Association of Diabetes with Heart Rate Variability during Hemodialysis: Insights from the Frequent Hemodialysis Network Daily Trial.

Abstract

Background: Autonomic dysfunction is common among patients with diabetes receiving hemodialysis (HD). We wished to explore the association of diabetes with heart rate variability (HRV; a surrogate of autonomic dysfunction) and whether HRV mediates the association of diabetes with intra-dialytic hypotension (IDH).

Methods: In this secondary analysis of the Frequent Hemodialysis Network Daily Trial, we performed: 1) random effects linear regression to estimate the association of diabetes with log-transformed low-frequency power [LF, proxy of sympathetic activity], high-frequency power [HF, proxy of parasympathetic activity], ratio of LF/HF (proxy for sympathovagal balance), and standard deviation of the normal-to-normal R-R interval [SDNN] measured at baseline and 12-months); 2) linear regression to explore the association of diabetes with changes in HRV parameters over 12 months. Models were adjusted for age, sex, designated race, height, access type, HD vintage, history of heart failure, pre-HD systolic BP, heart rate, ultrafiltration rate, hemoglobin, serum albumin, beta-blocker use, calcium channel blocker use, diuretic use, left ventricular mass, and randomized treatment assignment.

Results: Of the 198 patients without baseline atrial fibrillation, 82 (41%) had self-reported diabetes. In adjusted random effects models, diabetes (vs. no diabetes) was associated with lower SDNN -18% (95%CI -27, -9) on a per session basis. The presence of diabetes was not associated with differences in LF 7% (95%CI -20, 43), HF 10% (95%CI -10, 33), or LF/HF -4% (95%CI -19, 14). Diabetes (vs. no diabetes) was not associated with a change from baseline to 12 months in any HRV parameter. SDNN did not attenuate the observed association of diabetes with IDH.

Conclusions: Among participants in the FHN Daily Trial, diabetes (vs. no diabetes) was associated with 18% lower SDNN. The association of diabetes with IDH did not appear to be mediated by SDNN. The reasons for higher rates of IDH in patients with diabetes remain elusive.