In our study, we determined that HbA1c levels
may be a predictor of LVDD in type 2 DM
patients. Hyperglycemia is a risk factor for HF
in individuals with type 2 DM.[
11] Structural,
functional, and metabolic disorders develop as a
result of the relationship between DM and HF.
This leads to the emergence of more comorbid
diseases and a worse prognosis. In addition, LVDD
can be defined as the earliest functional change in
type 2 DM patients.[
12] Type 2 DM is known as an
important factor associated with hypertension or
obesity, as well as HFpEF, which often manifests
as LVDD. Additionally, higher HbA1c levels
have been associated with increased mortality in
HF patients.[
13] Hyperglycemia has deleterious
effects on the myocardium. It up-regulates the
renin-angiotensin-aldosterone system, increases
oxidative stress, leads to the accumulation of
glycation end products, and causes interstitial
fibrosis in the heart muscle.[
14] The HbA1c level is
now recommended as the standard for testing and
monitoring diabetes.[
15] Giorda et al.[
16] found that
HbA1c is correlated with LVDD in patients with
type 2 DM. Zuo et al.[
17] revealed that the correlation
between LVDD and HbA1c in type 2 DM patients
was higher in patients with a normal body mass
index. In a study by Di Pino et al.,[
18] elevated
HbA1c levels were associated with subclinical
cardiac changes in patients with prediabetes,
resulting in a lower E/A ratio and higher left atrial
volume. Additionally, an independent relationship
was found between E/e' ratio and HbA1c in this
study.[
18] In a recent study, it was emphasized that
an E/e' ratio higher than 15 was associated with
diastolic dysfunction.[
19] This is consistent with our
findings and previous studies conducted on patients
with alterations in glucose homeostasis. Stahrenberg
et al.[
20] demonstrated in their study that glucose
metabolism is associated with LVDD and HbA1c
is associated with E/e' ratio. In another recent
study, it was reported that hypoglycemia may also affect diastolic functions.[
21] In addition, another
study on the risk of atherosclerosis reported that
the E/e' ratio was often within the normal range
but was also positively associated with HbA1c.[
22]
These results reveal that HbA1c may be a marker of
asymptomatic LVDD, the most prominent feature
of DCM.[
23] It has also been reported that a 1%
increase in HbA1c level is associated with an 8%
increase in the risk of HF.[
24] Jain et al.[
25] reported
that the frequency of LVDD increases as the HbA1c
level increases. Hameedullah et al.[
26] found a strong
correlation between HbA1c levels and diastolic
indices in their study on 60 patients with type 2 DM.
The results we obtained in our study support all
these findings in the literature. As mentioned
earlier, the pathogenesis of cardiac dysfunction
associated with DM is multifactorial. Type 2 DM
is thought to play a key role in the development
of LVDD-related HFpEF.[
23] Since there is still
no effective pharmacological treatment in HFpEF
patients, the importance of simple glycemic control
with HbA1c monitoring becomes evident.
The main limitations of this study are its
retrospective design and the relatively limited
number of patients. In this respect, the results of
the study cannot be generalized. In addition, we
did not measure left atrial volume index (LAVI)
during ECHO. In this respect, we did not examine
all parameters indicative of diastolic dys function.
Although we excluded many parameters that may
affect diastolic functions, we could not exclude
parameters that may affect diastolic functions such
as chronic kidney disease, hypertension, and age.
However, since there was no significant difference
between the groups in terms of these parameters,
we think that our study has a limited effect on the
results. A single HbA1c value may not reflect the
effect of hyperglycemia on diastolic function. In
addition, we could not exclude the use of drugs that
may have an effect on diastolic parameters.
In conclusion, as LVDD is quite common in the
type 2 DM patient population and hyperglycemia is
closely related to LVDD, providing close glycemic
monitoring with HbA1c levels can reduce HFpEF
development due to LVDD. Preventing the
development of HFpEF is also of great importance in
preventing long-term comorbid conditions.
Ethics Committee Approval: The study protocol
was approved by the Bakırçay University Çiğli Training and Research Hospital Ethics Committee (Date/no:
29.04.2022/580). The study was conducted in accordance
with the principles of the Declaration of Helsinki.
Patient Consent for Publication: A written informed
consent was obtained from each patient.
Data Sharing Statement: The data that support the
findings of this study are available from the corresponding
author upon reasonable request.
Author Contributions: Idea/concept, design, data
collection and/or processing, literature review, writing the
article: T.G.; Idea/concept, design, control/supervision, data
collection and/or processing, literature review, critical review:
M.K.; Control/supervision, data collection and/or processing,
analysis and/or interpretation, critical review: O.Ş.
Conflict of Interest: The authors declared no conflicts
of interest with respect to the authorship and/or publication
of this article.
Funding: The authors received no financial support for
the research and/or authorship of this article.
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