Quality of care and quality of life in coronary artery disease

Abstract

The aim was to study the efficacy in primary care of Case method learning (CML) in secondary prevention of patients with coronary artery disease (CAD). A further aim was to explore the structure of health related quality of life (HRQL) in these patients and its relations to chest pain and ill health.

54 general practitioners and 255 consecutive patients with CAD participated in a randomised controlled educational trial with the intention to improve the quality of care in secondary prevention of CAD. Practice guidelines were initially distributed and presented at a lecture. General practitioners - whose Primary health care centre (PHCC) - was randomised to the intervention group participated in recurrent interactive Case method learning dialogues at their own PHCC during the two years of the study. Statistical analysis was performed according to intention-to-treat based on group affiliation at baseline.

CML resulted in a lipid lowering in patients in primary care - whose general practitioners participated in recurrent interactive CML dialogues - comparable to what was concurrently achieved at a specialist clinic. Presentation of practice guidelines had no effect per se. Low-density lipoprotein cholesterol concentration decreased 9.3% from 4.2 (CI 4.0-4.5) to 3.7 (CI 3.4-4.0) mmol/l in the intervention group and was 0.5 (CI 0.1-0.9) mmol/l lower (effect size 0.56) in the intervention group as compared to the control group (p < 0.05) after two years. We found no change in the control group. The cost of the education represented only 2% of the cost of lipid lowering drugs. The resulting discounted cost per gained QALY was equal to US$ 24 300. This indicates that CML supported lipid lowering is a cost-effective strategy.

HRQL was assessed by the Cardiac Health Profile (CHP), EuroQol-VAS and EuroQol-5D questionnaires. Chest pain was ranked according to the Canadian Cardiovascular Society (CCS) classification. Principal component analysis of HRQL - as assessed by CHP - identified four principal components (independent sub domains) representing perceived cognitive function, physical function/general health, and social respectively emotional functions. All components correlated to EuroQoL-VAS. Perceived cognitive function - reflecting the ability to concentrate, activity drive, memory and problem solving - had a major impact on HRQL. Physical function/general health (p = 0.000000) and emotional domains (p<0.04) related to CCS but perceived cognitive function and social function did not. Furthermore, both perceived cognitive function (p=0.0006) and physical function/general health predicted unemployment at baseline and at two years in patients at a working age. CCS decreased during the two years (p<0.00022). By contrast, HRQL did not change as assessed by any of the instruments or sub domains.

To conclude, CML for general practitioners resulted in lipid lowering in their CAD patients due changed clinical practice. Furthermore, CML is cost-effective. The low cost in addition to its positive effects should probably warrant its use in the improvement of the quality of care of other major diseases. Perceived cognitive function is a major determinant of HRQL in CAD patients and predicts ill health as assessed by prevalence of unemployment. Perceived cognitive function was not related to prevalence and grade of chest pain. Furthermore, the major part of the HRQL in these unselected patients was insensitive to change in chest pain symptoms during a two-year period.