Published papers

INTRODUCTION: We aimed to determine the correlation between the serum urea-to-creatinine ratio and residual kidney function (RKF) in patients undergoing peritoneal dialysis (PD), as well as its predictive value for PD-related outcomes. METHODS: This study included a cross-sectional study to assess the correlation between serum urea-to-creatinine ratio and RKF in 50 patients on PD and a retrospective cohort study to assess the association between serum urea-to-creatinine ratio and PD-related outcomes in 122 patients who initiated PD. RESULTS: Serum urea-to-creatinine ratios had significant positive correlations with renal Kt/V and creatinine clearance values (r = 0.60, p < 0.001 and r = 0.61, p < 0.001, respectively). Additionally, serum urea-to-creatinine ratio was significantly associated with a lower risk of transfer to hemodialysis or PD/hemodialysis hybrid therapy (hazard ratio: 0.84, 95% confidence interval: 0.75-0.95). CONCLUSION: The serum urea-to-creatinine ratio can be an indicator of RKF and a prognostic factor in patients undergoing PD.

During the coronavirus disease 2019 pandemic, the Japanese Society of Diabetes and Pregnancy proposed the use of random plasma glucose and glycated hemoglobin measured 1 month after delivery combined with pre-pregnancy body mass index to detect postpartum glucose intolerance instead of carrying out the oral glucose tolerance test in women with gestational diabetes. We retrospectively evaluated the clinical utility of this strategy to detect postpartum glucose intolerance evaluated by the oral glucose tolerance test after delivery. A total of 275 Japanese women with gestational diabetes were included in the present study. The specificity of 1-month postpartum random plasma glucose and glycated hemoglobin combined with pre-pregnancy body mass index to predict postpartum glucose intolerance was 98.0%, with a negative predictive value of 72.6%. However, sensitivity was 6.4%, with a positive predictive value of 55.6%. In conclusion, this Japanese Society of Diabetes and Pregnancy strategy showed high specificity, but low sensitivity, for detecting glucose intolerance postpartum.

Hyperkalemia is a well-recognized electrolyte abnormality in patients with chronic kidney disease (CKD). Potassium binders are often used to prevent and treat hyperkalemia. However, few studies have evaluated the difference in serum potassium (K+) level-lowering effect during the post-acute phase between the novel potassium binder, sodium zirconium cyclosilicate (ZSC), and conventional agents. This retrospective study included patients who received potassium binders (either ZSC or calcium polystyrene sulfonate [CPS]) in our hospital between May 2020 and July 2022. The patients were divided into the ZSC and CPS groups. After propensity score matching, we compared changes from baseline to the first follow-up point, at least 4 weeks after initiating potassium binders, in electrolytes including K+ level between the two groups. Of the 132 patients, ZSC and CPS were administered in 48 and 84 patients, respectively. After matching, 38 patients were allocated to each group. The ZSC group showed greater reduction in K+ levels than did the CPS group (P < 0.05). Moreover, a significant increase in serum sodium minus chloride levels, a surrogate marker for metabolic acidosis, was observed in the ZSC group (P < 0.05). Our results demonstrated that ZSC could potentially improve hyperkalemia and metabolic acidosis in patients with CKD.

A commutability confirmation test for the blood aldosterone measurement was performed on liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) as a designated comparison method (DCM) and four chemiluminescent enzyme immunoassay (CLEIA) measurement procedures based on metrological traceability. A conventional radioimmunoassay (RIA) and two measurement procedures of CLEIA which obtains RIA equivalent values were also compared. The relationship between the DCM value and the CLEIA value with respect to 120 pg/mL of the RIA value, which is the screening criterion of primary aldosteronism (PA) was clarified. For the correlation test, 75 samples of patient serum and plasma were used. Regression analysis revealed that the standardized LC-MS/MS and four CLEIA measurement procedures were in good agreement. This is the effect of measurement specificity and calibration using by certified reference material (CRM). The median of the LC-MS/MS corresponding to 120 pg/mL of RIA was 48.5 pg/mL. In the mean of standardized four CLEIA values corresponding to the 48.5 pg/mL of LC-MS/MS value was 47.51 pg/mL and the standard deviation (SD) was 2.93 pg/mL. However, the correlation between the RIA value and the RIA equivalent of the two measurement procedures by CLEIA differed depending on the measurement procedure. This is due to the influence of RIA measurement performance. Standardized CLEIA measurements are suitable for routine measurement procedure. When converting the LC-MS/MS equivalent value by the standardized CLEIA to the conventional RIA value, it is necessary to use the conversion formula.

