1. What type of study design was used to compare the risk of self-harm behaviors before and after bariatric surgery (hint: Check out the Study Design section under Methods)?
a. Cross Sectional
b. Crossover design
c. Retrospective
d. Case Control

2. What is the null hypothesis of the study?
a. There is a difference in self-harm behaviors before and after bariatric surgery.
b. There is no difference in self-harm behaviors before and after bariatric surgery.
c. There is a difference in self-harm incidence between patients with normal and obese BMI.
d. There is no difference in self-harm incidence between patients with normal and obese BMI.

3. What is the corresponding alternative hypothesis of the study?
a. There is a difference in self-harm behaviors before and after bariatric surgery.
b. There is no difference in self-harm behaviors before and after bariatric surgery.
c. There is a difference in self-harm incidence between patients with normal and obese BMI.
d. There is no difference in self-harm incidence between patients with normal and obese BMI.

4. What was the total sample size of patients who were treated gastric bypass? a. 8815
b. 7176
c. 8681
d. 7063

5. True or False: The majority of the cohort were male.

6. The relative risk was NOT calculated for what stratification?
a. Sex
b. Income
c. Business location
d. Age

7. What is the prevalence of morbid obesity in Americans due to insufficiency of treatment? Report in decimal format.

8. Which of the following was NOT included as an excluding criteria?
a. Over the age of 65
b. Invalid Ontario health card
c. Under the age of 18
d. Bariatric surgery naïve

9. What was the total follow-up time for each patient in years (i.e. combined total of before and after surgery)?

10. Which of the following were categorized as distinct mechanisms of self-harm behaviors?
a. Alcohol
b. Medications
c. Physical Trauma
d. All of the above

11. ICD-10 codes were extracted from what data source for self-harm information?
a. Ontario Health Insurance Plan
b. Registered Persons Database
c. National Ambulatory Care Reporting System
d. ICD-10 codes were not used in this study.

12. True or False: The use of ICD-10 codes for identifying self-harm information is considered a limitation to the study.

13. Which of following mental health diagnoses were most prevalent in patients undergoing bariatric surgery?
a. Anxiety
b. Depression
c. Alcohol
d. All of the above had equal prevalence in the cohort.

14. What is the 95% confidence interval for rate ratio of self-harm emergencies after versus before among patients living in a rural area?
a. (1.03, 2.30)
b. (1.05, 2.94)
c. (1.20, 3.65)
d. (1.42, 29.63)

15. True or False: The investigators rejected the null hypothesis based on the rate ratio for total study population?

16. Which of the following was listed as a limitation to the study?
a. Important surgery-related factors were not accounted for when determining self-harm behaviors post-surgery.
b. Patients could've possibly had bariatric surgery outside of the study location.
c. Self-harm injuries are under-reported in emergency departments.
d. All of the above were limitations to this study.

Original Investigation

Article - Self-harmEmergencies After Bariatric Surgery A Population-Based Cohort Study