1. Metformin and Kidney Function:

   • Metformin is used cautiously in those with impaired kidney function due to the risk of lactic acidosis. It doesn't directly increase creatinine but kidney issues can.

2. Sitagliptin:

   • Generally safe for kidneys, but dose adjustments are necessary if kidney function declines.

3. Bypass Surgery Impact:

   • Surgery can affect kidney function, potentially raising creatinine levels.

4. Insulin:

   • Does not raise creatinine levels.

Recommendation:

• Increased creatinine is likely due to surgery's impact on kidneys, not Janumet. Monitor kidney function closely and consult your cardiologist or nephrologist for medication adjustments.