Elevated serum alkaline phosphatase and cardiovascular or all-cause mortality risk in dialysis patients: A meta-analysis

Predicting life span of type 2 diabetes patients through alkaline phosphatase and vitamin D: Results from NHANES 1999-2018

BACKGROUND AND AIMS

Disparities in serum biomarker levels related to mortality persist within the US diabetic population. We conducted a study to explore the impact of alkaline phosphatase (ALP) on all-cause mortality and cardiovascular disease (CVD) mortality in type 2 diabetes patients.

METHODS

We analyzed a nationally representative sample of individuals aged 20 years and above from the National Health and Nutrition Examination Survey (NHANES) conducted in the United States between 1999 and 2018. Baseline demographic information and biochemical markers, including blood glucose, γ-glutamyltranspeptidase, vitamin D and albumin, were collected. Participants were divided into four groups based on ALP levels and linked to the National Death Index to assess mortality. Follow-up continued until December 2019, and multiple mediation analyses were performed to assess the combined impact of different indicators on ALP differences in all-cause mortality and cardiovascular mortality risk.

RESULTS

Our analysis included 6481 NHANES participants, categorized as follows: 1626 (21.9%) had ALP levels below 58 U/L, 1674 in the second quartile (58-72 U/L), 1569 in the third quartile (72-88.3 U/L), and 1612 in the fourth quartile (above 88.3U/L). Significantly higher all-cause mortality and cardiovascular mortality rates were observed among participants in the 4th ALP quartile compared to other levels. The all-cause mortality rate was 38.06 per 1000 person-years (95% CI 34.89-41.51), and the cardiovascular mortality rate was 10.67 (9.06-12.57). Mediation analysis indicated that Vitamin D and albumin played a mediating role in the association between all-cause mortality, cardiovascular mortality, and ALP levels, with mediation proportions ranging from 10.33% to 27.64%.

CONCLUSIONS

Our study suggests that ALP levels have clinical value in predicting all-cause and CVD mortality risk in T2DM patients. The upregulation of Vitamin D and albumin might play a significant role in improving risk prediction and enable targeted interventions for reducing mortality risk in this population.

Serum alkaline phosphatase is a strong predictor of mortality in ESKD patients: analysis of the RISCAVID cohort

BACKGROUND

Mortality in hemodialysis (HD) patients remains unacceptably high compared with that of the general population and despite the continuous improvement of dialysis techniques. This study aimed to assess the role of alkaline phosphatase serum levels on cardiovascular and overall mortality in the RISCAVID study cohort through a long follow-up period, looking for associations with known risk factors for poor outcome.

METHODS

In June 2004, a prospective observational study was started focusing on the cardiovascular risk in hemodialysis patients who lived in the north-west area of Tuscany (RISCAVID, "RISchio CArdiovascolare nei pazienti afferenti all'Area Vasta In Dialisi"). The RISCAVID cohort included 572 prevalent patients on maintenance HD for at least three months. Morbid or fatal events were prospectively recorded at 6-month intervals for a follow up time of 216 months.

RESULTS

In univariable Cox regression analysis, dialysis technique, Geriatric Nutritional Risk Index, peripheral vascular disease, and intact parathyroid hormone and total calcium serum levels were significantly associated with baseline alkaline phosphatase serum levels. Cox multivariable analysis showed that elevated serum alkaline phosphatase levels (the highest quartile), advanced age, dialysis vintage, type of vascular access, Geriatric Nutritional Risk Index, C-reactive protein and calcium serum levels, history of cardiovascular disease and peripheral vascular disease were independent predictors of overall mortality in maintenance HD patients. The fourth quartile of alkaline phosphatase was associated with all-cause 10-year mortality (HR: 1.47; 95% CI: 1.177-1.834) with a 47% increase with respect to the 1st, 2nd, and 3rd quartiles. This was also observed for 18-year all-cause mortality.

CONCLUSIONS

Adjusted proportional analysis showed the alkaline phosphatase value to be an independent and powerful predictor of overall mortality in the hemodialysis population.

Alkaline Phosphatase and Parathyroid Hormone Levels: International Variation and Associations With Clinical Outcomes in the DOPPS

Introduction

Secondary hyperparathyroidism (SHPT) increases the risk of fractures and cardiovascular (CV) disease in patients on hemodialysis (HD). The relationship between parathyroid hormone (PTH) and outcomes has been inconsistent, possibly due to variable bone responsiveness to PTH. The KDIGO guideline suggests monitoring total alkaline phosphatase (ALP), but the role of ALP versus PTH in the management of mineral and bone disorder (MBD) is not clear.

Methods

The analysis included 28,888 patients on HD in 9 countries in Dialysis Outcomes and Practice Patterns Study (DOPPS) phase 3 to 7 (2005-2021). The primary exposures of interest were normalized ALP and PTH, which are raw values divided by facility upper normal limit, measured at study enrollment. Cox models were used to estimate hazard ratios of all-cause or CV mortality and any or hip fracture adjusted for potential confounders. Linear mixed models, adjusted for potential confounders, were employed to investigate the relationship between normalized ALP levels and patient characteristics.

