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Cardiovascular autonomic neuropathy (CAN) is a frequent complication of diabetes mellitus and is associated with increased morbidity and mortality in patients with diabetes. Hence, early and correct diagnosis of CAN is crucial. Standard cardiovascular reflex rests (CARTs) have been the gold standard of CAN assessment. Originally, CARTs consisted of five reflex tests, but measuring diastolic blood pressure response to sustained handgrip exercise has no longer been suggested as an established clinical test. Increasing body of evidence suggests that isometric handgrip test should no longer be used for the evaluation of sympathetic dysfunction during cardiovascular autonomic neuropathy assessment in diabetic patients. The associations of isometric handgrip test results with parameters of hypertension and markers of hypertension-related target-organ damage in diabetic and non-diabetic individuals point toward its potential role as a screening tool to identify patients with high cardiovascular risk. The current review summarizes historical view of standard cardiovascular reflex tests and latest data on isometric handgrip test., Competing Interests: Declaration of competing interest The authors have no conflicting interest to declare., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: Historically, a set of 5 Cardiovascular Autonomic Reflex Tests (CARTs) were considered to be the gold standard in the assessment of Cardiovascular Autonomic Neuropathy (CAN). However, measuring diastolic Blood Pressure (BP) response to sustained handgrip is omitted in recent guidelines. We aimed to assess the association between the handgrip and the other 4 tests as well as to identify determinants of the handgrip test results in diabetic patients., Patients and Methods: 353 patients with diabetes (DM) were recruited (age: 60.2±7.4 years; female: 57.2%; BMI: 29.3±2.1 kg/m2; DM duration: 15.6±9.9 years; HbA1c: 7.8±1.4% (66 mmol/mol); with type 1 DM: 18.1%). CAN was assessed by 5 CARTs: the deep breathing test, Valsalva ratio, 30/15 ratio, handgrip and orthostatic hypotension test., Results: Sensitivity and specificity of the handgrip test in the diagnosis of definite CAN were 24.6% (95%CI 17.7-33.1%) and 79.4% (95%CI 73.3-84.4%), respectively. Results of the handgrip test did not show any association with those of the deep-breathing test (y=0.004, p=0.563), 30/15 ratio (y=0.282, p=0.357), Valsalva ratio (y=-0.058, p=0.436) and orthostatic hypotension (y=-0.026, p=0.833). Handgrip test abnormality showed an independent association with higher initial diastolic BP (OR 1.05, p=0.0009) and an independent inverse association with the presence of hypertension (OR=0.42, p=0.006)., Conclusion: Our data confirm that the handgrip test should no longer be part of the cardiovascular autonomic testing being highly dependent on hypertensive status and baseline diastolic BP. Exaggerated exercise pressor response is proposed as putative mechanism for the inverse association between abnormal results of the handgrip test and hypertension. Adequate CARTs are important to allow their use in clinical trials and for the prevention of DM-associated complications by initiating early treatment.