A novel association between nondipping and painful diabetic polyneuropathy.

OBJECTIVE We hypothesized themeaningful coexistence of neuropathic pain and nondipping in painful diabetic polyneuropathy (PDPN). RESEARCH DESIGN AND METHODS In 113 patients with PDPN, with painless diabetic polyneuropathy (DPN+) and without DPN (DPN2), neuropathic pain, sleep, risk for obstructive sleep apnea (OSA), autonomic function, and blood pressure (BP) circadian pattern were assessed using the Douleur Neuropathique en 4 Questions (DN4), the Medical Outcomes Study Sleep Scale, the Berlin Questionnaire, cardiovascular reflex tests, and ambulatory BP monitoring. RESULTS Patients with PDPN showed higher nighttime systolic BP (130.4 6 15.6 mmHg) than both DPN2 (119.9610.6mmHg; P < 0.0001) and DPN+ patients (124.2612.3 mmHg; P < 0.05), and lower day–night difference (Δ) in systolic BP (5.5 6 6.5 vs. 8.667.7%; P < 0.05) and diastolic BP than DPN2 patients. In a stepwise regression analysis, orthostatic hypotension, high risk for OSA, and PDPN (DN4 interview) were independent determinants of Δ in systolic BP (r = 0.46; P = 0.0001), Δ in diastolic BP, and nighttime systolic BP. CONCLUSIONS PDPN is associated with higher nocturnal systolic BP and impaired BP circadian pattern independent of pain-related comorbidities, suggesting a condition of high cardiovascular risk.