Key Points: In individuals undergoing bariatric surgery, the magnitude of decline in GFR postbariatric surgery is directly associated with presurgery GFR. Reductions in GFR postsurgery were only weakly correlated with weight loss. In obese individuals, GFR-estimating equations performed best when deindexed and when applied in people with reduced kidney function. Background: Important questions remain about how bariatric ( i.e ., weight loss) surgery affects measured GFR (mGFR) and eGFR as well as what factors influence change in mGFR postsurgery. Methods: Data were pooled from all seven available studies (dates: 2004–2018) measuring GFR prebariatric and postbariatric surgery using gold standard methods. Change in postsurgery mGFR, factors that could influence change in mGFR, and effects on five GFR-estimating equations were analyzed using standard statistical methods. Results: The cohort included 105 individuals from the United States and Europe. Sixty-eight percent were female, 97% were White, the mean age was 50 years (range, 24–70), and the mean body mass index was 46±8 kg/m ² . The mean presurgery mGFR of 107 ml/min (range, 31–215) fell to 92 ml/min (−14%; 95% confidence interval, −21 to −10) postsurgery, with a strong linear relationship existing between presurgery mGFR and % change in GFR ( r =−0.51; −0.64 to −0.35). Individuals with presurgery mGFR ≥90, 60 to <90, and<60 ml/min had −25 (−32 to −19), 1 (−11 to 13), and 7 (0 to 14) ml/min mean postoperative changes in mGFR. Change in weight was significantly correlated with change in mGFR ( r =0.22; 0.03 to 0.40). After adjusting for sex, changes in mGFR postsurgery were associated with higher presurgical age (−0.6 ml/min per year; −1.1 to −0.2), mGFR (−0.5 ml/min per 1 ml/min; −0.6 to −0.4), and change in systolic BP (−0.3 ml/min per 1 mm Hg; −0.6 to 0.0). All GFR-estimating equations significantly underestimated postsurgical GFR reductions in people with preserved kidney function and had improved bias, precision, and accuracy when deindexed and applied to individuals with mGFR <90 ml/min. Conclusions: In individuals with obesity undergoing bariatric surgery, the magnitude of postsurgical decline in mGFR was directly associated with presurgery GFR and weakly correlated with weight loss. In addition, GFR-estimating equations' performance improved when deindexed and used in people with reduced kidney function, with the combined creatinine/cystatin C equations having the best overall performance.

Purpose: Water balance disorders are associated with a high risk of death in elderly patients. The role of osmotic stress intensity and its direction toward hypo- or hypernatremia is a matter of controversy regarding patients’ survival. The aims of this study were, first, to measure the frequency of cellular hydration disorders in patients over 75 years old hospitalized in nephrology department for reversible acute renal failure, and second, to compare the impact of hyperhydration and hypohydration on the risk of death at 6 months. Patients and methods: We retrospectively studied the data of 279 patients with chronic kidney disease (CKD), aged 75 years or older, with pre-renal azotemia who experienced dysnatremia. We classified them according to natremia levels and compared their outcome in univariate and multivariate analysis. Results: The patients were on average 83.2±5.4 years old. Among them, 128 were normonatremic, 82 were hyponatremic and 69 were hypernatremic. Osmotic stress intensity appreciated by the variation rate of natremia did not differ significantly between hyper- and hyponatremic patients. Patients had CKD stage 3B and 4 with acute kidney injury (AKI) of different severities. We observed that only hypernatremia was linked to death in the first 6 months following hospital discharge. Conclusion: Hypernatremia is a strong predictor of fatal outcome in elderly patients suffering from chronic kidney impairment and referred for pre-renal azotemia.

Background: Bariatric surgery (BS) might be a nephroprotective treatment in obese patients with chronic kidney disease (CKD), and the non-linear relation between body surface area (BSA) and extracellular fluid volume (ECFV) in obese people raises the question of the most relevant way to scale glomerular filtration rate (GFR) for assessing renal function changes after BS. Methods: We screened 1774 BS candidates and analysed 10 consecutive participants with CKD stage 3. True GFR (mGFR), measured by the renal clearance of ⁵¹Cr-ethylenediaminetetraacetic acid (EDTA), was scaled either to BSA (mGFR_BSA) or to ECFV measured by ⁵¹Cr-EDTA distribution volume (mGFR_ECFV) before and one year after BS. Results: The 10 candidates for BS had a mean body mass index of 43.3 ± 3.6 kg/m² and a mean GFR of 48 ± 8 mL/min/1.73 m². Six participants had a sleeve gastrectomy and four had a Roux-en-Y gastric bypass. One year after BS, ECFV decreased (23.2 ± 6.2 to 17.9 ± 4.3 L, p = 0.001), absolute mGFR was not significantly modified (74 ± 23 versus 68 ±19 mL/min), mGFR_BSA did not change significantly (53 ± 18 versus 56 ± 17 mL/min/1.73 m²) whereas mGFR_ECFV significantly increased (42 ± 13 versus 50 ± 14 mL/min/12.9 L, p = 0.037). The relation between mGFR_ECFV and mGFR_BSA was different from the identity line before (p = 0.014) but not after BS (p = 0.09). Conclusion: There is a difference between mGFR_BSA and mGFR_ECFV following BS and the latter might better reflect the adequacy between renal function and corpulence.

DOI: 10.20452/pamw.16538, Published online: July 25, 2023, Authors: Micheline Razzouk-Cadet, Caroline Grangeon-Chapon, Dann Ouizeman, Guillaume Favre, Rodolphe Anty

BACKGROUND: Radiolabeled white blood cells (WBCs) prepared in radiopharmacies are used to detect infectious or inflammatory sites with scintigraphy. Radiolabeling can be performed by using a disposable closed device, Lettkokite. Nevertheless, owing to the high radiosensitivity of lymphocytes, the question of eliminating lymphocytes before granulocyte radiolabeling is still a controversial step. The aim of this study was to assess a new modified Leukokit (R) with a protocol that allows granulocyte radiolabeling only. METHODS: Seventy patients (male/female: 40/30, mean age: 61 years) with suspected infectious diseases underwent labeled leukocyte scintigraphy by radiolabeling with a density gradient medium in addition to Leukokit (R). Compliance and quality of radiolabeling were checked according to the following criteria: visual inspection, labeling efficiency, cell viability (Trypan blue exclusion test), cell subset recovery test. lymphocyte elimination rate (granulocyte/WBC rate) and sterility test using media fills. RESULTS: Visual inspection showed that all cell preparations were free of residual cell clumps or fibrin clots. Mean labeling efficiency was 70.4 +/- 9.4% compliant with EANM Guidelines for leukocyte labeling. The mean cell viability was 97.7 +/- 1.4% (>96%). The mean number of leucocytes injected was 116x10(6) +/- 62x10(6) (>50x10(6)). The mean etythrocyte/WBC ratio was 2.1 +/- 0.9 (90%). Finally, the three sterility tests were negative and therefore successful. CONCLUSIONS: Purification of granulocytes with Leukokit (R) can safely, easily and effectively be performed using a density gradient medium. Moreover, clarification regarding the status of density gradient medium could provide support for its clinical use even if further studies are needed. Since all technical obstacles have been removed, the precautionary principle should apply and lead users to eliminate lymphocytes that are highly radiosensitive cells and whose in viva fate is uncertain.