[General practice and surveillance: the example of influenza in France]. / Médecin généraliste et veille sanitaire: l'exemple de la grippe en France.

UNLABELLED: Data registration by the GROG national network (Regional Group for the Surveillance of Influenza) since 1984 has helped to identify methodological problems. The choice of sentinels and the selection of indicators depend on the analysis of actual influenza consequences. Various sentinels may be concerned: health insurance companies, private companies, schools, physicians, pharmacists. Health care organization modifies the validity of indicators. In France, for instance, home visits were an excellent indicator for early warning before 1995 but this indicator is no longer as efficient as before. The virological detection of Influenza depends on the organization of transportation (samples, results). The predictive value of cases definitions depends on the incidence of infection. The level of choice between specificity and sensibility modifies the perception of outbreaks. Sentinel participation rate influences the sample representativity. The farther this rate is from 100%, the more result validity decreases (in the same way that patients lost to follow-up compromise the validity of results in clinical trials). The publication of results can modify health expenses and behaviors. CONCLUSION: The GROG network stresses the important role that general practitioners play in health surveillance; it also raises questions in the field of mathematics, statistics, professional organization, training, education, and politics.

Treatment with metformin of non-diabetic men with hypertension, hypertriglyceridaemia and central fat distribution: the BIGPRO 1.2 trial.

BACKGROUND: In the BIGPRO 1 trial, one year of treatment with metformin in non-diabetic obese subjects with a central fat distribution had no significant effect on fasting plasma triglyceride concentration or on blood pressure despite a decrease in weight, fasting plasma insulin and glucose concentrations. To re-evaluate the effect of metformin on fasting triglyceride concentration and on blood pressure, the BIGPRO 1.2 trial included non-diabetic men (n=168) with a fasting plasma triglyceride concentration > or =1.7 and < or =6.5 mmol/l, high blood pressure (systolic > or =140 and < or =180 and/or diastolic > or =90 and < or =105 mmHg, or treatment for hypertension) and a waist-to-hip ratio > or =0.95. METHODS: A randomised double-blind trial comparing metformin treatment (850 mg bid) with placebo. RESULTS: Metformin had no significant effect either on blood pressure or plasma triglyceride concentration. In comparison with the placebo group, fasting plasma insulin (p<0.04), total cholesterol (p<0.05) and Apo B (p<0.008) concentrations decreased more in the metformin group in the BIGPRO 1. 2 trial, confirming most of the previous results of the BIGPRO 1 trial. Tissue plasminogen activator antigen concentration decreased significantly (p<0.01) only in the metformin group, but this was not significantly different from the placebo group (p<0.12); further, there were no significant differences in the change in plasminogen activator inhibitor 1. CONCLUSIONS: The consistency of the two BIGPRO trials supports the conclusion that metformin affects several cardiovascular risk factors favourably in non-diabetic subjects with a central fat distribution.