ОПРЕДЕЛЕНИЕ СРОКОВ НАЧАЛА ГЕМОДИАЛИЗА: РАЗРАБОТКА И ПОДТВЕРЖДЕНИЕ ШКАЛЫ START

Aim. The optimal time for initiating of chronic dialysis remains unknown. The scale for mortality risk assessment could help in decision-making concerning dialysis start timing.Methods. We randomly divided 1856 patients started dialysis in 2009–2016 into developmental and validation group (1:1) to create and validate scoring system «START» predicting mortality risk at dialysis initiation in order to fi nd unmodifi able and modifi able factors which could help in the decision-making of dialysis start. In the series of univariate regression models in the developmental set, we evaluated the mortality risk linked with available parameters: age, eGFR, serum phosphate, total calcium, hemoglobin, Charlson comorbidity index, diabetes status, urgency of start (turned to be signifi cant) and gender, serum sodium, potassium, blood pressure (without impact on survival). Similar hazard ratios were converted to score points.Results. The START score was highly predictive of death: C-statistic was 0.82 (95% CI 0.79–0.85) for the developmental dataset and 0.79 (95% CI 0.74–0.84) for validation dataset (both p < 0.001). On applying the cutoff between 7–8 points in the developmental dataset, the risk score was highly sensitive 81.1% and specifi c 67.9%; for validation dataset, the sensitivity was 78.9%, specifi city 67.9%. We confi rmed the similarity in survival prediction in the validation set to developmental set in low, medium and high START score groups. The difference in survival between three levels of START-score in validation set remained similar to that of developmental set: Wilcoxon = 8.78 (p = 0.02) vs 15.31 (p < 0.001) comparing low–medium levels and 25.18 (p < 0.001) vs 39.21 (p < 0.001) comparing medium–high levels.Conclusion. Developed START score system including modifi able factors showed good mortality prediction and could be used in dialysis start decision-making. Цель. Оптимальное время начала лечения гемодиализом (ГД) остается неопределенным. Создание шкалы для оценки рисков для пациента, начинающего диализ, поможет в принятии решения о сроках его начала.Методы. По данным регистра пациентов на заместительной почечной терапии проанализированы результаты лечения 1856 пациентов, начавших диализ в 2009–2016 гг. Случайным образом их разделили в соотношении 1:1 на группу разработки и группу подтверждения для создания прогностической шкалы оценки вероятности летального исхода при лечении программным гемодиализом (шкала START). При этом учитывали модифицируемые и немодифицируемые факторы риска. В серии регрессионных моделей с одной переменной в группе разработки шкалы мы оценивали риски смерти, связанные с доступными для анализа модифицируемыми и немодифицируемыми параметрами. Среди них значимыми оказались возраст, расчетная скорость клубочковой фильтрации (рСКФ), уровни фосфатов, общего кальция, гемоглобина, индекс коморбидности Чарлсон, наличие сахарного диабета, экстренность старта диализа. Пол, уровни натрия, калия, артериального давления не оказали влияния на выживаемость. Близкие по величине риски были преобразованы в баллы шкалы.Результаты. Шкала START продемонстрировала высокую предсказательную ценность в отношении риска смерти: AUC 0,82 (95% ДИ 0,79–0,85) для группы разработки шкалы и 0,79 (95% ДИ 0,74–0,84) для группы подтверждения (для обеих p < 0,001). Для точки отсечения 7–8 баллов чувствительность метода составила 81,1%, специфичность 69,9% для группы разработки и 78,9 и 67,9% соответственно – для группы подтверждения. Мы подтвердили близкие значения выживаемости пациентов в обеих группах для низких, средних и высоких значений шкалы START. Различия в выживаемости для подгрупп с тремя уровнями шкалы были близкими для групп разработки и подтверждения: критерий Wilcoxon = 8,78 (p = 0,02) vs 15,31 (p < 0,001) при сравнении выживаемости подгрупп низких и средних величин шкалы и 25,18 (p < 0,001) vs 39,21 (p < 0,001) при сравнении выживаемости подгрупп средних и высоких величин шкалы.Заключение. Разработанная шкала START, включающая модифицируемые факторы риска, продемонстрировала хорошую предсказательную ценность в отношении 5-летней летальности и может использоваться при принятии решения о времени старта диализа.

