Demographics
There were no baseline differences between HD patients and controls in
age, sex, prevalence of atrial fibrillation/flutter, prevalence of heart
failure (HF), cardiac medication regimen (beta-blocker, calcium channel
blocker, antiarrhythmic drug, or digoxin use), device type, most recent
EF, most recent thyroid function testing, or levothyroxine use. However,
HD patients were more likely to have OSA (55% vs 9.1%, p = 0.001,Table 1 ). Additionally, the control group had a higher number
of white patients compared to the HD group (HD 10/22 vs control 18/22, p
= 0.01, Table 1 ). Of patients on HD, 12 (54.5%) were
maintained on a Monday-Wednesday-Friday schedule, 9 (40.9%) on a
Tuesday-Thursday-Saturday schedule, and one patient (4.5%) was
maintained on a specialized home HD schedule (five HD sessions per week,
three hours per session). The mean dialysis vintage was 3.36 ± 2.5
years. There were no differences in baseline characteristics between HD
patients who did and did not suffer a VA event. Finally, there were no
differences between HD patients and controls in prevalence of device
type. Among patients with ICDs, no differences existed between groups in
device indication (i.e. equivalent rates of primary and secondary
prevention ICDs, Table 2 ).
In total, HD patients experienced 206 events, while control patients
experienced 164 (Figure 1 ). Of the 206 total events in the HD
group, 168 were NSVT (81.6%), 2 were VT (0.97%), and 36 were VF
(17.5%). Of the 164 total events in the control group, 142 were NSVT
(86.6%), 1 was VT (0.6%), and 21 were VF (12.8%). There was no
difference between groups in the proportion of patients experiencing any
VA overall (HD 45.4% vs control 63.6%, p = 0.226). There were no
differences between groups in the adjusted overall event rate (HD 9.81 x
10-5 ± 1.5 x 10-3events/patient-hours vs control 3.71 x 10-5 ± 9.1 x
10-4 events/patient-hours, p = 0.902), NSVT adjusted
event rate (8.00 x 10-5 ± 9.7 x 10-4vs 3.58 x 10-5 ± 8.7 x 10-4, p =
0.910), VT event rate (5.35 x 10-5 ± 0 vs 4.29 x
10-5 ± 0, p = N/A), or VF event rate (9.48 x
10-4 ± 8.1 x 10-4 vs 1.29 x
10-4 ± 8.4 x 10-5, p = 0.154). There
were no differences in device indication between groups (Table
2 ).
Though we found a similar rate of VA events in both groups, the control
group had a higher incidence of VA requiring therapies. As stated, HD
patients experienced a total of 38 VT/VF events, compared to 22 events
in the control group. Despite experiencing fewer numbers of VT/VF
events, control patients required significantly higher rates of device
therapy in the form of both ATP episodes and ICD shocks (total ATP
episodes 2/38 in HD vs 10/22 in controls, p = 0.0002, total ICD shocks
10/38 in HD vs 17/22 in controls, p = 0.0001, Table 2 ). The
significance observed in these therapies was driven primarily by
statistically-significant differences in VF episodes requiring device
intervention (Table 2 ).