There was a very important study done which reflects on the question of which is a better predictor for CHD, a high insulin level or high blood glucose level.
This is important since the standard treatment for advanced diabetes is to increase insulin with the goal being to keep the blood glucose levels low. But is this the smartest strategy? Results from the Helsinki Policemen Study cohort indicate that reducing blood glucose at the cost of increasing insulin levels is not a wise approach (Acta Med Scand Suppl. 1985;701:38-52. Plasma insulin as coronary heart disease risk factor: relationship to other risk factors and predictive value during 9 1/2-year follow-up of the Helsinki Policemen Study population. Pyörälä K, Savolainen E, Kaukola S, Haapakoski J.).
The test subjects were.
982 men aged 35—64 years and free of coronary heart disease (CHD) at entry plasma insulin level (fasting, 1-hour and 2-hour plasma insulin after oral glucose load) … during a 9½-year follow-up
The result was.
Plasma insulin levels showed positive correlations, besides to blood glucose levels, to body mass index, plasma triglyceride level and blood pressure and inverse correlations to leisure time physical activity and objectively measured physical fitness.
So all of that makes some sense if you understand insulin sensitivity. But here is the unexpected part.
In multivariate analyses the predictive value of high plasma insulin with respect to CHD risk was found to be independent of other risk factors, including blood glucose levels.
Insulin levels are a better predictor than blood glucose levels. That sounds exactly the opposite of conventional wisdom. What I find particularly disturbing is that this study was done in 1985.
A similar study which looked at other studies concluded (The American Journal of Clinical Nutrition, Volume 98, Issue 6, 1 December 2013, Pages 1543–1554, https://doi.org/10.3945/ajcn.113.065565. Fasting insulin concentrations and incidence of hypertension, stroke, and coronary heart disease: a meta-analysis of prospective cohort studies. Pengcheng Xun Ying Wu Qianchuan He Ka He).
A higher fasting insulin concentration or hyperinsulinemia was significantly associated with an increased risk of hypertension and CHD but not stroke.