The role of serum magnesium and calcium on the association between adiponectin levels and all-cause mortality in end-stage renal disease patients

Therapeutic potential of adiponectin in prediabetes: strategies, challenges, and future directions

Adiponectin, an adipose-derived hormone, plays a pivotal role in glucose regulation and lipid metabolism, with a decrease in circulating adiponectin levels being linked to insulin resistance and prediabetes. This review examines the therapeutic potential of adiponectin in managing prediabetes, elucidating on multiple aspects including its role in glucose and lipid metabolism, influence on insulin sensitivity, and anti-inflammatory properties. Moreover, the paper highlights the latest strategies to augment adiponectin levels, such as gene therapy, pharmacological interventions, dietary modifications, and lifestyle changes. It also addresses the challenges encountered in translating preclinical findings into clinical practice, primarily related to drug delivery, safety, and efficacy. Lastly, the review proposes future directions, underlining the need for large-scale human trials, novel adiponectin analogs, and personalized treatment strategies to harness adiponectin's full therapeutic potential in preventing the transition from prediabetes to diabetes.

The association between serum magnesium and chronic kidney disease in Chinese adults: a cross-sectional study

BACKGROUND

Magnesium (Mg) is both an essential macro-element and a known catalyst, and it plays a vital role in various physiological activities and mechanisms in relation to chronic kidney disease (CKD). However, epidemiological evidence involving this is limited and not entirely consistent. This study aims to explore the association of serum Mg concentrations with the risk of CKD among general Chinese adults.

METHODS

A total of 8,277 Chinese adults were included in the wave of 2009 from the China Health and Nutrition Survey (CHNS). The primary outcome was the risk of CKD, which was defined as the estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2. Multivariable logistic regression model was used to examine the relationship of serum Mg concentrations with the risk of CKD.

RESULTS

Included were 8,277 individuals, with an overall CKD prevalence of 11.8% (n = 977). Compared with the first quartile of serum Mg, the multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for participants in the second, third, and fourth quartiles of serum Mg were 0.74 (0.58, 0.93), 0.87 (0.69, 1.11) and 1.29 (1.03, 1.61), respectively. Similar results were observed in our several sensitivity analyses. Restricted cubic spline analysis demonstrated a nonlinear (similar "J"-shaped) association between serum Mg concentrations and the risk of CKD (Pnonlinearity <0.001), with a threshold at around a serum Mg value of 2.2 mg/dL.

CONCLUSIONS

Our results suggested a similar "J"-shaped association between serum Mg concentration and the risk of CKD among Chinese adults. Further large prospective studies are needed to verify these findings.

Lower product of magnesium × potassium is associated with higher mortality in chronic hemodialysis patients: a cohort study

This study aimed to investigate the Mg × K product on the mortality risk of hemodialysis patients with concomitant hypokalemia and lower magnesium levels. This was a prospective observational study of patients in a HD center in southern Taiwan. A total of 444 HD patients were divided into 5 groups by the Mg × K product: group 1, bottom quintile, median Mg × K: 7.87, IQR: 7.03-8.12 (n = 89, age: 64 ± 13 years old); group 2, median Mg × K: 9.37, IQR: 8.97-9.86 (n = 89, age:62 ± 13 years old); group 3, median Mg × K: 10.95, IQR: 10.50-11.26 (n = 89, age:64 ± 13 years old); group 4, median Mg × K: 12.30, IQR: 11.87-12.82 (n = 89, 61 ± 12 years old); and group 5, top quintile, median Mg × K: 14.92, IQR:14.07-16.23 (n = 88, 62 ± 11 years old). The patients were followed up for 2 years to determine the risk of all-cause mortality. Patients with a lower Mg × K product had more comorbidities, malnutrition-inflammation status, and a higher mortality risk. Using multivariable Cox regression analysis, a higher Mg × K [HR, 0.89; 95%CI (0.81-0.98)] was found to be an independent predictor of better survival. HD patients with a lower Mg × K product had more comorbidities, a marked malnutrition-inflammation status, and were associated with long-term mortality. A higher Mg × K value is a favorable survival factor.

Bone Mineral Parameters in Peritoneal Dialysis Patients after Lowering Calcium Concentration in Dialysis Fluids: A Case Series in Patients Using Icodextrin

In patients treated with peritoneal dialysis (PD), lowering the calcium level in PD fluids results in lower serum calcium levels and higher parathyroid hormone (PTH) levels. It is hypothesized that this effect is attenuated when patients are using icodextrin 7.5% for the once-daily long dwell (containing high calcium concentration). In this case series, we included 8 stable PD patients (mean age 68 ± 13 years, 7 male), all using icodextrin 7.5% (containing 1.75 mmol/L calcium) for the once-daily long dwell. The calcium content of the PD fluids for the remaining dwells was lowered from 1.75 mmol/L to 1.25 mmol/L. Bone mineral parameters and phosphate prescription at baseline, 6 weeks after this change, and after 6 months were compared. After lowering calcium concentration of the PD fluids - except for the icodextrin 7.5% - from 1.75 mmol/L to 1.25 mmol/L, calcium levels changed from 2.32 ± 0.11 to 2.29 ± 0.12 (p = NS); intact PTH (iPTH) from 39.6 ± 28.3 to 64.9 ± 34.5 pmol/L (p = 0.045); and alkaline phosphatase from 104.13 ± 48.75 to 101.38 ± 32.39 (p = NS). After 6 months, all bone mineral parameters were similar to baseline levels; however, slightly higher calcium-based phosphate binders were prescribed. Lowering calcium content from 1.75 mmol/L to 1.25 mmol/L in PD fluids in patients on icodextrin resulted in stable calcium values, a temporal increase in iPTH and a modest increase in calcium-based phosphate binder prescription. Using icodextrin for the long once-daily dwell appears to attenuate the effects on bone mineral parameters when lowering the calcium concentration of the short dwells.