Results

Normalized PTH showed a J-shaped association with all-cause or CV mortality, and a weak linear association with fracture. In contrast, normalized ALP showed a strong association with all outcomes. Factors associated with higher ALP levels after controlling for PTH included Black race, longer dialysis vintage, diabetes mellitus, hypocalcemia, hypophosphatemia, elevated C-reactive protein (CRP), and the use of cinacalcet.

Conclusion

Total ALP is a more robust exposure of adverse outcomes than PTH in patients on HD. PTH responsiveness is affected by race, primary renal disease, comorbidities, and mineral metabolism and therapy. Our results indicate that it may be useful to evaluate target organ response, rather than PTH alone when considering the consequences of (SHPT).

Data-driven, two-stage machine learning algorithm-based prediction scheme for assessing 1-year and 3-year mortality risk in chronic hemodialysis patients

Life expectancy is likely to be substantially reduced in patients undergoing chronic hemodialysis (CHD). However, machine learning (ML) may predict the risk factors of mortality in patients with CHD by analyzing the serum laboratory data from regular dialysis routine. This study aimed to establish the mortality prediction model of CHD patients by adopting two-stage ML algorithm-based prediction scheme, combined with importance of risk factors identified by different ML methods. This is a retrospective, observational cohort study. We included 800 patients undergoing CHD between December 2006 and December 2012 in Shin-Kong Wu Ho-Su Memorial Hospital. This study analyzed laboratory data including 44 indicators. We used five ML methods, namely, logistic regression (LGR), decision tree (DT), random forest (RF), gradient boosting (GB), and eXtreme gradient boosting (XGB), to develop a two-stage ML algorithm-based prediction scheme and evaluate the important factors that predict CHD mortality. LGR served as a bench method. Regarding the validation and testing datasets from 1- and 3-year mortality prediction model, the RF had better accuracy and area-under-curve results among the five different ML methods. The stepwise RF model, which incorporates the most important factors of CHD mortality risk based on the average rank from DT, RF, GB, and XGB, exhibited superior predictive performance compared to LGR in predicting mortality among CHD patients over both 1-year and 3-year periods. We had developed a two-stage ML algorithm-based prediction scheme by implementing the stepwise RF that demonstrated satisfactory performance in predicting mortality in patients with CHD over 1- and 3-year periods. The findings of this study can offer valuable information to nephrologists, enhancing patient-centered decision-making and increasing awareness about risky laboratory data, particularly for patients with a high short-term mortality risk.

Associations of serum alkaline phosphatase level with all-cause and cardiovascular mortality in the general population

Background and aims

There are few population studies on the associations of serum alkaline phosphatase (AlkP) with all-cause and cardiovascular mortality. We aimed to investigate the relevancy of serum AlkP with all-cause and cardiovascular mortality in the general population.

Methods and results

Our research included 34,147 adults in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2014. Cox proportional hazards regression models were used to assess the associations of serum AlkP with all-cause and cardiovascular mortality. Mediation analysis was used to analyze mechanisms that might link serum AlkP to all-cause and cardiovascular mortality. After 139.7 ± 57.8 months of follow-up, 5413 participants experienced all-cause death and 1820 participants experienced cardiovascular death. Mortality rates per 1000 person-years from various diseases increased with increasing serum concentrations of AlkP, especially all-cause death, cerebrovascular disease and cardiovascular death. High serum AlkP level significantly increased all-cause and cardiovascular mortality. After multivariate adjustment, the highest AlkP group had the highest risk to experience all-cause (hazard ratio [HR] = 1.30, P < 0.001) and cardiovascular mortality (HR = 1.39, P < 0.001) than the lowest AlkP group. γ-glutamyl transpeptidase (GGT) (13.33% and 15.79%), followed by Vitamin D (8.33% and 7.14%) and C-reactive protein (CRP) (7.69% and 10.35%) were identified as possible major mediators.

Conclusion

Higher AlkP concentrations were associated with higher all-cause and cardiovascular mortality, largely related to mediated factors such as GGT, Vitamin D, and CRP. These findings suggest that lower serum AlkP level may reduce all-cause and cardiovascular mortality in general population.

