Usefulness of ambulatory blood pressure monitoring in predicting the presence of autonomic neuropathy in type I diabetic patients

Abstract

This study investigated whether nondipping (defined as a day-night change in blood pressure (BP) p0%) could be assumed as a diagnostic index for autonomic neuropathy, and assessed its accuracy in discriminating between type I diabetic patients with and without autonomic neuropathy. In 87 type I diabetic patients with normal renal function (age 36711, duration 1779 years, serum creatinine 67.2715.9 lmol/l), four cardiovascular tests and 24-h BP monitoring were performed, and the percentage day-night change (D) in systolic (SBP) and diastolic BP (DBP) was calculated. Sixteen patients had DSBP and/or DDBP p0%. In a multiple logistic regression with adjustment for sex, age, and body mass index, the odds ratio for having autonomic neuropathy was seven times higher in patients with DSBP p0% as opposed to those without (odds ratio 6.97, CI 1.4-34.9, P ¼ 0.018). Using Receiver Operating Characteristic (ROC) analysis, DBP showed an acceptable accuracy in discriminating between patients with and without autonomic neuropathy (area under the ROC curve 0.6970.06 and 0.7270.05 for DSBP and DDBP, respectively). Adequate cutoff values were 0% for DSBP (sensitivity, 26%; specificity, 95%; positive predictive value, 87%) and 5% for DDBP (sensitivity, 26%; specificity, 92%; positive predictive value, 81%). In type I diabetic patients with normal renal function, a value of DSBP p0% identifies the presence of autonomic neuropathy with a very high chance. Nondipping at the cutoff proposed could be considered an adjunctive marker of autonomic neuropathy provided with a high specificity and low sensitivity.

Reappraisal of the diagnostic role of orthostatic hypotension in diabetes

“…the loss of circadian BP rhythm, not an uncommon feature in diabetic patients closely associated with autonomic dysfunction [33]. An AUC of 0.77 indicated a moderate diagnostic accuracy of orthostatic systolic BP fall in discriminating between patients with and without nondipping.…”

“…In addition, the day-night difference (D) in systolic and diastolic BP as a percentage of day values was calculated [(day BP-night BP) · 100/day BP]. Patients with a value of systolic or diastolic D BP of 0% or less were considered nondippers [33,34].…”

“…does orthostatic hypotension also contain a diagnostic value for nondipping, i.e. the loss of circadian BP rhythm, that was recently demonstrated to be a valid index of autonomic neuropathy in type 1 diabetes [33]? and finally, what is the relationship in diabetic patients between orthostatic symptoms and orthostatic fall in systolic BP?…”

Circadian Rhythm of Blood Pressure in Diabetes Mellitus: Evidence, Mechanisms and Implications

“…2) MESOR and mean of SBP and DBP were higher in diabetic patients than in healthy subjects [20, 22-23, 25, 27, 35, 37-38]; 3) diabetic patients had a high prevalence of increased night time BP or non-dipping profile [19,21,24,26,[28][29] that could reflect a) the presence of autonomic neuropathy [29,42], whose prevalence increases with age and diabetes duration, but also b) the circadian misalignment due to obstructive sleep apnea in obese subjects with type 2 diabetes [43]; 4) alterations in BP detected by ABPM, including BP variability, were associated with cardiovascular events and microvascular complications [20-21, 23, 28, 31-33, 36]; 5) ABPM recordings, even though discontinuous, can also allow to estimate HR variability [15,36] thus adding information beyond that of other ABPM components and ABPM-derived indices. The disappearance of HR circadian rhythm (detected with ABPM data analysed chronobiologically) in patients with type 1 diabetes mellitus has been suggested for the diagnosis of silent cardiac dysautonomia [44].…”

Prognostic Value of Blood Pressure Variability and Average Blood Pressure Levels in Patients With Hypertension and Diabetes

“…In particular, an impaired nocturnal BP fall (i.e., nondipping) or even increase in nighttime BP (i.e., rising pattern) has been shown to be common in this population, with a prevalence that may be as high as 30 and 31%, respectively (83). Proposed mechanisms for these abnormalities in circadian BP rhythms include alterations in autonomic CV modulation (which are frequently associated with diabetes) (84,85) but also other conditions such as obstructive sleep apnea, commonly observed in obese diabetic subjects (86). …”