Background — Adhesive small bowel obstruction (aSBO) is among the most common reasons for admission to a surgical service. While operative intervention for aSBO is associated with a lower risk of recurrence, current guidelines continue to advocate a trial of non-operative management. The impact of the increased risk for recurrence on long-term survival is unknown. We sought to explore the potential for improved survival with operative management through the prevention of admissions for recurrence of aSBO and the associated risks.
Methods — This is a population-based retrospective cohort study using administrative data. We identified patients admitted to hospital for their first episode of aSBO from 2005-2014 and created a propensity-matched cohort to compare survival of patients managed operatively to those managed non-operatively. To test whether survival differences were mediated by recurrence prevention, a competing risk regression was used to model the sub-distribution hazard of death when accounting for the risk of recurrence. An instrumental variable approach was used as a secondary analysis to compare survival while accounting for unmeasured confounding.
Results — 27,904 patients were admitted for their first episode of aSBO between 2005-2014. The mean age was 61.2 years (std dev:13.6) and 51% were female. Operative management was associated with a significantly lower risk of death (HR:0.80, 95%CI:0.75-0.86), which was robust to instrumental variable analyses, and a lower risk of recurrence (HR:0.59, 95%CI:0.54-0.65). When adjusting for the risk of recurrence, operative intervention was not associated with improved survival, suggesting that the survival benefit is mediated through prevention of recurrences of aSBO.
Conclusion — In patients admitted for their first episode of aSBO, operative intervention is associated with a significant long-term survival benefit. This survival benefit appears to be mediated through the prevention of recurrences of aSBO.