Circulating and Adipose Tissue Adiponectin Level and Outcomes in Incident Peritoneal Dialysis Patients

Rationale & Objective

Cardiovascular disease is the major cause of mortality and morbidity in peritoneal dialysis (PD) patients. Adiponectin, a key adipokine, is related to obesity and insulin resistance. We determined the clinical and prognostic value of plasma adiponectin level and its adipose tissue messenger RNA (mRNA) expression in new PD patients.

Study Design

Retrospective analysis of a prospective observational study.

Setting & Participants

152 new PD patients from a single center; 6 adults undergoing abdominal surgeries without kidney disease served as controls.

Predictors

Plasma adiponectin level and its adipose tissue mRNA expression.

Outcomes

Body build and composition, patient and technique survival.

Analytical Approach

Adiponectin level and mRNA expression were grouped in quartiles for correlation analysis for body build and Cox regression for survival analysis.

Results

The median plasma adiponectin level was 31.98 μg/mL (IQR, 16.81-49.49 μg/mL), and adiponectin mRNA expression in adipose tissue was 1.65 times higher than in controls (IQR, 0.98-2.63). There was a modest but statistically significant correlation between plasma adiponectin and its adipose tissue mRNA expression (r = 0.40, P < 0.001). Plasma adiponectin level inversely correlated with body mass index, waist-hip ratio, mid-arm circumference, adipose tissue mass, plasma triglyceride (r = -0.39, -0.38, -0.41, -0.38, and -0.30, respectively; P < 0.001 for all), as well as serum insulin level (r = -0.24, P = 0.005). Similar correlations were present but less marked with adipose tissue adiponectin mRNA level. Neither plasma adiponectin level nor adipose tissue adiponectin mRNA level predicted patient or technique survival.

Limitations

Observational study, single center, single baseline measurement.

Conclusions

Plasma adiponectin level correlated with the degree of adiposity in new PD patients. However, neither plasma adiponectin level nor its adipose tissue mRNA expression was an independent prognostic indicator in kidney failure patients newly started on PD.

New Insights into Adiponectin and Leptin Roles in Chronic Kidney Disease

Chronic kidney disease (CKD) is commonly associated with a high burden of comorbidities and poor clinical outcomes. Malnutrition–inflammation–atherosclerosis syndrome is common in the more severe stages of CKD, suggesting a close interplay for these three comorbid conditions. Both malnutrition and obesity are associated with a disturbed adipokine profile and inflammation, contributing to a higher risk of cardiovascular disease (CVD) events. Adiponectin and leptin have important roles in carbohydrate and lipid metabolism, and in the inflammatory process. The effects of adiponectin and leptin alterations in CKD, which are usually increased, and their association with the different comorbidities found in CKD, will be focused on to understand their crosstalk with the risk of CVD events. Nonetheless, although adiponectin and leptin contribute to a higher risk of CVD events, further studies are warranted to fully clarify their roles, especially when different comorbidities exist.

Association between hypomagnesemia and mortality among dialysis patients: a systematic review and meta-analysis

Background

Malnutrition-inflammation-atherosclerosis (MIA) syndrome is caused by the inflammatory cytokines in end stage renal disease (ESRD) patients, and MIA complex-related factors may be associated with hypomagnesemia and mortality. However, the association between serum magnesium level and mortality for dialysis patients is still not clear. Additionally, no meta-analysis has investigated the impact of serum magnesium on peritoneal dialysis and hemodialysis, separately.

Methods

We searched published studies in PubMed, Embase, Cochrane, Collaboration Central Register of Controlled Clinical Trials, and Cochrane Systematic Reviews through April 2022. Studies associated with serum magnesium and all-cause mortality or cardiovascular (CV) mortality in ESRD on kidney replacement therapy (KRT) patients were included. A hazard ratio (HR) with 95% confidence intervals (CI) was used to report the outcomes.

Results

Twenty-one studies involving 55,232 patients were included. Overall, there was a significant association between hypomagnesemia and all-cause mortality for dialysis patients (HR: 1.67, 95% CI [1.412-2.00], p < 0.001; certainty of evidence: moderate) using a mixed unadjusted and adjusted HR for analysis. There was also a significantly increased risk of CV mortality for individuals with hypomagnesemia compared with the non-hypomagnesemia group (HR 1.56, 95% CI [1.08-2.25], p < 0.001; certainty of evidence: moderate). In addition, a subgroup analysis demonstrated that hypomagnesemia was associated with a high risk of both all-cause mortality and CV mortality (all-cause mortality, HR:1.80, 95% CI [1.48-2.19]; CV mortality, HR:1.84, 95% CI [1.10-3.07]) in hemodialysis (HD) patients, but not in participants receiving peritoneal dialysis (PD; all-cause mortality, HR:1.26, 95% CI [0.84-1.91]; CV mortality, HR:0.66, 95% CI [0.22-2.00]). The systematic review protocol was prespecified and registered in PROSPERO [CRD42021256187].

Conclusions

Hypomagnesemia may be a significant risk factor for all-cause mortality and CV mortality in KRT patients, especially in those receiving hemodialysis. However, because of the limited certainty of evidence, more studies are required to investigate this association.

