Circadian rhythm of cardiac troponin I and its clinical impact on the diagnostic accuracy for acute myocardial infarction.

BACKGROUND: High-sensitivity cardiac troponin T (hs-cTnT) blood concentrations were shown to exhibit a diurnal rhythm, characterized by gradually decreasing concentrations throughout daytime, rising concentrations during nighttime and peak concentrations in the morning. We aimed to investigate whether this also applies to (h)s-cTnI assays and whether it would affect diagnostic accuracy for acute myocardial infarction (AMI). METHODS: Blood concentrations of cTnI were measured at presentation and after 1 h using four different cTnI assays: three commonly used sensitive (s-cTnI Architect, Ultra and Accu) and one experimental high-sensitivity assay (hs-cTnI Accu) in a prospective multicenter diagnostic study of patients presenting to the emergency department with suspected AMI. These concentrations and their diagnostic accuracy for AMI (quantified by the area under the curve (AUC)) were compared between morning (11 p.m. to 2 p.m.) and evening (2 p.m. to 11 p.m.) presenters. RESULTS: Among 2601 patients, AMI was the final diagnosis in 17.6% of patients. Concentrations of (h)s-cTnI as measured using all four assays were comparable in patients presenting in the morning versus patients presenting in the evening. Diagnostic accuracy for AMI of all four (h)s-cTnI assays were high and comparable between patients presenting in the morning versus presenting in the evening (AUC at presentation: 0.90 vs 0.93 for s-cTnI Architect; 0.91 vs 0.94 for s-cTnI Ultra; 0.89 vs 0.94 for s-cTnI Accu; 0.91 vs 0.94 for hs-cTnI Accu). CONCLUSIONS: Cardiac TnI does not seem to express a diurnal rhythm. Diagnostic accuracy for AMI is very high and does not differ with time of presentation. CLINICAL TRIAL REGISTRATION: NCT00470587, http://clinicaltrials.gov/show/NCT00470587.

Evaluation of a physical activity promotion program in primary care.

BACKGROUND: Physical inactivity increases the risk of many chronic disorders. It is not clear which strategies are the most appropriate to enable people to adopt a more active lifestyle. Randomized controlled trials have found that brief advice from GPs supported by written material had a significant positive effect on patient's physical activity. The pilot project 'Move for Health and the Environment' translated this evidence into a program suitable for the real-life situation of busy practices. The aim of this study was to evaluate the change in physical activity level of the participating patients 1 year after the intervention. METHODS: Patients aged 16-65 years completed a screening questionnaire before consultation with their physician. Insufficiently active patients were offered an information leaflet and a voucher for a physical activity counselling session. One year later, all inactive patients and a random selection of the active were re-contacted and invited to answer identical questions. RESULTS: A total of 1239 (73.9%) returned the follow-up questionnaire. In all, 37.3% of the formerly inactive patients met the threshold of sufficient activity at follow-up, whereas 20.3% of the previously active no longer did. Formerly inactive patients reported an increase of 58.8 minutes/week of moderate and 34.6 minutes/week of vigorous activity and spending more time walking and cycling. Formerly active patients reported less time spent in moderate activities. CONCLUSIONS: Systematic counselling in primary care encouraged insufficiently active patients to adopt a more active lifestyle. Yet it became evident that active patients also need counselling to maintain their activity levels.