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68 Blue monday - association between incidence of STEMI and day of the week
  1. Jack Laffan1,
  2. Simon Walsh2,
  3. Robert Byrne3,
  4. Jaimie Coburn4,
  5. Conor McCann5,
  6. Jim Crowley6,
  7. Mark McKane7,
  8. Peter Kearney8,
  9. Mark Kennedy9,
  10. Charles McCreery10,
  11. Tom Kiernan11,
  12. Gavin Blake12,
  13. Andrew Maree13,
  14. Aaron Peace14
  1. 1Belfast Trust
  2. 2Belfast Trust
  3. 3Mater Private Hospital
  4. 4Belfast Trust
  5. 5Belfast Trust
  6. 6University Hospital Galway
  7. 7Western Trust
  8. 8Cork University Hospital
  9. 9Beaumont Hospital
  10. 10St Vincent’s Hospital
  11. 11University Hospital Limerick
  12. 12Mater Misericordiae Univeristy Hospital
  13. 13St James’ Hospital
  14. 14Western Trust


Background Previous studies have shown a circadian association with the incidence of myocardial infarction, with a higher incidence on a Monday. We sought to establish whether there was any association between rates of ST-segment elevation myocardial infarction (STEMI) and day of the week in an Irish population

Methods All STEMIs recorded in the Republic of Ireland national ACS database, and from both centres providing primary PCI in Northern Ireland, from January 2013 through March 2018 were included in the analysis. Dates of admission were grouped by day of the week. Chi-Square goodness-of-fit test was performed across the entire data set. Odds ratios and Chi-Square independence tests were calculated for each day versus the mean of the other 6 days of the week.

Results 10,528 patients were included in the analysis (7,112 in the Republic of Ireland, 3,416 in Northern Ireland). Chi-Square goodness-of-fit test showed a significant deviation from an even distribution across the week (p<0.000). The total number of STEMI vs mean by day of week are reported in Figure 1 below. The incidence of STEMI was significantly higher on Mondays: OR 1.13 (p=0.015). Relative odds ratios and p values are reported in Figure 2 below.

Summary We found an association between the incidence of STEMI and the start of the working week. There is a significantly higher incidence of STEMI on Mondays.

Abstract 68 Figure 1

Incidence of STEMI by day of the week. (NB truncated y-axis)

Abstract 68 Figure 2

Relative odds ratio of STEMI by day of the week. P values from Chi-square vs other 6 days

Conflict of Interest None

  • Population science
  • Circadian rhythym

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