Associations between the serum magnesium and all-cause or cardiovascular mortality in chronic kidney disease and end-stage renal disease patients: A meta-analysis

BACKGROUND

Some studies have found that hypomagnesemia is associated with vascular calcification, atherosclerosis, and cardiovascular disease, which may lead to increased mortality in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) who need to maintain hemodialysis (HD). However, the conclusion of these studies remain controversial.

METHODS

Relevant literature was retrieved from the database of Cochrane library, PubMed, EMBASE, and CNKI until December 2020, without any language restrictions. The data was analyzed using the Stata 12.0 software.

RESULTS

A total of 31 studies were included, involving 205436 participants. The results showed that after multivariable adjusted, hypomagnesemia was significant associated with the risk of all-cause mortality in patients with CKD and end-stage renal disease (ESRD) (hazard ratios [HR] 1.955; 95% confidence interval (95% CI) 1.511-2.528; P = .000; hypomagnesemia vs normal magnesium or hypermagnesemia). In contrast, in patients with CKD and ESRD, hypermagnesemia was negatively correlated with all-cause mortality (HR 0.873; 95% CI 0.793-0.960; P = .005) (per unit increase). Moreover, in the adjusted model, it was observed that hypermagnesemia was significantly associated with a reduced risk of cardiovascular death (HR 0.598; 95% CI 0.094-1.102, P = .020). In addition, subgroup analysis found that hypomagnesemia was closely related to the increase of all-cause mortality in HD patients (HR 1.799; 95% CI 1.375-2.354; P = .000) (hypomagnesemia vs normal magnesium or hypermagnesemia).

CONCLUSION

Our results show that hypomagnesemia is significantly associated with cardiovascular and all-cause mortality in maintenance HD patients. Further studies should be conducted to evaluate the benefits of magnesium correction in maintenance dialysis patients with hypomagnesemia.

Comorbidity burden may explain adiponectin's paradox as a marker of increased mortality risk in hemodialysis patients

Despite experimental evidence of beneficial metabolic, antiatherosclerotic and antiinflammatory effects of the 30 kDa adipokine, adiponectin, maintenance hemodialysis (MHD) patients with high adiponectin blood levels have paradoxically high mortality rates. We aimed to examine the direction of the associations between adiponectin and all-cause and cardiovascular mortality as well as with markers of oxidative stress, inflammation and nutrition in MHD patients with varying degrees of comorbidities. A cohort of 261 MHD patients (mean age 68.6 ± 13.6 years, 38.7% women), grouped according to baseline comorbidity index (CI) and serum adiponectin levels, were followed prospectively for six years. High and low concentrations were established according to median CI and adiponectin levels and cross-classified. Across the four CI-adiponectin categories, the group with low comorbidities and high adiponectin exhibited the best outcomes. Conversely, the high comorbidity group with high adiponectin levels had the lowest survival rate in both all-cause mortality (log rankχ² = 23.74, p < 0.001) and cardiovascular mortality (log rankχ² = 34.16, p < 0.001). Further data adjustment for case-mix covariates including fat mass index did not substantially affect these results. In conclusion, the direction of adiponectin’s prognostic associations in MHD patients is inverse in those with few comorbidities and direct in those with many comorbidities.

Emperor's syndrome in the COVID-19 era: Time for patient-centered nephrology?

The coronavirus disease-19 (COVID-19) pandemic has been a wake-up call in which has forced us to react worldwide. Health policies and practices have attracted particular attention in terms of human and financial cost. Before COVID-19, chronic kidney disease was already considered a risk multiplier in patients with diabetes and hypertension, the two now being the major risk factors for COVID-19 infection and adverse outcome. In contrast to the urgent need for action, the nephrology field is considered to be in a state of stagnation regarding the management of chronic kidney disease patients who still experience unacceptably high morbidity and mortality. Ironically and paradoxically in a field lacking robust clinical trials, clinical practice is driven by guidelines-based medicine on weak evidence. The Emperor's syndrome, referring to Hans Christian Andersen's fairy tale, has been described in medicine as voluntary blindness to an obvious truth, being a weak evidence-based therapeutic intervention or weak health care. A promising positive example of improving heart and kidney outcomes is the emerging treatment with sodium-glucose cotransporter 2 inhibitors. COVID-19 could boost actions for patient-centered care as a positive shift in nephrology care.

Prognostic Value of Serum Magnesium in Mortality Risk among Patients on Hemodialysis: A Meta-Analysis of Observational Studies

Background

Previous studies have reported that serum magnesium (Mg) deficiency is involved in the development of heart failure, particularly in patients with end-stage kidney disease. The association between serum Mg levels and mortality risk in patients receiving hemodialysis is controversial. We aimed to estimate the prognostic value of serum Mg concentration on all-cause mortality and cardiovascular mortality in patients receiving hemodialysis.

Methods

We did a systematic literature search in PubMed, EMBASE, Cochrane Library, and Web of Science to identify eligible studies that reported the prognostic value of serum Mg levels in mortality risk among patients on hemodialysis. We performed a meta-analysis by pooling and analyzing hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

We identified 13 observational studies with an overall sample of 42,967 hemodialysis patients. Higher all-cause mortality (adjusted HR 1.58 [95% CI: 1.31–1.91]) and higher cardiovascular mortality (adjusted HR 3.08 [95% CI: 1.27–7.50]) were found in patients with lower serum Mg levels after multivariable adjustment. There was marked heterogeneity (I² = 79.6%, p < 0.001) that was partly explained by differences in age stratification and study area. In addition, subgroup analysis showed that a serum Mg concentration of ≤1.1 mmol/L might be the vigilant cutoff value.

Conclusion

A lower serum Mg level was associated with higher all-cause mortality and cardiovascular mortality in patients receiving hemodialysis.

