Research Article: Effects of intensive blood pressure lowering on mortality and cardiovascular and renal outcomes in type 2 diabetic patients: A meta-analysis

Date Published: April 12, 2019

Publisher: Public Library of Science

Author(s): Jing Wang, Yalei Chen, Weihao Xu, Nianfang Lu, Jian Cao, Shengyuan Yu, Jennifer A. Hirst.

http://doi.org/10.1371/journal.pone.0215362

Abstract

Previous studies have demonstrated that intensive blood pressure (BP) lowering treatment reduces the risk of all-cause mortality and provides greater vascular protection for patients with hypertension. Whether intensive BP lowering treatment is associated with such benefits in patients with type 2 diabetes mellitus remain unknown. We aimed to clarify these benefits by method of meta-analysis.

The PubMed, EMBASE, Science Citation Index and Cochrane Library databases were searched to identify randomized controlled trials (RCT) that fulfilled study inclusion criteria. Two investigators independently extracted and summarized the relevant data of the included trials. Random-effects model was applied to calculate the estimates of all effect measures.

We included 16 RCTs and our meta-analysis showed that intensive BP lowering treatment vs less intensive BP lowering treatment resulted in significant reductions in the all-cause mortality risk [relative risk (RR), 0.82; 95% CI, 0.70–0.96], major CV events (RR, 0.82; 95% CI, 0.73–0.92, MI (RR, 0.86; 95% CI, 0.77–0.96), stroke (RR, 0.72; 95% CI, 0.60–0.88, CV death (RR, 0.73; 95% CI, 0.58–0.92) and albuminuria progression (RR, 0.91 95% CI, 0.84–0.98). However, intensive BP lowering treatment had no clear effect on non-CV death (RR, 0.97; 95% CI, 0.79–1.20), heart failure (HF) (RR, 0.88; 95% CI, 0.71–1.08) or end-stage kidney disease (ESKD) (RR, 1.00; 95% CI, 0.75–1.33). Subgroup analysis showed that the reduction in all cause-mortality was consistent across most patient groups, and intensive BP lowering treatment had a clear benefit even in patients with systolic blood pressure lower than 140 mm Hg. However, the benefit differed in patients with different CV risk (≥10%: RR, 0.77, 95%CI, 0.64–0.91; <10%: RR, 1.04, 95%CI, 0.84–1.29; Phetero = 0.028). Our data indicate that intensive BP lowering treatment provides greater benefits than less intensive treatment among patients with type 2 diabetes mellitus. Further studies are required to more clearly evaluate the benefits and harms of BP targets below those currently recommended with intensive BP lowering treatment.

Partial Text

Diabetes mellitus (DM) is a global public health problem. DM is estimated to affect 116 million Chinese people, according to a recent epidemiological survey[1], and is estimated to affect 400 million individuals worldwide by the year of 2030[2]. People with DM are at high risk of cardiovascular (CV) events, such as stroke and myocardial infarction (MI), and all-cause mortality at any level of blood pressure (BP)[3–5].

This meta-analysis, which included 24,444 diabetic patients, demonstrates clear overall benefits for intensive BP lowering treatment. The risk of all-cause mortality was reduced by 18%, and the risks of most CV outcomes, including major CV events, MI, stroke and CV death, and albuminuria progression were also significantly reduced. However, there was no evidence to suggest that intensive BP lowering treatment reduced or increased the risk of non-CV death, HF or ESKD. The beneficial effect for all-cause mortality was consistent across most patient subgroups. Additionally, a significant benefit was achieved for those with baseline SBPs lower than 140 mm Hg and from further lowering the SBP to lower than 130 mm Hg. We also observed a possibility of a mortality benefit in trials that included patients with CV risks higher than 10% (P = 0.028).

In conclusion, this systematic review and meta-analysis provides clear evidence of the benefits of intensive BP lowering treatment for type 2 diabetic patients. The results also provide some supporting evidence for the latest BP guideline of lowering BP to a goal of <130/80 mm Hg. More well-designed RCTs are needed to further evaluate the benefits or harms of a goal of <130/80 mm Hg with intensive BP lowering treatment.   Source: http://doi.org/10.1371/journal.pone.0215362

 

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