Disparities in pathways for anaemia care and recovery among women after major abdominal surgery: secondary analysis of a prospective cohort study in 29 countries.

Abstract

Background: Anaemia is a common modifiable risk factor in surgery, yet how it is recognized and managed in women across different surgical pathways is unknown. This study aimed to evaluate anaemia prevalence in women and its management across surgical pathways and life stages, examine associations with 30-day outcomes, and estimate the potential benefit of anaemia correction.

Methods: A secondary analysis was conducted of a prospective cohort study from 427 hospitals in 29 countries, including women having elective major abdominal surgery. The primary exposure was surgical pathway (gynaecology versus non-gynaecology), used as a pragmatic proxy for pathway design. Preoperative anaemia and perioperative iron therapy were conceptualized as mediators; menopausal status (pre- versus postmenopausal, by age) was a prespecified effect modifier. Coprimary outcomes were 30-day unplanned readmission and days alive and out of the hospital 30 days from surgery (DAOH30). Mixed-effects logistic regression was used with a hospital random intercept for readmission, and quantile regression for DAOH30. A 2000-iteration cluster bootstrap estimated absolute risk reduction and number needed to treat (NNT = 1/absolute risk difference) for counterfactual anaemia correction in key subgroups. Natural-effects models assessed whether recorded perioperative iron therapy partly explained the pathway differences in readmission.

Results: A total of 10 114 women (median age 57.6 years (interquartile range 48.0-69.0)) were included; 3590 (35.5%) were premenopausal and 3214 (31.8%) underwent gynaecological surgery. Preoperative anaemia was present in 29.0% and was more frequent in non-gynaecology than gynaecology (31.9% versus 22.8%). Thirty-day unplanned readmission occurred in 7.2%. In adjusted models, the gynaecology pathway had lower odds of readmission than non-gynaecology (adjusted odds ratio 0.78, 95% confidence interval 0.62 to 0.97), whereas preoperative anaemia was associated with higher readmission (adjusted odds ratio 1.28, 1.06 to 1.56). Lower perioperative iron use in non-gynaecology partly mediated the pathway gap (indirect effect odds ratio 1.06, 1.02 to 1.09; proportion mediated 15.2%). The largest model-based absolute risk difference was observed among women of premenopausal age undergoing non-gynaecological surgery: predicted readmission was 11.8% with anaemia versus 6.4% without anaemia, corresponding to an absolute risk difference of 5.32% and an NNT estimand of 19. Median DAOH30 was 26 days (interquartile range 23-28). Anaemia was associated with fewer days at home, with the largest decrement among those with poorest recovery (10th percentile β -3.0 days, 95% confidence interval -4.0 to -2.0), a smaller reduction at the median (β -1.0 days, -1.3 to -0.72), and no difference at the 90th percentile.

Conclusion: For women, pathway design, not only patient risk, shapes whether anaemia is recognized and treated. The greatest avoidable harm falls on premenopausal women outside gynaecology. Health systems should embed universal screening and optimization, adopt standardized iron protocols across all pathways, and track life-stage-stratified performance metrics to close this gap and increase days at home.