The association between circulating magnesium and clinically relevant outcomes in patients with chronic kidney disease: A systematic review and meta-analysis

BACKGROUND & AIMS

Despite modern treatment, risk for cardiovascular disease and mortality in patients with chronic kidney disease (CKD) is unacceptably high. Observational studies have shown associations of magnesium with risk for several clinical outcomes in CKD of variable magnitude. The aim of this review is to provide a systematic overview and meta-analysis of longitudinal studies assessing the association of plasma magnesium concentration with clinically relevant outcomes in adult patients with chronic kidney disease, with a minimal follow-up of 6 months. Primary outcomes of interest were all-cause mortality, cardiovascular mortality, cardiovascular events, sudden death and hospitalisation.

METHODS

The electronic databases PubMed, Embase and The Cochrane Library were searched using terms relating to plasma magnesium and CKD patients, and two authors independently selected eligible studies. Study quality was assessed according to the Newcastle-Ottawa Scale. Results of studies with a comparable magnesium exposure and outcome measure, were pooled using a random-effects meta-regression analysis.

RESULTS

The search yielded 6156 records of which 33 studies, involving 348,059 patients, met the eligibility criteria. Finally, 22 studies could be included in the meta-analysis. Higher magnesium was associated with a lower risk for all-cause mortality (HR 0.90 [0.87-0.94] per 0.1 mmol/L increase of magnesium) and cardiovascular mortality and events (HR 0.85 [0.77-0.94] per 0.1 mmol/L).

CONCLUSIONS

Magnesium concentration is inversely associated with all-cause mortality and cardiovascular mortality and events. Therefore, increasing magnesium may improve risk in patients with chronic kidney disease. This meta-analysis forms a firm base for future prospective trials to test whether increasing plasma magnesium, indeed has beneficial effects on clinical outcomes.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Serum magnesium, mortality and disease progression in chronic kidney disease

Introduction

Magnesium disorders are commonly encountered in chronic kidney disease (CKD) and are typically a consequence of decreased kidney function or frequently prescribed medications such as diuretics and proton pump inhibitors. While hypomagnesemia has been linked with increased mortality, the association between elevated magnesium levels and mortality is not clearly defined. Additionally, associations between magnesium disorders, type of death, and CKD progression have not been reported. Therefore, we studied the associations between magnesium levels, CKD progression, mortality, and cause specific deaths in patients with CKD.

Methods

Using the Cleveland Clinic CKD registry, we identified 10,568 patients with estimated Glomerular Filtration Rate (eGFR) between 15 and 59 ml/min/1.73 m² in this range for a minimum of 3 months with a measured magnesium level. We categorized subjects into 3 groups based on these magnesium levels (≤ 1.7, 1.7–2.6 and > 2.6 mg/dl) and applied cox regression modeling and competing risk models to identify associations with overall and cause-specific mortality. We also evaluated the association between magnesium level and slope of eGFR using mixed models.

Results

During a median follow-up of 3.7 years, 4656 (44%) patients died. After adjusting for relevant covariates, a magnesium level < 1.7 mg/dl (vs. 1.7–2.6 mg/dl) was associated with higher overall mortality (HR = 1.14, 95% CI: 1.04, 1.24), and with higher sub-distribution hazards for non-cardiovascular non-malignancy mortality (HR = 1.29, 95% CI: 1.12, 1.49). Magnesium levels > 2.6 mg/dl (vs. 1.7–2.6 mg/dl) was associated with a higher risk of all-cause death only (HR = 1.23, 95% CI: 1.03, 1.48). We found similar results when evaluating magnesium as a continuous measure. There were no significant differences in the slope of eGFR across all three magnesium groups (p = 0.10).

Conclusions

In patients with CKD stage 3 and 4, hypomagnesemia was associated with higher all-cause and non-cardiovascular non-malignancy mortality. Hypermagnesemia was associated with higher all-cause mortality. Neither hypo nor hypermagnesemia were associated with an increased risk of CKD progression.

Serum magnesium, mortality, and cardiovascular disease in chronic kidney disease and end-stage renal disease patients: a systematic review and meta-analysis

BACKGROUND

Previous studies reported that magnesium deficiency was associated with vascular calcifications, atherosclerosis and cardiovascular disease, which might play an independent pathogenic role in chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients. However, the results of these studies were somewhat underpowered and inconclusive.

METHODS

Literature was identified by searching PubMed, EMBASE, Web of Science and the Cochrane Central Register of Controlled Trials (CENTRAL). We included studies that investigated the association between serum magnesium with mortality risk in CKD and ESRD patients. Unadjusted and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) were pooled.

RESULTS

Twenty studies involving 200,934 participants were included, and the results showed that there was a strong association between hypomagnesemia and the risk of all-cause mortality in patients with CKD and ESRD (HR 1.32; 95% CI 1.19-1.47; p < 0.00001) (hypomagnesemia vs. normal magnesium or hypermagnesemia) after multivariable adjusted. On the contrary, hypermagnesemia was inversely associated with all-cause mortality in patients with CKD and ESRD (HR 0.86; 95% CI 0.79-0.94; p = 0.001) (per unit increase). Moreover, a significant association between hypermagnesemia and decreased risk of cardiovascular mortality was observed (HR 0.71; 95% CI 053-0.97, p = 0.03) in the adjusted model. In addition, subgroup analysis found that hypomagnesemia was strongly associated with increased all-cause mortality in hemodialysis patients (HR 1.29; 95% CI 1.12-1.50; p = 0.0005) (hypomagnesemia vs. normal magnesium or hypermagnesemia).

