Acute cannabis intoxication in the emergency department: the effect of legalization.

BACKGROUND: On October 17, 2018, the Cannabis Act decriminalized the recreational use of cannabis in Canada. This study seeks to determine how legalization of cannabis has impacted emergency department (ED) visits for acute cannabis intoxication. METHODS: We conducted a retrospective chart review at an academic ED in Hamilton, Ontario. We assessed all visits with a cannabis-related ICD-10 discharge code 6 months before and after legalization (October 17, 2018) to determine cases of acute cannabis intoxication. The primary outcome was the rate of ED visits. Secondary outcomes included number of visits distributed by age, length of stay, co-ingestions, and clinical course in the emergency department (investigations and treatment). RESULTS: There was no difference in the overall rate of ED visits following legalization (2.44 vs. 2.94 visits/1000, p = 0.27). However, we noted a 56% increase in visits among adults aged 18-29 (p = 0.03). Following legalization, a larger portion of patients required observation without interventions (25% vs 48%, p < 0.05). Bloodwork and imaging studies decreased (53% vs. 12%, p < 0.05; 29% vs. 2%, p < 0.05); however, treatment with benzodiazepines increased (24% vs. 51%, p < 0.05). CONCLUSIONS: Legalization was not associated with a change in the rate of cannabis-related ED visits in our study. More research is needed regarding changing methods of cannabis ingestion and trends among specific age groups.

Does consecutive influenza vaccination reduce protection against influenza: A systematic review and meta-analysis.

INTRODUCTION: Vaccination against influenza on an annual basis is widely recommended, yet recent studies suggest consecutive vaccination may reduce vaccine effectiveness (VE). PURPOSE: To assess whether when examining the entirety of existing data consecutive influenza vaccination reduces VE compared to current season influenza vaccination. DATA SOURCES: MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to April 26, 2017; citations of included studies. STUDY SELECTION: Randomized, controlled trials (RCTs) and observational studies of children, adults and/or the elderly that reported laboratory-confirmed influenza infection over 2 or more consecutive influenza seasons were eligible. DATA EXTRACTION: Data related to study characteristics, participant demographics, cases of influenza infection by vaccination group and risk of bias assessment was extracted in duplicate. DATA SYNTHESIS: Five RCTs involving 11,987 participants did not show a significant reduction in VE when participants vaccinated in two consecutive seasons (VE 71%, 95% CI 62-78%) were compared to those vaccinated in the current season (VE 58%, 95% CI 48-66%) (odds ratio [OR] 0.88, 95% CI 0.62-1.26, p = 0.49, I2 = 39%). Twenty-eight observational studies involving 28,627 participants also did not show a reduction (VE for two consecutive seasons 41%, 95% CI 30-51% compared to VE for current season 47%, 95% CI 39-54%; OR 1.14, 95% CI 0.98-1.32, p = 0.09, I2 = 63%). Results from subgroup analyses by influenza type/subtype, vaccine type, age, vaccine match and co-morbidity support these findings; however, dose-response results were inconsistent. Certainty in the evidence was assessed to be very low due to unexplained heterogeneity and imprecision. LIMITATIONS: The inclusion of studies with relatively small sample sizes and low event rates contributed to the imprecision of summary VE and OR estimates, which were based on unadjusted data. CONCLUSION: Available evidence does not support a reduction in VE with consecutive influenza vaccination, but the possibility of reduced effectiveness cannot be ruled out due to very low certainty in this evidence. FUNDING SOURCE: CIHR Foundation Grant (PROSPERO: CRD42017059893).