Good point.
2023 stats below. This study was done in Italy and published on the website of the U.S. National Institute of Health.
Studies of predictive prognosis indices, incidence of postoperative complications, and survival rates in different geographical areas may not be comparable.
Primary prediction criteria for survival:
… age, body condition score (BCS), packed cell volume (PCV) and total plasma protein (TPP) before and after surgery, amount of reflux, type of disease, type of lesion, duration of surgery and surgeon’s experience, and amount of intra- and postoperative fluids administered affected the outcome.
The multivariate analysis revealed that PCV at arrival, TPP after surgery, and BCS had the highest predictive power.
Colic surgery, despite the improvements in recent years, is not without risks and still has a high risk of death compared with other procedures. Although about 90% of cases of colic in horses resolve spontaneously or with medical treatment, the remaining 10% can be fatal if not treated surgically. [Italian study.]
Furthermore, postoperative complications can have important welfare and economic consequences.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10044551/#:~:text=The%20survival%20rate%20was%2068.5,of%20the%20horses%20surviving%20anaesthesia.
I’m noting that they say ‘survival’, so I’m assuming that means being alive after the operation for some period of time. Days? Weeks?
It does not say ‘recovery’. Or what degree of recovery. Or what life was like for the horse, post-surgery, post-recovery. As is proper for definitive research, the study was focused narrowly around a small criteria.
So … what does this study tell us? Someone with more background in medical studies and in vet medicine generally could say better than me.