Associations of patient knowledge with drug-modifiable cardiovascular risk factor control in coronary artery disease patients with and without diabetes mellitus: results from the cross-sectional KNOW-ABC study

BACKGROUND: Control of major drug-modifiable risk factors for glycated hemoglobin (HbA1c), blood pressure (BP), and low-density lipoprotein cholesterol (LDL-C) remains unsatisfactory in the secondary prevention of coronary artery disease (CAD). We aimed to analyze patient knowledge and attainment of LDL-C, BP, and HbA1c treatment goals and associated factors in German CAD patients with and without diabetes mellitus (DM). METHODS/RESULTS: A total of 204 CAD patients (68 ± 8 years; 75.0% male; 84 with DM (41.2%)) completed a questionnaire assessing their knowledge of LDL-C (< 55 mg/dL), BP (age-adapted), and HbA1c (< 7.0%) treatment goals and levels of information on predefined CAD topics as well as associated factors, including CAD duration, adherence to pharmacotherapy, and physician monitoring of secondary prevention. LDL-C, BP, and HbA1c were measured. The mean duration of CAD was 9.8 ± 8 years. A total of 98.5% reported good adherence to pharmacotherapy. Measurements of LDL-C (81.4%) and HbA1c (71.4%) were predominantly performed by general practitioners. LDL-C goals were attained significantly better in patients with DM (39.3% with vs. 16.7% without DM, p < 0.01). The attainment of BP goals did not differ between patients with and without DM (71.4% vs. 72.5%, p = 0.87). HbA1c goals were attained by 48.8% of DM patients. LDL-C goals were known by 6.0% of patients with vs. 9.2% without DM (p = 0.44), and BP goals were known by 36.9% with vs. 30.0% without DM (p = 0.36). Knowledge of HbA1c goals was prevalent in 53.6% of DM patients. Subjective levels of information on CAD topics did not differ between patients with and without DM. Logistic regression revealed that DM (odds ratio (OR) 3.73, 95% confidence interval (CI) 1.82-7.63) and knowledge of treatment goals were associated with LDL-C goal attainment (OR 3.84, CI 1.19-12.41); no such associations were identified for BP or HbA1c. CONCLUSIONS: In German CAD patients with and without DM, a remarkable lack of knowledge and attainment of LDL-C treatment goals exists compared with BP and HbA1c. DM and knowledge of treatment goals were significantly associated with LDL-C treatment goal attainment. General practitioners rather than cardiologists or other specialties currently manage risk factor control. TRIAL REGISTRATION: German Clinical Trials Register studyID DRKS00030703.