Meta-Analysis
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Meta-Anal. Oct 28, 2020; 8(5): 400-410
Published online Oct 28, 2020. doi: 10.13105/wjma.v8.i5.400
Comparing the incidence of major cardiovascular events and severe microvascular complications in patients with type 2 diabetes mellitus: A systematic review and meta-analysis
Ying-Ying Zhu, Zu-Yao Yang, Ping Li, Xin-Ying Huang, Xue-Hong Zhang, Li-Nong Ji, Jin-Ling Tang
Ying-Ying Zhu, Zu-Yao Yang, Ping Li, Xin-Ying Huang, Jin-Ling Tang, Division of Epidemiology, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
Xue-Hong Zhang, Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, United States
Li-Nong Ji, Department of Endocrinology and Metabolism, Peking University People's Hospital, Peking University Diabetes Centre, Beijing 100044, China
Author contributions: Tang JL conceived the research idea and supervised the study; Zhu YY, Yang ZY, Li P and Huang XY were involved in data collection, including literature search, study selection, and data extraction; Zhu YY, Li P and Huang XY were involved in data analysis with the guidance of Tang JL and Yang ZY; Zhu Y drafted the manuscript; Tang JL, Yang ZY, Ji LN and Zhang XH critically reviewed and revised the manuscript; the corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.
Conflict-of-interest statement: The authors deny any conflict of interest.
PRISMA 2009 Checklist statement:  The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Jin-Ling Tang, MD, PhD, Professor, Division of Epidemiology, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, 4/F, School of Public Health Building, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China. jltang@cuhk.edu.hk
Received: May 27, 2020
Peer-review started: May 27, 2020
First decision: September 14, 2020
Revised: October 9, 2020
Accepted: October 27, 2020
Article in press: October 27, 2020
Published online: October 28, 2020
Processing time: 154 Days and 5.7 Hours
Abstract
BACKGROUND

Type 2 diabetes mellitus (T2DM) causes both macrovascular and microvascular complications. However, currently, selection of glycemic measures and their thresholds to diagnose T2DM, and efficacy outcomes in evaluation of anti-diabetic drugs is predominantly informed by the relation of T2DM to microvascular complications. We can be severely mistaken on T2DM by neglecting macrovascular complications which are generally more severe, if they also occur more commonly than microvascular complications.

AIM

To compare the incidence of major cardiovascular events (MACEs) and severe microvascular complications (SMICs) in T2DM patients.

METHODS

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched from inception to September 2017. Cohort studies or trials of T2DM patients aged 18 years or older that reported incidence of both MACEs and SMICs were included. MACEs were defined as nonfatal myocardial infarction and stroke, and cardiovascular death, while SMICs included serious retinopathy, nephropathy and diabetic disorder. The relative risk (RR) was estimated as the incidence of MACEs divided by that of SMICs in same patients and combined with meta-analysis in a random-effect model.

RESULTS

Twelve studies with a total of 16 cohorts and 387376 patients were included, and the combined RR was 2.02 (95%CI: 1.46–2.79). The higher incidence of MACEs remained in various subgroup and sensitivity analyses.

CONCLUSION

Patients with T2DM are much more likely to develop MACEs than SMICs. By taking more serious consequences and relatively higher incidence into consideration, macrovascular complications deserve more emphasis in developing the diagnostic criteria of T2DM and in evaluating the efficacy of anti-diabetic drugs.

Keywords: Diabetes mellitus; Diabetic complications; Cardiovascular disease; Diabetic retinopathy; Diagnostic criteria; Anti-diabetic drugs

Core Tip: Microvascular complications currently predominate the definition and treatment evaluation of type 2 diabetes mellitus (T2DM). We can be severely mistaken by neglecting macrovascular complications which are generally more severe, if they also occur more commonly than microvascular complications. This systematic review and meta-analysis shows that major cardiovascular events are twice as common as severe microvascular complications in T2DM patients, suggesting that macrovascular complications should be emphasized over microvascular complications in developing the diagnostic criteria of T2DM and in evaluating the efficacy of anti-diabetic drugs.