It has long been suspected that patients who have a myocardial infarction (MI) at the weekend do less well than those who present during the week. The speed of accurate diagnosis and the availability of subsequent treatment options will vary throughout the week and also over the 24-hour period. This American study found differences in mortality between patients admitted for an MI on a weekday and those admitted on weekends.

More than 230,000 patients presenting with a first MI between 1987 and 2002 were identified using a data system not dissimilar to the MINAP dataset in the UK. Overall there were no significant differences between the weekday and weekend groups in terms of demographics, comorbidity or site of infarction.

It was found that, overall, patients admitted on weekends were significantly less likely to undergo invasive cardiac procedures, especially during the first two days of their admission. The procedures analysed were cardiac catheterisation, primary percutaneous coronary intervention and coronary artery bypass grafting.

Additionally, for patients admitted during the final three years of the study, there was an increased 30-day mortality noted in the weekend group. This difference persisted at 12 months, although the absolute difference in mortality was only 1%. Interestingly, this difference disappeared after adjustment for invasive cardiac procedures.

This study adds support to the notion that patients who are admitted over the weekend with an MI do less well than those admitted during the week, primarily because of poorer provision of invasive cardiac procedures.