Point-of-care ultrasound for the nephrologist: emphysematous pyelonephritis versus staghorn calculus

Correction to: Characteristics of membranoproliferative glomerulonephritis based on a new classification at a single center In the Original publication, the authors found few errors in the text.

Considering the utility of cognitive remediation therapy in chronic kidney disease

Prevalence of cognitive impairment among peritoneal dialysis patients: a systematic review and meta-analysis Abstract Background Cognitive impairment (CI) is common among patients on peritoneal dialysis (PD), but it is under-recognized and systematic review on its prevalence and impact across different geographical locations or patient characteristics is lacking. Methods A search of the literature on CI in PD patients published between 1 Jan 1980 and 25.April 2019 was conducted. Meta-analysis using a random effects model was performed to determine the pooled estimate of the prevalence of CI. Meta-regression was performed to identify factors contributing to the variance of prevalence rate. A systematic review was also performed to study risk factors of CI and its impact on clinical outcomes. Results Eight studies were included and the relevant data from 1736 patients were extracted for analysis. Meta-analysis revealed a pooled prevalence of CI at 28.7% (95% CI 15.9–46%). Meta-regression analyses showed that the prevalence of CI was unrelated to patient’s age, gender, duration of PD, healthcare policy of dialysis modality, the prospective or retrospective nature of studies, or year of publication. Systematic review of 20 studies showed that older age, female sex and lower education were risk factors for CI. Potential reversible factors for CI include electrolytes disturbances, depression and vitamin D deficiency. Also, CI was associated with a higher risk of hospitalization, mostly due to PD-related peritonitis. Conclusions CI is common in patients on long-term PD. Screening for CI should be considered in PD patients with increased risk.

Treatment for renal anemia and outcomes in non-dialysis patients with chronic kidney disease: the current status of regional medicine according to the Kyoto Fushimi Renal Anemia (KFRA) study Abstract Background The baseline data obtained in the CKD-JAC demonstrated that insufficient treatment was being provided for renal anemia by institutions specializing in renal disease. The objective of this study was to investigate the status of treatment for renal anemia, including renal/cardiovascular outcomes and mortality, at regional medical facilities since the development of long-acting erythropoiesis-stimulating agents (LA-ESA). Methods Non-dialysis outpatients with chronic kidney disease and renal anemia were eligible. Anemia was treated based on the clinical condition of each patient and targeted hemoglobin (Hb) levels. Results A total of 283 patients from 21 institutions were enrolled and followed up for a maximum of 3 years. A doubling of the serum creatinine level was observed in 89 patients, and renal replacement therapy was initiated in 57 patients. Multivariate Cox regression analysis revealed that a lower mean Hb level (mHb) and receiving fewer frequency of ESA during the follow-up period were independent determinants of the composite renal outcome and overall mortality. During the follow-up period, the percentages of patients with mHb of 10–10.9 g/dL and ≥ 11 g/dL were increased. Similar trends were seen regardless of whether the patients were treated by nephrologists or non-nephrologists. The frequency of ESA treatment was increased among the patients treated by non-nephrologists; however, it was much lower than nephrologists. Conclusion This study demonstrated that, in the era of LA-ESA treatment, higher Hb levels are associated with reduced composite renal outcomes at regional medical facilities. The importance of renal anemia management should be highlighted, even among non-nephrologists.

New selectivity index calculated using protein fraction as a substitute for the conventional selectivity index Abstract Background Selectivity index (SI) of proteinuria, calculated using the clearance ratio of immunoglobulin G to transferrin, predicts the response to glucocorticoids in patients with nephrotic syndrome. However, there is disagreement regarding the suitability of SI. Therefore, alternate indices should be considered. This study investigated whether or not selectivity index protein fraction (SIPF) was inferior to SI for the prediction of the response to glucocorticoids. Methods Forty-nine patients with nephrotic syndrome were evaluated. On the basis of molecular weight and protein fraction, as an inexpensive substitute for SI, the clearance ratio of the albumin to γ fractions measured in serum and urine protein fractions was defined as SIPF. The quality of SIPF was examined. Moreover, the best cutoff value of SIPF was determined; and SIPF distribution, according to histopathological diagnosis by renal biopsy, was examined. Results SIPF was strongly correlated with SI (r = 0.79, P < 0.001). The area under the receiver operating characteristic (ROC) curve of SIPF and SI was not significantly different (P = 0.18). The best cutoff value of SIPF was 0.45. In the group with SIPF > 0.45, only two patients with minimal change disease (MCD) achieved complete remission. In the group with SIPF ≤ 0.45, all patients with MCD achieved complete remission, although eight patients with other histopathological diagnoses did not achieve complete remission. Conclusions Analysis of protein fractions as a substitute for SI may be useful for predicting response to glucocorticoids in patients with nephrotic syndrome.

Increase of 1,25 dihydroxyvitamin D in sarcoidosis patients with renal dysfunction Abstract Introduction In sarcoidosis, renal involvement includes hypercalcemia-related nephrocalcinosis and granulomatous tubulointerstitial nephritis. Hypercalcemia is thought to be due to increased production of 1,25 dihydroxyvitamin D (1-25D), but 1-25D levels have not been evaluated in sarcoidosis patients with renal dysfunction. Materials and Methods We enrolled 9 sarcoidosis patients who underwent renal biopsy, and compared the serum 1-25D concentration and eGFR with those in 428 non-sarcoidosis patients who had renal dysfunction (stage 2 or higher CKD with an estimated glomerular filtration rate < 90). Results Serum calcium and 1-25D levels were significantly higher in the sarcoidosis patients than in the non-sarcoidosis patients (p < 0.01 and p = 0.01, respectively). There was a positive correlation between 1-25D and eGFR in the patients without sarcoidosis (r = 0.693; p < 0.01). As the renal function of sarcoidosis patients was improved by steroid therapy, the serum 1-25D and adjusted serum calcium levels decreased to near the median values in non-sarcoidosis patients. On renal biopsy, CD68 staining was positive for tissue macrophages in all 8 patients who had tubulointerstitial nephritis (with or without typical granulomas), while Von Kossa staining showed calcification of tubules near or inside granulomas in 6 of these 8 patients. Conclusion While tissue macrophages promote development of tubulointerstitial nephritis and 1-25D overproduction in renal sarcoidosis, hypercalcemia secondary to elevation of 1-25D may be related to renal calcification and granuloma formation.

