Quantifying the role of factors that limit attainment of K/DOQI urea reduction ratio dialytic goal.
BACKGROUND
For many ESRD patients who are prescribed a certain level of hemodialysis (HD), delivered dose often does not achieve prescription. While various causes have been well-documented in the literature, there are no available data that may be used in predicting the likelihood of achieving a particular urea reduction ratios (URR) goal based on the number of these factors present. This study evaluated URRs of all patients in an outpatient HD unit for a 6-month period to identify factors significant in attaining goal in order to predict likelihood of goal attainment based on number of factors present.


METHODS
The inclusion criterion in this study was any HD patient during the study period with > or = 3 monthly URR measurements. Of 203 patients, 169 qualified for 900 treatments. A database was created for each patient that included demographics, factors affecting K(urea), time and access. After grouping percentages of patients with URR > or = 70%, 65 - < 70%, and < 65%, we studied a subset of 107 patients (568 treatments) that had at least 1 URR < 70% to identify factors associated with a URR of > or = 65% vs. < 65%. To determine factors predictive of URR > or = 65%, a sum percentage across all treatments was created for each patient. Mean percentages were compared between groups created by constant characteristics (e.g. gender, DM). Variables, e.g. catheters, were summarized as a percentage for each patient, and these percentages were correlated with rate of URR > or = 65%. Time was assigned a value of 0 (prescribed), positive (longer), negative (shorter), summarized as per-patient mean. After these factors were identified, each treatment was reviewed to determine the percentage of treatments > or = 65% with the number of statistically significant factors present.


RESULTS
The average, across all patients, of percentage of treatments meeting URR > or = 65% was 87.95% while a mean of 66.65% met URR > or = 70%. Factors associated with percentage of treatments per patient not meeting K/DOQI goal included catheter use (Spearman's correlation = -0.31, p = 0.001), blood flow < 90% of prescription (Spearman's correlation = -0.17, p = 0.041), younger age (> or = 61 years vs. < 61 years, p = 0.001: patients > or = 61 years had a higher percentage of URR > or = 65%), inadequate access for prescribed blood flow (Spearman's correlation = -0.32, p = 0.001), actual time vs. prescribed time (Spearman's correlation = 0.25, p = 0.009), and HD w/o heparin (Spearman's correlation = -0.21, p = 0.031). In 178 treatments, all having "good" values (no catheter, blood flow > or = 90% prescribed, age < or = 61 years, etc.), the percentage of treatments meeting URR of < or = 65 was 96.1%. With 1 bad value factor: 83.8% of 216 treatments met goal, 2 bad value factors: 71.7% of 106 met goal, 3 bad value factors: 60.5% of 43 met goal. With 4 or 5 bad value factors: only 36.1% of 25 treatments met goal.


CONCLUSIONS
Significant factors in meeting adequacy defined by K/DOQI in rank order (excluding age) include inadequate access for prescribed blood flow, catheter use, time, lack of heparin and inability to achieve blood flow > or = 90% prescribed. A direct correlation exists between number of these factors present and K/DOQI goal attainment in a given treatment.
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The Lankenau Hospital and Institute for Medical Research, Wynnewood, PA, USA.
Benz
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D000368:Aged; D001699:Biometry; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000379:methods* / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014508:Urea / Q000378:metabolism*
D014508:Urea