Diabetes outcomes in heart failure patients with hypertrophic cardiomyopathy

Roles of cMyBP-C phosphorylation on cardiac contractile dysfunction in db/db mice

Type 2 diabetes mellitus (T2DM) is a metabolic disease and comorbidity associated with several conditions, including cardiac dysfunction leading to heart failure with preserved ejection fraction (HFpEF), in turn resulting in T2DM-induced cardiomyopathy (T2DM-CM). However, the molecular mechanisms underlying the development of T2DM-CM are poorly understood. It is hypothesized that molecular alterations in myopathic genes induced by diabetes promote the development of HFpEF, whereas cardiac myosin inhibitors can rescue the resultant T2DM-mediated cardiomyopathy. To test this hypothesis, a Leptin receptor-deficient db/db homozygous (Lepr db/db) mouse model was used to define the pathogenesis of T2DM-CM. Echocardiographic studies at 4 and 6 months revealed that Lepr db/db hearts started developing cardiac dysfunction by four months, and left ventricular hypertrophy with diastolic dysfunction was evident at 6 months. RNA-seq data analysis, followed by functional enrichment, revealed the differential regulation of genes related to cardiac dysfunction in Lepr db/db heart tissues. Strikingly, the level of cardiac myosin binding protein-C phosphorylation was significantly increased in Lepr db/db mouse hearts. Finally, using isolated skinned papillary muscles and freshly isolated cardiomyocytes, CAMZYOS ® (mavacamten, MYK-461), a prescription heart medicine used for symptomatic obstructive hypertrophic cardiomyopathy treatment, was tested for its ability to rescue T2DM-CM. Compared with controls, MYK-461 significantly reduced force generation in papillary muscle fibers and cardiomyocyte contractility in the db/db group. This line of evidence shows that 1) T2DM-CM is associated with hyperphosphorylation of cardiac myosin binding protein-C and 2) MYK-461 significantly lessened disease progression in vitro, suggesting its promise as a treatment for HFpEF.

Is Type 2 Diabetes Mellitus an Independent Risk Factor for Mortality in Hypertrophic Cardiomyopathy?

Background

The mortality rate of hypertrophic cardiomyopathy (HCM) has decreased between 1999 and 2020. The risk factors for sudden cardiac death (SCD) in HCM were updated in the American Heart Association (AHA)/American College of Cardiology Foundation (ACCF) 2020 guidelines by adding new risk factors, like the late gadolinium enhancement on cardiac magnetic resonance imaging (MRI). Type 2 diabetes mellitus (T2DM) is a major risk factor for most cardiac diseases; however, it is not included in these guidelines due to a lack of strong evidence of a correlation between T2DM and mortality in HCM. Therefore, we sought to investigate if T2DM increases the 5-year risk rate for adverse outcomes, such as heart failure and all-cause mortality in patients with HCM.

Methods

We collected patient data from January 1, 2018, to March 1, 2023, using the TriNetX database. The sample included 80,502 individuals with HCM, then divided into two cohorts based on the absence (58,573; cohort 1) or presence (15,296; cohort 2) of T2DM. The two matched groups then underwent survival and risk analyses for all-cause mortality or the first incidence of heart failure diagnosis within 5 years from the point in time when the selection criteria were first met.

Results

We found a statistically significant increase in all-cause mortality and new-onset heart failure in HCM patients with diabetes compared to those without diabetes after adjusting for major risk factors.

Conclusions

This is one of the largest retrospective cohort studies that examined the correlation between T2DM and adverse outcomes in patients with HCM. This underlines the need for future prospective studies investigating the effects of T2DM on HCM outcomes.

Overweight and obesity are associated with better survival in STEMI patients with diabetes

OBJECTIVE

The relationship between obesity and in-hospital outcomes in individuals with type 2 diabetes mellitus (T2DM) who develop an ST-elevation myocardial infarction (STEMI) was assessed.

METHODS

Data from the National Inpatient Sample (NIS) from 2008 to 2017 were analyzed. Patients with STEMI and T2DM were classified as being underweight or having normal weight, overweight, obesity, and severe obesity. The temporal trend of those BMI ranges and in-hospital outcomes among different obesity groups were assessed.

RESULTS

A total of 74,099 patients with T2DM and STEMI were included in this analysis. In 2008, 35.8% of patients had obesity, and 37.3% had severe obesity. However, patients with obesity accounted for most of the study population in 2017 (57.8%). During the observation period, mortality decreased in underweight patients from 18.1% to 13.2% (p < 0.001). Still, it gradually increased in all other BMI ranges, along with cardiogenic shock, atrial fibrillation, and ventricular fibrillation (p < 0.001 for all). After the combination of all patients during the observation period, mortality was lower in patients with overweight and obesity (adjusted odds ratio = 0.625 [95% CI 0.499-0.784]; 0.606 [95% CI 0.502-0.733], respectively).

CONCLUSIONS

A U-shaped association governs the relationship between BMI and mortality in STEMI patients with diabetes, with those having overweight and obesity experiencing better survival.

Type 2 diabetes and in-hospital sudden cardiac arrest in ST-elevation myocardial infarction in the US

Aims

We aimed to assess the impact of diabetes on sudden cardiac arrest (SCA) in US patients hospitalized for ST-elevation myocardial infarction (STEMI).

Methods

We used the National Inpatient Sample (2005-2017) data to identify adult patients with STEMI. The primary outcome was in-hospital SCA. Secondary outcomes included in-hospital mortality, ventricular tachycardia (VT), ventricular fibrillation (VF), cardiogenic shock (CS), acute renal failure (ARF), and the revascularization strategy in SCA patients.

Results

SCA significantly increased from 4% in 2005 to 7.6% in 2018 in diabetes patients and from 3% in 2005 to 4.6% in 2018 in non-diabetes ones (p < 0.001 for both). Further, diabetes was associated with an increased risk of SCA [aOR = 1.432 (1.336-1.707)]. In SCA patients with diabetes, the mean age (SD) decreased from 68 (13) to 66 (11) years old, and mortality decreased from 65.7% to 49.3% during the observation period (p < 0.001). Compared to non-diabetes patients, those with T2DM had a higher adjusted risk of mortality, ARF, and CS [aOR = 1.72 (1.62-1.83), 1.52 (1.43-1.63), 1.25 (1.17-1.33); respectively] but not VF or VT. Those patients were more likely to undergo revascularization with CABG [aOR = 1.197 (1.065-1.345)] but less likely to undergo PCI [aOR = 0.708 (0.664-0.754)].

Conclusion

Diabetes is associated with an increased risk of sudden cardiac arrest in ST-elevation myocardial infarction. It is also associated with a higher mortality risk in SCA patients. However, the recent temporal mortality trend in SCA patients shows a steady decline, irrespective of diabetes.