R-R variability during deep breathing as a diagnostic marker of cardiac autonomic neuropathy in Type 2 diabetes

Q: What are the key findings of this study?

Type 2 diabetes patients had significantly reduced R-R variability during deep breathing compared to controls, with lower E:I ratio (1.24 vs 1.53, p<0.001) and Delta HR (15.09 vs 32.11, p<0.001).

Q: What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Type 2 diabetes mellitus and cardiac autonomic neuropathy (n=170). Intervention: Type 2 diabetes mellitus vs. Age-matched normal controls. Primary outcome: R-R variability during 1-minute deep breathing: Expiration:Inspiration (E:I) ratio (p=<0.001).

Q: What does this research mean for the field?

Patients with type 2 diabetes exhibit significantly reduced R-R variability during deep breathing compared to healthy individuals, with the reduction being particularly pronounced in those with poor glycemic control. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To assess R-R variability during deep breathing as an early predictor of cardiac autonomic neuropathy and evaluate how glycemic status and diabetes duration affect heart rate variability.

M Anbarasi; R. Rajendran; Rajkumar G; Sureshbalaji RA

doi:10.5005/njp-11056-04_01_01

June 1, 2016National Journal of PhysiologyOpen Access

R-R variability during deep breathing as a diagnostic marker of cardiac autonomic neuropathy in Type 2 diabetes

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Key result

Type 2 diabetes is linked to significantly reduced deep-breathing heart rate variability versus controls.

P<0.001
n=170

Why the study?

Does Type 2 diabetes mellitus and poor glycemic control reduce R-R variability during deep breathing and resting heart rate variability compared to normal controls?

Key Points

To assess R-R variability during deep breathing as an early predictor of cardiac autonomic neuropathy and evaluate how glycemic status and diabetes duration affect heart rate variability.
Administered an autonomic symptom questionnaire to 72 Type 2 diabetic patients and 98 normal controls.
Recorded resting heart rate variability and heart rate variability during 1 minute of deep and controlled breathing.
Analyzed resting heart rate, RMSSD, SDANN, pNN50, E: I ratio, and Delta HR, including subgroup comparisons by diabetes duration and HbA1c levels.
Autonomic dysfunction symptoms were reported in 44.4% (32/72) of diabetic participants compared to 7.1% (7/98) of controls (p < 0.0001).
Diabetic patients showed significantly lower resting heart rate variability and deep breathing indicators, including E: I ratio (1.24 ± 0.213 vs 1.53 ± 0.22) and Delta HR (15.09 ± 7.67 vs 32.11 ± 10.2; p < 0.001).
Subgroup analysis revealed significantly lower E: I ratio (1.11 ± 0.29 vs 1.28 ± 0.11) and Delta HR (14.40 ± 5.44 vs 20.67 ± 11.8) in patients with HbA1c > 9 compared to HbA1c < 7 (p = 0.02), whereas diabetes duration showed no significant differences.

Study Design

Type

Cross-Sectional (n=170)

Multicenter

No

Structured PICO

Does Type 2 diabetes mellitus and poor glycemic control reduce R-R variability during deep breathing and resting heart rate variability compared to normal controls?

P

Population

170 adults (72 with Type 2 diabetes mellitus and 98 age-matched healthy controls) aged 35-60 years (38.2% female) in India, free of prior myocardial infarction, diabetic foot ulcers, or retinopathy, evaluated in a cross-sectional study.

E

Exposure

Type 2 diabetes mellitus evaluated by resting Heart Rate Variability (HRV) after 15 minutes of supine rest and R-R variability during 1 minute of deep, controlled breathing (6 breaths per minute: 5 seconds inspiration and 5 seconds expiration).

C

Comparator

Age-matched normal controls (n=98) undergoing the same autonomic symptom questionnaire, resting HRV recording, and 1-minute deep breathing R-R variability test.

O

Outcome

R-R variability during 1-minute deep breathing, measured by Expiration:Inspiration (E:I) ratio and difference between maximum and minimum heart rate (Delta HR), and resting time-domain HRV parameters (resting heart rate, RMSSD, SDANN, pNN50).surrogate

Main Result

Absolute Event Rate: 1.24% vs 1.53%

p-value: p=<0.001

Resting heart rate and R-R variability during 1-minute deep breathing are simple, non-invasive, early markers of cardiac autonomic neuropathy in Type 2 diabetes that worsen with poor glycemic control.

Limitations

Limited to only one autonomic reflex test (R-R variability during deep breathing).
HRV in deep breathing does not seem to distinguish between minimal involvement and serious autonomic damage.
The study was limited to only one autonomic reflex test (R-R variability during deep breathing)
HRV during deep breathing does not distinguish between minimal autonomic involvement and serious damage

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Implication

Supports R-R variability as early autonomic neuropathy marker in type 2 diabetes; hypothesis-generating and requires prospective validation before adoption.

Abstract

Background: Studies have shown that simple Heart Rate Variability (HRV) measurement is useful in screening for and diagnosing Cardiac autonomic neuropathy (CAN).Aim: This study was aimed to assess the usefulness of R-R variability during deep breathing as the earliest predictor of CAN and to evaluate the effect of glycemic status and duration of diabetes on HRV.Materials and Methods: After obtaining ethical clearance and written informed consent, 72 Type 2 diabetic patients and 98 normal controls were administered an autonomic symptom questionnaire and subjected to recording of resting HRV and HRV during 1 minute deep and controlled breathing.Statistical analysis was done by appropriate tests using SPSS 20.0.Results: 44.4% of participants in the diabetic group had symptoms of autonomic dysfunction in contrast to 7.1 % of the control group (p < 0.0001).Resting HRV parameters and indicators of R-R variability during deep breathing like E/I ratio and Delta HR were significantly reduced (p < 0.001) in the diabetic group compared to controls.Subgroup analysis within the diabetic group showed significant decrease in E/I ratio and Delta HR in groups with poor glycemic control.Simple linear regression sought between resting heart rate and E/I ratio showed a highly significant inverse relationship (p = 0.0001).Conclusion: Our findings suggested that R-R variability during 1 minute deep breathing and resting heart rate are reliable and early predictors of CAN.Employing these simple tests in newly diagnosed patients and those in the pre-diabetic state could help control the emergence of CAN.

Discussion

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Cite This Study

Anbarasi et al. (2016) conducted a cross-sectional in Type 2 diabetes mellitus and cardiac autonomic neuropathy (n=170). Type 2 diabetes mellitus vs. Age-matched normal controls was evaluated on R-R variability during 1-minute deep breathing: Expiration:Inspiration (E:I) ratio (p=<0.001). Type 2 diabetes patients had significantly reduced R-R variability during deep breathing compared to controls, with lower E:I ratio (1.24 vs 1.53, p<0.001) and Delta HR (15.09 vs 32.11, p<0.001).

synapsesocial.com/papers/6a8588862e6b8eab48d4cd0f https://doi.org/10.5005/njp-11056-04_01_01

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R-R variability during deep breathing as a diagnostic marker of cardiac autonomic neuropathy in Type 2 diabetes

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

R-R variability during deep breathing as a diagnostic marker of cardiac autonomic neuropathy in Type 2 diabetes

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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