Long-term survival in patients discharged alive from hospital following an intensive care unit admission with sepsis or septic shock in Australia and New Zealand: an observational cohort study

Background Data on long-term survival after intensive care unit (ICU) admission for sepsis and septic shock are limited. This study aimed to evaluate survival over five years among critically ill sepsis or septic shock patients discharged alive from hospital. Methods This retrospective cohort study of adults who survived to hospital discharge after non-elective ICU admission (2018–2024) used Australian and New Zealand Intensive Care Society Adult Patient Database. Sepsis, septic shock, or non-sepsis patients were classified using diagnostic codes and physiological/laboratory criteria during first 24-h of ICU admission. Mixed-effects Cox models with time-varying covariate effects were used, adjusting for demographics, comorbidities, frailty, illness severity, and ICU interventions. Findings Of 557,538 hospital survivors, 7.3% had sepsis without shock, 11.5% septic shock, and 81.2% non-sepsis conditions. At five-years, unadjusted survival was lowest for septic shock (68.0%, 95% confidence interval/CI = 67.6–68.4%), sepsis without shock (74.2%, 73.7–74.6%), and non-sepsis (78.2%, 78.1–78.3%). After adjustment, hazards ratio/HR for sepsis without shock remained at or below the null relative to non-sepsis; 0–1 year: HR=0.95, 0.92–0.98; 1–3 years: 0.96, 0.93–1.00; 3–5 years: 1.03, 0.97–1.08, while septic shock showed persistent independent excess mortality; 0–1 year: HR=1.05,1.03–1.08; 1–3 years: 1.03, 1.00–1.06; and 3–5 years:1.09,1.05–1.14. Major predictors of mortality included age, frailty, comorbidities, and organ support. Interpretation Septic shock was associated with persistent independent excess mortality over five years after hospital discharge, whereas in sepsis without shock, this was largely explained by pre-existing comorbidity and frailty. Funding Medical Research Future Fund.