Resea ch A icle
Associa ion o Con inuous-Equi alen U ea Clea ances wi h
Dea h Risk in In e mi en Hemodialysis
Aa ne Va ia,1Heini Huh ala,2and Jukka Mus onen3,4
1Sa onlinna Cen al Hospi al, 57120 Sa onlinna, Finland
2School o Heal h Sciences, Uni e si y o Tampe e, 33014 Tampe e, Finland
3School o Medicine, Uni e si y o Tampe e, 33014 Tampe e, Finland
4Tampe e Uni e si y Hospi al, 33521 Tampe e, Finland
Co espondence should be add essed o Aa ne Va ia; aa ne. a [email protected]
Recei ed 19 Janua y 2016; Accep ed 30 Ma ch 2016
Academic Edi o : Deepak Malho a
Copy igh © 2016 Aa ne Va ia e al. This is an open access a icle dis ibu ed unde he C ea i e Commons A ibu ion License,
which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal wo k is p ope ly ci ed.
Backg ound. Se e al epo s desc ibe a o able esul s om equen hemodialysis, bu due o he lack o unequi ocal dose measu es
i is no clea whe he he bene i s a e due o mo e e icien oxin emo al o o he ac o s. Me hods.Theassocia ionswi hdea h
isk o six con inuous-equi alen u ea clea ance measu es we e compa ed in 57 con en ional in-cen e hemodialysis ea men
pe iods o 51 pa ien s, oge he 114 pa ien yea s. The double pool dose measu es we e calcula ed wi h he Solu e-Sol e p og am
and sepa a ely scaled o u ea dis ibu ion olume o no malized wi h body su ace a ea. Resul s. Mo ali y associa ed signi ican ly
wi h equi alen enal u ea clea ance (EKR) scaled o u ea dis ibu ion olume (𝑉)(𝑝 = 0.033)andwi hEKRno malizedwi h
body su ace a ea (BSA) (𝑝 = 0.044)bu no wi h𝑉-scaled (𝑝 = 0.059) no BSA-no malized (𝑝 = 0.183) s anda d clea ance
(s dK). Women had signi ican ly highe no malized p o ein ca abolic a e (nPCR), EKR/𝑉,ands dK/𝑉 han men bu sligh ly
lowe BSA-no malized dose measu es and lowe mo ali y. P o ein ca abolic a e and dialysis dose co ela ed posi i ely wi h each
o he and wi h su i al. Conclusions. The p ognos ically mos alid con inuous-equi alen clea ance in he p esen ma e ial was
EKR/𝑉, calcula ed om double pool u ea gene a ion a e, dis ibu ion olume, and ime-a e aged concen a ion.
1. In oduc ion
Su i al co ela es wi h u ea-based hemodialysis session
dose in many la ge egis y s udies (Low ie e al. [1]: 43,334
pa ien s, Po e al. [2]: 84,936 pa ien s, and Mille e al. [3]:
88,153 pa ien s) in con en ional h ice-weekly schedule, bu
in he andomizedcon olledHEMO ialmeanequilib a ed
K𝑡/𝑉 (eK𝑡/𝑉) 1.53 did no esul in a signi ican ly be e
ou come han 1.16 [4].
In e mi en hemodialysis ea men s can be compa ed
o each o he by he session dose measu es URR, K𝑡,K𝑡/𝑉,
and eK𝑡/𝑉 only i he ea men equency is equal. Se e al
obse a ional s udies, e e ed o in [5, 6], and he andom-
ized con olled FHN ial [7] desc ibe posi i e esul s om
equen (“daily”) hemodialysis. Howe e , he ole o solu e
emo al e iciency emains obscu e.
U ea dis ibu ion olume (𝑉)isanessen ial a iable
in kine ic modeling and can be used as a ep esen a i e
o pa ien size, a scaling ac o . Howe e , i may ha e also
an independen e ec on ou come [1, 8], which weakens
he alue o K𝑡/𝑉 as a p ognos ic ac o . BSA has ecen ly
been ecommended o scaling o dialysis dose simila ly
as in exp essing he glome ula il a ion a e [9]. 𝑉-scaled
dosing may esul in subop imal ou come in women and
child en.
