Higher risk of adverse cardiovascular outcomes in women with type 2 diabetes mellitus: an umbrella review of systematic reviews

Funding Acknowledgements

Type of funding sources: None.

Background

Previous studies have shown that females with type 2 diabetes mellitus (T2DM) may have an excess mortality risk compared to males. Furthermore, other studies have reported sex differences in managing cardiovascular risk factors, such as controlling hypertension and hypercholesterolemia.

Purpose

With the growing evidence from systematic reviews examining the sex differences in cardiovascular outcomes for patients with T2DM, an umbrella review is an essential next step to synthesising and assessing the strength of the available evidence.

Methods

Medline and Embase were searched from inception till 7th August 2022 for systematic reviews and meta-analyses studying the effects of sex on cardiovascular outcomes in T2DM patients. Results from reviews were synthesised with a narrative synthesis, with a tabular presentation of findings and forest plots for reviews that performed a meta-analysis. AMSTAR 2 tool was used to assess the methodological quality of included reviews, while the GRADE assessment was used to assess the quality of evidence for outcomes.

Results

A total of 28 studies evaluating sex differences in cardiovascular outcomes were included. Females with T2DM had a higher risk of developing coronary heart disease (CHD; RRR 1.52, 95%CI 1.32–1.76, p<0.001), acute coronary syndrome (ACS; RRR 1.38, 95%CI 1.25–1.52, p<0.001), and heart failure (RRR 1.09, 95%CI 1.05–1.13, p<0.001) than males. In terms of mortality outcomes, females had a higher risk of all-cause mortality (RRR 1.13, 95%CI 1.07–1.19, p<0.001), cardiac mortality (RRR 1.49, 95%CI 1.11–2.00, p=0.009) and CHD mortality (RRR 1.44, 95%CI 1.20–1.73, p<0.001) as compared to males. In patients undergoing percutaneous coronary intervention, females reported higher odds of MACE (OR 1.49, 95%CI 1.07–2.07, p=0.020) and all-cause mortality (OR 1.71, 95%CI 1.46–2.00, p<0.001) compared to males. Females in Asia (RRR 1.12, 95%CI 1.03–1.21, p=0.006) and North America (RRR 1.10, 95%CI 1.08–1.12, p<0.001) were at increased risk of all-cause mortality while females in Western countries had an increased risk for cardiac death (RRR 1.84, 95%CI 1.45–2.32, p<0.001) compared to males. Six reviews were rated as high in quality; eight reviews were rated as moderate, and fourteen reviews were rated as low in quality. Regarding the quality of outcomes, all outcomes in non-interventional studies had a moderate quality of evidence, while all outcomes in interventional studies achieved a high quality of evidence.

Conclusions

This umbrella review evaluated the quality of meta-analyses and demonstrated that females with T2DM have a higher risk of cardiovascular outcomes than their male counterparts. Future studies examining the sex differences in outcomes should attempt to address the heterogeneity and epidemiological factors for a better quality of evidence. Policymakers should consider sex-specific differences in implementing effective tailored strategies to tackle T2DM.

Metabolic associated fatty liver disease increases risk of adverse events after acute coronary syndrome

 

Metabolic Associated Fatty Liver Disease (MAFLD) was recently introduced as an alternative definition for fatty liver, that has been linked to an increased risk of systemic end-organ damage. However, current studies have not examined the impact of MAFLD on patients presenting with acute coronary syndrome (ACS). Here, we present a retrospective analysis on the short and long-term outcomes of ACS patients with MAFLD.

Methods

A retrospective analysis was conducted in a tertiary care centre. Hepatic steatosis and fibrosis was examined with hepatic steatosis index and fibrosis-4 (FIB-4) index. The primary and secondary outcomes of the analysis were long term all-cause mortality, and in-hospital all-cause mortality, stroke, heart failure and cardiogenic shock respectively. Adjusted analysis was conducted for primary and secondary outcomes with covariates including age, sex, race, type of ACS and previous myocardial infarction.