Prognostic value of preoperative serum alkaline phosphatase for predicting 3-year mortality in patients undergoing kidney transplantation: A retrospective study

Serum alkaline phosphatase (ALP) levels are related to high-turnover bone disease and reflect vascular calcification and inflammation. ALP has been reported to have a prognostic impact in various cohorts including chronic kidney disease. This study investigated whether preoperative serum ALP level could be used for predicting mortality in patients undergoing kidney transplantation. We retrospectively reviewed 1,718 patients who underwent kidney transplantation between November 2005 and June 2017. Finally, 1,533 patients who met the inclusion criteria were classified into tertiles based on preoperative serum ALP level (< 51, 51–72, > 72 IU/L). The incidence of mortality was compared among the three tertiles, and a stepwise logistic regression analysis was performed to evaluate the predictors for mortality. The incidence of 3-year mortality was the highest in the third tertile (1.0% vs. 2.5% vs. 4.4% in the first, second, and third tertile, respectively, p = 0.003). The third tertile of ALP level (odds ratio [OR] 1.855, 95% CI 1.192–2.886, p = 0.006), age (OR 1.052, 95% CI 1.022–1.082, p = 0.011), and history of hypertension (OR 0.401, 95% CI 0.210–0.765, p = 0.006) remained as independent predictors of mortality. Preoperative serum ALP level was significantly higher in the non-survivor group than in the survivor group (58.00 [44.00–76.00] vs. 75.00 [56.25–113.00], p = 0.003). The optimal cut-off value of serum ALP to predict 3-year mortality was 71 IU/L (area under the curve 0.636, 95% CI 0.554–0.719, p = 0.003). Therefore, preoperative serum ALP level was an independent predictor of 3-year mortality in patients undergoing kidney transplantation.

Non-Linear Association Between Serum Alkaline Phosphatase and 3-Month Outcomes in Patients With Acute Stroke: Results From the Xi'an Stroke Registry Study of China

Background

Alkaline phosphatase (ALP) is associated with an increased risk of cardiovascular events and is closely related to adverse outcomes after stroke. However, the regional investigation into the associations of ALP with acute stroke (AS) outcomes is limited. This study aimed to identify the association between serum ALP levels and clinical outcomes 3 months after AS in the Xi'an district of China.

Methods

We enrolled all patients with AS from 4 hospitals in the Xi'an district from January to December 2015. ALP levels and related patient information were collected at admission, and the events of stroke outcomes were followed up 1 and 3 months after diagnosis. ALP levels were analyzed as continuous variables and quartiles (Q1–Q4). The outcomes included all-cause mortality, recurrent stroke, and poor functional outcomes (modified Rankin Scale score of 3–6) within 3 months. A multivariate logistic regression and interaction analyses were performed to evaluate the independent association between serum ALP level and 3-month stroke outcomes.

Results

Overall, 2,799 patients with AS were enrolled in this study. The mean age was 63.9 ± 12.5 years. In the Q4 (≥93.0 U/L) group, the incidences of all-cause mortality, recurrent stroke, and poor functional outcomes were 7.8, 2.7, and 24.9%, respectively. After being adjusted for confounding variables, patients in Q4 (≥93.0 U/L) were related to an increased risk of all-cause mortality [odds ratio (OR) = 2.17, 95% CI: 1.19–3.96; P = 0.011] and patients in Q3 (76.8–92.9 U/L) were related to a lower risk of recurrent stroke (OR = 0.37, 95% CI: 0.14–0.97; P = 0.043) at the 3-month time point, compared to those in Q2 (63.0–76.7 U/L). The optimal range of ALP for all-cause mortality was seen in Q2, with a nadir level of 70 U/L. However, differences were statistically insignificant between ALP levels and poor functional outcomes (P > 0.05). Moreover, there was no significant interaction between ALP levels and age, gender, drinking status, smoking status, or pneumonia (P > 0.05) for all outcomes.

Conclusion

Non-linear associations were observed between serum ALP levels and 3-month outcomes in patients with AS. It might be beneficial to reduce the risk of all-cause mortality and recurrent stroke by maintaining ALP at optimal ranges.

Comparative Effectiveness of Dialysis Modality on Laboratory Parameters of Mineral Metabolism

INTRODUCTION

Chronic kidney disease-mineral and bone disorders (CKD-MBD) are prevalent in patients undergoing maintenance dialysis. Yet, there are limited and mixed evidence on the effects of different dialysis modalities involving longer treatment times or higher frequencies on CKD-MBD markers.

METHODS

This cohort study used data from 132,523 incident dialysis patients treated with any of the following modalities: conventional thrice-weekly in-center hemodialysis, nocturnal in-center hemodialysis (NICHD), home hemodialysis (HHD), or peritoneal dialysis (PD) from 2007 to 2011. We used marginal structural models fitted with inverse probability weights to adjust for fixed and time-varying confounding and informative censoring. We estimated the average effects of treatments with different dialysis modalities on time-varying serum concentrations of CKD-MBD markers: albumin-corrected calcium, phosphate, parathyroid hormone (PTH), and alkaline phosphatase (ALP) using pooled linear regression.