Equi alen enal u ea clea ance (EKR, Casino and Lopez)
[10] and s anda d clea ance (s dK, Go ch) [11, 12] ake
ea men equency and esidual enal unc ion (RRF) in o
accoun and hey we e in ended o use in compa ing dialysis
doses in di e en schedules and o con inuous dialysis and
enal unc ion [13, 14].
RRFmaycon ibu esigni ican ly o he o alweekly
solu e emo al [14] bu only minimally (usually <1%) o he
deli e ed K𝑡/𝑉o URR measu ed om blood samples. Renal
clea ance (K ) can be added ma hema ically o session K𝑡/𝑉
[15–17]. Con inuous-equi alen clea ance based on UKM
Hindawi Publishing Co po a ion
Ad ances in Neph ology
Volume 2016, A icle ID 9342853, 8 pages
h p://dx.doi.o g/10.1155/2016/9342853
2Ad ances in Neph ology
Table 1: Associa ion o pa ien cha ac e is ics and dialysis dose measu es wi h dea h isk in 57 hemodialysis ea men pe iods o 51 pa ien s.
Mean SD Min Max Uni a ia e
𝑝OR 95% CI
Age Yea s 61.6 15.5 16.7 91.6 0.103 1.038 0.993–1.085
Weigh kg 75.1 18.2 44.2 123.6 0.525 0.989 0.957–1.023
BMI kg/m226.1 5.5 16.3 43.7 0.198 0.924 0.819–1.042
BSA m21.84 0.25 1.31 2.34 0.872 0.823 0.078–8.727
𝑉L 31.8 6.7 20.5 50.3 0.637 1.021 0.936–1.113
nPCR g/kg/day 1.15 0.24 0.73 1.74 0.058 0.065 0.004–1.095
nK mL/min/1.73 m21.7 1.4 0.0 6.0 0.861 0.963 0.631–1.469
nEKR mL/min/1.73 m212.5 1.3 8.4 16.4 0.044 0.611 0.379–0.988
ns dK mL/min/1.73 m28.5 1.0 6.2 12.2 0.183 0.638 0.330–1.235
nEKRan mL/min/1.73 m215.1 2.3 8.3 20.3 0.113 0.806 0.617–1.053
ns dKan mL/min/1.73 m210.2 1.6 6.1 14.3 0.232 0.785 0.527–1.168
EKR/𝑉/week 4.35 0.64 2.36 5.82 0.033 0.326 0.117–0.912
s dK/𝑉/week 2.93 0.39 1.73 3.88 0.059 0.205 0.040–1.060
/week 2.9 0.3 2.0 3.7 0.413 0.503 0.097–2.606
𝑡dh/week 13.5 2.3 7.7 18.4 0.077 0.786 0.602–1.027
Table 2: Hemodialysis ea men pe iod du a ions and easons o
discon inua ion.
𝑁%Du a ion (yea s)
Mean SD Min Max
Con inuing 19 33.3 2.5 1.7 0.4 5.8
Dea h 16 28.1 2.3 1.6 0.6 6.9
T ansplan a ion 8 14.0 1.4 1.3 0.6 4.6
T ans e o ano he uni 8 14.0 1.3 1.2 0.3 3.8
T ans e o pe i oneal dialysis 3 5.3 2.1 1.4 0.7 3.5
Decision 3 5.3 0.8 0.3 0.6 1.1
The numbe s include hemodialysis ea men pe iods ongoing on Janua y
1, 1998 ( om ha da e on), and inciden pe iods du ing he nine-yea
obse a ion ime un il Decembe 31, 2006 (unless e mina ed ea lie ).
includes K au oma ically. Renal unc ion is “quali a i ely”
be e han dialysis wi h equal u ea clea ance [18].
