Insulin Therapy and Falls Due to Orthostatic Hypotension

Overview

In the proposed study, the investigators examine in older adults with Type 2 diabetes the impact of beginning insulin therapy on the orthostatic drop in blood pressure as well as the response of arterial blood pressure and Doppler measures of cerebral blood flow during upright tilt. The investigators hypothesize that in older adults with Type 2 diabetes, the cardiovascular effects of insulin would precipitate or worsen orthostatic intolerance not present at baseline.

Full Title of Study: “Insulin Therapy and Falls Due to Orthostatic Hypotension (Pilot Study)”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Non-Randomized
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Diagnostic
    • Masking: None (Open Label)
  • Study Primary Completion Date: January 2, 2018

Detailed Description

Before and 2 weeks after the start of standard insulin therapy several tests will be done: – orthostatic hypotension will be tested for with 3 orthostatic maneuvers – vasovagal syncope will be tested with 2 tilt table tests, one augmented with 400ug of nitroglycerin – MCA velocity will be measured with a transcranial doppler – Heart Rate and Blood Pressure will be measured throughout the test with a Finometer and Power Lab on a beat to beat basis

Interventions

  • Other: Insulin
    • Initiation of insulin administration will be determined as part of standard of care by the subjects diabetologist in the VGH Diabetes Centre and not as part of participation in this study.
  • Other: No Insulin
    • Study session will occur prior to initiation of insulin therapy.

Arms, Groups and Cohorts

  • Other: Before Initiation of Insulin Therapy
    • Study sessions will occur before the initiation of insulin therapy (no insulin). Initiation of insulin administration will be determined as part of standard of care by the subjects diabetologist in the VGH Diabetes Centre and not as part of participation in this study.
  • Other: After Initiation of Insulin Therapy
    • Study session will take place 2-4 weeks after the initiation of insulin therapy. Initiation of insulin administration will be determined as part of standard of care by the subjects diabetologist in the VGH Diabetes Centre and not as part of participation in this study.

Clinical Trial Outcome Measures

Primary Measures

  • 1. Presence or absence of orthostatic hypotension
    • Time Frame: 1 day
    • defined as a drop in systolic blood pressure greater than 20 mmHg after 3 minutes upright standing

Secondary Measures

  • 1. The nadir of middle cerebral artery (MCA) velocity
    • Time Frame: 1 day
    • lowest middle cerebral artery flow velocity determined by transcranial Doppler
  • 2. The presence or absence of a positive augmented tilt table test
    • Time Frame: 1 day
    • The augmented tilt table test will occur after receiving 300 μg nitroglycerin (GTN), and is a recognized method of testing for risk of vasovagal syncope. The tilt table will be considered positive and aborted prior to the 20 minutes if the subjects have a syncopal spell or demonstrate presyncopal (lightheadedness) symptoms in association with a 30 mm Hg drop in systolic blood pressure.
  • 3. The nadir of systolic blood pressure (SBP) and diastolic blood pressure (DBP) during tilt table test.
    • Time Frame: 1 day
    • lowest systolic blood pressure and diastolic blood pressure during tilt table tests and when they occur.

Participating in This Clinical Trial

Inclusion Criteria

  • All subjects must be 65 years of age or older – All must have been diagnosed with Type 2 diabetes for at least 5 years – All subjects must be insulin-naïve on recruitment – All subjects must be eligible to start insulin therapy (long or intermediate acting) as determined by their diabetologist Exclusion Criteria:

  • Anemia, as determined by serum hematocrit – Abnormal liver function tests – Elevated creatinine – Smoker – Musculoskeletal or neurological condition that would preclude tilt table testing or orthostatic vitals

Gender Eligibility: All

Minimum Age: 65 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • University of British Columbia
  • Provider of Information About this Clinical Study
    • Principal Investigator: Kenneth Madden, Principal Investigator – University of British Columbia
  • Overall Official(s)
    • Kenneth M Madden, MD, Principal Investigator, University of British Columbia

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