RESULTS

Most of the cohort were exclusively treated with conventional in-center hemodialysis, while few were ever treated with NICHD or HHD. At the baseline, PD patients had the lowest mean and median values of PTH, while NICHD patients had the highest median values. During follow-up, compared to hemodialysis patients, patients treated with NICHD had lower mean serum PTH (19.8 pg/mL [95% confidence interval: 2.8, 36.8] lower), whereas PD and HHD patients had higher mean PTH (39.7 pg/mL [31.6, 47.8] and 51.2 pg/mL [33.0, 69.3] higher, respectively). Compared to hemodialysis patients, phosphate levels were lower for patients treated with NICHD (0.44 mg/dL [0.37, 0.52] lower), PD (0.15 mg/dL [0.12, 0.19] lower), or HHD (0.33 mg/dL [0.27, 0.40] lower). There were no clinically meaningful associations between dialysis modalities and concentrations of calcium or ALP.

CONCLUSION

In incident dialysis patients, compared to treatment with conventional in-center hemodialysis, treatments with other dialysis modalities with longer treatment times or higher frequency were associated with different patterns of serum phosphate and PTH. Given the recent growth in the use of dialysis modalities other than hemodialysis, the associations between the treatment and the CKD-MBD markers warrant additional study.

Interaction of Serum Alkaline Phosphatase and Folic Acid Treatment on Chronic Kidney Disease Progression in Treated Hypertensive Adults

The relation of alkaline phosphatase (ALP) with chronic kidney disease (CKD) is still uncertain. We aimed to examine the prospective association between serum ALP and CKD progression, and the modifying effect of serum ALP on folic acid in preventing CKD progression in treated hypertensive patients. This is a post-hoc analysis of 12,734 hypertensive adults with relevant measurements and without liver disease at baseline from the renal sub-study of the China Stroke Primary Prevention Trial, where participants were randomly assigned to daily treatments of 10 mg enalapril and 0.8 mg folic acid, or 10 mg enalapril alone. The primary outcome was CKD progression, defined as a decrease in estimated glomerular filtration rate (eGFR) of ≥30% and to a level of <60 ml/min/1.73 m² if baseline eGFR was ≥60 ml/min/1.73 m²; or a decrease in eGFR of ≥50% if baseline eGFR was <60 ml/min/1.73 m²; or end-stage renal disease. Over a median of 4.4 years, in the enalapril only group, participants with baseline serum ALP≥110IU/L (quartile 4) had a significantly higher risk of CKD progression (3.4% vs 2.3%; adjusted OR,1.61; 95%CI:1.11, 2.32), compared with those with ALP<110IU/L. For those with enalapril and folic acid treatment, compared with the enalapril only treatment, the risk of CKD progression was reduced from 3.4 to 2.1% (adjusted OR, 0.53; 95%CI:0.34, 0.83) among participants with baseline ALP≥110IU/L, whereas there was no significant effect among those with ALP<110IU/L. In hypertensive patients, higher serum ALP was associated with increased risk of CKD progression, and this risk was reduced by 47% with folic acid treatment.

Association Between Alkaline Phosphatase and Clinical Outcomes in Patients With Spontaneous Intracerebral Hemorrhage

Background: Spontaneous intracerebral hemorrhage (ICH) is associated with high rates of mortality and morbidity. Alkaline phosphatase (ALP) is related to increased risk of cardiovascular events and is also closely associated with adverse outcomes after ischemic or hemorrhagic stroke. However, there are limited data about the effect of ALP on clinical outcomes after ICH. Therefore, we aimed to investigate the relationship between serum ALP level and prognosis in ICH patients. Methods: From January 2014 to September 2016, 939 patients with spontaneous ICH were enrolled in our study from 13 hospitals in Beijing. Patients were categorized into four groups based on the ALP quartiles (Q1, Q2, Q3, Q4). The main outcomes were 30-day, 90-day, and 1-year poor functional outcomes (modified Rankin Scale score of 3-6). Multivariable logistic regression and interaction analyses were performed to evaluate the relationships between ALP and clinical outcomes after ICH. Results: In the logistic regression analysis, compared with the third quartile of ALP, the adjusted odds ratios of the Q1, Q2, and Q4 for 30-day poor functional outcome were 1.31 (0.80-2.15), 1.16 (0.71-1.89), and 2.16 (1.32-3.55). In terms of 90-day and 1-year poor functional outcomes, the risks were significantly higher in the highest quartile of ALP compared with the third quartile after adjusting the confounding factors [90-day: highest quartile OR = 1.86 (1.12-3.10); 1-year: highest quartile OR = 2.26 (1.34-3.80)]. Moreover, there was no significant interaction between ALP and variables like age or sex. Conclusions: High ALP level (>94.8 U/L) was independently associated with 30-day, 90-day, and 1-year poor functional outcomes in ICH patients. Serum ALP might serve as a predictor for poor functional outcomes after ICH onset.

Serum alkaline phosphatase is associated with arterial stiffness and 10-year cardiovascular disease risk in a Chinese population

BACKGROUND

Serum alkaline phosphatase (ALP) has been recognized as a biomarker of cardiovascular disease (CVD) risk, recently. This study aimed to explore the association of ALP with arterial stiffness and 10-year CVD risk.

