December’s Paper of the Month looks at whether defunctioning ileostomies, which are commonly used to protect low rectal anastomoses, pose a risk of short- and long-term kidney injury, and what happens after stoma reversal.
The impact of defunctioning ileostomies on postoperative kidney function in rectal cancer surgery
Gustav Sandén, Ida Hed Myrberg, Sol Erika Boman, Caroline Nordenvall, Juan-Jesus Carrero, Peter Matthiessen, Martin Rutegård
Colorectal Disease. 2025;27:e70329. doi:10.1111/codi.70329
What is known about the subject
Low anterior resection for rectal cancer carries a substantial risk of anastomotic leakage, particularly for low anastomoses; defunctioning stomas (most commonly loop ileostomies) help to mitigate the risk of clinically significant leaks and their consequences. However, these ileostomies are not always reversible and can lead to dehydration, electrolyte imbalances, and acute kidney injury (AKI), particularly in cases of high-output stoma. Previous registry studies have suggested an association between defunctioning ileostomies and renal failure but they did not clearly differentiate between acute and chronic kidney outcomes, nor did they adjust for important socioeconomic confounders.
There is a lack of robust, population-based data specifically investigating kidney outcomes as well as the effects of stoma reversal and anastomotic leakage after low anterior resection.
What the study adds
Using the nationwide Swedish CRCBaSe registry linkage, the authors identified 5,286 patients (aged ≤80 years, ASA class ≤III and tumour height ≤12 cm) who underwent elective anterior resection for rectal cancer between 2007 and 2021. Of these patients, 4,623 (87%) received a defunctioning ileostomy, while 663 (13%) did not. Propensity score overlap weighting balanced a wide range of clinical and socioeconomic variables between the two groups. Follow-up was limited to 5 years in order to assess kidney outcomes. Defunctioning ileostomy was not found to significantly increase the risk of chronic kidney failure requiring dialysis or transplantation, nor of chronic kidney disease overall (HR 1.69 and 1.65, respectively, both non-significant). However, ileostomy formation was associated with a threefold increase in acute kidney injury (AKI) (HR 3.01, 95% CI 1.61–5.64) and a fourfold increase in dehydration (HR 4.01, 95% CI 2.32–6.93), particularly in the early postoperative period.
Stoma reversal markedly reduced the risk: among patients with ileostomies, reversal (within or after 90 days) was associated with lower rates of acute kidney injury (HRs ~0.2–0.4 vs no reversal). This suggests that renal impairment may be partially reversible once bowel continuity is restored. Defunctioning ileostomies decreased the incidence of clinically evident anastomotic leakage (OR 0.59 vs no stoma), and leakage itself increased the risk of AKI and dehydration. However, mediation analysis showed only a minor indirect effect through leakage - most of the renal risk appears to be directly linked to the ileostomy and its physiological effects. Sensitivity analyses limited to minimally invasive surgery, low tumours (≤10 cm), or registered total mesorectal excision confirmed the pattern of increased short-term kidney injury and dehydration associated with ileostomy, with no clear indication of accelerated progression to end-stage renal disease within five years.
Implications for colorectal practice
- When counselling patients undergoing low anterior resection, surgeons should not only discuss the mitigating effect of defunctioning ileostomies on anastomotic leakage but also the substantially increased risk of early dehydration and acute kidney injury (AKI).
- Perioperative pathways for patients with defunctioning ileostomies should prioritise kidney protection by providing proactive stoma education, monitoring of fluid balance and renal function closely, enabling the early recognition and management of high-output stomas, and ensuring rapid access to stoma nurses and medical support.
- Particular vigilance is warranted in patients with baseline renal vulnerability or significant co-morbidities, for whom options such as a defunctioning colostomy or selective omission of a stoma when the risk of leakage is deemed low may be worth considering.
- Timely stoma reversal appears to be beneficial for renal health and should be considered where clinically feasible; prolonged diversion without a clear indication may expose patients to unnecessary kidney risks.
Overall, this work confirms that defunctioning ileostomies do not clearly increase the progression to end-stage renal disease within five years. However, it emphasises that kidney injury might be a relevant short-term consequence of diversion. This should be considered when deciding on the creation and type of stoma in rectal cancer surgery and included in counselling.
References
- Sandén G, Hed Myrberg I, Boman SE, Nordenvall C, Carrero J-J, Matthiessen P, et al. The impact of defunctioning ileostomies on postoperative kidney function in rectal cancer surgery. Colorectal Dis. 2025;27:e70329. https://doi.org/10.1111/codi.70329
- Matthiessen P, Hallböök O, Rutegård J, Simert G, Sjödahl R. Defunctioning stoma reduces symptomatic anastomotic leakage after low anterior resection of the rectum for cancer: a randomized multicenter trial. Ann Surg. 2007;246(2):207–214. https://doi.org/10.1097/SLA.0b013e3180603024
- Gessler B, Haglind E, Angenete E. A temporary loop ileostomy affects renal function.
Int J Colorectal Dis. 2014;29(9):1131–1135. https://doi.org/10.1007/s00384-014-1949-0 - Rutegård M, Häggström J, Back E, Holmgren K, Wixner J, Rutegård J, Matthiessen P, Sjöström O. Defunctioning loop ileostomy in anterior resection for rectal cancer and subsequent renal failure: nationwide population-based study. BJS Open. 2023 May 5;7(3):zrad010. https://doi.org/doi:10.1093/bjsopen/zrad010