P160
TWICE-WEEKLY INCREMENTAL DIALYSIS DOES NOT COMPROMISE
SURVIVAL
Enric Vilar, Humza Chandna, Laura Mawer, Ken Farrington
Lister Renal Unit
Background
Thrice weekly haemodialysis (3HD) is the norm for patients receiving maintenance
haemodialysis (HD), irrespective of the prevailing level of residual kidney function. The
rationale for this has not been examined. We examined the difference in long-term survival
between patients who had received periods of twice-weekly haemodialysis (2HD) and those on
long-term 3HD in our incremental HD programme.
Methods
We examined the electronic records of patients initiating dialysis in our centre over a 20 year
period. Those transferring from other centre already on dialysis, those transferring from
peritoneal dialysis, and those returning following a failed transplant were excluded. Patients
who had dialysed 2HD during the first 12 months following initiation were identified for
comparison with patients treated solely by 3HD during the same period. Data was extracted to
allow comparison of these groups with respect to age, sex, comorbidity, residual urea clearance,
serum albumin and survival.
Results
We identified 195 patients who had received 2HD in this time period for 3-51 months (mean 8
months. Eight patients received 2HD as part of a palliative approach and a further 10 during
delayed recovery from AKI. The remaining 177 had received this treatment as part of an
incremental dialysis programme – treatment being carefully monitored by monthly estimates of
total Kt/V – combining dialysis and native kidney urea clearance. These 177 form the basis of
the following analysis in which outcomes are compared with those of 771 patients dialysed
3HD during the same period. 2HD patients were younger (59 ± 16 v 62 ± 15 years: p = 0.11).
There were no gender differences, nor any with respect to the prevalence of diabetes, ischaemic
heart disease, peripheral vascular disease or malignancy. However residual native kidney
function was higher in the 2HD group - median maximal urea clearance in 12 months following
initiation 5.3 (range 14.3) v 2.4 ml/min (range 10.6). Median survival in the 2HD group was
greater than that in the 3HD group [5.5 (95% CI 4.2 – 6.9) v 4.4 (95% CI 4.0 – 4.7) year: p
<0.001]. The differences remained significant after adjustment for age, sex, prevalence of
diabetes, ischaemic heart disease, peripheral vascular disease, malignancy, serum albumin and
residual function (adjusted survival 5.9 v 4.9 years: P= 0.038).
Conclusion
We have found no evidence of a detrimental effect on survival of twice-weekly HD provided it
is part of an incremental programme based on regular assessment of residual kidney function.
The survival benefit of twice-weekly treatment seen in this study is most likely due to lead time
bias and other unaccounted for variables including late presentation in the thrice-weekly group.