Hospital cost associated with anemia in elective colorectal surgery: a historical cohort study

  • Simon Feng
  • Joshua Greenberg
  • Husein Moloo
  • Kednapa Thavorn
  • Daniel I. McIsaacEmail author
Reports of Original Investigations



Anemia is highly prevalent in the colorectal surgery population, affecting 30–70% of patients. Anemia is associated with significant morbidity and mortality; however, there is a lack of evidence on how much anemia impacts healthcare costs. This study aims to determine the hospital cost of index surgical admission, postoperative length of stay, and transfusion rate associated with preoperative anemia in elective major colorectal surgery.


This historical cohort study included 851 adult inpatients having elective colorectal surgery at a tertiary care academic health sciences network between April 2010 and February 2016. Anemia was defined as hematocrit ≤ 39%. The primary outcome was total hospital costs standardized to 2016 CAD. Secondary outcomes were postoperative length of stay and transfusion. Multivariable regression analyses and propensity score methods were used to measure adjusted associations between anemia and outcomes.


Before surgery, 381/851 (45%) patients were anemic. The mean (standard deviation [SD]) cost of index admission for an elective colorectal surgery was 20,040 (23,219) CAD. Anemia was associated with an adjusted 14% relative increase in costs (95% confidence interval [CI], 6 to 23; P < 0.001). The total hospitalization cost attributable to anemia was 3,027 CAD (95% CI, 2,670 to 3,388). Hospital costs and length of stay were highly associated; anemia was associated with an 18% increase in length of stay (95% CI, 7 to 30; P < 0.001) and increased transfusion rates (risk ratio, 4.7; 95% CI, 2.71 to 8.33; P < 0.001).


Over 2,600 CAD per index surgical admission is attributable to preoperative anemia. Preoperative interventions with per patient cost of less than 2,600 CAD could be cost effective at the hospital level.

Trial registration (NCT03476707); registered 26 March, 2018.

Les coûts hospitaliers associés à l’anémie lors d’une chirurgie colorectale non urgente: une étude de cohorte historique



La prévalence de l’anémie est très élevée dans la population subissant une chirurgie colorectale, touchant 30–70 % des patients. L’anémie est associée à une morbidité et une mortalité importantes; toutefois, nous manquons de données probantes pour estimer les coûts des soins de santé associés à l’anémie. Cette étude avait pour but de déterminer les coûts hospitaliers de l’admission chirurgicale initiale, la durée de séjour postopératoire et le taux de transfusion associés à une anémie préopératoire lors de chirurgie colorectale majeure non urgente.


Cette étude de cohorte historique a inclus 851 patients adultes hospitalisés et subissant une chirurgie colorectale non urgente dans un réseau hospitalier universitaire de soins tertiaires entre avril 2010 et février 2016. L’anémie était définie comme un hématocrite ≤ 39 %. Le critère d’évaluation principal était les coûts hospitaliers totaux standardisés à la valeur du dollar canadien en 2016. Les critères d’évaluation secondaires étaient la durée de séjour postopératoire et les transfusions. Des analyses de régression multivariée et des évaluations par score de propension ont été utilisées pour mesurer les associations ajustées entre l’anémie et nos critères d’évaluation.


Avant la chirurgie, 381/851 (45 %) patients étaient anémiques. Le coût moyen (écart type [ÉT]) de l’admission initiale pour une chirurgie colorectale non urgente était de 20 040 (23 219) CAD. L’anémie a été associée à une augmentation relative ajustée de 14 % des coûts (intervalle de confiance [IC] 95 %, 6 à 23; P < 0,001). Les coûts d’hospitalisation totaux attribuables à l’anémie étaient de 3027 CAD (IC 95 %, 2670 à 3388). Les coûts hospitaliers et la durée de séjour étaient très fortement associés; l’anémie a été associée à une augmentation de 18 % de la durée de séjour (IC 95 %, 7 à 30; P < 0,001) et des taux de transfusion (risque relatif, 4,7; IC 95 %, 2,71 à 8,33; P < 0,001).


Plus de 2600 CAD pour l’admission chirurgicale initiale sont attribuables à l’anémie préopératoire. Des interventions préopératoires ayant un coût par patient de moins de 2600 CAD pourraient être rentables au niveau hospitalier.

Enregistrement de l’étude (NCT03476707); enregistrée le 26 mars 2018.


Conflicts of interest

None declared.

Editorial responsibility

This submission was handled by Dr. Philip M. Jones, Associate Editor, Canadian Journal of Anesthesia.

Author contributions

Simon Feng and Daniel I. McIsaac contributed to all aspects of this manuscript, including study conception and design, acquisition, analysis, and interpretation of data, and drafting the article. Joshua Greenberg, Husein Moloo, and Kednapa Thavorn contributed to the conception and design of the study and interpretation of data. Kednapa Thavorn contributed to the analysis of data.

Supplementary material

12630_2019_1379_MOESM1_ESM.pdf (120 kb)
Supplementary material 1 (PDF 119 kb)


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Copyright information

© Canadian Anesthesiologists' Society 2019

Authors and Affiliations

  • Simon Feng
    • 1
  • Joshua Greenberg
    • 2
  • Husein Moloo
    • 2
    • 3
  • Kednapa Thavorn
    • 3
    • 4
  • Daniel I. McIsaac
    • 1
    • 3
    • 4
    • 5
    Email author
  1. 1.Department of Anesthesiology and Pain MedicineThe Ottawa Hospital and University of OttawaOttawaCanada
  2. 2.Department of SurgeryThe Ottawa Hospital and University of OttawaOttawaCanada
  3. 3.Ottawa Hospital Research InstituteOttawaCanada
  4. 4.School of Epidemiology and Public HealthUniversity of OttawaOttawaCanada
  5. 5.Department of Anesthesiology & Pain MedicineThe Ottawa HospitalOttawaCanada

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