Secondary prevention clinics for coronary heart disease: a 10-year follow-up of a randomised controlled trial in primary care

Abstract

Objectives: To evaluate the effects of nurse-led secondary prevention clinics for coronary heart disease (CHD) in primary care on total mortality and coronary event rates after 10 years.

Design: Follow-up of a randomised controlled trial by review of national datasets.

Setting: Stratified random sample of 19 general practices in northeast Scotland.

Participants: Original study cohort of 1343 patients, aged <80 years, with a working diagnosis of CHD, but without dementia or terminal illness and not housebound.

Intervention: Nurse-led secondary prevention clinics promoted medical and lifestyle aspects of secondary prevention and offered regular follow-up for 1 year,

Main outcome measures: Total mortality and coronary events (non-fatal myocardial infarctions (MIs) and coronary deaths).

Results: Mean (SD) follow-up was at 10.2 (0.19) years. No significant differences in total mortality or coronary events were found at 10 years. 254 patients in the intervention group and 277 patients in the control group had died: cumulative death rates were 38% and 41%, respectively (p = 0.177). 196 coronary events occurred in the intervention group and 195 in the control group: cumulative event rates were 29.1% and 29.1%, respectively (p = 0.994). When Kaplan-Meier survival analysis, adjusted for age, sex and general practice, was used, proportional hazard ratios were 0.88 (0.74 to 1.04) for total mortality and 0.96 (0.79 to 1.18) for coronary death or non-fatal MI. No significant differences in the distribution of cause of death classifications was found at either 4 or 10 years.

Conclusions: After 10 years, differences between groups were no longer significant. Total mortality survival curves for the intervention and control groups had not converged, but the coronary event survival curves had. Possibly, therefore, the earlier that secondary prevention is optimised, the less likely a subsequent coronary event is to prove fatal.