The protocol was approved by 1 central Institutional Review Board (IRB), Schulman Associates IRB Inc. (Cincinnati, OH) prior to patient recruitment. A list of 37,234 physicians [obtained with permission from IMS Health (Westport, CT)] was generated, representing the top 26% of prescribers of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) in 2002. These physicians were responsible for ~55% of all prescriptions for lipid-altering drugs written that year. From this list, a sample of 18,286 physicians (13,555 primary care and 4,731 subspecialists) was randomly selected after stratification by region and specialty. The country was divided into 8 regions and physicians were first classified as primary care (family practice, general practice, and internal medicine) or subspecialist (cardiology and endocrinology) and then invited to participate in the study. Of these, 1,441 (77% primary care, 23% subspecialists) expressed interest, and 401 (83% primary care, 17% subspecialists) completed investigator training and obtained IRB approval.
Eligibility for physician investigators was based on: (1) ability to upload data to the central database by the internet, (2) ability to use the designated central IRB, and (3) availability to attend an investigator meeting for training purposes. The main reason for lack of participation among those who expressed interest was inability to attend one of the 8 regional investigator meetings.
Physicians were asked to enroll 10 consecutive patients who were undergoing treatment for dyslipidemia. Subsequently, because fewer investigators had been recruited than the 500 originally projected, a randomly selected subset of 158 physicians was asked to enroll an additional 10 consecutive patients in order to insure an adequate sample for analysis.
All patients were recruited from the existing practices of participating physicians during a regularly scheduled visit. Patients were selected according to the following criteria: (1) men and women 20 to 75 years of age with dyslipidemia, (2) treatment with diet and/or drug therapy (stable dose) for at least 3 months, and (3) availability of a recent (within 3 months) fasting lipoprotein profile that, in the physician's judgment, was representative of the patient's current status. Patients were excluded for any of the following: a recent history (within the past 3 months) of major trauma, surgery requiring anesthesia, or myocardial infarction; acute infection within the past month requiring antibiotic therapy; a recent (within the past month) or sudden change in their usual diet; women who were pregnant, lactating, or had been pregnant within the previous 6 months; and any secondary cause of dyslipidemia or other condition the physician believed would interfere with evaluation of the patient.
After signing an informed consent form, patients provided a medical history to study personnel, which was entered into a hand-held, personal digital assistant (PDA, Palm Tungsten T; Palm Inc., Milpitas, CA) using a NEPTUNE II data collection program (developed for use in this survey). Specific training on how to ascertain risk factor variables based on the NCEP Third Adult Treatment Panel (ATP III) definitions was provided to all study physicians at regional training meetings. Additional data for CHD risk stratification and assessment of current lipid management were collected at the visit and/or from the patient's chart.
Low-density lipoprotein cholesterol treatment goals were determined for each patient based on the NCEP ATP III definitions: <4.14 mmol/L (160 mg/dL) for patients with 0 to 1 risk factor in the absence of CHD or risk equivalents, <3.37 mmol/L (130 mg/dL) for patients with ≥2 risk factors in the absence of CHD or risk equivalents, and <2.59 mmol/L (100 mg/dL) for patients with CHD or CHD risk equivalents (CHD RE). Major CHD risk factors were defined according to the ATP III guidelines: cigarette smoking; hypertension (blood pressure ≥140/90 mm Hg or on antihypertensive medication); family history of premature CHD; age (men ≥45 years, women ≥55 years); and low high-density lipoprotein cholesterol (HDL-C) (<1.04 mmol/L [40 mg/dL]). HDL-C ≥1.55 mmol/L (60 mg/dL) was counted as a “negative” risk factor.
One LDL-C measurement was used to determine whether a patient's LDL-C treatment goal was achieved. This level was assessed either at the clinic visit when the patient's other CHD risk factor information was collected (immediately prior to or up to 2 weeks afterward), or at a previous visit that occurred within 3 months of that clinic visit.
SAS® version 8.2 (SAS Institute, Cary, NC) was used for all analyses. Means and standard deviations are used to describe continuous variables. Frequency counts and percentages are presented for categorical data. P-values ≤.05 were used to designate statistical significance.
Pearson's χ2 test was used to assess differences between AA and NHW patients in the prevalence of risk factors and frequencies of goal achievement for each risk category and overall. Two-way analysis of variance (ethnicity and risk category) was used to assess differences for continuous variables and t-tests were used to compare values within risk categories.
Multivariate logistic regression was used to produce adjusted odds ratios and 95% confidence intervals for treatment success in AA versus NHW patients. Models included terms for risk category, ethnicity (AA vs NHW [referent]) and other predictors of treatment success. Interaction terms were included in the initial models to investigate whether other predictors modified the relationship between ethnicity and goal achievement. Where no interaction was present at the 5% level of significance, the interaction term was dropped from the model.