In heo y, he con inuous-equi alen a e age clea ance
basedondoublepoolUKMandincludingRRFis ine,bu
he bes measu e is he one mos closely associa ed wi h
ou come. Only ew ea lie epo s co ela e mo ali y di ec ly
wi h ECC [7, 19–22]. The aim o he p esen p elimina y s udy
was o compa e he p ognos ic alue o di e en con inuous-
equi alen u ea clea ances as dialysis dose measu es.
2. Subjec s and Me hods
The s udy is a e ospec i e egis y analysis om a hospi al
p o iding adul hemodialysis se ices in a dis ic wi h
a ca chmen a ea o some 50,000 inhabi an s in Eas e n
Finland. The obse a ion ime was nine yea s, om Janua y
1, 1998, o Decembe 31, 2006. The ma e ial comp ises 57
con en ional in-cen e hemodialysis ea men pe iods o 51
pa ien s, in o al 114 pa ien yea s. Pe iods las ing unde 90
days a e no included. Pa ien cha ac e is ics a e desc ibed
in Table 1. Table 2 p esen s he cha ac e is ics o he dialysis
ea men pe iods. “Decision” e e s o a unanimous decision
by pa ien and physician o discon inue enal eplacemen
he apy.
Dosing o dialysis, including ea men equency, was
p esc ibed by he i s au ho on mul iple c i e ia (weigh ,
hyd a ion s a us, p edialysis plasma u ea concen a ion, and
o he labo a o y alues, eK𝑡/𝑉 a ge s, and pa ien ’s p e -
e ences). Renal diagnosis, como bidi y, unc ional s a us,
wai ing o ansplan a ion, age, an icipa ed su i al ime,
andp o einca abolic a e(PCR)we eno usedasdosing
c i e ia. The pa ien s we e encou aged by a die ician o use
a die con aining p o ein 1.2 g/kg/day, bu he ac ual die a y
p o ein in ake was no con olled.
U ea kine ic modeling wi h in e dialysis u ine collec ion
was pe o med mon hly. K was in e pola ed om p e ious
and nex measu emen s i u ine collec ion occasionally ailed.
RRF was de ec ed in 68% o UKM sessions. In 15% o hem,
K was in e pola ed. The numbe s desc ibing he pa ien
cha ac e is ics and dialysis dose measu es a e means o each
ea men pe iod.
Double pool UKM calcula ions we e conduc ed wi h he
Solu e-Sol e p og am e sion 1.97 (July 2, 2010, wi h sou ce
code) [23], accessed No embe 12, 2015: h p://www.u eak-
ine ics.o g/.
Dialyze mass a ea coe icien (K0𝐴) epo edby he
dialyze manu ac u e is used in Solu e-Sol e in calcula ing
dialyze clea ance (Kd) om𝑄band 𝑄dwi h Michaels’
equa ion [24].
Six double pool con inuous-equi alen u ea clea ance
measu es we e compa ed:
EKR/𝑉 (/week).
nEKR (mL/min/1.73 m2).
nEKRan (mL/min/1.73 m2).
s dK/𝑉 (/week).
ns dK (mL/min/1.73 m2).
ns dKan (mL/min/1.73 m2).
Ad ances in Neph ology 3
Table 3: Dialysis ea men pe iods di ided in o wo g oups wi h app oxima ely equal mean nPCR.
