Prediabetes Or Diabetes

The goal of this study is to measure the prevalence and risks of hyperglycemia in surgical patients with prediabetes. The main questions it aims to answer are: * What is the prevalence of hyperglycemia in surgical patients with prediabetes? * What is the relative risk of postoperative complications associated with hyperglycemia? To answer these questions, surgical patients with prediabetes will undergo universal glucose measurement in the perioperative period. Glucose data will be analyzed in conjunction with electronic health record (EHR) data describing patient outcomes.

This study will test whether glucose sensor data can be used to identify the time of day when adults with prediabetes are most likely to have high blood sugar after meals. Participants will first wear a continuous glucose monitor and wrist activity monitor and record meal times for 10 days. These data will be used to classify each participant's personal "glycemic vulnerability window," such as morning, evening, or generally variable patterns. Participants will then be randomly assigned to either personalized meal timing plus a short walk after their most vulnerable meal, or to an attention-matched control group receiving sleep hygiene and general step-count advice. The main outcome will be the change in post-meal glucose exposure during each participant's vulnerable window after 4 weeks.