CONCLUSIONS

Our results indicate that hypomagnesemia is significantly associated with cardiovascular and all-cause mortality in patients with CKD and ESRD. Further studies evaluating benefits of magnesium correction in CKD and dialysis patients with hypomagnesemia should be performed.

Circulating adiponectin levels are paradoxically associated with mortality rate. A systematic review and meta-analysis

CONTEXT

Some studies have surprisingly indicated that serum adiponectin is positively related to mortality rate, thus casting doubts on its role as a therapeutic target for cardiovascular disease.

OBJECTIVE

To summarize evidence about direction, strength and modulators of this controversial association.

DATA SOURCES

MEDLINE, Web of Science, CINHAL, Cochrane Library and Scopus from inception through June 2018.

STUDY SELECTION

English-language prospective studies reporting the association between adiponectin and all-cause or cardiovascular mortality.

DATA EXTRACTION

Two investigators independently extracted data and assessed study quality using standard criteria following the Preferred Reporting Items for Systematic Reviews and Meta-analyses and The Newcastle-Ottawa Scale, respectively. Pooled hazard ratios (HRs) (95% confidence intervals-CIs) were derived using a fixed or random effects models when appropriated and were expressed for one standard deviation (SD) increment of adiponectin.

DATA SYNTHESIS

We identified fifty-five (n=61,676 subjects) and twenty-eight (n=43,979 subjects) studies for all-cause and cardiovascular mortality, respectively. Pooled HRs, were 1.24 (1.17-1.31) and 1.28 (1.19-1.37) for all-cause and cardiovascular mortality, respectively. Similar results were obtained also for High Molecular Weight adiponectin. When meta-analyses were restricted to studies reporting data on natriuretic peptides a 43% and 28% reduction on a log scale of these associations were observed after natriuretic peptides adjustment.

CONCLUSIONS

Our results strongly points to a paradoxical association between high adiponectin levels and increased mortality rate, which is partly modulated by natriuretic peptides.

Serum magnesium and cardiovascular mortality in peritoneal dialysis patients: a 5-year prospective cohort study

The aim of this study was to explore the association between serum Mg and cardiovascular mortality in the peritoneal dialysis (PD) population. This prospective cohort study included prevalent PD patients from a single centre. The primary outcome of this study was cardiovascular mortality. Serum Mg was assessed at baseline. A total of 402 patients (57 % male; mean age 49·3±14·9 years) were included. After a median of 49·9 months (interquartile range: 25·9-68·3) of follow-up, sixty-two patients (25·4 %) died of CVD. After adjustment for conventional confounders in multivariate Cox regression models, being in the lower quartile for serum Mg level was independently associated with a higher risk of cardiovascular mortality, with hazards ratios of 2·28 (95 % CI 1·04, 5·01), 1·41 (95 % CI 0·63, 3·16) and 1·62 (95 % CI 0·75, 3·51) for the lowest, second and third quartiles, respectively. A similar trend was observed when all-cause mortality was used as the study endpoint. Further analysis showed that the relationships between lower serum Mg and higher risk of cardiovascular and all-cause mortality were present only in the female subgroup, and not among male patients. The test for interaction indicated that the associations between lower serum Mg and cardiovascular and all-cause mortality differed by sex (P=0·008 and P=0·011, respectively). In conclusion, lower serum Mg was associated with a higher risk of cardiovascular and all-cause mortality in the PD population, especially among female patients.

Associations of Adiponectin, Leptin Levels, and the Change of Body Composition in Patients on Peritoneal Dialysis: A Prospective Cohort Study

Background

Although the association between adipokines such as adiponectin, leptin, and body composition has been noted, whether they could predict the change of fat mass and lean body mass is unknown. We aimed to examine these associations in patients on peritoneal dialysis (PD) through a prospective cohort study.

Methods

Body composition (by dual-energy x-ray absorptiometry) including fat mass and lean body mass were examined at baseline and then at year 3. Serum leptin and adiponectin levels were measured. Demographic data, comorbidity, biochemical data, inflammation (high-sensitive C-reactive protein [hs-CRP]) and insulin resistance (homeostatic model assessment [HOMA-IR]) were also examined.

Results

At baseline, serum adiponectin levels were significantly inversely correlated with weight, lean body mass index (LBMI), fat mass index (FMI), lean body mass (LBM), and fat mass (FM) in 213 prevalent patients. At year 3, FMI, LBMI, FM, and the percentage of FM (FM%) increased while the percentage of LBM (LBM%) significantly decreased despite unchanged weight and LBM among the remaining 112 patients. After adjustment for demographic data, comorbidities, hs-CRP, HOMA-IR, and daily energy intake (DEI), serum adiponectin at baseline was not associated with increases in LBMI, FMI, and FM, but independently associated with an increase in FM% and a decrease in LBM%. The predictive effect of high-serum adiponectin level on mortality disappeared after adjusting for diabetes and cardiovascular disease. Serum leptin was not associated with any changes in body composition during the follow-up, nor with the mortality in this cohort.

Conclusions

A high adiponectin level could predict an increase in FM% and a decrease in LBM% during a 3-year follow-up in PD patients. Serum adiponectin could not independently predict mortality in PD patients.

