Continue or Withhold? Perioperative SGLT2 Inhibitors and Cardiorenal Outcomes: A Systematic Review and Meta-Analysis

Every year, millions of people undergo surgical procedures, from heart valve replacements to the insertion of stents to open blocked arteries. These interventions are life-saving, but they place a heavy burden on the body's internal machinery. The heart and kidneys, working in tandem to filter blood and maintain balance, face sudden stress from the surgery itself, the use of contrast dye to guide instruments, and the temporary interruption of blood flow. For decades, doctors have managed a specific class of medications called SGLT2 inhibitors with caution during these times. These drugs, originally designed to lower blood sugar in people with diabetes, work by helping the kidneys remove excess sugar through urine. Because they alter how the kidneys handle fluids and salts, and because there was a theoretical fear that stopping blood sugar control right before surgery could lead to dangerous metabolic shifts, the standard advice was often to pause the medication. The question remained: was this pause necessary, or was it depriving patients of a shield that could protect their organs during the most vulnerable moments of their recovery?

A comprehensive new analysis, bringing together data from forty-seven different studies, has begun to answer this question with surprising clarity. Researchers scoured medical records from around the world, including extensive databases in China, to compare the outcomes of patients who continued taking these drugs through their surgery against those who stopped. They looked at a wide range of procedures, including open-heart surgery, minimally invasive valve replacements, and procedures involving the heart's arteries. The goal was to see if keeping the medication on board offered any protection against acute kidney injury, a common and serious complication where the kidneys suddenly stop filtering waste effectively, or if it improved survival rates and reduced dangerous heart rhythm disturbances.

The findings suggest that the old rule of thumb may need to be rewritten. The analysis revealed that patients who continued taking SGLT2 inhibitors during their perioperative period—the time leading up to, during, and immediately after surgery—were significantly less likely to suffer from acute kidney injury. This protective effect was particularly strong in specific scenarios. For patients undergoing transcatheter aortic valve replacement, a procedure where a new valve is inserted through a blood vessel, the risk of kidney damage was cut by more than half. Similarly, in patients having open-heart surgery involving a heart-lung machine, those who stayed on the medication saw a dramatic reduction in kidney injury compared to those who did not. The benefit extended to procedures using contrast dye as well, where the drugs appeared to shield the kidneys from the toxic effects of the dye.

Beyond protecting the kidneys, the data pointed to broader benefits for the heart itself. In populations undergoing valve replacements or procedures for heart attacks, patients who continued their medication had lower rates of death from any cause. The analysis also uncovered a striking reduction in new-onset atrial fibrillation, a chaotic and rapid heart rhythm that often complicates recovery after surgery. Patients taking the drugs were far less likely to develop this condition than those who did not. Perhaps most reassuring for clinicians and patients alike was the safety profile. The feared risk of diabetic ketoacidosis, a serious condition where the body produces high levels of blood acids, was extremely rare. In the entire collection of studies, only a single case was reported among those who continued the medication, and there was no increase in low blood sugar or the need for additional surgeries.

The researchers noted that the benefits were not identical for every drug in the class. The evidence was strongest and most consistent for a specific drug called dapagliflozin, which showed a uniform protective effect with no statistical variation across the studies that used it. While other drugs in the same family showed promise, the data for them was more mixed, suggesting that the specific chemical structure of the medication might matter. The study also highlighted that the protection seemed to happen quickly. In one large randomized trial, patients who took just four doses of the drug starting the day before surgery saw a massive reduction in kidney injury, indicating that the benefit comes from an immediate physiological effect rather than long-term changes to the body.

This body of work challenges the long-held practice of routinely stopping these medications before surgery. While the authors caution that the decision should still be individualized, particularly for patients facing major surgery with long periods of fasting where metabolic risks might be higher, the overall message is one of continuity. The data suggests that for many patients, the safety net provided by these drugs is active and effective precisely when the body is under the most stress. Rather than removing a layer of protection, continuing the medication appears to help the heart and kidneys withstand the shock of surgery, leading to fewer complications and better survival rates. As more randomized trials are conducted to confirm these observations, the standard of care for managing these patients may shift from a strategy of caution to one of confidence, keeping the protective shield in place when it is needed most.