Reply




We much appreciate careful review and comments that Ms. Cooper and Dr. Laiteerapong have raised regarding the analysis of our report on preventable coronary heart disease (CHD) events in US adults with type 2 diabetes mellitus. Regarding the point about individualized glycemic goals, as noted, less intensive goals for glycated hemoglobin (HbA1c) (e.g., <8%) have been recommended for those with more complicated diabetes. Although we had excluded those with pre-existing cardiovascular disease at baseline from our analysis (because we are focusing on incident CHD), as a surrogate for “more complicated diabetes,” we looked how modifying those with a diabetes duration of ≥10 years to a goal of <8% would affect our results (while keeping those with a lesser duration at the previously stated goal of <7%). Instead of projecting 11.6% of CHD events would be prevented, had we used <7% for everyone (as in our report), we would now project prevention of 7.9% of CHD events.


It was also pointed out that the blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) reductions we proposed may be unrealistic. It should first be pointed out that the project was originally designed based on the BP goals of <130/80 mm Hg that were in effect until recent changes in guidelines. In addition, not everyone is “treated” but only patients who are above the prespecified goals (<130/80 mm Hg for BP, 100 mg/dl for LDL-C, and 7% for HbA1c). We did note that if we use the newer systolic BP goal of <140 mm Hg, it does change the proportion of CHD events preventable from 6.7% to 4.0%, although this has a negligible effect on the effect of all risk factor control from prevention of 38.3% of CHD events to 36.3%. Regarding total cholesterol, again it is important to know that we are only “treating” those above our specified goal of 170 mg/dl (roughly equivalent to LDL-C of 100 mg/dl; however, UK Prospective Diabetes Study had total cholesterol and not LDL-C in their equation, so we had to use the former). Given powerful moderate- or high-intensity statins that are frequently given to those with diabetes and now recommended in the new American College of Cardiology/American Heart Association guidelines, which often result in LDL-C or total cholesterol reductions of 50%, we believe our model is neither uncommon nor unrealistic.


The suggestion from Ms. Cooper and Dr Laiteerapong for programming a lower limit for SBP is certainly consistent with concerns and findings of recent trials. If we program a lower limit of 130 mm Hg, it results in 4.2% and 4.8% of events prevented from nominal and aggressive control of systolic BP, respectively, in contrast to 6.7% and 10.2% of events prevented as we currently report.


On the issue of our chosen percentage reductions, they were based on what was believed to be realistically achievable by currently available therapies based on nominal and intensive control scenarios. It is important to note that the HbA1c reductions of 1% and 2% were “absolute” reductions, whereas the systolic BP and total cholesterol reductions and high-density lipoprotein cholesterol increases were “relative” changes.


Overall, from the effect of individualizing HbA1c goals to 8% for those with longer duration diabetes (as noted previously) and setting a cap of 130 mm Hg for SBP, this would minimally affect our estimates of preventable CHD events from control of all risk factors in the nominal control scenario to 36.3% (previously 36.7%) and aggressive control to 49.6% (previously 54.8%).


We again do appreciate the suggestions from Ms. Cooper and Dr. Laiteerapong, which when accounting for both individualized goals for HbA1c and using lower limits for systolic BP would have a minimal effect on reducing our estimates of preventable CHD events.

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Dec 1, 2016 | Posted by in CARDIOLOGY | Comments Off on Reply

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