Recorded ASA physical status and major postoperative complications after colorectal cancer surgery in Jeddah: a secondary cohort analysis with a source-data audit

Abstract

Background: ASA physical status is widely recorded around surgery, but its association with the severity of postoperative morbidity depends on case mix and outcome ascertainment. We estimated adjusted absolute risks in an open Saudi colorectal surgery dataset while documenting source limitations and potentially overlapping prior evidence.

Methods: We reanalyzed 120 records from King Abdulaziz University Hospital, Jeddah, covering January 2016–June 2019. A frozen plan compared ASA III–V with I–II for recorded Clavien–Dindo III–V complications. Firth logistic regression adjusted for age, sex, body mass index and emergency surgery. The primary measure was a marginal standardized risk difference with a 1,000-sample bootstrap interval. Prespecified analyses added operative approach, excluded ASA IV–V, examined any complication and used propensity overlap weighting.

Results: There were 69 ASA-I–II and 51 ASA-III–V records, with 9 and 15 major complications, respectively. Standardized risks were 15.2% and 28.6%; the difference was 13.4 percentage points (95% CI, -0.7 to 28.8). The conditional odds ratio was 2.31 (95% profile CI, 0.89–6.28). Excluding the 3 ASA-IV–V records gave a difference of 9.7 percentage points (95% CI, -4.0 to 22.8). Overlap weighting gave 13.4 percentage points (95% CI, -1.4 to 28.0). Four source records had grade 0 despite a named complication indicator. The assessor, precise ASA assessment time and uniform active 30-day grade ascertainment were undocumented.

Conclusions: The point estimate suggested greater major morbidity in higher recorded ASA classes, but uncertainty included no difference. Source coding, selection and possible patient overlap with a later same-center publication restrict interpretation. These results are an auditable secondary severity analysis, not an independently validated risk tool or a causal effect of ASA class.

Keywords

• ASA physical status
• Clavien–Dindo
• colorectal surgery
• postoperative complications
• Saudi Arabia
• perioperative assessment
• secondary data analysis