Association between high ultrafiltration rates and mortality in uraemic patients on regular haemodialysis. A 5-year prospective observational multicentre study.
BACKGROUND
High ultrafiltration rate on haemodialysis (HD) stresses the cardiovascular system and could have a negative effect on survival.


METHODS
The effect of ultrafiltration rate (UFR; ml/h/kg BW) on mortality was prospectively evaluated in a cohort of 287 prevalent uraemic patients in regular HD from 1 January 2000 to 31 December 2005.


METHODS
165 men and 122 women, age 66 +/- 13 years, on regular HD for at least 6 months, median: 48 months (range 6-372 months). Mean UFR was 12.7 +/- 3.5 ml/h/kg BW, Kt/V: 1.27 +/- 0.13, body weight (BW): 62 +/- 13 kg, PCRn: 1.11 +/- 0.20 g/kg/day, duration of dialysis: median 240 min (range 180-300 min), mean arterial blood pressure (MAP) 99 +/- 9 mm/Hg. One hundred and forty nine patients (52%) died, mainly for cardiovascular reasons (69%). Multivariate Cox regression analysis was utilized to evaluate the effect on mortality of UFR, age, sex, dialytic vintage, cardiovascular disease (CVD), diabetes, dialysis modality, duration of HD, BW, interdialytic weight gain (IWG), body mass index (BMI), MAP, pulse pressure (PP), Kt/V, PCRn.


RESULTS
Age (HR 1.06; CI 1.04-1.08; P < 0.0001), PCRn (HR 0.17, CI 0.07-0.43; P < 0.0001), diabetes (HR 1.81, CI 1.24-2.47; P = 0.007), CVD (HR 1.86; CI 1.32-2.62; P = 0.007) and UFR (HR 1.22; CI 1.16-1.28; P < 0.0001) were identified as factors independently correlated to survival. We estimated the discrimination potential of UFR, evaluated at baseline, in predicting death at 5 years, calculating the relative receiver operating characteristic (ROC) curves and the cut-off that minimizes the absolute difference between sensitivity and specificity.


CONCLUSIONS
High UFRs are independently associated with increased mortality risk in HD patients. Better survival was observed with UFR < 12.37 ml/h/kg BW. For patients with higher UFRs, longer or more frequent dialysis sessions should be considered in order to prevent the deleterious consequences of excessive UFR.
Movilli
Ezio
E
Division of Nephrology, Spedali Civili and Section of Nephrology, University of Brescia, 25123 Brescia, Italy. eziomov@libero.it
Gaggia
Paola
P
Zubani
Roberto
R
Camerini
Corrado
C
Vizzardi
Valerio
V
Parrinello
Giovanni
G
Savoldi
Silvana
S
Fischer
Marie Stephanie
MS
Londrino
Francesco
F
Cancarini
Giovanni
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods*; D015996:Survival Rate; D013997:Time Factors; D014462:Ultrafiltration; D014511:Uremia / Q000401:mortality* / Q000628:therapy*