METHODS

A total of 12 539 participants without CVD who underwent health examinations including serum ALP level were retrospectively analysed. Arterial stiffness was measured by brachial-ankle pulse wave velocity (baPWV), and 10-year CVD risk was evaluated by Framingham risk score.

RESULTS

All participants were stratified into four groups according to the quartile of serum ALP. Participants with high ALP quartiles had higher cardiovascular parameters and baPWV, as well as an increase 10-year CVD risk. There was a dose-response relationship between serum ALP level and baPWV (OR = 1.134, 95% CI 1.103-1.165, P < .001). Logistic regression analysis showed that serum ALP was positively associated with elevated baPWV and 10-year CVD risk after adjustment for traditional CVD risk factors in both women and men. In receiver operating characteristic (ROC) curve analysis, the optimal cut-off point of serum ALP for elevated baPWV was 84U/L and the area under the ROC curve (AUROC) was 0.740 (95% CI 0.726-0.754, P < .001), with 71.2% and 63.4% sensitivity and specificity, respectively, in women. The AUROC of serum ALP in women was larger than that in men [0.575 (95% CI 0.559-0.590), P < .001].

CONCLUSIONS

Serum ALP is independently associated with arterial stiffness and 10-year CVD risk. Our results imply that serum ALP may be a promising marker to identify an increased risk for subclinical atherosclerosis in women needing further evaluation.

Association Between Alkaline Phosphatase and Muscle Mass, Strength, or Physical Performance in Patients on Maintenance Hemodialysis

Introduction: Alkaline phosphatase (ALP) is an indicator for checking liver or bone disorders, but recent studies have shown the possibility of an additive indicator beyond the simple mineral-bone status in dialysis patients. The aim of the study was to evaluate the ALP level and various indicators for malnutrition, physical performance, or hospitalization in patients on hemodialysis (HD).

Methods: This study was an observational study (n = 84). We included all patients undergoing HD with the following criteria: age ≥ 20 years, duration of dialysis ≥ 6 months, ability to ambulate without an assistive device, ability to communicate with the interviewer, and no hospitalization within the last 3 months before enrollment. Furthermore, none of the patients had liver disease. We recommended abstinence of alcohol for ≥ 1 month for the duration of the study. The patients were divided into tertiles based on the ALP level. Muscle mass [appendicular muscle mass index using dual-energy X-ray absorptiometry (ASM/Ht²), thigh muscle area index using computed tomography (TMA/Ht²)], strength [handgrip strength (HGS)], and physical performance [gait speed (GS), sit-to-stand for 30-s test (STS30), 6-min walk test (6-MWT), or Short Physical Performance Battery test (SPPB)] were evaluated. The number of hospitalizations was also evaluated.

Results: The ALP level in the low, middle, and high tertiles was 50.5 ± 7.5, 69.8 ± 5.4, and 113.3 ± 47.3 IU/l, respectively. The high tertile group showed the poorest trends in ASM/Ht², TMA/Ht², HGS, GS, STS30, and 6-MWT compared to the other tertile groups. Logistic regression analysis showed that the high tertile group for low HGS, low GS, or low SPPB had a higher odds ratio compared to the other tertiles. Subgroup analyses according to age, sex and diabetes mellitus showed similar trends as in the total cohort. Hospitalization-free survival rates after 300 days in the high tertile and the other tertiles were 53.8 and 77.2%, respectively (P = 0.105).

Conclusion: The present study demonstrated that ALP is associated with muscle mass, strength, and physical performance in patients on maintenance HD. In addition, the trend showed better hospitalization-free survival in the low or middle tertiles than in the high tertile. ALP can be considered as a simple and useful indicator to detect malnutrition, physical performance, or hospitalization in patients on HD.

Survival and analysis of predictors of mortality in patients undergoing replacement renal therapy: a 20-year cohort

Background

optimal management of end-stage renal disease (ESRD) in hemodialysis (HD) patients should be more studied because it is a serious risk factor for mortality, being considered an unquestionable global priority.

Methods

we performed a retrospective cohort study from the Nephrology Service in Brazil evaluating the survival of patients with ESRD in HD during 20 years. Kaplan-Meier method with the Log-Rank and Cox’s proportional hazards model explored the association between survival time and demographic factors, quality of treatment and laboratory values.

Results

Data from 422 patients were included. The mean survival time was 6.79 ± 0.37. The overall survival rates at first year was 82,3%. The survival time correlated significantly with clinical prognostic factors. Prognostic analyses with the Cox proportional hazards regression model and Kaplan-Meier survival curves further identified that leukocyte count (HR = 2.665, 95% CI: 1.39–5.12), serum iron (HR = 8.396, 95% CI: 2.02–34.96), serum calcium (HR = 4.102, 95% CI: 1.35–12.46) and serum protein (HR = 4.630, 95% CI: 2.07–10.34) as an independent risk factor for the prognosis of survival time, while patients with chronic obstructive pyelonephritis (HR = 0.085, 95% CI: 0.01–0.74), high ferritin values (HR = 0.392, 95% CI: 0.19–0.80), serum phosphorus (HR = 0.290, 95% CI: 0.19–0.61) and serum albumin (HR = 0.230, 95% CI: 0.10–0.54) were less risk to die.