Results

A total of 5770 patients were included in the analysis, and 21% of ACS patients had concomitant MAFLD. MAFLD resulted in a 23% increase in long-term all-cause mortality compared to non-MAFLD (HR: 1.230, CI: 1.065 to 1.420, p=0.005). MAFLD increased the risk of in-hospital mortality, stroke, heart failure and cardiogenic shock compared to non-MAFLD. A sensitivity analysis conducted based on MAFLD with advance fibrosis, chronic kidney disease and diabetes also demonstrated significantly increased effect size magnitude of all-cause mortality, compared to non-MAFLD.

Conclusion

MAFLD represents an encapsulation of metabolism dysregulation and has been associated with increased risk of systematic disease. The present study shows that MAFLD is associated with significantly increased adverse prognostic outcomes after ACS compared to non-MAFLD. An increase in awareness of MAFLD is required beyond the field of hepatology for improvements in multidisciplinary care and management.

Funding Acknowledgement

Type of funding sources: None.

The prognostic outcomes of acute myocardial infarction stratified according to metabolic health and obesity status

Background

There has been emerging evidence on the favourable cardiovascular disease incidence in non-obese subjects with healthy metabolism. However, little is known regarding the prognosis across the metabolic phenotypes once cardiovascular disease is established. This study examines the prognosis of patients with acute myocardial infarction (AMI) stratified according to metabolic health and obesity status.

Methods

A retrospective study conducted in a tertiary hospital between 2014–2021. Consecutive patients with AMI were allocated into 4 groups based on metabolic and obesity profile: metabolically healthy obesity (MHO), metabolically healthy non-obesity (MHNO), metabolically unhealthy obesity (MUO) and metabolically unhealthy non-obesity (MUNO). The primary outcome was all-cause mortality. Cox regression examined the independent association between mortality and metabolic phenotypes, adjusting for age, sex, AMI type and ejection fraction.

Results

A total of 9958 patients were studied with majority (68.5%) in the MUNO group, followed by MUO (25.1%), MHNO (5.6%), and MHO (0.8%). MHO patients had lowest mortality (7.4%), followed by MHNO (9.7%), MUO (19.2%) and MUNO (22.6%, p<0.001). Relative to MHNO, MUO (HR 1.610, 95% CI 1.198–2.163, p=0.002) and MUNO (HR 1.383, 95% CI 1.043–1.835, p=0.024) had significantly higher mortality risk, but not MHO (HR 1.514, 95% CI 0.649–3.534, p=0.337), after adjusting for confounders. Kaplan-Meier curves showed favourable survival in metabolically healthy groups with clear divergence from metabolically unhealthy groups (p<0.001). There were stepwise increments in mortality with increasing number of metabolic risk factors regardless of obesity status (p<0.001). Favourable survival was observed in overweight and obese versus normal weight patients regardless of metabolic health.

Conclusion

Metabolically healthy AMI patients had favourable prognosis compared to metabolically unhealthy patients. The obesity paradox was observed in the AMI cohort, but the beneficial effects of obesity appeared not as pronounced in magnitude as in metabolically healthy groups.

Funding Acknowledgement

Type of funding sources: None.

Smaller size of high metabolic rate organs explains lower resting energy expenditure in Asian-Indian Than Chinese men

BACKGROUND

In Singapore, the obesity prevalence is disproportionately higher in the Asian-Indians and Malays than the Chinese. Lower resting energy expenditure (REE) may be a contributory factor.

OBJECTIVE

We explored the association between ethnicity and REE in Chinese, Asian-Indian and Malay men living in Singapore and determined the influence of body composition, mass/volume of high metabolic rate organs, represented by brain volume and trunk fat-free mass (FFM), and physical activity on ethnic differences.

DESIGN

Two hundred and forty-four men from Singapore (n=100 Chinese, 70 Asian-Indians and 74 Malays), aged 21-40 years and body mass index of 18.5-30.0 kg m(-2), were recruited in this cross-sectional study. REE was assessed by indirect calorimetry and body composition by dual-energy X-ray absorptiometry. Brain volume was measured by magnetic resonance imaging. Physical activity was assessed by the Singapore Prospective Study Program Physical Activity Questionnaire.