EKR/𝑉𝑝 alue
Low High
Mean SD Mean SD
Age Yea s 60.8 13.2 62.5 17.7 0.668
Weigh kg 77.1 21.2 72.9 14.7 0.393
BMI kg/m226.5 6.5 25.7 4.4 0.595
BSA m21.86 0.27 1.81 0.22 0.441
𝑉L 33.7 7.5 29.8 5.1 0.024
nPCR g/kg/day 1.19 0.28 1.12 0.19 0.283
nK mL/min/1.73 m22.0 1.4 1.4 1.4 0.102
nEKR mL/min/1.73 m212.1 1.5 13.0 1.0 0.005
ns dK mL/min/1.73 m28.3 1.1 8.7 0.9 0.240
nEKRan mL/min/1.73 m214.2 2.4 16.2 1.7 0.001
ns dKan mL/min/1.73 m29.8 1.7 10.7 1.3 0.023
EKR/𝑉/week 3.99 0.59 4.72 0.45 <0.001
s dK/𝑉/week 2.75 0.38 3.12 0.30 <0.001
T ea men equency /week 2.8 0.4 3.1 0.2 0.006
T ea men ime h/week 12.6 2.5 14.4 1.7 0.003
T ea men pe iods 𝑛29 28
Women % 31.0 46.4 0.233
Diabe ics % 37.9 46.4 0.516
E n di ng w i h d e a h % 3 7.9 1 7. 9 0 . 0 92
Pa ien yea s 𝑛49.8 64.5
Dea hs 𝑛11 5
Mo ali y /1000 py 221 78 0.049
Thei de ini ions a e desc ibed in he Appendix. EKR is based
on ime-a e aged u ea concen a ion; s dK is based on a e -
age peak concen a ion. All include di usion, con ec ion,
and enal clea ance.
2.1. S a is ical Me hods. Con inuous a iables a e exp essed
as means wi h s anda d de ia ions (SD) and minimum and
maximum alues. Ca ego ical a iables a e exp essed as
pe cen ages.
Uni a ia e and mul i a iable bina y logis ic eg ession
analyses we e pe o med o iden i y a iables associa ed wi h
dea h. Va iables wi h a uni a ia e 𝑝 alue <0.10 we e en e ed
in o he mul i a iable models. Odds a ios (ORs) and 95%
con idence in e als (CIs) a e epo ed.
Linea eg ession analysis was used o e alua e he in e -
ac ion o dialysis dose and nPCR (Figu e 1) and he ma e ial
was spli in o wo g oups on he basis o EKR/𝑉 and nPCR
(Table 3).
SPSS 22.0 and STATA 13.1 we e used in s a is ical calcula-
ions. The g aph was d awn wi h Excel 2007.
3. Resul s
The o e all mo ali y was 140 pe 1,000 pa ien yea s. The
main esul s a e shown in Table 1. Mo ali y was signi ican ly
associa ed only wi h EKR/𝑉 and nEKR. In mul i a iable
analysis, EKR/𝑉 was he only a iable ha ing an associa ion
wi h dea h isk (OR = 0.326, CI = 0.117–0.912, and 𝑝 = 0.033).
Figu e 1 illus a es he linea eg ession be ween nPCR
and EKR/𝑉. To elimina e he con ounding e ec o nPCR
on he dose-mo ali y ela ionship, he ma e ial was spli
in o wo g oups wi h app oxima ely equal mean nPCR bu
di e en mean EKR/𝑉.Thelinesepa a ing heg oupsis
depic ed in Figu e 1. Table 3 shows ha he di e ence in
mo ali y be ween he low and high dose g oups is s ill
signi ican .
Men had lowe nPCR, EKR/𝑉,ands dK/𝑉 and highe
mo ali y han women (Table 4). Diabe ics had highe weigh ,
BMI, and BSA bu did no di e signi ican ly om nondiabe -
ics in mo ali y (Table 5).
Co ela ions be ween some pa ien cha ac e is ics and
con inuous-equi alen clea ances a e shown in Table 6. All
clea ances co ela e wi h each o he .
4. Discussion
The associa ion o six con inuous-equi alen u ea clea ance
measu es wi h dea h isk was e alua ed by s a is ical analysis.
The mos signi ican p edic o in uni a ia e analysis and he
only signi ican one in mul i a iable analysis was EKR/𝑉,
calcula ed om TAC (𝑝 = 0.033). The 𝑝 alue o s dK/𝑉
( om PAC) was 0.059. In he old NCDS, TAC had a close
co ela ion wi h ou come han PAC [25]. The s dK concep is
complian wi h he peak concen a ion hypo hesis [26], no
suppo ed by he p esen esul s.