The Adiponectin Paradox for All-Cause and Cardiovascular Mortality

Basic science studies have shown beneficial effects of adiponectin on glucose homeostasis, chronic low-grade inflammation, apoptosis, oxidative stress, and atherosclerotic processes, so this molecule usually has been considered a salutary adipokine. It was therefore quite unexpected that large prospective human studies suggested that adiponectin is simply a marker of glucose homeostasis, with no direct favorable effect on the risk of type 2 diabetes and cardiovascular disease. But even more unforeseen were data addressing the role of adiponectin on the risk of death. In fact, a positive, rather than the expected negative, relationship was reported between adiponectin and mortality rate across many clinical conditions, comprising diabetes. The biology underlying this paradox is unknown. Several explanations have been proposed, including adiponectin resistance and the confounding role of natriuretic peptides. In addition, preliminary genetic evidence speaks in favor of a direct role of adiponectin in increasing the risk of death. However, none of these hypotheses are based on robust data, so further efforts are needed to unravel the elusive role of adiponectin on cardiometabolic health and, most important, its paradoxical association with mortality rate.

Associations of adiponectin and leptin levels with protein-energy wasting, in end stage renal disease patients

OBJECTIVE

The aim of the study was to examine the prevalence of protein-energy wasting (PEW) in hemodialysis (HD) and peritoneal dialysis (PD) patients in our center and determine whether adiponectin and leptin are involved in the development of PEW.

DESIGN

Prospective (18 months).

SETTING

University Hospital of Heraklion, Crete, Greece.

SUBJECTS

Seventy-four end-stage-renal-disease patients, 47 on HD and 27 on PD.

MAIN OUTCOME MEASURES

At three sequential time points (baseline, 6 and 18 months) anthropometric, nutritional and inflammatory status data were collected. Serum adiponectin and leptin were also assessed at each time point. Patients were allocated to 3 strata according to PEW severity (0, 1-2 and ≥3 criteria for PEW).

RESULTS

Adiponectin and leptin levels were greater among PD compared to HD patients (p≤0.035). Adiponectin levels were incrementally greater across increasing strata of PEW (p≤0.002). Leptin showed the opposite trend, with lower levels in malnourished patients and higher levels in patients with zero PEW criteria (p≤0.042). Alterations of adiponectin levels during the observation period were dependent on PEW stratum (p≤0.021) and mode of dialysis (p≤0.002), after adjustment for age, dialysis vintage, gender and fat mass index. Particularly, adiponectin levels increased over time in HD patients with ≥3 criteria for PEW, whereas adiponectin levels decreased in PD patients with ≥3 criteria for PEW throughout the study. Leptin alterations over time were not affected by dialysis mode or PEW stratification.

CONCLUSIONS

Our study provides evidence that increased adiponectin and decreased leptin levels are independently associated with PEW and thus, poor prognosis.

New-Onset Diabetes After Kidney Transplantation and Pretransplant Hypomagnesemia

AIM

Hypomagnesemia is a frequent finding in kidney transplant patients and plays a causal role in insulin resistance and diabetes. The aim of this study was to investigate whether the pretransplant magnesium (Mg) level is a risk factor for the development of new-onset diabetes after kidney transplantation (NODAT) and the presence of relationship between pretransplant hypomagnesemia and the development period of NODAT.

METHODS

Four hundred and nineteen nondiabetic renal transplant recipients were evaluated retrospectively. The patients were divided into NODAT and non-NODAT groups. The time of diagnosis of patients with NODAT was divided into 0 to 3, 3 to 6, 6 to 12 months, and after 12 months. Patients' characteristics and pretransplant Mg levels in NODAT were compared with non-NODAT, and it was investigated whether pretransplant hypomagnesemia was a risk factor for the development of NODAT.

RESULTS

Totally 70 (16.6%) patients (36 female [F], mean age 51.7 ± 8.2 years) were diagnosed with NODAT. Three hundred and forty-nine patients (115 F, mean age 43.2 ± 12.5 years) did not have NODAT. Pretransplant mean Mg level was 1.97 ± 0.40 mg/dL in patients with NODAT, while it was 2.5 ± 0.45 mg/dL in non-NODAT patients (P < .001). Serum Mg level was found to be similar in subgroups according to the development period of NODAT (P = .07). When patients were stratified according to quartiles of Mg level, the frequency of NODAT was significantly higher in patients in the lower quartile (Mg < 2.1 mg/dL; P < .001). Older age, high body mass index, and low pretransplant serum Mg levels were established as risk factors for developing NODAT. According to the quartile of Mg level, the risk of developing NODAT was highest in the lowest quartile.

CONCLUSION

Pretransplant hypomagnesemia is an independent risk factor of NODAT. Therefore, it is necessary to closely monitor the Mg levels in the posttransplant period.

Serum calcium and incident diabetes: an observational study and meta-analysis

The study aimed to prospectively evaluate if serum calcium is related to diabetes incidence in Hong Kong Chinese. The results showed that serum calcium has a significant association with increased risk of diabetes. The result of meta-analysis reinforced our findings.

INTRODUCTION

This study aimed to evaluate the association of serum calcium, including serum total calcium and albumin-corrected calcium, with incident diabetes in Hong Kong Chinese.

METHODS

We conducted a retrospective cohort study in 6096 participants aged 20 or above and free of diabetes at baseline. Serum calcium was measured at baseline. Incident diabetes was determined from several electronic databases. We also searched relevant databases for studies on serum calcium and incident diabetes and conducted a meta-analysis using fixed-effect modeling.

RESULTS

During 59,130.9 person-years of follow-up, 631 participants developed diabetes. Serum total calcium and albumin-corrected calcium were associated with incident diabetes in the unadjusted model. After adjusting for demographic and clinical variables, the association remained significant only for serum total calcium (hazard ratio (HR), 1.32 (95 % confidence interval (CI), 1.02-1.70), highest vs. lowest quartile). In a meta-analysis of four studies including the current study, both serum total calcium (pooled risk ratio (RR), 1.38 (95 % CI, 1.15-1.65); I (2) = 5 %, comparing extreme quantiles) and albumin-corrected calcium (pooled RR, 1.29 (95 % CI, 1.03-1.61); I (2) = 0 %, comparing extreme quantiles) were associated with incident diabetes. Penalized regression splines showed that the association of incident diabetes with serum total calcium and albumin-correlated calcium was non-linear and linear, respectively.

CONCLUSIONS

Elevated serum calcium concentration is associated with incident diabetes. The mechanism underlying this association warrants further investigation.

Association of Adiponectin with High-Sensitivity C-Reactive Protein and Clinical Outcomes in Peritoneal Dialysis Patients: A 3.5-Year Follow-Up Study

Introduction

Adiponectin (ADPN), one of most abundant fat-derived biologically active substances, plays an important role in anti-atherosclerotic process. There are conflicting results about the impact of ADPN on cardiovascular (CV) outcomes and mortality, particularly in patients undergoing peritoneal dialysis (PD). Moreover, the relationship between ADPN and inflammatory mediators has been seldom explored in this population. Therefore, we examined the relationship between ADPN and longitudinal high-sensitivity C-reactive protein (hs-CRP) changes and investigated whether ADPN or hs-CRP levels could predict CV outcomes and mortality in prevalent PD patients after comprehensive adjustment of possible confounders.

Methods

In this prospective cohort study, 78 PD patients were enrolled and followed from February 2009 to August 2012. During follow-up, CV events and all-cause mortality were recorded.

Results

The mean baseline ADPN value was 29.46±18.01 μg/ml and duration of PD treatment was 37.76±36.96 months. In multiple linear regression analysis, plasma ADPN levels positively correlated with high-density lipoprotein and negatively associated with hs-CRP, body mass index, D4/D0 glucose, triglyceride, and duration of PD treatment. After stratified by genders, the inverse association between baseline ADPN and hs-CRP was more significant in the female group. The hs-CRP levels were followed up annually and remained significantly lower in the high ADPN group in the first 2 years. Patients were then stratified into two groups according to the median ADPN value (23.8 μg/ml). The results of Kaplan-Meier survival analysis demonstrated less CV events and better survival in high ADPN group. On multivariate Cox regression analysis, only ADPN level (HR: 0.93, 95% CI: 0.88–0.98, p = 0.02), age and history of CV diseases were independent risk factors for future CV events. Furthermore, hs-CRP (HR: 1.11, 95% CI:1.001–1.22, p = 0.04) was identified as independent predictor of all-cause mortality.

Conclusions

Serum hs-CRP levels were consistently lower in the high ADPN group during 2-year follow-up. We also demonstrated the importance of ADPN and hs-CRP in predicting CV events and all-cause mortality in PD population during 3.5-year follow-up.

Serum Magnesium and Mortality in Hemodialysis Patients in the United States: A Cohort Study

BACKGROUND

Low serum magnesium levels in patients with kidney disease have been linked to increased mortality. This study investigated whether similar associations existed in maintenance hemodialysis (HD) patients.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

All Fresenius Medical Care North America in-center HD patients with available serum magnesium measurements were studied. The initial exploratory study in 21,534 HD patients evaluated associations among serum magnesium level, dialysate magnesium concentration, and mortality from April 2007 through June 2008. The follow-up study in 27,544 HD patients evaluated associations between serum magnesium levels and mortality over 1 year (January through December 2008).

PREDICTORS

The primary predictor was serum magnesium level, with adjustment for case-mix (age, sex, race, diabetes, and dialysis vintage and additionally for follow-up study: body surface area and vascular access) and laboratory variables (albumin, hemoglobin, phosphorus, equilibrated Kt/V, potassium, calcium, and intact parathyroid hormone values).

OUTCOME

Primary outcome variable was 1-year mortality risk, evaluated using Cox proportional hazards models.

RESULTS

Among 21,534 HD patients in the exploratory study, there were 3,682 deaths. Higher dialysate magnesium level was associated with higher serum magnesium level (R=0.22; P<0.001). Patients with the lowest serum magnesium levels (<1.30 mEq/L) were at highest risk for death (HR, 1.63; 95% CI, 1.30-1.96; reference serum magnesium, 1.60-<1.90 mEq/L). Among 27,544 HD patients in the follow-up study, there were 4,531 deaths. In Cox proportional hazards models, there was a linear decline in death risk from the lowest to the highest serum magnesium category, with the best survival at serum magnesium levels ≥ 2.50 mEq/L (HR, 0.68; 95% CI, 0.56-0.82). However, risk estimates were attenuated with case-mix and lab adjustment. This pattern was consistent within diabetes subgroups and for cardiovascular or noncardiovascular causes of death.

LIMITATIONS

Observational study with cross-sectional serum magnesium measurements and no information for oral magnesium intake.

CONCLUSIONS

Elevated serum magnesium levels > 2.10 mEq/L were associated with better survival than low serum magnesium levels < 1.30 mEq/L in HD patients. Prospective studies may determine whether manipulation of low serum magnesium levels affects survival.

Effects of magnesium depletion on inflammation in chronic disease

PURPOSE OF REVIEW

To update findings supporting the opinion that commonly occurring subclinical magnesium deficiency induced by a low dietary intake is a predisposing factor for chronic inflammatory stress that contributes to the incidence of chronic diseases such as cardiovascular disease and diabetes.

RECENT FINDINGS

Both deficient magnesium intakes (<250 mg/day) and serum magnesium concentrations (≤ 0.75 mmol/l) have been associated with elevated serum C-reactive protein concentration, a widely used indicator of inflammation. Achieving magnesium intakes or serum magnesium concentrations that indicate an adequate magnesium status generally attenuates elevated serum C-reactive protein to concentrations that are not indicative of chronic low-grade inflammation. Individuals that are obese or have chronic diseases for which low-grade inflammation is a risk factor are commonly found to be magnesium-deficient.