Angiotensin receptor-neprilysin inhibitors (ARNIs) have been approved as antihypertensive agents in Japan, and thiazide diuretics (TZDs) are widely used concomitantly with renin-angiotensin system inhibitors (RASIs) for hypertension. This retrospective study included patients with hypertension who switched from RASI to ARNI therapy (ARNI group) and those who were prescribed TZDs with RASIs (TZD/RASI group). Drug-related changes in the estimated glomerular filtration rate (eGFR), blood pressure (BP), body weight (BW), serum electrolytes, uric acid (UA), and triglyceride levels were compared between the two groups. Overall, 70 participants (31 and 39 in the ARNI and TZD/RASI groups, respectively) were enrolled and observed for a median of 2 months. According to linear mixed models, compared with the TZD/RASI group, the ARNI group exhibited a significant change in mean eGFR of 3.71 mL/min/1.73 m2 [95% confidence interval (CI), 0.57-6.84; P = 0.02] from the time of switching drug to the next outpatient visit. Further, compared with the TZD/RASI group, the ARNI group exhibited significant changes in mean serum UA (-1.27; 95% CI, -1.66 to -0.88), sodium (1.22; 95% CI, 0.12 to -2.32), chloride (2.14; 95% CI, 0.75-3.52), and triglyceride (-52.1; 95% CI, -100.9 to -3.29) levels. Conversely, serum potassium levels, BW, and systolic and diastolic BP did not differ significantly between the two groups (P = 0.69, 0.44, 0.49, and 0.66, respectively). Compared with the combination therapy of TZD and RASI, ARNI therapy causes less renal dysfunction, hyperuricemia, and hypertriglyceridemia with fewer electrolyte abnormalities and no significant difference in antihypertensive effects.

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder, characterized by the progressive formation of renal cysts. Although ADPKD is strongly associated with cerebral and cardiovascular complications, cerebral ischemia caused by dissection of thoracic and carotid arteries has rarely been reported. We report the case of a 71-year-old Japanese woman who complained of hemiparesis. She required maintenance hemodialysis therapy with a background of ADPKD. Cerebral infarction was initially diagnosed by excluding intracranial hemorrhage and aneurysm rupture that are recognized as common complications of ADPKD and thereby anticoagulation therapy was initiated. However, the patient was suspected as having painless aortic dissection because a chest X-ray examination showed expanded upper mediastinum. Sequential vascular imagings revealed dissection of the aorta, originating from brachiocephalic trunk to the right common carotid artery with mediastinal hematoma. The patient died from progression of dissection. Herein, we described a case of the ADPKD patient that an acute aortic dissection without any pain induced the occlusion of supplying vessels to the brain, resulting in cerebral ischemic symptoms. A high level of clinical vigilance for an acute aortic dissection should be maintained in the ADPKD population with sudden onset of neurological symptoms even in the absence of pain. Furthermore, the initiation of anticoagulation treatment for cerebral ischemia which may aggravate the risk of further dissection requires careful consideration.

A 61-year-old woman with a 4-year history of maintenance hemodialysis due to end-stage renal disease of unknown cause was admitted because of a recurrent fever and abdominal pain lasting for 3 months. She had rheumatoid arthritis as a complication and had taken sulfasalazine for over 4 years. Laboratory data revealed thrombocytopenia, hypocomplementemia, a high C-reactive protein level, and positivity for antinuclear antibody and anti-double strand DNA antibody. Gallium scintigraphy showed pericarditis, pleuritis, and peritonitis. Nonscarring alopecia was also noted. She was diagnosed as having systemic lupus erythematosus (SLE). Drug-induced lupus elicited by sulfasalazine was ruled out because the symptoms did not improve even after the discontinuation of the drug upon admission. Oral prednisolone treatment markedly improved her symptoms and laboratory data. However, she later died of sepsis arising from proctitis on day 71 of admission. This report underscores the necessity of considering new-onset SLE in patients with unexplained fever and serositis, including pleuritis, peritonitis, or pericarditis, even if they are receiving maintenance dialysis.