Methods

IMPROVE HF is a prospective cohort study designed to characterize management of patients diagnosed with HF or previous myocardial infarction (MI) and left ventricular systolic dysfunction in outpatient cardiology (single specialty or multispecialty) practice settings. The objectives, design, and detailed methods of IMPROVE HF have previously been published. Patients were eligible for enrollment in IMPROVE HF if they were ≥18 years of age, had a primary or secondary diagnosis of HF or previous MI, and moderate-to-severe left ventricular dysfunction (LVD) confirmed qualitatively or by a quantitative LV ejection fraction ≤35%. LV ejection fraction ≤35% was measured by the most recent echocardiogram, nuclear multiple-gated acquisition scan, contrast ventriculogram, or magnetic resonance imaging scan. Patients were excluded from the study cohort if they were not expected to survive ≥12 months due to medical conditions other than HF or if they had undergone heart transplantation surgery. Patients with preserved systolic function or without measurements of LV ejection fraction were also excluded.

Baseline patient data were collected by trained chart abstractors and included demographic and clinical characteristics, medical history, previous treatments, results from laboratories and diagnostic tests, current treatments for HF, and any contraindications or documentation of other reasons (e.g., economic, social, religious reasons, noncompliance, and other reasons for refusal) for not prescribing evidence-based therapies. Self-identified race was collected by administrative or medical staff and abstracted as documented in the medical record. Inter-rater variability of chart reviewers was measured and demonstrated a high level of consistency (kappa = 0.82). In addition, 1.7 automated data-quality checks were performed for each data field and data quality was monitored and reports generated monthly. The registry co-ordinating center is Outcome Sciences, Inc. (Cambridge, Massachusetts). The IMPROVE HF registry and this study are sponsored by Medtronic, Inc. (Minneapolis, Minnesota). The authors are solely responsible for the design and conduct of this study, all study analyses, drafting and editing of the report, and its final contents.

Adjunctive care measurements were developed for HF therapies with American College of Cardiology/American Heart Association class IIA recommendations and for therapies to manage co-morbid conditions or related risks with American College of Cardiology/American Heart Association class I recommendations. The following adjunctive measurements were defined and included in this analysis: pneumococcal vaccination for all patients; HYD/ISDN in Black patients with HF and LVD; statin use for patients with HF and CAD, cerebral or peripheral vascular disease, or LVD after MI; low-density lipoprotein cholesterol levels <100 mg/dl in patients with HF and CAD, cerebral or peripheral vascular disease, or LVD after MI; antiplatelet therapy (aspirin or clopidogrel) for patients with HF and CAD, cerebral or peripheral vascular disease, or LVD after MI; smoking-cessation counseling for current smokers with HF or LVD after MI; conventional blood pressure control to decrease systolic blood pressure to <140 mm Hg in patients with HF or LVD after MI; and newer optimal control of blood pressure to decrease systolic blood pressure <130 mm Hg in patients with HF or LVD after MI.

This analysis included all baseline data entered into the registry from May 2005 to June 2007 and included 15,381 patients from 167 university-affiliated and nonaffiliated cardiology and multispecialty practices located in the United States. A representative sample of medical records was screened to yield an average of 90 eligible patients from each practice using the methods described in the design publication. The present analysis of conformity with adjunctive care metrics was prespecified in the study protocol. Each cardiology practice received previous approval to participate in the study from a local or central institutional review board or a waiver to disclose patient health information in compliance with the Health Insurance Portability and Accountability Act.

All statistical analyses were performed by independent biostatisticians contracted by Outcome Sciences, Inc. Data are reported as the number and frequency of patients currently managed using each of the 7 adjunctive therapies described earlier. Data were analyzed per practice for mean, SD, median, 25th and 75th percentiles of conformity, and 10th and 90th percentiles of conformity for each measurement. Evaluation of conformity included only patients documented to be eligible to receive a specific adjunctive therapy.

Results

Baseline demographic and clinical characteristics of enrolled patients are listed in Table 1 . Mean and median ages were 69 and 70 years, with 71% men, and, where a racial designation was available, 9.1% were Black. Participating practice characteristics are listed in Table 2 . All regions of the country were represented. Most participating practices were nonacademic (64.7%), 41.3% had established HF clinics, and 52.1% reported use of electronic health records.

Rates of adherence to guideline-recommended, adjunctive HF therapies are presented in Figure 1 and Table 3 . The highest conformity was evident for control of systolic blood pressure <140 mm Hg with a mean adherence rate of 82.0% for practices. Remarkably, median practice adherence rates for pneumococcal vaccination and HYD/ISDN were 0.0% for the 2 care measurements and mean practice adherence rates for pneumococcal vaccination and HYD/ISDN therapy were 1.0% and 7.3%, respectively ( Table 3 ).

Proportions of patients receiving each of the adjunctive HF therapies is shown across all practice sites. Statin and antiplatelet therapy was indicated for patients with CAD, cardiovascular disease, or peripheral vascular disease. LDL = low-density lipoprotein; SBP = systolic blood pressure.

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