RESULTS

REE was significantly lower in Asian-Indians compared with that in Chinese after adjusting for body weight. FFM (total, trunk and limb) and total fat mass were important predictors of REE across all ethnic groups. Brain volume was positively associated with REE only in Malays. Moderate and vigorous physical activity was positively associated with REE only in Asian-Indians and Malays. The difference in REE between Asian-Indians and Chinese was attenuated but remained statistically significant after adjustment for total FFM (59±20 kcal per day), fat mass (67±20 kcal per day) and brain volume (54±22 kcal per day). The association between REE and ethnicity was no longer statistically significant after total FFM was replaced by trunk FFM (which includes heart, liver, kidney and spleen) but not when it was replaced by limb FFM (skeletal muscle).

CONCLUSIONS

We have demonstrated a lower REE in Asian-Indians compared with Chinese who may contribute to the higher rates of obesity in the former. This difference could be accounted for by differences in metabolically active organs.

Ethnic differences in insulin sensitivity and beta-cell function among Asian men

BACKGROUND AND OBJECTIVES

Lean Asian Indians are less insulin sensitive compared with Chinese and Malays, but the pancreatic beta-cell function among these ethnic groups has yet to be studied in depth. We aimed to study beta-cell function in relation to insulin sensitivity among individuals of Chinese, Malay and Asian-Indian ethnicity living in Singapore.

SUBJECTS AND METHODS

This is a sub-group analysis of 59 normoglycemic lean (body mass index (BMI) <23 kg m(-)(2)) adult males (14 Chinese, 21 Malays and 24 Asian Indians) from the Singapore Adults Metabolism Study. Insulin sensitivity was determined using fasting state indices (homeostatic model assessment-insulin resistance), the euglycemic-hyperinsulinemic clamp (ISI-clamp) and a liquid mixed-meal tolerance test (LMMTT) (Matsuda insulin sensitivity index (ISI-Mat)). Beta-cell function was assessed using fasting state indices (homeostatic model assessment-beta-cell function) and from the LMMTT (insulinogenic index and insulin secretion index). The oral disposition index (DI), a measure of beta-cell function relative to insulin sensitivity during the LMMTT, was calculated as a product of ISI-Mat and insulin secretion index.

RESULTS

Asian Indians had higher waist circumference and percent body fat than Chinese and Malays despite similar BMI. Overall, Asian Indians were the least insulin sensitive whereas the Chinese were most insulin sensitive. Asian Indians had higher beta-cell function compared with Chinese or Malays but these were not statistically different. Malays had the highest incremental area under the curve for glucose during LMMTT compared with Asian Indians and Chinese. However, there were no significant ethnic differences in the incremental insulin area under the curve. The oral DI was the lowest in Malays, followed by Asian Indians and Chinese.

CONCLUSION

Among lean Asians, Chinese are the most insulin sensitive whereas Asian Indians are the least insulin sensitive. However, Malays demonstrate higher postprandial glucose excursion with lower beta-cell response compare with Chinese or Asian Indians. The paths leading to type 2 diabetes mellitus might differ between these Asian ethnic groups.

Associations between ethnicity, body composition, and bone mineral density in a Southeast Asian population

CONTEXT AND OBJECTIVE

Chinese men in Singapore have a higher incidence of hip fractures than Malay and Indian men. We investigated whether there were corresponding ethnic differences in peak bone mineral density (BMD) in young men and whether differences in body composition influenced peak BMD.

DESIGN AND SETTING

This was a cross-sectional study of healthy volunteers in a tertiary medical center.

PARTICIPANTS

A total of 100 Chinese, 82 Malay, and 80 Indian men aged 21 to 40 years, with body mass index between 18 and 30 kg/m(2) underwent dual-energy x-ray absorptiometry to assess BMD, lean mass (LM) and fat mass (FM), and magnetic resonance imaging to quantify abdominal subcutaneous and visceral adipose tissue. Multiple linear regression models, with adjustment for age and height (as a proxy for skeletal size), were used.

