newly diagnosed with coronary heart disease or diabetes in a commercial HMO

Abstract

Background: Patients beginning treatment with lipid-modifying drugs should have their serum lipid levels monitored and, if necessary, their drug therapy adjusted to reach and maintain their treatment goals. Patients with coronary heart disease or diabetes are at high risk of coronary events and are particularly important target groups for monitoring and dose adjustment of lipid-modifying drug therapy.

Objective: to determine from administrative claims the rates of lipid testing, treatment with low-density lipoprotein cholesterol (LDL-C)-lowering drug therapy, and LDL-C goal attainment defined as LDL-C < 100 mg per DL in the time period after a new diagnosis of coronary heart disease or diabetes among patients who had not previously received lipid-modifying drug therapy.

Methods: an index date was defined by a new diagnosis of coronary heart disease or diabetes between January 1, 1999 and December 31, 2000, preceded by a 12-month pre-index period without lipid-modifying drug treatment in a commercial health maintenance organization (HMO) database for the southeastern united states. coronary heart disease (CHD) was defined by a diagnosis code for myocardial infarction (International Classification of Diseases, Ninth Edition, Clinical Modification [ICD-9-CM] code 410.xx) or angina/ischemic heart disease (411.xx), or a procedural code for angioplasty (icd-9-cM 36.1x-36.3x; Current Procedural Terminology [CPT] 92980-92984, 92995-92996) or coronary artery bypass graft (icd-9-cM 36.01, 36.02, 36.05, 36.09; CPT 33510-33545). diabetes was identified either by an icd-9-cM diagnosis code 250.xx or a pharmacy claim for an antihyperglycemic medication. Patients were followed in the post-index period until loss of eligibility or a maximum of 42 months (mean = 26 months, range=12-42 months). We calculated the proportion of patients with lipids treated and at LDL-C goal (defined as V < 100 mg per DL) in months 1-6 after the index date. among those not at goal in months 1-6, we estimated the proportion treated to goal in months 7-12 and in month 7 to the end of the post-index period. Logistic regression was used to estimate the odds of goal attainment in months 7-12 and in month 7 to the end of the post-index period among patients who were not at goal in months 1-6.

Results: Laboratory lipid values were available for 4,676 (40.4%) of 11,552 patients who had not previously received lipid-modifying drug therapy in months 1-6 after the index date, of whom 72.7% (n = 3,400) had an LDL-C > or =100 mg per DL (63.5% for CHD and 76.7% for diabetes). Of 1,245 patients tested and treated with lipid-modifying therapy in months 1-6, 485 (39.0%) were at LDL-C goal in months 1-6 (48.2% of CHD and 28.8% of diabetes patients), and 760 (61.0%) were not at LDL-C goal (51.8% of those with CHD and 71.2% of those with diabetes). Goal attainment (cumulative) among those treated improved to 50.1% in months 7-12 and 58.4% in month 7 to the end of the post-index period. Patients not attaining goal in months 1-6, and who continued treatment in months 7-12 and month 13 to the end of the post-index period, had a 48.8% (95% confidence interval [CI], 44.0%-53.6%) predicted probability of attaining their goals. The odds of goal attainment in month 7 to the end of post-index period (among those not at goal in months 1-6) were greater for (a) age e 65 years (odds ratio [or] = 2.45, 95% CI, 1.62-3.72), (b) history of hypertension (or = 1.91, 95% CI, 1.20-3.03), (c) greater number of distinct medications (or = 1.07, 95% CI, 1.01-1.14 per additional medication), (d) months of observation post-index (or = 1.04, 95% CI = 1.01-1.08 per additional month), and (e) months supply of lipid-modifying medication (or = 1.04, 95% CI, 1.01-1.07 per additional month), and were lower for LDL-C > or = 130 mg per DL in months 1-6 (or = 0.53, 95% CI, 0.35-0.82) and a history of dyslipidemia (or = 0.54, 95% CI, 0.35-0.83). The odds of LDL-C goal attainment were not affected by diagnosis (CHD vs. diabetes), gender, statin titration (34% of patients), lipid-modifying drug switching (39% of patients), or treatment with a high-potency LDL-C-lowering drug dosage (one of sufficient strength to reduce LDL-C by > 40%).

Conclusion: of patients receiving lipid testing and lipid drug treatment in the 6 months after an initial diagnosis of CHD or diabetes, 61% were not at the LDL-C goal of < 100 mg per DL. Among those not at LDL-C goal in the first 6 months of treatment, only about half who continued treatment subsequently attained their LDL-C goal, despite statin titration or switching of their lipid-modifying drug therapy.