Conclusion

survival remains low in the early years of ESRD treatment. The present study identified that elevated values of ferritin, serum calcium, phosphorus, albumin, leukocyte, serum protein and serum iron values as a useful prognostic factor for the survival time.

Intestinal alkaline phosphatase modulation by food components: predictive, preventive, and personalized strategies for novel treatment options in chronic kidney disease

Alkaline phosphatase (AP) is a ubiquitous membrane-bound glycoprotein that catalyzes phosphate monoesters' hydrolysis from organic compounds, an essential process in cell signaling. Four AP isozymes have been described in humans, placental AP, germ cell AP, tissue nonspecific AP, and intestinal AP (IAP). IAP plays a crucial role in gut microbial homeostasis, nutrient uptake, and local and systemic inflammation, and its dysfunction is associated with persistent inflammatory disorders. AP is a strong predictor of mortality in the general population and patients with cardiovascular and chronic kidney disease (CKD). However, little is known about IAP modulation and its possible consequences in CKD, a disease characterized by gut microbiota imbalance and persistent low-grade inflammation. Mitigating inflammation and dysbiosis can prevent cardiovascular complications in patients with CKD, and monitoring factors such as IAP can be useful for predicting those complications. Here, we review IAP's role and the results of nutritional interventions targeting IAP in experimental models to prevent alterations in the gut microbiota, which could be a possible target of predictive, preventive, personalized medicine (PPPM) to avoid CKD complications. Microbiota and some nutrients may activate IAP, which seems to have a beneficial impact on health; however, data on CKD remains scarce.

Liver Function Enzymes are Potential Predictive Markers for Kidney Allograft Dysfunction

Introduction

Biopsy of the allograft is the gold standard for assessing kidney allograft dysfunction. The aim of our pilot study was to identify serum biomarkers that could obviate the need for biopsy.

Materials and Methods

We conducted a study to identify the biomarkers in the serum from different groups of chronic kidney disease (CKD) patients and kidney transplanted patients vs. healthy individuals. The four groups (n=25 in each group) were as follows: 1) Patients with unstable kidney allograft transplants requiring biopsy for cause, 2) Patients with stable kidney allograft transplants, 3) Patients with CKD not on immunosuppressive therapy and, 4) healthy subjects. We measured the activity and level of serum alkaline phosphatase (ALP) and other liver enzymes (alanine transaminase (ALT) and aspartate transaminase (AST)) as potential serum biomarkers in acute allograft dysfunction.

Results

We found that ALP correlated with allograft biopsy findings, liver function, and clinical outcomes and possibly graft survival. Additionally, AST and ALT were higher in patients with graft rejection compared to non-rejected and stable kidney transplants. Moreover, the low Pearson correlations (r- values) between ALP level with age (r=0.179), gender, body mass index (r=0.236), creatinine (r=0.044) or estimated glomerular filtration rate (r=0.048) suggest that ALP may be an independent biomarker which is relatively unaffected by other individual-level variables.

Conclusion

ALP may be a putative biomarker to predict kidney allograft function and rejection. Data also indicated that liver function plays an important role for the overall success of kidney transplantation.

The combined prognostic significance of alkaline phosphatase and vascular calcification in patients with end-stage kidney disease

BACKGROUND AND AIMS

Little is known about the interaction between serum alkaline phosphatase (ALP) and vascular calcification (VC) affecting cardiovascular events (CVE) and mortality in end-stage kidney disease (ESKD) patients. This study investigated the combined effect of ALP and VC on prognosis in ESKD patients starting dialysis.

METHODS AND RESULTS

Data from 587 ESKD patients treated at a single center between January 2006 and July 2017 were retrospectively evaluated. VC was assessed by the aortic calcification index (ACI) using abdominal computed tomography. Patients were stratified into four groups according to the median ACI (17.18) and serum ALP value (108.0 U/L) as low ACI-low ALP, low ACI-high ALP, high ACI-low ALP, or high ACI-high ALP. The association between ALP and VC and the composite of CVE and death was analyzed. During a median follow-up of 3.1 years (range, 1.5-5.6 years), 140 patients (23.8%) developed CVE and 130 deaths (22.1%) occurred. In the stratified analysis, patients with high ACI-low ALP had a greater risk of the composite endpoint than patients with low ACI-low ALP (adjusted hazard ratio, 2.09; 95% confidence interval, 1.58-2.60; P = 0.004). Patients with high ACI-high ALP had the greatest risk (adjusted hazard ratio, 2.25; 95% confidence interval, 1.77-2.72; P = 0.001). The interaction between ACI and ALP on CVE and mortality was statistically significant (P < 0.05).

