Jun 01, 2023
O valor prognóstico de URR é igual ao de Kt/V para todos
Relatórios Científicos volume 13,
Scientific Reports volume 13, Número do artigo: 8923 (2023) Citar este artigo
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1 Altmétrica
Detalhes das métricas
As medições de Kt/V e URR (relação de redução de ureia) representam a adequação da diálise. O Kt/V de pool único é teoricamente um método superior e é recomendado pelas diretrizes da Kidney Disease Outcomes Quality Initiative. No entanto, o valor prognóstico da URR em comparação com o Kt/V para todas as causas de mortalidade é desconhecido. Os modificadores de efeito e os valores de corte dos dois parâmetros não foram comparados. Investigamos 2.615 pacientes incidentes em hemodiálise com URR de 72% e Kt/V (Daugirdas) de 1,6. A idade média dos pacientes foi de 59 anos, 50,7% eram do sexo feminino e 1.113 (40,2%) morreram em 10 anos. URR e Kt/V foram associados positivamente com fatores nutricionais e sexo feminino e negativamente associados com peso corporal e insuficiência cardíaca. Nos modelos de regressão de Cox para mortalidade por todas as causas, as taxas de risco (HRs) dos grupos URR altos (65–70%, 70–75% e > 75%) e o grupo URR < 65% foram 0,748 (0,623– 0,898), 0,693 (0,578–0,829) e 0,640 (0,519–0,788), respectivamente. As FCs dos grupos de Kt/V alto (Kt/V 1,2–1,4, 1,4–1,7 e > 1,7) e do grupo Kt/V < 1,2 foram 0,711 (0,580–0,873), 0,656 (0,540–0,799) e 0,623 ( 0,498–0,779), respectivamente. Na análise de subgrupo, o Kt/V não foi associado à mortalidade por todas as causas em mulheres. O valor prognóstico da URR para todas as causas de mortalidade é tão grande quanto o do Kt/V. URR > 70% e Kt/V > 1,4 foram associados a maior sobrevida. O Kt/V pode ter um valor prognóstico mais fraco para as mulheres.
A inadequação da diálise afeta a morbimortalidade dos pacientes em hemodiálise (HD)1,2. A inadequação da diálise pode ser avaliada de várias maneiras, incluindo depuração de moléculas pequenas e médias3,4, equilíbrio ácido-base e eletrólitos e status de fluidos5. A depuração da ureia continua sendo a medida mais fortemente recomendada para a adequação da diálise na prática clínica5, com medidas que incluem Kt/V e URR (razão de redução da ureia). Kt/V [K: depuração do dialisador (mL/min); t: tempo de diálise (min); V: volume de distribuição de ureia (mL)] foi desenvolvido por Frank Gotch e John Sargent6 e posteriormente equilibrado por Daugirdas na década de 19907; continua sendo o principal indicador da adequação da diálise5,8. Um estudo randomizado controlado de referência em 2002, o estudo HEMO, descobriu que um único pool Kt/V (spKt/V) > 1,2 está associado a menor mortalidade em pacientes em HD9. As diretrizes do KDOQI (Kidney Disease Outcomes Quality Initiative) recomendam um spKt/V alvo de 1,4 por sessão de HD para pacientes tratados três vezes por semana, com um spKt/V mínimo administrado de 1,25. A URR é calculada por meio de uma equação relativamente simples desenvolvida por Lowrie e Lew em 199110. A dosagem recomendada de URR varia de > 65% a > 75% de acordo com diferentes estudos11,12. A Sociedade de Nefrologia de Taiwan usa URR na prática clínica e sugere URR > 65% como requisito mínimo.
Devido a razões que incluem a faixa mais estreita de doses alcançadas durante HD para URR em comparação com Kt/V, a variação da relação curvilínea entre os dois parâmetros (porque Kt/V considera o volume de distribuição de uréia e UF)13 e URR diminui substancialmente durante a substituição renal contínua terapia8. O Kt/V há muito é preferido ao URR como padrão para prescrever a dosagem de HD e é recomendado pelo KDOQI5,8. Entretanto, o Kt/V também tem suas potenciais desvantagens que podem superar seus benefícios e tem sido discutido nas últimas décadas.
O Kt/V, que considera o volume de distribuição de ureia no corpo, é considerado mais preciso do que o URR. No entanto, V e Kt são considerados fatores associados à sobrevivência, o que pode causar um efeito de compensação14,15. Por exemplo, para pacientes com menor massa, o Kt/V alto ocorre mais facilmente devido ao V menor, o que causa superestimação da dosagem de diálise16,17. Embora os estudos tenham tentado estabelecer uma associação entre Kt/V e URR, as medidas não podem ser convertidas com precisão devido ao nível de ultrafiltração (UF) e ao tempo de diálise 8,18. O valor prognóstico do Kt/V é teoricamente maior do que o da URR, mas a comparação direta não foi feita.