No malizing wi h BSA was es ed by he a iables nEKR
and ns dK, wi h mL/min/1.73 m2(o L/week/1.73 m2)as hei
uni . nEKR was signi ican ly associa ed wi h dea h isk, bu
ns dK was no . In he p esen s udy, Kdwas de i ed om
𝑄b,𝑄d,andK
0𝐴 epo ed by he dialyze manu ac u e .
4Ad ances in Neph ology
Table4:Dialysis ea men pe iodsbygende .
Women Men 𝑝 alue
Mean SD Mean SD
Age Yea s 63.3 14.5 60.6 16.1 0.529
Weigh kg 65.2 15.3 81.2 17.4 0.001
BMI kg/m225.7 5.9 26.3 5.3 0.694
BSA m21.66 0.17 1.95 0.22 <0.001
𝑉L 26.1 3.6 35.3 5.7 <0.001
nPCR g/kg/day 1.23 0.23 1.10 0.24 0.043
nK mL/min/1.73 m21.9 1.4 1.6 1.4 0.467
nEKR mL/min/1.73 m212.4 1.1 12.7 1.5 0.401
ns dK mL/min/1.73 m28.2 0.7 8.7 1.1 0.066
nEKRan mL/min/1.73 m214.8 1.9 15.4 2.6 0.349
ns dKan mL/min/1.73 m29.8 1.2 10.5 1.7 0.082
EKR/𝑉/week 4.64 0.57 4.17 0.62 0.005
s dK/𝑉/week 3.07 0.36 2.85 0.39 0.036
T ea men pe iods 𝑛22 35
Ending wi h dea h % 13.6 37.1 0.055
Pa ien yea s 𝑛50.6 63.7
Dea hs 𝑛313
Mo ali y /1000 py 59 204 0.040
2.00
2.50
3.00
3.50
4.00
4.50
5.00
5.50
6.00
0.40 0.80 1.20 1.60 2.00
EKR/V (/week)
nPCR (g/kg/day)
Di ision line
Reg ession line
y = 1.50x + 2.66
y = 1.40x + 2.73
R2= 0.29
Figu e 1: Linea eg ession be ween nPCR and dialysis dose
(EKR/𝑉) and he line sepa a ing he g oups o Table 3.
Calcula ed wi h Michaels’ equa ion [24], a 50% e o in K0𝐴
causes an e o o some 10% in Kdwi h usual 𝑄band 𝑄d.
E o s in Kdcause in UKM p opo ional e o s in 𝑉and 𝐺.
In EKR/𝑉 and s dK/𝑉, he e o s cancel each o he ou , bu
no in nEKR and ns dK.
Two o he BSA-no malized con inuous-equi alen clea -
ances nEKRan and ns dKan we e calcula ed applying he
me hod o Daugi das e al. desc ibed in he Appendix [9,
27]. The an h opome ic o al body wa e is usually la ge
compa ed o he kine ic 𝑉. Thus, nEKRan and ns dKan
a e highe han he simple BSA-no malized alues. They
a e UKM-based con inuous-equi alen hemodialysis dose
measu es, whe e he possible e o s in Kda e elimina ed,
no malized wi h wo an h opome ic measu es o body size
and wi h mL/min/1.73 m2as uni . Howe e , no malizing wi h
BSA wi h ei he me hod did no imp o e he p edic i e alue
o EKR/𝑉 and s dK/𝑉.
In heHEMO ial, heage-adjus edmo ali ydidno
di e signi ican ly be ween gende s, bu women did bene i
om highe dose [28]. In he p esen s udy, women had lowe
mo ali y and go highe EKR/𝑉 and s dK/𝑉 bu sligh ly
lowe BSA-no malized doses (Table 4). Como bidi y o he
han diabe es was no analyzed.
The a he wide ange o dialysis doses in he p esen
s udyisp obablydue o heoppo unis icaspec :mo emay
be be e , bu wi h la ge pa ien s i is no easy o achie e a high
dose (Table 6). In Table 3, he dis ibu ion olume and he
p opo ion o men we e highe in he low dose g oup. Men
had highe mo ali y and olume and lowe 𝑉-scaled dialysis
dose (Table 4).
