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How Hypertension Increases Risk for Diabetes and CVD

Feb 26, 2019
 

Author: Steve Freed, R.PH., CDE


New study shows 25% increase in diabetes for each 1-mmol/L increase in 2-hour plasma glucose at baseline.

Hypertension is more prevalent in people with impaired glucose tolerance (IGT), but whether higher blood pressure per se or the mild hyperglycemia in combination with the hypertension enhanced the risk of cardiovascular disease (CVD) remains unclear.

Five hundred and sixty-eight participants with IGT in the original Da Qing diabetes prevention study, 297 with hypertension (HBP) and 271 without hypertension (NBP), were enrolled in 1986 and the intervention phase lasted for 6 years. In 2009, they were followed up to assess the outcomes of cardiovascular events (including stroke and myocardial infarction) and incidence of diabetes.

The results are important since adults with impaired glucose tolerance and hypertension are at greater risk for diabetes and cardiovascular disease events than those without hypertension, according to findings published in the Journal of Diabetes.

The study also showed a 9% increase in diabetes risk for every 10-mm Hg increase in systolic blood pressure among patients with hypertension. The researchers also found that those with hypertension at baseline had a higher risk for cardiovascular events, compared with participants without hypertension. The findings were based on a post hoc analysis of the Da Qing Diabetes Prevention Study.

The original study measured 2-hour plasma glucose levels after a breakfast of 100 g of steamed bread among 110,660 adults in China in 1986. Participants then attended biannual follow-up for 6 years.

They conducted their analysis as a 23-year follow-up in 568 participants who had IGT from the original study to assess diabetes prevalence and the incidence of CVD events. The cohort was divided into two groups, with one composed of participants with hypertension at baseline (n = 297; mean age, 47.4 years; 43.4% women) and the other composed of participants without hypertension (n = 271; mean age, 42.8 years; 48% women).

The researchers found a higher incidence of diabetes in participants with hypertension at baseline (80.8%) compared with participants without hypertension (72.3%; P = .02). Participants with hypertension at baseline were 26% more likely to develop diabetes (HR =1.26%; 95% CI, 1.04-1.54) than their nonhypertensive counterparts.

For every 1-mmol/L increase in 2-hour plasma glucose at baseline in participants with hypertension, there was a 25% increase in risk for diabetes (HR = 1.25; 95% CI, 1.08-1.44). The same participants had a 9% increase in risk for diabetes development for every 10-mm Hg increase in systolic blood pressure (HR = 1.09; 95% CI, 1.02-1.16). For participants without hypertension, the associated increase in risk for diabetes development was 36% (HR = 1.36; 95% CI, 1.16-1.6) for every 1-mmol/L increase of 2-hour plasma glucose. However, an association between systolic BP and diabetes development was not found in this group.

The risk for CVD events was higher for participants with hypertension at baseline (46.2%) compared with participants without hypertension (31.5%; P =. 04). This equated to a 35% higher risk for a CVD event for participants with hypertension (HR = 1.35; 95% CI, 1.01-1.81). CVD event incidence was higher after the development of diabetes for participants with hypertension (HR = 1.77; 95% CI, 1.21-2.58) and without (HR = 2.09; 95% CI, 1.22-3.59). The researchers noted a 97% higher risk for a CVD event associated with the progression from IGT to diabetes (HR = 1.97; 95% CI, 1.38-2.8). Additionally, for every 10-mm Hg increase in systolic BP, there was a 7% increase in risk for a CVD event (HR = 1.07; 95% CI, 1.01-1.12).

Current evidence recognizes that patients with IGT have a higher risk and should be treated more aggressively to prevent CV events.

From the results, it was concluded that hypertension predicted diabetes and enhances long-term risk of CVD events in patients with IGT. An individualized strategy that targets hypertension as well as hyperglycemia is needed for diabetes and its cardiovascular complications.

The findings in the study suggest that preventing the onset of diabetes and decreasing the BP should be considered key strategies for reducing the macro-complications of diabetes.

Practice Pearls:

  • The results of this paper is a post-hoc analysis of the original Da Qing Prevention Study.
  • The findings showed that hypertension per se not only led to a higher incidence of cardio-cerebral-vascular disease, but also increased the risk of cardiovascular disease events by accelerating the development of diabetes among subjects with impaired glucose tolerance.
  • It suggested that an individualized intervention targeting to manage hypertension together with preventing the development of diabetes may favor the reduction of the diabetes-related macro-complications among the impaired glucose tolerance population with hypertension.

First published: 16 December 2018   https://doi.org/10.1111/1753-0407.12887