RESULTS

Malay and Indian men had significantly higher BMD than Chinese men at the lumbar spine (Malay: B, 0.06 ± 0.02, P = .001; Indian: B, 0.03 ± 0.02, P = .049), femoral neck (Malay: B 0.04 ± 0.02, P = .034; Indian: B, 0.04 ± 0.02, P = .041), hip (Malay: B, 0.05 ± 0.02, P = .016; Indian: B, 0.06 ± 0.02, P = .001), and ultradistal radius (Malay: B, 0.03 ± 0.01, P < .001; Indian: B, 0.02 ± 0.01, P = .029), and this difference was retained after adjustment for LM and FM, except in Malay men at the femoral neck and in Indian men at the ultradistal radius. LM was an important independent determinant of BMD at all sites, whereas FM, subcutaneous adipose tissue, and visceral adipose tissue were not significantly associated with BMD at any site.

CONCLUSIONS

Lower peak BMD in Chinese men may partly explain the higher fracture incidence in this ethnic group. Further studies are needed to elucidate the reasons for these ethnic differences in bone accumulation.

Insulin resistance is associated with a metabolic profile of altered protein metabolism in Chinese and Asian-Indian men

AIMS/HYPOTHESIS

Insulin resistance (IR) is associated with obesity, but can also develop in individuals with normal body weight. We employed comprehensive profiling methods to identify metabolic events associated with IR, while controlling for obesity.

METHODS

We selected 263 non-obese (BMI approximately 24 kg/m2) Asian-Indian and Chinese men from a large cross-sectional study carried out in Singapore. Individuals taking medication for diabetes or hyperlipidaemia were excluded. Participants were separated into lower and upper tertiles of IR based on HOMA indices of < or =1.06 or > or =1.93, respectively. MS-based metabolic profiling of acylcarnitines, amino acids and organic acids was combined with hormonal and cytokine profiling in all participants.

RESULTS

After controlling for BMI, commonly accepted risk factors for IR, including circulating fatty acids and inflammatory cytokines, did not discriminate the upper and lower quartiles of insulin sensitivity in either Asian- Indian or Chinese men. Instead, IR was correlated with increased levels of alanine, proline, valine, leucine/isoleucine, phenylalanine, tyrosine, glutamate/glutamine and ornithine, and a cluster of branched-chain and related amino acids identified by principal components analysis. These changes were not due to increased protein intake by individuals in the upper quartile of IR. Increased abdominal adiposity and leptin, and decreased adiponectin and IGF-binding protein 1 were also correlated with IR.

CONCLUSIONS/INTERPRETATION

These findings demonstrate that perturbations in amino acid homeostasis, but not inflammatory markers or NEFAs, are associated with IR in individuals of relatively low body mass.

Type 2 diabetic patients with resistant hypertension should be screened for primary aldosteronism

BP control in diabetic patients is often poor. The contribution of secondary hypertension due to undiagnosed PA in hypertensive type 2 diabetic patients is not well studied. We prospectively screened 100 consecutive Asian type 2 diabetic patients with difficult-to-control or resistant hypertension for PA. PAC (pmol/L) to PRA (ng/mL/h) ratio was measured; those with PAC-to-PRA ratio >550 (corresponding PAC >415) underwent intravenous 0.9% SLT. Patients with PAC >/=140 following SLT had CT adrenals and bilateral AVS. Thirteen patients (13%) were confirmed to have PA, and all had resistant hypertension. Eight had a surgically correctable form of PA. Patients with PA had higher mean (SD) systolic [159.0 (10.6) vs. 146.0 (10.7) mmHg, p=0.001] and diastolic BP [94.6 (6.0) vs. 87.6 (5.9) mmHg, p=0.001], lower serum potassium [3.5 (0.6) vs. 4.3 (0.5) mmol/L, p=0.001], and higher PAC [679.3 (291.0) vs. 239.5 (169.4) pmol/L, p=0.001]. Identification and institution of definitive treatment for PA resulted in better BP control and in a reduction in the use of antihypertensive medications. Our findings demonstrate a high prevalence of PA in type 2 diabetic patients with resistant hypertension. Systematic screening for PA in this select group is recommended, as targeted treatment improves BP control.