The pa ien cha ac e is ics and dialysis dose measu es
ha e mul iple co ela ions o dependencies (Table 6). Figu e 1
shows he linea eg ession be ween nPCR and EKR/𝑉.
PCR is a unc ion o EKR/𝑉 o s dK/𝑉 ((B.3) and (B.4)
in Appendix). Thus, ma hema ical coupling is ine i able. I
is also possible ha nPCR depends on he dialysis dose
Ad ances in Neph ology 5
Table5:Dialysis ea men pe iodsbydiabe ics a us.
Diabe es 𝑝 alue
Yes No
Mean SD Mean SD
Age Yea s 61.2 14.9 62.0 16.1 0.842
Weigh kg 81.7 18.5 70.2 16.7 0.018
BMI kg/m228.1 6.3 24.6 4.4 0.016
BSA m21.92 0.22 1.78 0.25 0.037
𝑉L 32.9 6.3 30.9 6.9 0.260
nPCR g/kg/day 1.16 0.23 1.14 0.26 0.739
nK mL/min/1.73 m21.5 1.0 1.9 1.6 0.243
nEKR mL/min/1.73 m212.7 0.9 12.4 1.6 0.356
ns dK mL/min/1.73 m28.6 0.8 8.4 1.1 0.350
nEKRan mL/min/1.73 m215.8 1.9 14.6 2.5 0.055
ns dKan mL/min/1.73 m210.7 1.3 9.9 1.7 0.047
EKR/𝑉/week 4.43 0.47 4.29 0.74 0.427
s dK/𝑉/week 2.99 0.27 2.89 0.46 0.360
T ea men pe iods 𝑛24 33
Ending wi h dea h % 25.0 30.3 0.660
Pa ien yea s 𝑛54.3 60.0
Dea hs 𝑛610
Mo ali y /1000 py 110 167 0.439
Table 6: Spea man’s co ela ions, signi ican a he 0.01 le el (2- ailed).
Weigh BMI BSA 𝑉nPCR nEKR ns dK nEKRan ns dKan EKR/𝑉s dK/𝑉
Weigh 1 0.854 0.950 0.748 0.352 0.453 0.530
BMI 0.854 1 0.658 0.455 0.393 0.427
BSA 0.950 0.658 1 0.817 0.364 0.430 0.521
𝑉0.748 0.455 0.817 1 0.436 −0.475 −0.354
nPCR 1 0.493 0.519 0.535 0.609
nEKR 1 0.929 0.694 0.711 0.566 0.631
ns dK 0.352 0.364 0.436 0.929 1 0.569 0.686 0.351 0.509
nEKRan 0.453 0.393 0.430 0.493 0.694 0.569 1 0.962 0.821 0.850
ns dKan 0.530 0.427 0.521 0.519 0.711 0.686 0.962 1 0.706 0.809
EKR/𝑉−0.475 0.535 0.566 0.351 0.821 0.706 1 0.961
s dK/𝑉−0.354 0.609 0.631 0.509 0.850 0.809 0.961 1
(causali y)o ha dosingo dialysisisguidedbyu ea
concen a ions o adjus ed o p o ein ca abolic a e [29] as
ecommended by Go ch e al. [12, 30, 31] ( e e se causali y).
All hese ac o s may ha e a ole in he p esen s udy, bu hei
sepa a e con ibu ion could no be speci ied. In he HEMO
ial, he e ec o dose on nPCR and he ole o ma hema ical
couplingwe ees ima ed obesmall[32].
