- Preoperative (≤180 days) metformin prescriptions (PMPs) are associated with reduced postoperative mortality and readmission following major surgery in patients with diabetes.
Why this matters
- Almost 50% of people with type 2 diabetes require surgery during their lifetime.
- Health system electronic health record data for 10,088 adults with diabetes who underwent a major operation during 2010-2016.
- 59% had PMPs, and 54% were propensity score matched (2730 each with and without PMPs), followed until December 18, 2018.
- Funding: UPMC; NIH.
- PMPs were associated with significant absolute risk reduction (ARR) for mortality by day 90: 1.28% (0.26%-2.31%).
- No reduction seen at day 30, however.
- Patients with PMPs had lower HR for mortality by:
- Day 90: 0.72 (P=.02); and
- Year 5: 0.74 (P=.001).
- With PMP, significant ARRs (95% CIs) were observed for readmission by:
- Day 30: 2.09% (0.35%-3.82%); and
- Day 90: 2.78% (0.62%-4.95%).
- Association also seen with death as a competing risk at:
- Day 30: sub-HR, 0.84 (0.72-0.98);
- Day 90: 0.86 (0.77-0.97).
- Patients with PMPs had significantly lower mean preoperative neutrophil-to-leukocyte ratio vs no metformin (4.5 vs 5.0; P<.001>
- Potential residual confounding.
- Single health care system database.
- Death, readmission likely underrepresented.
- Operative duration, metformin dose unknown.
- Multiple surgery types.