SUMMARY

Subclinical magnesium deficiency caused by low dietary intake often occurring in the population is a predisposing factor for chronic inflammatory stress that is conducive for chronic disease. Magnesium deficiency should be considered a nutrient of significant concern for health and well-being.

Potential cardiovascular risk protection of bilirubin in end-stage renal disease patients under hemodialysis

We evaluated the potential cardiovascular risk protection of bilirubin in hemodialysis (HD) patients. An enlarged set of studies were evaluated in 191 HD patients, including hematological study, lipid profile, iron metabolism, nutritional, inflammatory markers, and dialysis adequacy. The TA duplication screening in the UDP-glucuronosyltransferase 1 A1 (UGT1A1) promoter region was also performed. The UGT1A1 genotype frequencies in HD patients were 49.2%, 42.4%, and 8.4% for 6/6, 6/7, and 7/7 genotypes, respectively. Although no difference was found in UGT1A1 genotype distribution between the three tertiles of bilirubin, significant differences were found with increasing bilirubin levels, namely, a decrease in platelet, leukocyte, and lymphocyte counts, transferrin, oxidized low-density lipoprotein (ox-LDL), ox-LDL/low-density lipoprotein cholesterol ratio, apolipoprotein (Apo) A, Apo B, and interleukin-6 serum levels and a significant increased concentration of hemoglobin, hematocrit, erythrocyte count, iron, transferrin saturation, Apo A/Apo B ratio, adiponectin, and paraoxonase 1 serum levels. After adjustment for age these results remained significant. Our data suggest that higher bilirubin levels are associated with beneficial effects in HD patients, by improving lipid profile and reducing the inflammatory grade, which might contribute to increase in iron availability. These results suggest a potential cardiovascular risk protection of bilirubin in HD patients.

Is the dialysate calcium concentration of 1.75 mmol/L suitable for Chinese patients on maintenance hemodialysis?

We studied the effects of increasing the dialysate calcium concentration (DCa) to 1.75 mmol/L on controlling chronic kidney disease-mineral and bone disorder in Chinese patients on maintenance hemodialysis (MHD). We reviewed the data of MHD patients in one center (cohort 1) during prior 10 years and analyzed the risk factors of mortality and transference calcification (TC) in120 MHD patients surviving in 2003 (cohort 2). A multicenter, prospective, parallel-group, controlled trial (cohort 3) was also conducted from January 2011 to December 2012. The DCa at one center was increased from 1.5 to 1.75 mmol/L but was not changed at the other two centers. The clinical outcomes, biochemical parameters, medicine treatments, and TC markers [aortic arch calcification score (AoACS)] were compared between groups. In cohort 1, the annual mean serum iPTH increased significantly over 10 years. In cohort 1, 72 patients survived for 10 years, whose doses of calcium salts and active vitamin D3 and AoACs increased progressively. In cohort 2, the main cause of death was cardiocerebrovascular disease (CCVD) (n = 18, 48.6 %). Male sex and lower serum calcium concentrations were independent risk factors for CCVD mortality. In cohort 3, serum phosphorus, iPTH, and 25(OH)D decreased and serum calcium increased significantly; also, the doses of calcium and vitamin D3 decreased from 2011 to 2012 in the DCa 1.75 group. There were no significant differences in clinical outcomes either between groups or between the two calendar years. Our results indicate that increasing DCa to 1.75 mmol/L can decrease the elevated levels of serum iPTH and phosphorus, reduce the doses of calcium and vitamin D3, and be safe for short periods of time.

Hypomagnesemia in hemodialysis patients: role of proton pump inhibitors

BACKGROUND

Recent observations have associated hypomagnesemia with increased risk of cardiovascular morbidity and mortality in hemodialysis patients.

METHODS

We did a 3-month chart review of 62 chronic hemodialysis patients at a single US hospital. All were dialyzed using a dialysate [Mg] of 0.75-1.0 mEq/l. Patients were divided into two groups: hypomagnesemic (mean predialysis plasma [Mg] <1.5 mEq/l) and non-hypomagnesemic (mean predialysis plasma [Mg] ≥1.5 mEq/l).

RESULTS

All patients were male; mean age was 64.3 ± 8.7 years and the majority (73%) diabetic. 24 patients (39%) had hypomagnesemia and 38 (61%) were not hypomagnesemic. There were no significant differences between the two groups in age, diabetes status, blood pressure, duration of dialysis, plasma calcium, phosphorus, albumin, intact parathyroid hormone (PTH), dialysis adequacy (Kt/V), or dietary protein intake (as estimated by normalized protein catabolic rate, nPCR). However, use of proton pump inhibitors (PPIs) was significantly associated with hypomagnesemia (plasma [Mg] 1.48 ± 0.16 mEq/l in the PPI group vs. 1.65 ± 0.26 mEq/l in the non-PPI group, p = 0.007). Adjustment for age, diabetes status, duration of dialysis, plasma albumin, Kt/V, nPCR, and diuretic use did not affect the association between PPI use and hypomagnesemia.

CONCLUSIONS

Use of PPIs in patients dialyzed using a dialysate [Mg] of 0.75-1.0 mEq/l is associated with hypomagnesemia. We suggest monitoring plasma [Mg] in patients taking PPIs, with discontinuation of the medication if possible and/or adjustment of dialysate [Mg] to normalize plasma [Mg].