Type 2 Diabetes and Ambulatory Surgery Patients
Condition: Diabetes Type 2
MeSH terms: Diabetes Mellitus, Type 2
Study type: Interventional
Phase: Phase 4

Summary: 
      Patients scheduled to undergo ambulatory surgery are usually made non per os (NPO) at
      midnight on the day prior to surgery. In the case of patients with type 2 diabetic mellitus
      (DM) on treatment with oral hypoglycemic agent (OHA), patients are instructed to temporarily
      discontinue treatment on the day prior to surgery. This advice is based on the concern for
      intraoperative and postoperative hypoglycemia in this group of patients. Metformin , a
      dimethylbiguanide, is widely used as an oral antihyperglycemic drug in the long term
      treatment of type 2 DM. This instruction to withhold treatment may be imprudent given that
      metformin by virtue of its mechanism of action does not cause hypoglycemia. Another concern
      often cited as a reason to withhold metformin is the reported adverse effect of lactic
      acidosis. However, a recent metanalysis by the Cochrane group found no cases of fatal or
      nonfatal lactic acidosis in 70,490 patient-years of metformin use, or in 55,451 patient-years
      for those not on metformin. Furthermore, discontinuing OHA treatment can result in disruption
      of established glycemic control and intraoperative and postoperative hyperglycemia all of
      which can be deleterious to the patient.

      We hypothesize that uninterrupted treatment with OHA in type 2 DM patients undergoing
      ambulatory surgery will not result in intraoperative and postoperative hypoglycemia (defined
      as blood glucose < 60mg/dl) compared to patients withholding OHA treatment on the day of
      surgery.
    

Detailed description: 
      Patients with established diagnosis of type 2 Diabetes Mellitus (DM) who are on OHA
      monotherapy or combination OHA and are scheduled to undergo ambulatory surgery will be
      identified. Informed consent will be obtained from 160 consecutive study participants.
      Patients will be randomized into 2 groups - OHA treatment on day of surgery (Metformin
      continue) (H1 group, n= 80) and patients not receiving OHA on day of surgery (OHA
      discontinue) (H0, n=80) as prescribed by their provider. All patients will be processed
      through the anesthesia preoperative clinic and instructions regarding preoperative medication
      handling will be provided to study participants by the investigator. The instructions will be
      reinforced by the clinic nursing staff in the usual fashion.

      On the morning of the surgical procedure, the investigator will verify that medication
      administration instructions provided to the study participant was adhered to. The patient
      will be checked-in into the ambulatory surgery suite and usual surgical preparatory
      procedures followed. Pre-anesthesia capillary blood glucose measurement will be performed and
      recorded in the pre-surgical area.

      Anesthesia will be induced and maintained in the usual fashion. Intraoperative capillary
      blood glucose levels will be checked and recorded.The investigator will ensure that glucose
      containing maintenance intravascular fluids are avoided throughout the anesthesia and surgery
      unless specifically indicated for treatment. All patients will be awakened and extubated at
      the end of surgery and transferred to the post anesthesia recovery (PAR) area as appropriate.
      Capillary blood glucose will be measured after arrival in the PAR. The capillary glucose
      tests obtained in this study is part of established and standard care and will be paid for by
      the patient.
    

Intervention name(s): Metformin continue; Metformin discontinue
Intervention type(s): Drug; Drug
Intervention description(s): Oral hypoglycemic agent continue on the day of ambulatory surgery; Oral hypoglycemic agent discontinue on the day of ambulatory surgery
Other intervention name(s): Metformin; Metformin
Intervention MeSH terms: Metformin
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention