Background: We require an quantitative imaging technique for the diagnosis and assessment of chronic kidney disease (CKD). Renal elastography has been widely used in recent years in different studies; however, the results across them are not consistent and, as a result, we conducted a meta-analysis of the published literature on this topic. Methods: The databases of PubMed, Medscape, Medline were searched for all studies published in English from 2010 until November 2021 that evaluated kidney shear wave speed (SWS) by elastography in patients with CKD. Trial design, methodological information, patient characteristics, interventions, results, and outcome data were all collected from each study according to a set protocol. Results: We found 37 publications, yet only 18 studies that utilized point shear wave elastography (Virtual Touch Quantification—VTQ system) were compared because the values achieved using different types of elastography are not evaluable. Finally, 1995 attendees (1241 patients with CKD versus 781 healthy subjects as the control group) were included. When comparing mean values of kidney SWS between studies we found increased heterogeneity Q = 513.133; DF = 10; p < 0001, I2 (inconsistency) = 98.12% (95% CI for I2 97.52–98.57%). With a standardized mean difference of −0.216, patients with CKD have a lower kidney SWS than healthy controls. A positive association between kidney SWS and eGFR was also discovered across the presented studies, with a pooled correlation coefficient of 0.38 (Z = 10.3, p < 0.001), Q = 73.3, DF = 5, p < 000.1, I2 = 93.18% (95% CI for I2 87.86 to 96.18). The pooled area under the ROC curve for kidney SWS to predict chronic kidney disease was 0.831 (95% CI, p < 0.001), Q = 28.32, DF = 6, p = 0.0001, I2 = 78.8% (95% CI for I2 56.37 to 89.72). In the four articles that used the Elast-PQ method, the data presented were insufficient for statistical analysis: area under the curve (AUC) values are used to compare distinct characteristics (differentiating kidney SWS between mildly and moderately impaired kidneys, between non-diabetic/prediabetic/diabetic patients, or kidney SWS between the CKD and control group), therefore not being suitable for further evaluation. Conclusions: The results show that patients with CKD have a lower kidney SWS than healthy controls. However, the number of studies involving renal elastography that have been published is limited and show an increased heterogeneity. Further research is needed to determine which factors actually influence kidney SWS in CKD patients and, as a result, to specify the role and indication of renal elastography in clinical practice.

BACKGROUND AND AIMS Haemodialysis patients are known to be susceptible to a wide range of early and long-term complications such as chronic inflammation, infections, malnutrition, mineral bone disorders (CKD-MBD) and cardiovascular disease that significantly affect the incidence of mortality.The aim of this study is to assess the presence of traditional risk factors for mortality such as diabetes mellitus or cardiovascular disease on one hand and non-traditional risk factors on the other hand (chronic inflammation, CKD-MBD). METHOD We conducted a single-centre study that included 63 CKD G5D patients (haemodialysis for 1–5 years) followed up for 48 months. All patients have been assessed at baseline, regarding cardiovascular disease (medical history, echocardiography and ECG), we performed using standard methods blood biochemistry, complete blood count and markers of inflammation (CRP, IL-6) and markers of CKD-MBD (sKlotho, iPTH, serum calcium and serum phosphorus). RESULTS After 24 months of follow-up, we found a mortality rate of 22.23%, while after 48 months, the mortality rate was of 50.73%.   Baseline plasma IL-6 levels showed a strong statistically significant correlation with sKlotho (r = 0.57, P = 0.001), but no statistically significant correlation with other elements of CKD-MBD was present (serum calcium, serum phosphorus and iPTH). sKlotho showed a positive correlation with haemodialysis efficiency (eKTV) (r = 0.26, P = 0.04)., Decreased levels of sKlotho at baseline correlated significantly with the presence of signs of ischaemia on ECG (190.3 versus 381.57 pg/mL; P = 0.028). Inflammation markers (IL-6 and CRP) showed no statistically significant correlation with any of the markers of cardiovascular disease (presence of vascular calcifications and of left ventricular hypertrophy).   The level of iPTH at baseline was significantly lower in the group of patients that survived the following 4 years of haemodialysis (428.08 ± 315.39 versus 666.76 ± 484.55 pg/mL, P = 0.029).   In a Cox proportion-hazards regression analysis of predicting factors of mortality, only age and not inflammation markers (IL-6 and CRP) showed a statistically significant correlation with 4-year mortality (P = 0.032). Patients with higher levels of sKlotho showed a decreased risk of mortality, however not statistically significant. We found a higher risk of all-cause mortality after 24 months in patients with diabetes mellitus [OR 6.9, 95% confidence interval (95% CI) 1.6924–28.1469; P = 0.007], and after 48 months in patients with a history of cerebro-vascular disease (OR 21.8571, 95% CI 1.2018–397.5026; P = 0.0371) and with left ventricular hypertrophy (OR 2.7259, 95% CI 0.9596–7.7437; P = 0.0598). CONCLUSION In our study, although the inflammation marker IL-6 showed correlations with features of CKD-MBD, it did not lead to an increased mortality, which was influenced rather by traditional risk factors such as age, diabetes mellitus or history of cardiovascular disease, but also by CKD-MBD (iPTH).