CONCLUSIONS

The combined effect of VC and higher ALP was associated with a greater risk of CVE and death, and high serum ALP amplified the risk associated with VC in ESKD patients starting dialysis.

Fatigue in Peritoneal Dialysis Patients and an Exploration of Contributing Factors: A Cross-Sectional Study

CONTEXT

Fatigue is a common and detrimental symptom in dialysis patients; however, our understanding of it and investigation of its contributing factors is still very limited, especially in peritoneal dialysis (PD) patients.

OBJECTIVES

To assess fatigue in PD patients and identify contributing factors.

METHODS

One hundred eight PD patients in a comprehensive hospital in China were recruited. The fatigue severity of the participants was assessed using the Chalder Fatigue Scale 11. Demographic factors and results of physiological tests were collected. Quality of sleep, mental health, and social support were assessed with the Pittsburgh Sleep Quality Index, Symptom Checklist 90, and Social Support Rating Scale, respectively. Multiple linear regression models were conducted with candidate variables with a P-value of less than 0.1 on univariate analysis and variables that were clinically relevant to identify contributing factors for fatigue.

RESULTS

The fatigue level in PD patients was significantly higher than the community population, and 78.7% of them were suffering from fatigue. The factors that were significantly associated with fatigue were quality of sleep, normalized protein nitrogen appearance, transferrin, alkaline phosphatase, and total cholesterol (adjusted R squared 0.86). Among them, quality of sleep, transferrin, alkaline phosphatase, and total cholesterol were significant contributors for physical fatigue, whereas the quality of sleep and normalized protein nitrogen appearance were contributing factors for mental fatigue.

CONCLUSION

Fatigue is a common symptom in PD patients, suggesting that increased awareness of this symptom is required. The identification of correlates by extensive exploration of multidimensional factors in this study may help practitioners to identify patients at higher risk and to develop a multidimensional and targeted intervention plan.

Nutritional Status and Mortality Predictability for Time-Varying Serum Alkaline Phosphatase in Hemodialysis Patients: A Longitudinal Study

OBJECTIVE

Higher serum alkaline phosphatase (sALP) levels associate with a poor prognosis in maintenance hemodialysis patients. However, little is known about the meaning of lower sALP in this population. We hypothesized that lower sALP concentrations may express nutritional status and survival accordingly.

METHODS

A retrospective, longitudinal cohort study of a clinical database containing the medical records of 554 patients (367 men and 187 women, mean age 67.6 ± 14.2 years) receiving maintenance hemodialysis from November 2007 to July 2018 in a single center was conducted. sALP, nutritional, bone turnover, and inflammatory marker levels were recorded at 0, 6, 12, 18, 24, 30,and 36 months followed by 58 additional months of clinical observations.

RESULTS

The median sALP level was 90.0 (71.0-125.8) U/L. In a linear mixed effects model adjusted for baseline demographics and clinical parameters, each 1.0 U/L increase above the mean sALP at baseline was associated with 0.7% slower rate of decline in geriatric nutritional risk index per 3 years (P = .02 for sALP × time interaction). sALP remained associated with the rate of change in geriatric nutritional risk index, even after controlling for C-reactive protein and intact parathyroid hormone levels. For each 1.0 U/L increase in sALP over time, the fully adjusted all-cause mortality hazard ratio using Cox models with the time-varying risk effect was 0.996 (95% confidence interval 0.993-1.000, P = .04).

CONCLUSIONS

Increasing longitudinal levels of sALP associate with improved nutritional status and lower mortality rates. sALP can be used as an integrated marker, combining the properties of the nutritional marker, the marker of mineral-bone disease and inflammation, according to its levels.

Osteopontin Levels in Patients With Chronic Kidney Disease Stage 5 on Hemodialysis Directly Correlate With Intact Parathyroid Hormone and Alkaline Phosphatase

Chronic kidney disease stage 5 (CKD5) marks the fifth stage of renal failure, frequently causing dysregulation of bone and mineral metabolism. Challenges exist in evaluating and managing chronic kidney disease–mineral bone disorder (CKD-MBD) with the standard panel of biomarkers. Our objective was to profile osteopontin (OPN) in patients with CKD5 on maintenance hemodialysis (CKD5-HD) and elucidate its relationship to phosphorus (P), calcium (Ca²⁺), alkaline phosphatase (AP), and intact parathyroid hormone (iPTH) to improve understanding of the present model of CKD-MBD. Elevation of plasma OPN was seen in the CKD5-HD cohort (n = 92; median: 240.25 ng/mL, interquartile range [IQR]: 169.85 ng/mL) compared to a normal group (n = 49; median: 63.30 ng/mL, IQR: 19.20 ng/mL; p < .0001). Spearman correlation tests revealed significant positive correlations of OPN with iPTH (p < .0001; r = 0.561, 95% confidence interval = 0.397-0.690) and OPN with AP (p < .0001; r = 0.444, 95% confidence interval = 0.245-0.590) in CKD5-HD patients. Ultimately, OPN may play an integral role in the MBD axis, suggesting that it may be important to actively monitor OPN when managing CKD5-HD.

