ObjectivesTo evaluate the determinants of orthostatic hypotension (OH) in type 2 diabetes (T2D) and the usefulness of Δheart rate (HR)/Δsystolic blood pressure (SBP), index of cardiac baroreflex function, in identifying neurogenic OH. MethodsIn 208 participants with T2D, we performed 3 HR-based cardiovascular reflex tests (HR-CARTs) and OH test and assessed clinical history and variables. We defined OH as SBP falls of ≥20 and ≥30 mm Hg with supine SBPs of <140 and ≥140 mm Hg, respectively, and early and confirmed cardiovascular autonomic neuropathies (CANs) based on 1 and 2 abnormal HR-CART results. In participants with OH, we measured ΔHR/ΔSBP, using data from the lying-to-standing and OH test and its diagnostic accuracy for neurogenic OH (as OH plus confirmed HR-CAN). ResultsOH was present in 25 participants and associated with lower HR-CART scores (P = .01), higher glycosylated hemoglobin level (P = .0048), the presence of CAN (P = .0058), retinopathy (P = .037), and peripheral vascular disease (P = .0056), the absence of hypertension (P = .0008), and physical activity (P = .0214) but not with interfering drugs and β-blockers. In a multiple logistic regression, HR-CAN was the main independent determinant of OH (odds ratio, 4.74) with physical activity and hypertension (odds ratios, 0.16 and 0.23; R2 = 0.22). ΔHR/ΔSBP had a good diagnostic accuracy for neurogenic OH (area under the receiver operating characteristic curve, 0.816 ± 0.087) and, at the cutoff of 0.5 bpm/mm Hg, a sensitivity of 100% and specificity of 63.2%. ConclusionCAN remains the primary determinant of OH in T2D but does not explain all its variance with contribution of comorbidities and physical inactivity. The index ΔHR/ΔSBP may represent a useful clinical tool to identify neurogenic OH.