BACKGROUND AND AIMS It is known that chronic kidney disease (CKD) is associated with complications such as anaemia, mineral bone disorders (CKD-MBD) or diselectrolytemia.Therefore, the diet of renal patients is restricted in different nutrients such as potassium or phosphorus, a fact that could potentially increase oxidative stress [1]. We investigated the relationship between an oxidative damage marker (malondialdehyde-MDA) on the one hand, and plasma antioxidant status (glutathione peroxidase-GPx) activity on the other hand with the nutritional status and with complications associated with CKD (anaemia, CKD-MBD). METHOD We conducted a single-centre cross-sectional study that included 58 CKD G5D patients (mean age of 60.39 ± 11.73 years; 33 males, 25 females; mean haemodialysis vintage of 6.43 ± 4.89 years). All patients have been assessed regarding dialysis status (medical history). We performed analysis before the dialysis session using standard methods blood biochemistry, complete blood count and using spectrophotometry (HPLC)-malondialdehyde and glutathione peroxidase. RESULTS The studied patients’ mean malondialdehyde was 1.41 ± 0.42 mcmol/L, while mean glutathione peroxidase was 58.65 ± 12.15 U/g Hg. The oxidative stress markers did not show any statistically significant correlation with age, gender, dialysis vintage or with predialysis urea and bicarbonate. Patients with a BMI &gt; 30 kg/sqm (21 versus 37 patients) showed a significantly higher level of MDA 1.57 ± 0.51 mcmol/L versus 1.31 ± 0.33 mcmol/L, P = 0.02. We have also found a negative statistically significant correlation between MDA level and serum K (r = –0.29, P = 0.02) and serum phosphorus (r = –0.29, P = 0.03). Patients with predialysis K of higher then 5.5 mEq/L had a statistically significant lower MDA (1.29 ± 0.4 mcmol/L versus 1.54 ± 0.4 mcmol/L, P = 0.025) and a non-significant higher GPx (59.0 ± 12.58 U/g Hg versus 58.2 ± 11.87 U/g Hg, P = 0.8). We found a negative statistically significant correlation of the MDA level with haemoglobin (r = –0.39, P = 0.002) and with haematocrit (r = –0.35, P = 0.006). No statistically significant correlation of the plasma antioxidant GPx with the studied parameters of anaemia and CKD-MBD has been found. CONCLUSION In our study, we found that increased oxidative stress (expressed through the malondialdehyde level) is associated with obesity and more severe anaemia. The indirect relationship found with serum K and phosphorus could indicate the risk of oxidative stress, and therefore it could be useful to take into account the dietary antioxidants when recommending low potassium and low phosphorus diet.

BACKGROUND AND AIMS We require an imagistic quantitative technique for the diagnosis and assessment of chronic kidney disease (CKD). Renal elastography has been widely used in the last years in different studies; however, the results across them are not consistent and, as a result, we conducted a meta-analysis of the published literature on this topic. METHOD The databases of PubMed, Medscape and Medline were searched for all studies published in English from 2010 until November 2021 that evaluated kidney shear wave speed (KSWS) by elastography in patients with CKD. Trial design, methodological information, patient characteristics, interventions, results and outcome data were all collected from each study according to a set protocol. RESULTS We found 33 publications, yet only 18 studies that utilized point shear wave elastography (Virtual Touch Quantification—VTQ system) were compared because the values achieved using different types of elastography are not evaluable. Finally, 1995 attendees (1241 patients with CKD versus 781 healthy subjects as the control group) were included. When comparing mean values of KSWS between studies, we found increased heterogeneity Q = 513.133; DF = 10; P &lt; .001, I2 (inconsistency) = 98.12% (95% CI for I2 97.52–98.57%). With a standardized mean difference of –0.216, patients with CKD have a lower KSWS than healthy controls. A positive association between KSWS and eGFR was also discovered across the presented studies, with a pooled correlation coefficient of 0.38 (Z = 10.3, P &lt; .001), Q = 73.3, DF = 5, P &lt; .001, I2 = 93.18% (95% CI for I2 87.86–96.18). The pooled area under the ROC curve for KSWS to predict mild renal disease was 0.831 (95% CI, P &lt; .001), Q = 28.32, DF = 6, P = .0001, I2 = 78.8% (95% CI for I2 56.37–89.72). In the four articles that used the Elast-PQ method, the data presented were insufficient for statistical analysis: area under the curve values are used to compare distinct characteristics (differentiating KSWS between mildly and moderately impaired kidneys, between non-diabetic, prediabetic and diabetic patients, or KSWS between CKD and control group), therefore not being suitable for further evaluation. CONCLUSION The results show that patients with CKD have a lower KSWS than healthy controls. It remains a viable method for monitoring the progression of CKD but because the number of studies involving renal elastography that have been published is limited and show an increased heterogeneity more research is needed to determine which factors actually influence KSWS in CKD patients and, as a result, to specify the role and indication of renal elastography in clinical practice.

BACKGROUND AND AIMS Vitamin K deficiency is a common feature of CKD, leading to impaired bone quality and an increased risk of vascular calcifications. A method to indirectly measure vitamin K status is measuring the blood level of vitamin K dependent proteins (VKDP)- osteocalcin (OC) and matrix GLA protein (MGP). The aim of this study is to correlate the level of OC and MGP with markers of CKD mineral bone disorder (CKD-MBD). METHOD We conducted a single-centre cross-sectional study that included 45 CKD G5D patients (haemodialysis for 6 months–10 years). All patients have been assessed regarding their dialysis status (medical history), we performed analysis before the dialysis session using standard methods blood biochemistry, complete blood count and intact osteocalcin and matrix GLA protein. RESULTS In the studied haemodialysis patients mean OC was 169.06 ± 128.28 ng/mL, while mean MGP was 3285.93 ± 2092.85 pmol/L. No statistically significant correlation has been found between OC and MGP. We found a strong statistically significant correlation of OC with the markers of CKD-MBD such as: iPTH (r = 0.48, P = 0.0007), serum calcium (r = 0.49, P = 0.0005) and serum phosphorus (r = 0.29, P = 0.04). No statistically significant correlation has been found between MGP and the above- mentioned markers. Only 2 out of 45 patients recorded a past history of bone fractures. Regarding the relationship with the nutritional status of the patients, no statistically significant correlations of the assessed VKDP with BMI and serum albumin have been found. However, a strong indirect statistically significant correlation of OC with abdominal circumference was observed (r = –0.43, P = 0.003). There was also a statistically significant correlation of MGP with markers of inflammation (CRP) (r = 0.55, P = 0.004). No statistically significant differences have been found regarding the level of VKDP between patients with and without a history of diabetes mellitus (13/45), coronary heart disease (18/45) stroke (5/45). The group of patients that are currently under treatment with vitamin K antagonists (13 out of 45) showed significantly higher levels of MGP (5693.0 ± 1728.64 versus 2276.5 ± 1232.54 pmol/L; P &lt; 0.01). Treatment with non-calcium-based phosphate binders (20 patients) was associated to significantly higher levels of MGP compared with treatment with calcium-based phosphate binders (15 patients) (4089.2 ± 2045.79 versus 2134.86 ± 1944.63 pmol/L; P = 0.019). Treatment with vitamin D receptor activator-paricalcitol (20 patients) was associated to significantly increased levels of MGP (4224.55 ± 2162.32 versus 2503.75 ± 1709.31 pmol/L; P = 0.005). CONCLUSION In our study, we found that vitamin K deficiency, measured indirectly using the level of VKDP is associated to CKD-MBD, could be influenced by features of malnutrition-inflammation. The use of medications such as phosphate binders that reduce vitamin K absorbtion, vitamin D that increases vitamin K requirements and also vitamin K antagonists, seems to have an influence on the blood level of VKDPs.