Risk indicators for out-of-hospital cardiac arrest in patients with coronary artery disease.

The objective of this study was to identify risk factors for sudden cardiac arrest (SCA) in patients with coronary artery disease (CAD). A retrospective case-control study was performed consisting of a group of unselected patients who had suffered SCA and had a clinical history of CAD, and a group of unselected age- and gender-matched CAD control patients living in the region of Maastricht. Information about previous myocardial infarction (MI), left ventricular ejection fraction (LVEF), hypertension, hypercholesterolemia, diabetes mellitus, smoking, and coffee and alcohol consumption was collected. A logistic regression model was fitted to all mentioned variables including age and genders. Included were 117 SCA cases (84% men, mean age 65 years [+/-7]) and 144 control patients (83% men, mean age 63 years [+/-8]). Previous MI (odds ratio [OR] 4.0, 95% confidence interval [CI] 1.7-9.3), hypertension (OR 2.9, 95% CI 1.5-6.1), heavy coffee consumption (>10 cups per day) (OR 55.7, 95% CI 6.4-483), and a LVEF <40% (OR 11.2, CI 4.4-28.5) were independent risk indicators for SCA in patients with CAD. Alcohol consumption (1-21 glasses per week) seemed to protect patients with CAD from SCA (OR 0.5, 95% CI 0.2-0.98). These observations suggest that changes in lifestyle factors can be of potential importance in protecting patients with CAD from dying suddenly.

The effect of smoking on influenza, influenza vaccination efficacy and on the antibody response to influenza vaccination.

We examined the relation between cigarette smoking and (1) the occurrence of influenza, (2) the efficacy of influenza vaccination and (3) the antibody response to influenza vaccination in fifteen family practices in South-Limburg, the Netherlands, during the influenza season 1991 1992. Data were used from a randomized double-blind placebo-controlled trial into the efficacy of influenza vaccination in which smoking status was measured 10 weeks after the start of the trial. A total of 1838 subjects aged 60 years or older, of whom 1531 subjects (321 smokers, 1152 non-smokers and 58 cigar/pipe smokers) who returned the smoking questionnaire and were not previously vaccinated, were used in the analyses. The main outcome measures were serological influenza (fourfold increase of antibody titre between 3 weeks and 5 months after vaccination); clinical influenza as determined by criteria of the Dutch Sentinel Stations from self reported symptoms in postal questionnaires 10 weeks and 5 months after vaccination; increases after vaccination and decreases after 5 months in logarithmic titres of antibody against the vaccine strains. No relation between smoking and either serological or clinical influenza was found, although the risk for serological influenza was slightly (not significantly) elevated in smokers compared to non-smokers. A statistical interaction was found between smoking and vaccination when serological influenza was the outcome measure indicating that the efficacy of vaccination was greater in smokers than in non-smokers (comparison of model with and without interaction; likelihood ratio test, p < 0.0001). This finding is supported by a greater titre rise 3 weeks after vaccination for two out of four strains, but not by the antibody response after vaccination in previous studies on influenza and other infectious diseases. Also, this possible difference of immunogenicity is not reflected in a better protection for clinical influenza. The rise in antibody titre 3 weeks after vaccination was higher in smokers for A/Singapore/6/86 and B/Beijing/11/87, but not for the other two strains. Decline in titres after 5 months was similar for smokers and non-smokers. We conclude that smoking has no clinical or preventive significance for risk of influenza in the elderly.

Leucocyte count as an alternative to ESR in general practice?

We investigated the ability of the leucocyte count to discriminate between "inflammatory diseases and malignancies" on the one hand and other, often harmless and self-limiting diseases on the other, and compared this ability with that of the erythrocyte sedimentation rate (ESR) in general practice. In cooperation with nine general practitioners (GP) we prospectively followed 151 patients who were seen by their GP because of a new complaint for which the GP wanted to know their ESR. ESR and one leucocyte count measurement (Technicon H6000) were performed at the local hospital laboratory. The patients were seen again after three months, to determine the follow-up diagnoses. By comparing the test results with the follow-up diagnoses, ESR was found to have a better discriminating ability than the leucocyte count test (ESR: sensitivity = 53%, specificity = 84%, positive predictive value = 29%, negative predictive value = 93%, Odds Ratio = 5.73). Using Receiver Operating Characteristic analysis, this conclusion could be shown to be independent of the chosen reference values. We conclude that the determination of the leucocyte count is not a clinically interesting alternative to ESR.