SMOKING AND ESTABLISHED CARDIOVASCULAR DISEASE: THE VARIABLE HABITS OF A PRIMARY CARE COHORT Dr Mairead Corrigan 1 PhD BSSc, Dr Margaret E Cupples 1 MD FRCGP, Mr Mike Stevenson 2 BSC FSS. Department of General Practice 1 & Department of Epidemiology and Public Health 2, Queen’s University, Belfast. Background: Smoking is the most important modifiable risk factor for coronary heart disease. Most studies of smoking behaviour amongst patients with coronary heart disease involve those enrolled after coronary angiography, cardiac surgery or recent myocardial infarction. Individual patterns of change in smoking habit for patients with established cardiovascular disease are poorly documented. Information relating to the smoking habits of a primary care population who require chronic disease management is relevant to the planning of appropriate resource provision. Objective: The objective of this study was to examine longitudinal variation in the self- reported smoking habit of a cross-section of individuals with an established diagnosis of angina over a five year period. Method: Patients, diagnosed at least six months previously as having angina, were identified from the disease registers of 18 different general practices in the Greater Belfast Area. All practices that were invited agreed to participate. The patients took part in a two year randomised controlled trial of a health education programme and in a further review three years later. At baseline, two years and five years a research worker administered a questionnaire which included questions about smoking habits. Self-reported smoking habit was validated by breath carbon monoxide measurements. Smokers were defined as those who smoked at least one cigarette daily. Full details of the method and other findings have been reported previously. 1,2 Results: Of the 487 who completed the five year follow-up out of an initial sample of 688 patients, 58% were male, their mean age was 62.8 years and 72% reported ever smoking. The prevalence of self-reported smoking was 19%, 19% and 15% at baseline, two and five years respectively. Overall, 55 (11%) participants reported changes in smoking habits which indicated periods of abstinence and resumption. Of the 92 who reported smoking at baseline, 34 (37%) subsequently reported non-smoking. At two years 16 (17%) reported non-smoking but four of these reported smoking again at five years. At five years 30 (33%) reported non-smoking. Only 12 of the 92 (13%) reported maintained cessation at two and five years. Of 395 non-smokers at baseline, 21 (5%) subsequently reported smoking. Four who were non-smokers at two years reported smoking again at five years. Eight smokers at two years reported non-smoking at five years. Nine reported persistent smoking at two and five years. Of those who reported having stopped for over a year, 6% subsequently resumed smoking. Longitudinal changes in reported cigarette smoking over five years (N=487) Footnotes: NS=Non-smoker; S=Smoker; *(x) no. with breath CO>10ppm; **Same individual with breath CO>10ppm. Discussion: Patterns of smoking cessation and resumption identified among 55 patients (11%) over the five years, confirms how cycles of abstinence and relapse may continue many years after diagnosis and long after when many studies have completed their follow up. The changing smoking habits of self reported non-smokers at baseline suggests that there is value in auditing smoking status yearly in patients with coronary heart disease. The number of smokers who subsequently reported not smoking (37%) indicates it is worthwhile to continue to promote smoking cessation among patients with established disease. References: 1. Cupples ME, McKnight A. Randomised controlled trial of health promotion in general practice for patients at high cardiovascular risk. BMJ 1994;309: Cupples ME, McKnight A. Five year follow up of patients at high cardiovascular risk who took part in a randomised controlled trial of health promotion. BMJ 1999;319: Smoking Status Initial S who change (n=34) NS *(4) S S S SS S NS *(1) S NS **(1) NS **(2) NS *(5) 9 (2) 18 (4) 4 (0.8) 12 (2.4) Baseline2 Yrs5 YrsTotal N(%) Continuous NS (n=374)NS *(1) NS *(3) 374 (77) Continuous S (n=58)SSS58 (12) Initial NS who change (n=21) NS *(1) NS *(2) S 4 (0.8) NS *(1) S 8 (1)