Severe mental illness and mortality in sepsis and septic shock: a systematic review and meta-analysis

Background: There have been conflicting reports regarding the case-fatality outcomes associated with sepsis and septic shock in patients with severe mental illness (SMI). Methods: We searched Medline®, Web of Science® and the Cochrane Library® databases (from inception to 4-July-2023) for papers reporting outcomes associated with sepsis and septic shock in adult with (cases) vs. without SMI (controls). The main study outcome was the unadjusted case-fatality rate at hospital discharge, or 30 days if unavailable. Secondary outcomes included the rates of adjusted case-fatality at hospital discharge. Results: A total of six studies were included in the systematic review, of which four provided data for meta-analysis involving 2,124,072 patients. Compared to controls, patients with SMI were younger and more frequently women. Unadjusted analyses showed that SMI patients had a lower case-fatality rate associated with sepsis and septic shock than their non-SMI counterparts (OR 0.61, 95% CI [0.58–0.65], PI 95% CI [0.49–0.77], I² = 91%). Meta-regression and subgroup analyses showed that the denominator of the study population (i.e. septic shock or sepsis) was associated with the outcome with an R² of 59.7%. Conclusion: In conclusion, our study reveals a survival advantage of SMI patients over their non-SMI counterparts. Further research is needed to fully elucidate the mechanisms involved and to develop targeted interventions that can improve the prognosis of both SMI and non-SMI patients facing sepsis.