THE ACHIEVABILITY OF TARGET CONVECTION VOLUMES IN ON-LINE HEMODIAFILTRATION

Aim. To evaluate the achievability of recommended convection volumes in hemodiafiltration (HDF) and impeding factors. Materials and methods. In short interventional one-center study among 67 stable prevalent dialysis patients we succeeded in achieving convection volume of more than 24 l/session in 60 patients (90%). Results. Substitution volume rose in the whole group from 21.1 ± 1.6 to 23.8 ± 1.2 l/session (p < 0.01). 12 patients, who didn`t achieve target volume had similar age, duration of renal replacement therapy and ultrafiltration rate as those who did. They differed from 55 patients who achieved target volume by substitution volume at first session in evaluation period (22.2 ± 1.7 vs. 23.6 ± 1.5 liters, р = 0.004), by transmembrane pressure (170 ± 40 vs. 146 ± 24 mmHg, р = 0.009) and by session duration (248 ± 15 vs. 262 ± 17 min, р = 0.0017). Blood flow rate also differed at the start of the study between the achievers and non-achievers: 353 ± 21 vs. 339 ± 19 ml/min, р = 0.035. The pressure in venous segment was lower in the achievers (154 ± 25 vs. 176 ± 36, р = 0.02) as well as transmembrane pressure (144 ± 24 vs. 164 ± 36, р = 0.014) which has been rising session by session in nonachievers. In non-achievers the membrane surface area was lower: 1.75 ± 0.2 vs. 1.91 ± 0.2 m2 (p = 0.02). In the multiple binary logistic regression model the session duration and membrane surface area were positive factors while the transmembrane pressure was negative one. Session prolonged by 15 min was associated with increase in relative chance to achieve target volume by 39% (95% CI 5–82%; р = 0.02). The membrane surface area enlarged by 0.1 m2 was linked with increase of chance by 4.2% (95% CI 0.2–8.4%; р = 0.04). The transmembrane pressure increased by 10 mmHg was associated with decreased chance to achieve target volume by 17% (95% CI 0–70%; р = 0.05). Conclusion. To achieve convection volume of 24 l/session one needs to afford effective blood flow rate, to increase the session duration and membrane surface area, avoiding high transmembrane pressure; severe comorbidity can hamper achieving target volume. Accumulating data of different studies are rather divergent in conclusions with regard to required target volume and ways to ensure its achievability, so study continuation is mandatory

DIALYSIS START TIMING: DEVELOPMENT AND VALIDATION OF START SCORING SCALE

Aim. The optimal time for initiating of chronic dialysis remains unknown. The scale for mortality risk assessment could help in decision-making concerning dialysis start timing.Methods. We randomly divided 1856 patients started dialysis in 2009–2016 into developmental and validation group (1:1) to create and validate scoring system «START» predicting mortality risk at dialysis initiation in order to fi nd unmodifi able and modifi able factors which could help in the decision-making of dialysis start. In the series of univariate regression models in the developmental set, we evaluated the mortality risk linked with available parameters: age, eGFR, serum phosphate, total calcium, hemoglobin, Charlson comorbidity index, diabetes status, urgency of start (turned to be signifi cant) and gender, serum sodium, potassium, blood pressure (without impact on survival). Similar hazard ratios were converted to score points.Results. The START score was highly predictive of death: C-statistic was 0.82 (95% CI 0.79–0.85) for the developmental dataset and 0.79 (95% CI 0.74–0.84) for validation dataset (both p < 0.001). On applying the cutoff between 7–8 points in the developmental dataset, the risk score was highly sensitive 81.1% and specifi c 67.9%; for validation dataset, the sensitivity was 78.9%, specifi city 67.9%. We confi rmed the similarity in survival prediction in the validation set to developmental set in low, medium and high START score groups. The difference in survival between three levels of START-score in validation set remained similar to that of developmental set: Wilcoxon = 8.78 (p = 0.02) vs 15.31 (p < 0.001) comparing low–medium levels and 25.18 (p < 0.001) vs 39.21 (p < 0.001) comparing medium–high levels.Conclusion. Developed START score system including modifi able factors showed good mortality prediction and could be used in dialysis start decision-making