Enhanced recovery after surgery in colorectal surgery: Do average benefits mask heterogeneous effects in patients underrepresented in trials?

Table 1 Summary of included study characteristics and quality assessment

Study type	Number of studies	Quality assessment (NOS/RoB)	Key findings relevant to this review
Randomized controlled trials	8	Low-to-moderate RoB	ERAS reduces LOS by 2-3 days, complications by 30%-40%
Prospective multicenter cohorts	12	NOS 7-9 (high quality)	Dose-response: 10% compliance increment → approximately 5% complication reduction
Single-center retrospective cohorts	23	NOS 5-7 (moderate quality)	High-risk subgroups have lower compliance and worse outcomes
Registry analyses	7	NOS 7-8 (high quality)	Socioeconomic gradients in compliance and outcomes
Qualitative studies	4	CASP qualitative checklist	Barriers to adherence: Clinician judgement, patient factors, system constraints
Cognitive psychology/safety science	8	N/A (indirect evidence)	Automation bias, Goodhart’s Law - hypothesis-generating only

CASP: Critical Appraisal Skills Program; ERAS: Enhanced recovery after surgery; LOS: Length of stay; N/A: Not applicable; NOS: Newcastle-Ottawa Scale; RoB: Risk of bias.