75%) and Kt/V (< 1.2, 1.2–1.4, 1.4–1.7, > 1.7) levels, we found that more than half of the pa-tients had higher dialysis dose: 62.3% of patients had URR > 70%, and 69% of patients had Kt/V > 1.4. High-flux dialyzers were used in most of the patients during hemodialysis (98.7%), while low-flux dialyzers were more in patients with low URR or low Kt/V, but in very low percentage (1.3%). We observed that higher URR or Kt/V levels were associated with fe-male sex, higher age, absence of diabetes, and lower BW. Higher URR and Kt/V levels were both associated with higher nutritional markers (nPCR and total cholesterol) but lower WBC count and serum creatinine./p> 75% groups, respectively, and 110 (41.2%), 183 (33.7%), 326 (31.9%), and 247 (31.6%) deaths occurred in the Kt/V < 1.2, 1.2–1.4, 1.4–1.7, and > 1.7 groups, respectively. The lowest mortality rates among patients were of those who received URR of 70–75% and Kt/V > 1.7. Mortality rates were significantly higher for all cohort populations withURR < 70% vs > 70% (35.4% vs 31.7%)and Kt/V < 1.4 vs > 1.4(36.1% vs 31.7%; Table 1). In all study populations after adjustment, both higher URR (70–75%, > 75%)and Kt/V (1.4–1.7, > 1.7) groups had lower risk of all-cause mortality with adjusted hazard ratios (HRs) of 0.693 (95% confidence interval CI 0.578–0.829, P < 0.001) and 0.640 (95% CI 0.519–0.788, P < 0.001) in the URR group and 0.656 (95% CI 0.540–0.799, P < 0.001) and 0.623 (95% CI 0.498–0.779, P < 0.001) in the Kt/V group, compared with the URR < 65% and Kt/V < 1.2 groups. Although no matter higher Kt/V or URR groups both associated with lower HR, the effect of reduction of HR attenuating as in higher Kt/V or URR group. Moreover, each1SD increase in URR and Kt/V was associated with HRs of 0.896 (95% CI 0.844–0.952, P < 0.001) and 0.885(95% CI 0.824–0.952, P < 0.001), respectively (Table 3)./p> 1.2, single-pool Daugirdas formula or URR > 65%) were both associated with lower all-cause mortality compared with lower dialysis dose (Kt/V < 1.2, single-pool Daugirdas formula or URR < 65%). Moreover, in subgroup analysis, we found that higher dialysis dose was significantly associated with mortality in those with Kt/V < 1.4 but not in those with Kt/V ≥ 1.4. Kt/V was not associated with mortality in women./p> 1.2 is associated with better survival28,29. Studies have also suggested targeting Kt/V > 1.4 to achieve a minimum of Kt/V > 1.2 due to barriers to adequate delivery, such as lower blood flow, shorter time, recirculation, and use of a catheter for vascular access30,31. The KDOQI Clinical Practice Guideline for Hemodialysis Adequacy8 suggests a minimum URR dose of > 65% and a target dose of > 70% for patients receiving HD three times per week with treatment times less than 5 hours8. Barriers to URR and Kt/V correlation have been indicated, including higher UF, which may cause increased Kt/V, and long dialysis time, which may cause decreased URR8,18. Another study found that after stratifying patients into three BMI (body mass index) groups (low, medium, and high), the relative risk (RR) decreased when URR increased. Furthermore, patients treated with URR > 75% had a substantially lower RR than patients treated with URR 70–75% (P < 0.005 for medium and low BMI groups)12. Although patients benefit from higher Kt/V or URR, Chertowet al. demonstrated that patients with extremely high URR (> 75%) or single-pooled Kt/V (> 1.6) may be more severely malnourished, which may increase mortality and limit the utility of URR or Kt/V32. In our study, we found that URR > 70% or Kt/V > 1.4 was associated with better survival. In the subgroup analysis, we found that higher dialysis dose was significantly associated with mortality in those with Kt/V < 1.4 but not in those with Kt/V ≥ 1.4 which is compatible with the attenuation of HR we found in higher Kt/V or URR group in Table 3. However careful evaluation of the nutritional status of patients is also crucial./p> 75%) or single-pooled Kt/V (> 1.6) values (manifested in a lower V) due to malnutrition outweighed the benefits of greater urea clearance32. Moreover, studies also found that female HD patients tended to have more severe malnutrition35 and lower albumin levels36,outweighing the benefits of relatively high Kt/V. Due to this malnutrition factor, it is difficult to evaluate the actual benefits of increased dialysis dosage in women by using Kt/V. Our study found that sex modified the association between either Kt/V or URR and all-cause mortality, but BW did not. However, the conversion of BW to V was based on the Watson formula, which was designed in relation to a healthy Western population and might not reflect actual V in our study population37,38. In a later analysis in the HEMO study, increasing dialysis dose (double-pool Kt/V 1.53 vs double-pool Kt/V 1.16) in a subgroup of women reduced mortality by 19%; it did not cause a significant difference in men. This result persisted after adjustment for the interaction of dosage with body water volume or with other mass parameters, including weight and body mass index, which indicates that factors other than body size may have contributed to this result22. Another study found a similar sex difference in mortality benefit for women on HD in Japan with spKt/V levels ≥ 1.639. Although the previous studies were all favorable of underdialysis of woman in Kt/V, which is opposite to our result that no obvious prognosis value for woman with higher Kt/V, but in man. However, these studies all undeniably point out that sex difference did exist when using Kt/V. The mechanism of the sex difference modifying the association between Kt/V and all-cause mortality in our study remains unclear and maybe relate to race or specific population in our study. However, an optimal indicator for mortality should not generally be affected by age, sex, or comorbidities. Therefore, URR may have prognostic value for mortality equal to or greater than Kt/V, as shown in this study./p> 70%) and Kt/V (Kt/V > 1.4) were both associated with lower all-cause mortality in incident HD patients. Larger studies to compare the prognostic value of URR and Kt/V for mortality and more application of URR in the future studies are necessary. In addition, the prognostic value of Kt/V in women may warrant further investigation./p> 1.4) as suggested by KDIGO achieved. However, we will increase the surface area dialyzer if the minimal requirement of URR(> 65%) or Kt/V (> 1.2) were not achieved according to the guideline of Taiwan Society of Nephrology./p>
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