targeting glucose metabolism to stop strokes iris: insulin resistance … · 2019. 4. 15. ·...
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Targeting Glucose Metabolism to Stop Strokes IRIS: Insulin Resistance In Stroke study
Professor Gary Ford Chief Executive Officer, Oxford Academic Health Science Network Consultant Stroke Physician, Oxford University Hospitals Visiting Professor of Clinical Pharmacology, Oxford University UK Stroke Forum, Liverpool 29 November 2016
Insulin Resistance
Consequences: • Hyperinsulinemia • Hyperglycemia • Dyslipidemia • Inflammation • Vascular Smooth Muscle Cell Proliferation • Endothelial Dysfunction
A physiological state in which a normal amount of insulin produces a subnormal cellular response.
Insulin Resistance
• Associated with increased risk for Stroke Myocardial Infarction Diabetes
• Affects > 50% stroke patients without diabetes • Present in almost all patients with Type II
Diabetes
Excess Nutrient Intake Aging Diet Inactivity Genetics
Cellular Stress
Insulin Resistance
Increased Serum Glucose Metabolic Disease
CVD, Diabetes, Cancer
Tissue Inflammation Serum Free Fatty
Acids
JI Odegaard Science 2013;339:172
Insulin Resistance
Hyperglycaemia and Ischaemic Stroke Risk
T. Rundek Arch Neurol 2010;67:1195-1200. Emerg RF Collab Lancet 2010;375:2215. M Hyvarinen Stroke 2009;40:1633. AR Folsom Diab Care 1999;22:1077. EL Thacker Stroke 2011;42:3347
Adjusted RR for Stroke
Pioglitazone • Thiazolidinedione, ligand for
peroxisome proliferator-activated receptors (PPARs). Alters the transcription of genes
• Improves insulin sensitivity through its action at PPAR γ1 and PPAR γ2, and affects lipid metabolism through action at PPAR α
• ↑ glucose uptake and utilisation in peripheral organs, ↓ liver gluconeogenesis ↓ insulin resistance
IRIS – Insulin Resistance after Stroke Research Aims
IRIS – Insulin Resistance after Stroke Study Design
IRIS – Definition of Insulin Resistance
HOMA-IR = Fasting insulin (µU/ml) x Fasting glucose (mmol/L)
22.5
For IRIS, insulin resistance = HOMA-IR > 3.0
Homeostasis Model Assessment of Insulin Resistance
7634 Screened with HOMA Blood Test
3895 Randomized
1948 Pioglitazone 1947 Placebo
2796 (37%) Not Insulin Resistant
1939 Analyzed 1937 Analyzed
9 excluded 10 excluded
4865 (63%) Insulin Resistant
564 Retracted consent 379 Excluded other reasons
Randomisation by Country
USA Australia
Italy
Germany
Canada
UK
Israel
IRIS - Baseline Features
Pioglitazone (N=1939)
Placebo (N=1937)
Age, mean years 63.5 63.5 Male sex 67% 64% Black race 11% 12% Stroke at entry (vs. TIA) 87% 87% NIHSS ≥ 5 5% 4% Atrial Fibrillation 7% 7% Mean BMI, mean kg/m2 29.9 30.0 Event to rand, median d. 81 79
IRIS – Primary Outcome
Months in Trial
Cumulative Event-Free
Survival Probability
IRIS – Time to onset of Diabetes
Pioglitazone (N=1939)
Placebo (N=1937)
% (No.) % (No.) Hazard Ratio
(95% CI) P
Stroke or MI 9.0 (175) 11.8 (228) 0.76
(0.62, 0.93) 0.007 Cumulative
Incidence of Diabetes
Months in Trial
IRIS – Serious Adverse Events
Pioglitazone (N=1939)
Placebo (N=1937)
% (No.) % (No.) Hazard Ratio
(95% CI) P
Stroke or MI 9.0 (175) 11.8 (228) 0.76
(0.62, 0.93) 0.007
IRIS – Other Adverse Events
Pioglitazone (N=1939)
Placebo (N=1937)
% (No.) % (No.) Hazard Ratio
(95% CI) P
Stroke or MI 9.0 (175) 11.8 (228) 0.76
(0.62, 0.93) 0.007
IRIS – Summary of Results
• Among insulin resistant, non-diabetic patients with ischemic stroke or TIA, pioglitazone prevented:
Stroke or MI Absolute Risk Reduction = 2.9% Relative Risk Reduction = 24% Diabetes Absolute Risk Reduction = 3.9% Relative Risk Reduction = 52% • However, bone fracture requiring surgery or
hospitalization was more common with pioglitazone: 5.1% vs. 3.2% over 5 years
IRIS – Implications for Future Research
• Improving insulin resistance with thioglitazones reduced stroke risk
• Key proof of concept study • Trials of other therapies that reduce insulin resistance
should be considered - increased physical activity - obesity - other therapeutic agents
• Measure insulin resistance in future secondary prevention trials of other approaches to refine cardiovascular risk
IRIS – What the Guidelines say
• 2016 National Clinical Guidelines for Stroke • “People with stroke or TIA should not receive pioglitazone
for secondary vascular prevention.” • …..for every 100 patients treated with pioglitazone for about 5 years, 3 fewer
would suffer stroke or MI; 4 fewer would develop diabetes mellitus; 2 more would suffer bone fracture requiring hospitalisation; 18 more would gain >4.5 kg in weight, and 11 more would have new or worsening peripheral oedema. The study did not report quality of life outcomes and more evidence would be required before glitazone treatment can be recommended routinely for patients with insulin resistance. Targeting lifestyle modification, particularly exercise and diet, appears to be a safe and effective approach for reducing insulin resistance and progression to diabetes
IRIS – Implications for Clinical Practice • Consider introduction routine assessment insulin resistance
after TIA and ischaemic stroke • Promote interventions that reduce insulin resistance –
physical activity, weight loss, diet • Overall risk and benefit of pioglitazone therapy unclear. • In stroke survivors who remain insulin resistance – perhaps
pioglitazone should be an option available to informed patients, with registry follow up.
• 28 tab pack - Pioglitazone 30 mg £1.42 i.e. £17 / year
Increasing Physical Activity – Gym Members hip