Dynamic variation of kidney injury molecule-1 mRNA and protein expression in blood and urine of renal transplant recipients: a cohort study Abstract Background Acute renal dysfunction still constitutes a highly significant obstacle to renal transplantation outcome. Kidney injury molecule-1 is highly upregulated in proximal tubular cells and shed into the urine and blood circulation following kidney injury. The aim of current cohort study was to evaluate the urine KIM-1 (uKIM-1) mRNA expression level and its protein concentration in blood and urine samples to determine whether sequential monitoring of KIM-1 in renal allograft recipients is a reliable biomarker for predicting the clinical status and outcome. Methods Both uKIM-1 mRNA expression level and the level of serum and uKIM-1 protein concentration in the 52 renal transplant recipients were respectively quantified using real-time PCR and ELISA methods at 2, 90 and 180 days after transplantation. Result KIM-1 mRNA and protein expression level in the blood and urine samples of patients with graft dysfunction was significantly higher than patients with well-functioning graft on days 2, 90 and 180 after transplantation. Receiver-operating characteristic curve analysis of mRNA and protein expression levels showed that urinary and blood KIM-1 at months 3 and 6 could predict acute renal dysfunction at 6 months and 1 year after transplantation. Conclusion Sequential monitoring of uKIM-1 mRNA expression level and its protein concentration in the serum and urine samples of renal transplant patients suggests that KIM-1 could be a sensitive and specific biomarker for early diagnosis and prognosis of kidney allograft injury.

Long-term outcome of biopsy-proven cholesterol crystal embolism Abstract Background Cholesterol crystal embolism (CCE) causes renal damage, and there is an extremely high risk of end-stage renal disease. However, the time course of CCE-related renal deterioration varies and little is known about the subsequent risk of dialysis among patients with biopsy-proven CCE. Methods We performed a retrospective cohort study of 38 Japanese patients in whom a histological diagnosis of CCE was made from September 1992 to July 2005. Competing risk regression analysis was used to investigate the association between declining renal function ( ≥ 1.5 elevation of serum creatinine within 26 weeks after CCE) or its subtypes (acute [ < 1 week after CCE], subacute [1 to < 6 weeks], and chronic [6 to < 26 weeks]) and the risk of dialysis, with adjustment for age, baseline serum creatinine, and the precipitating event (iatrogenic or spontaneous). Results During a median follow-up period of 25.9 weeks, 14 patients (35.9%) started dialysis. Multivariable analysis showed that patients with declining renal function had a higher risk of commencing dialysis than those without declining function (subdistribution hazard ratio [SHR] 9.47; 95% confidence interval [CI] 1.34–66.8). Patients with different renal presentations had a similarly increased risk of commencing dialysis, with the risk being significantly higher for the subacute and chronic patterns of declining renal function (adjusted SHR [95% CI] for acute, subacute, and chronic declining renal function[vs. no decline]: 7.36 [0.85–63.6], 11.9 [1.36–101], and 10.7 [1.49–77.0], respectively). Conclusion Declining renal function after CCE, even later than 6 weeks, was significantly associated with the subsequent risk of dialysis.

The association between cardiac valvular calcification and fetuin-A levels in kidney transplant recipients Abstract Objectives Low fetuin-A levels in hemodialysis patients can be associated with development of vascular and valvular calcifications. The mechanisms underlying vascular and valvular calcifications are multifactorial. There are a few studies showing the relationship between low fetuin-A levels and valvular calcification after kidney transplantation. We aimed to evaluate the association between serum fetuin-A levels and valvular calcification in kidney transplant recipients. Methods The cardiac valvular calcification was assessed by echocardiography in 56 recipients. Patients were divided into two groups as those with (n = 11) and without (n = 45) aortic and/or mitral valve calcification. The extent of valvular calcification was visually assessed according to the standard visual score method: moderately (multiple larger spots) and heavily calcified (extensive thickening and calcification) of all cusps. Serum fetuin-A levels were measured. Results The demographic features of both groups were comparable. There was no significant difference between regular physical exercise (63.6% vs. 55.6%), obesity (18.2% vs. 17.8%), abdominal obesity (54.5% vs. 46.7%), smoking (0% vs. 13.3%), hypertension (63.6% vs. 68.9%), left ventricular hypertrophy (45.5% vs. 33.3%) and diabetes mellitus (9.1% vs. 20%) ratios in groups with or without valvular calcification, respectively (p > 0.05). Fetuin-A levels of both groups did not differ. Fetuin-A levels positively correlated with serum creatinine (r 0.326, p = 0.014), and negatively correlated with estimated glomerular filtration rate (r − 0.297, p = 0.026). Conclusions We could not find a relationship between serum fetuin-A levels and valvular calcification in kidney recipients. In this population, further studies are needed to assess the role of serum fetuin-A in valvular calcification.