PCR e lec s die a y p o ein in ake, which co ela es wi h
nu i ional s a us and ou come [33]. In a ecen la ge egis y
ma e ial mo ali y dec eased wi h inc easing nPCR un il
1.3 g/kg/day [34]. Table 3 shows ha in he p esen s udy
EKR/𝑉had a signi ican associa ion wi h mo ali y, al hough
nPCR was sligh ly highe in he low EKR/𝑉 g oup. nPCR
is associa ed wi h mo ali y di ec ly and wi h he dialysis
dose h ough he “ ea o high u ea concen a ions” e ec —
an example o he mechanisms possibly unde lying he dose-
a ge ing bias [35]. nPCR and dialysis dose may ha e a
syne gis ic e ec on su i al.
A limi a ion o he p esen s udy is he small numbe o
pa ien s, which p e en s obus conclusions. On he o he
hand, di e en dosing de ini ions we e compa ed in he same
ma e ial—a esponse o he challenge p esen ed by Debowska
e al. [36].
In summa y, EKR/𝑉and nEKR we e signi ican ly associ-
a ed wi h mo ali y bu s dK/𝑉and ns dK we e no . No mal-
izing wi h BSA [9, 37] did no imp o e he signi icance o he
ECC measu es.
Appendix
A. Con inuous-Equi alen Clea ance (ECC)
EKR (ECCTA )ands dK(ECC
PA ) a e based on he de ini ion
o clea ance (K):
K=𝐸
𝐶.(A.1)

6Ad ances in Neph ology
In s eady s a e, he emo al a e (𝐸) equals he gene a ion a e
(𝐺), and hus
K=𝐺
𝐶.(A.2)
In EKR, 𝐶is he ime-a e age concen a ion (TAC) and, in
s dK, i is he a e age p edialysis concen a ion (peak a e age
concen a ion, PAC):
EKR =𝐺
TAC ,(A.3)
s dK =𝐺
PAC .(A.4)
The uni is, o example, mL/min o L/week. Bo h may be
scaled o body size by di iding by u ea dis ibu ion olume
𝑉and exp essed as EKR/𝑉 and s dK/𝑉:
EKR/𝑉 = EKR
𝑉,(A.5)
s dK/𝑉 = s dK
𝑉.(A.6)
𝐺,𝑉, TAC, and PAC a e de e mined by kine ic modeling,
in he p esen s udy wi h Solu e-Sol e . TAC and PAC a e
whole-body wa e concen a ions and 𝑉is he pos dialysis
o al olume 𝑉𝑡. The mos p ac ical uni o EKR/𝑉 and
s dK/𝑉 is /week.
nEKR and ns dK a e ECC alues (ECCTA and ECCPA )
no malized wi h body su ace a ea analogically o glome ula
il a ion a e o enal clea ance, wi h mL/min/1.73 m2as he
uni :
nEKR =EKR
BSA ∗1.73,
ns dK =s dK
BSA ∗1.73.
(A.7)
Daugi das e al. ha e de eloped a me hod o ge a BSA-
no malized s dK𝑡/𝑉 [9, 27]:
SAn-s dK𝑡/𝑉 = s dK𝑡/𝑉 ∗ Van
BSA ∗20,(A.8)
whe e Van is an h opome ic TBW in li e s, BSA is in m2,
and hecons an 20is hemeano 𝑉/BSA (L/m2)in hei
ma e ial. Simila ly, nEKRan and ns dKan can be calcula ed
by using a combined an h opome ic scaling ac o Van /BSA
(=TBW/BSA):
nEKRan =EKR/𝑉 ∗ Van
BSA ∗1.73, (A.9)
ns dKan =s dK/𝑉 ∗ Van
BSA ∗1.73, (A.10)
wi h app op ia e uni con e sion ac o s. Van /BSA akes
gende in o accoun . In he p esen ma e ial, i s a e age
alue was 18.7 (18.3–20.3) L/m2 o women and 21.9 (20.2–
24.5) L/m2 o men.
