A novel association between nondipping and painful diabetic polyneuropathy.

Abstract

We hypothesized the meaningful coexistence of neuropathic pain and nondipping in painful diabetic polyneuropathy (PDPN). In 113 patients with PDPN, with painless diabetic polyneuropathy (DPN(+)) and without DPN (DPN(-)), 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. Patients with PDPN showed higher nighttime systolic BP (130.4 ± 15.6 mmHg) than both DPN(-) (119.9 ± 10.6 mmHg; P < 0.0001) and DPN(+) patients (124.2 ± 12.3 mmHg; P < 0.05), and lower day-night difference (∆) in systolic BP (5.5 ± 6.5 vs. 8.6 ± 7.7%; P < 0.05) and diastolic BP than DPN(-) patients. In a stepwise regression analysis, orthostatic hypotension, high risk for OSA, and PDPN (DN4 interview) were independent determinants of ∆ in systolic BP (r = 0.46; P = 0.0001), ∆ in diastolic BP, and nighttime systolic BP. 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.