Superstition in Surgery: A Population-Based Cohort Study to Assess the Association Between Surgery on Friday the 13th and Postoperative Outcomes

Objective

We sought to examine whether the outcomes of patients who receive a surgical procedure on Friday the 13th differ from patients who receive surgery on flanking Fridays.

Background

Numerous studies have demonstrated that increased anxiety from the provider or patient around the time of surgery can lead to worse outcomes. Superstitious patients often express significant concern and anxiety when undergoing a surgical procedure on Friday the 13th.

Methods

A retrospective, population-based cohort study of 19,747 adults undergoing 1 of 25 common surgical procedures on Friday the 13th or flanking control Fridays (Friday the 6th and Friday the 20th) between January 1, 2007, and December 31, 2019, with 1 year of follow-up. The main outcomes included death, readmission, and complications at 30 days (short-term), 90 days (intermediate-term), and 1 year (long-term).

Results

A total of 7,349 (37.2%) underwent surgery on Friday the 13th, and 12,398 (62.8%) underwent surgery on a flanking Friday during the study period. Patient characteristics were similar between the 2 groups. We found no evidence that patients receiving surgery on Friday the 13th group were more likely to experience the composite primary outcome at 30 days [adjusted odds ratio (aOR) = 1.02 (95% CI = 0.94-1.09)], 90 days [aOR = 0.97 (95% CI = 0.90-1.04)], and 1 year [aOR = 0.99 (95% CI = 0.94-1.04)] after surgery.

Conclusion

Patients receiving surgery on Friday the 13th do not appear to fare worse than those treated on ordinary Fridays with respect to the composite outcome.

Admission to bed 13 in the ICU does not reduce the chance of survival

PURPOSE

To examine whether admission to bed number 13 on our intensive care unit has any negative impact on the patient's hospital mortality.

MATERIALS AND METHODS

We conducted a retrospective cohort study of 1568 patients admitted to our ICU over a two-year period. Observed hospital mortality, predicted mortality using the ICNARC and APACHE II scoring systems and standardised mortality ratios were used to compared patients admitted to bed number 13 with those admitted to beds number 14-24.

RESULTS

Of the 1568 patients admitted to ICU, 110 were placed in bed number 13 and 1458 into bed numbers 14-24. Demographics and ICNARC and APACHE II scores were similar between the two groups. There was no significant difference in the ICNARC predicted hospital mortality (mean 21.0%, median8.5% in bed 13 compared with a mean 17.5%, median 6.4% in beds 14-24, p = 0.33), APACHE II predicted hospital mortality (mean 18.4%, median 9.9% in bed 13 compared with mean 18.7%, median 8.9% in beds 14-24, p = 0.74), or observed hospital mortality (20.2% compared with 15.2%, OR 1.41 (CI 0.87 to 2.30), p = 0.17).

CONCLUSIONS

Admission to bed number 13 was not associated with a significant increase in hospital mortality when compared to admission to other bed numbers.