B. nPCR
By de ini ion (see (A.4) and (A.6)),
𝐺=s dK/𝑉 ∗PAC ∗𝑉. (B.1)
In hemodialysis, nPCR is gene ally calcula ed by he Bo ah
equa ion [38] wi h Sa gen ’s modi ica ion [39]:
nPCR =(9.35 ∗ 𝐺 + 0.294 ∗ 𝑉)
(𝑉/0.58),(B.2)
whe e nPCR is exp essed in g/kg/day, 𝐺is exp essed in
millig ams o u ea-N/min, and 𝑉is exp essed in L. By sub-
s i u ing 𝐺 om (B.1) and using app op ia e uni con e sion
ac o s we ge
nPCR = 0.0151 ∗ s dK/𝑉 ∗ PAC +0.171, (B.3)
whe e nPCR is in g/kg/day, s dK/𝑉is in /week, and PAC is in
mmol/L. 𝑉will be elimina ed. nPCR is high i concen a ion
(PAC) is high despi e high o no mal clea ance (s dK/𝑉).
s dK/𝑉 andPACcanbesubs i u edwi hEKR/𝑉 and TAC:
nPCR = 0.0151∗ EKR/𝑉∗ TAC + 0.171. (B.4)
nPCR is ine i ably co ela ed wi h s dK/𝑉 and EKR/𝑉.The
body su ace a ea-no malized ECC measu es a e no so
closely associa ed wi h nPCR.
Abb e ia ions
BMI: Body mass index = weigh /heigh 2
BSA: Body su ace a ea
𝐶: Concen a ion
ECC: Con inuous-equi alen clea ance
EKR: Equi alen enal clea ance = 𝐺/TAC
EKR/𝑉:EKRscaled o𝑉
eK𝑡/𝑉:Equilib a edK𝑡/𝑉
: Dialysis session equency
𝐺: Gene a ion a e
Kd: Dialyze clea ance
K :Renalclea ance
K0𝐴:Dialyze massa eacoe icien
K𝑡: Clea ance ∗session ime
K𝑡/𝑉:K𝑡scaled o dis ibu ion olume =
Kd∗𝑡
d/𝑉𝑡
nEKR: EKR no malized wi h BSA
(mL/min/1.73 m2)
nEKRan : EKR no malized wi h BSA and Van
(mL/min/1.73 m2)
nK :K
no malized wi h BSA
(mL/min/1.73 m2)
ns dK: s dK no malized wi h BSA
(mL/min/1.73 m2)
ns dKan : s dK no malized wi h BSA and Van
(mL/min/1.73 m2)
nPCR: PCR scaled o no mal body weigh =
PCR/(𝑉/0.58) (g/kg/day)
Ad ances in Neph ology 7
PAC: A e age p edialysis concen a ion, peak
a e age concen a ion
PCR: P o ein ca abolic a e (g/day)
py: Pa ien yea s
𝑄b: Dialyze blood low
𝑄d: Dialysa e low
RRF: Residual enal unc ion
spK𝑡/𝑉:SinglepoolK𝑡/𝑉
s dK: S anda d clea ance = 𝐺/PAC
s dK/𝑉:s dKscaled o𝑉
TAC: Time-a e aged concen a ion
TBW: To al body wa e (Wa son) = Van
𝑡d: Dialysis session du a ion
UF: Ul a il a ion olume (posi i e, i luid is
emo ed)
UKM: U ea kine ic model
𝑉:Dis ibu ion olume
Van : An h opome ic 𝑉=TBW
𝑉𝑡:Pos dialysis𝑉.
E hical App o al
Thes udywasbasedonananalysiso egis e da acollec ed
andu ilizeddu ing he ou ineca eo pa ien sandconduc ed
wi h he pe mission o he medical di ec o o he hospi al.
The e was no con ol g oup o andomiza ion. The s udy
was no p esen ed o an e hics commi ee because he e
we e no in e en ions and, acco ding o Finnish law, egis y
epo s a e no subjec o e alua ion by e hics commi ees.
The pa ien da a we e anonymized and deiden i ied p io o
analysis.
Compe ing In e es s
The au ho s decla e ha hey ha e no compe ing in e es s.
Acknowledgmen s
The au ho s hank he eam o he Dialysis Uni o Sa onlinna
Cen alHospi al o ca e ulbloodandu inesampling.
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