Non-Dipping Heart Rate and Microalbuminuria in Type 2 Diabetes Mellitus

Abstract

Objectives: The aim of this study was to identify factors which are independently associated with non-dipping heart rate (HR) in a type 2 diabetic population at high risk of cardiovascular disease. Methods: The study recruited 179 type 2 diabetic subjects with a mean diabetes duration of 18.3 years and with proliferative retinopathy. All underwent 24-hour blood pressure and HR monitoring, and were assessed for markers of inflammation, insulin resistance, albuminuria, presence of peripheral neuropathy and peripheral vascular disease. Subjects whose night-time HR did not decrease by more than 10% as compared to daytime readings were classified as non-dippers. Results: Univariate analysis revealed that non-dippers had significantly higher logarithmic albumin-creatinine ratio (ACR; p = 0.001) and higher platelet count (p = 0.014). Also, non-dippers were more likely to be on β-blockers (p = 0.037). Binary logistic regression analysis showed that logarithmic ACR (p = 0.001) and platelet count (p = 0.026) were independent predictors of non-dipping HR, even when correcting for β-blocker use. Conclusions: In this high-risk type 2 diabetic population, non-dipping HR was independently associated with ACR and platelet count, suggesting that non-dipping HR might give an indication of underlying generalised atherosclerosis in diabetic patients. Also, non-dipping HR may represent a novel mechanism explaining the association of nephropathy with cardiovascular events. This merits further study.

Autonomic Dysfunction: How to Identify and When to Treat?

“…The authors observed that night-time ambulatory HR was a significant predictor of fatal and non-fatal cardiovascular events [25]. Non dipping status for HR is also a negative predictor in diabetic patients: Magri et al found that non dipping pattern for HR, in these patients, was associated with development of microalbuminuria [26]. In chronic kidney disease elevated night-time HR was found to be associated with an increased arterial stiffness [27].…”

Biomarkers in Diabetic Retinopathy

“…The presence or absence of (normal) nocturnal falls in BP, called dipping, is also implicated in diabetic vascular complication risk. Whilst best studied in diabetic nephropathy [198], non-dipping overnight blood pressure has also been associated with increased risk of diabetic retinopathy in type 2 diabetes subjects [199].…”

Non-Dipping Heart Rate, Microalbuminuria and Thrombocytosis in Type 2 Diabetes Mellitus: Can We Connect the Dots?

“…The question of whether ANS dysfunction in diabetics is merely a marker or causative factor to target end-organ damage (TOD), including retinopathy, nephropathy and CV complications, has continued to stimulate research interest. To that end, the study relating microalbuminuria, high platelet counts and non-dipping HR in patients with T2DM by Magri et al [5] in this issue of Cardiology is a welcome addition to an already existing pool of studies.…”

“…The main finding of the study is that patients with non-dipping HR independently had a significantly higher logarithmic albumin-creatinine ratio and higher platelet counts. The authors conclude that non-dipping HR might give an indication of underlying generalized atherosclerosis in diabetic patients [5]. …”

“…After so much ongoing multi-level research, we have not yet completely understood the pathophysiologies of numerous diabetes-related disease processes, such as atherosclerosis, angiogenesis, endothelial dysfunction, apoptosis and immunomodulation, and the list goes on! For example, pertaining to the study by Magri et al [5], how can we effectively tie in the findings of the ‘non-dipping' HR to retinopathy, nephropathy and TOD? How does non-dipping HR stimulate atherogenesis?…”