Prognostic impact of preoperative serum alkaline phosphatase level on a composite of morbidity and mortality after thoracic endovascular aortic repair: A retrospective study

BACKGROUND

Serum alkaline phosphatase (ALP) is related to vascular calcification and is known to have a prognostic impact in various cohorts. However, evidence in patients undergoing thoracic endovascular aortic repair (TEVAR) is lacking. Thus, we hypothesized that preoperative serum ALP level could be used for predicting adverse events after TEVAR.

METHODS

We retrospectively reviewed 167 patients who underwent TEVAR between February 2013 and December 2016. Patients were classified into tertiles according to preoperative ALP level (<69, 69-92, and >92 IU/L). The composite of morbidity and mortality (composite MM) was defined as the presence of one or more of the following: myocardial infarction, cerebrovascular accident, dialysis requirement, pulmonary complication, infection, and mortality within 1 year after TEVAR. The incidence of composite MM was compared among the 3 tertiles, and stepwise logistic regression analysis was performed to evaluate the predictors for composite MM.

RESULTS

The incidence of composite MM was 14.5% in the first tertile group, 17.9% in the second tertile group, and 35.7% in the third tertile group (P = .016). The third tertile of ALP level (odds ratio [OR] 1.766, 95% confidence interval [CI] 1.074-2.904, P = .025) and emergency TEVAR (OR 2.369, 95% CI 1.050-5.346, P = .038) remained as independent predictors of composite MM.

CONCLUSIONS

Our data showed an independent relationship between high preoperative ALP levels and adverse outcomes in patients undergoing TEVAR. This finding might suggest a potential role of ALP level as a risk stratification marker.

Factors associated with low trabecular bone scores in patients with end-stage kidney disease

The trabecular bone score (TBS) is a textural index that indirectly assesses bone trabecular microarchitecture using lumbar spine images obtained by dual-energy X-ray absorptiometry (DXA). This study compared the TBS of patients with end-stage kidney disease (ESKD) with that of matched controls to identify risk factors associated with a low TBS. TBS and bone mineral density (BMD) were assessed in ESKD patients (n = 76) and age- and sex-matched control subjects (n = 76) using DXA. The TBS of both groups was then compared, and risk factors associated with a low TBS (defined as ≤ 1.31) were evaluated. The mean TBS in the ESKD group was significantly lower than that in the control group (1.34 ± 0.15 vs. 1.43 ± 0.08, respectively; p < 0.001). More subjects in the ESKD group had a low TBS [34.2% (ESRD) vs. 5.3% (controls); p < 0.001]. The TBS was negatively correlated with age, alkaline phosphatase and C-reactive protein levels, and dialysis vintage, and positively correlated with BMD at the lumbar spine, femoral neck, and hip. Multivariate analysis identified lower estimated glomerular filtration rate and increased C-reactive protein levels as being significantly associated with a low TBS. In conclusion, ESKD patients had abnormal bone microarchitecture (as assessed by the TBS). The TBS was positively correlated with BMD. Renal function and inflammatory marker levels were independently associated with a low TBS. Thus, TBS may be a useful clinical tool for assessing cancellous bone connectivity in ESKD patients.

Prognostic value of serum alkaline phosphatase in the survival of prostate cancer: evidence from a meta-analysis

BACKGROUND

Many studies have evaluated the relationship between alkaline phosphatase (ALP) and the prognosis for prostate cancer (PCa). But they have not reached a widespread consensus yet. Therefore, we completed a meta-analysis to ascertain the significance of ALP and the prognosis for PCa.

METHODS

A literature search was performed in the PubMed, Embase, and Web of Science databases. HRs concerning overall survival (OS), progression-free survival (PFS), and cancer-specific survival (CSS) were extracted to evaluate the impacts of ALP on the prognosis for PCa. Subgroup analyses were conducted on different study types, regions, sample sizes, and cutoff values. Sensitivity analysis was performed by removing one study in sequence.

RESULTS

A total of 63 studies from 54 articles with 16,135 patients were included in this meta-analysis. The pooled results indicated that high baseline ALP was associated with obviously poor OS (HR=1.74, 95% CI: 1.47-2.06) and PFS (HR=1.60, 95% CI: 1.13-2.26) in patients with PCa. The pooled HR for bone-specific ALP and OS was 1.76 (95% CI: 1.45-2.15). However, no association between ALP and CSS (HR=1.002, 95% CI: 0.998-1.005) was found for PCa. The results of subgroup analyses were all in accordance with the main findings. Sensitivity analysis suggested that no single study could affect the stability of the results.

CONCLUSION

High serum ALP is significantly associated with poor OS and PFS except for CSS in PCa. ALP is an efficient and convenient biomarker for PCa prognosis.