Lifestyle Before Medication

A pharmacist's perspective on health and metabolic disease

Hyperinsulinaemia: Diagnosing the silent threat. (Youtube presentation)

I presented my thesis at the AUT Postgraduate Symposium (2015).  Here is the abstract of my presentation and a link to the video that was posted to Youtube .

“Hyperinsulinaemia, or chronically high levels of plasma insulin, heralds the onset of many non-communicable diseases including type 2 diabetes, vascular diseases, certain cancers, and dementia. This condition may affect a substantial proportion of population with no obvious signs or symptoms making the hyperinsulinaemia a “silent” condition. The difficulty with hyperinsulinaemia is the absence of a simple and reliable diagnostic test; fasting insulin is notoriously variable – even under controlled conditions. This presentation reports on my completed empirical research in the area understanding the risk of hyperinsulinaemia and recommending a reliable diagnostic test under the supervision of Prof Grant Schofield and Drs Caryn Zinn and Mark Wheldon.

During the course of my thesis I have conducted extensive literature reviews, secondary data analysis and primary data collection to draw together an understanding of hyperinsulinaemia and how it should be diagnosed.

My final study, and the topic of this presentation, considered whether the hyperinsulinaemia testing process could be simplified. The current testing process requires a fasting blood test, followed by consuming 100g glucose, then further blood tests at 30, 60, 120 and 180 minutes following the glucose load; a process with significant cost and time demands. Using the results of more than 7000 people who had this test performed, I could dichotomise these people into normal or high insulin tolerance patterns.   Then, using current clinical stratification, followed by sensitivity and specificity modelling, I developed an algorithm that determines the likelihood that a person is hyperinsulinaemic.

The results show that if a person has an elevated glycosylated haemoglobin (HbA1c) or fasting plasma insulin > 30 µU/mL, hyperinsulinaemia can be assumed. In people with normal glucose tolerance and fasting insulin ≤ 30 µU/mL, a 2-hour plasma insulin level ≥ 30 µU/mL should be considered diagnostic for hyperinsulinaemia (99% sensitivity and 62% specificity). Using a 2-hr insulin cut-off of 50 µU/mL the sensitivity and specificity became 72% and 99% respectively.

In the absence of an elevated HbA1c or fasting plasma insulin, a 2-hour plasma insulin > 30 µU/mL should be used to diagnose hyperinsulinaemia. Although the 62% specificity means that we may erroneously diagnose healthy people, the first line treatment is lifestyle change. This is preferred compared to wrongly concluding people with hyperinsulinaemia are healthy.

A 2-hr, 100g, oral glucose tolerance test with insulin assays should be the preferred test for clinical practice and future research in hyperinsulinaemia related conditions.”

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4 comments on “Hyperinsulinaemia: Diagnosing the silent threat. (Youtube presentation)

  1. Dr Dea Roberts MD
    November 6, 2015

    Catherine – great work, thanks! That info will really help make awareness of hyperinsulinemia more accessible, practical and thus help this concept move into routine clinical practice.
    I think you might want to reconsider the sentence “The results show that if a person has an elevated glycosylated haemoglobin (HbA1c) or fasting plasma insulin > 30 µU/mL, hyperinsulinaemia can be assumed.” and include a bit more description to clarify what you mean. Of course, an elevated HbA1c simply considered on it’s own without other data can mean hyperinsulimemia, hypoinsulinemia, or even “normal range” insulin levels in the face of high insulin resistance (i.e. late stage insulin resistance, with failure of sufficient pancreatic insulin response to meet elevated insulin demand to control blood glucose). I understand your meaning in terms of a useful testing protocol in those without diabetes, but I think it would be good to make the provisos more clear.
    Well done, and particularly thanks for making this video available – I will be sharing it often.

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    • pharmacistcatherine
      November 6, 2015

      Thanks Dea. As this was the abstract as written for the seminar, I thought I should publish it as written. It was really hard to convey such as complex topic in so few words. I do get your point, elevated HbA1c does not distinguish between type 1 and type 2 diabetes, so I will have another go at this shortly. I have a journal article under review at the moment that goes into this in a lot more detail, so as soon as that becomes available I will post it here as well. Thanks for your feedback. Catherine

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  2. Ian Young
    November 6, 2015

    Unfortunately an insulin cut-off can’t be used for this purpose, as different insulin assays give different results. You would need to have a different cut-off value which would depend on the assay used. See http://www.clinchem.org/content/53/4/711.full.pdf

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    • pharmacistcatherine
      November 8, 2015

      Hi Ian, Thanks for this reference – it isn’t one I currently have. Yes- insulin is a frustratingly fickle little protein to work with. Levels change whether you are working with plasma or serum and whether you use 6.0 or 6.945 to convert from pmol/L to mU/L. In an ideal world, we would determine each person’s full Kraft pattern for determine their insulin response status (I’ll post more about this shortly) but this is an expensive and time consuming study. This two-hour level is the best proxy I can find so far. I think one of the key points though is that fasting insulin doesn’t tell us much and we need to investigate post-prandial insulin levels. Hopefully also, on a clinical basis, the “dedicated instrumentation” are used more often than ELISA assays.

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This entry was posted on November 5, 2015 by in Uncategorized.
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