High Serum Alkaline Phosphatase, Hypercalcaemia, Race, and Mortality in South African Maintenance Haemodialysis Patients

Serum alkaline phosphatase and infection-related mortality in hemodialysis patients: ten-year outcomes of the Q-cohort study

BACKGROUND

High serum alkaline phosphatase (ALP) levels are associated with excess all-cause and cardiovascular mortality in patients undergoing hemodialysis (HD). However, the long-term relationship between serum ALP levels and infection-related mortality remains unclear.

METHODS

A total of 3502 maintenance HD patients were registered in the Q-Cohort Study, an observational cohort study in Japan. The primary outcome was infection-related mortality during a 10-year follow-up period. The covariate of interest was serum ALP levels at baseline. The association between serum ALP levels and infection-related mortality was calculated using a Cox proportional hazards model and a Fine-Gray subdistribution hazards model with non-infection-related death as a competing risk.

RESULTS

During the follow-up period, 446 patients died of infection. According to their baseline serum ALP levels, the patients were categorized into sex-specific quartiles (Q1-Q4). Compared with patients in the lowest serum ALP quartile (Q1), those in the highest quartile (Q4) had a significantly higher multivariable-adjusted hazard ratio (HR) of 1.70 [95% confidence interval (CI) 1.24-2.32] for infection-related mortality. Furthermore, the HR for every 50 U/L increase in serum ALP levels was 1.24 (95% CI 1.12-1.36) for infection-related mortality. These associations remained consistent in the competing risk model: subdistribution HR, 1.47; 95% CI 1.07-2.03 for Q4 compared with Q1.

CONCLUSION

Higher serum ALP levels were significantly associated with a higher risk of infection-related mortality in patients undergoing HD.

Relationship between serum alkaline phosphatase and poor 3-month prognosis in acute ischemic stroke patients with preserved renal function: results from Xi'an Stroke Registry Study of China

Background

In recent years, alkaline phosphatase (ALP) has been considered as one of the independent risk factors of acute ischemic stroke (AIS) and leads to worse clinical outcomes in patients with renal failure. In this study, we aim to investigate whether serum ALP level is associated with poor early-term prognosis in relationship of AIS patients with preserved renal function.

Methods

A prospectively collected database of AIS patients hospitalized in the Xi’an district of China from January to December, 2015 was analyzed. The demographics, serum ALP levels and stroke outcomes of all patients at 3 months were reviewed. Patients were routinely followed-up for 3 months. Serum ALP level was analyzed as a continuous variable and quintiles (Q1-Q5). Multivariate logistic regression model and a two-piecewise linear regression model were used to investigate the relationship and to determine the threshold effect regarding serum ALP levels and poor 3-month prognosis of AIS patients with preserved renal function.

Results

Overall, 1922 AIS patients were enrolled with 62.3% of them being men. The risk of having a poor 3-month prognosis was significantly increased in Q1, Q2, Q3 and Q5, when compared to that in Q4 being as the reference. The highest risk was noted in Q5 (odds ratio 2.21, 95% confidence interval: 1.32–3.73, P = 0.003) after being adjusted for confounders. Further analysis revealed a J-shaped curvilinear relationship between ALP levels and a poor 3-month prognosis of strokes (optimal threshold ALP level = 90 U/L). The relationship between both parameters was not significantly affected by age, sex, drinking, hypertension and leukocyte count (stratified by 10 × 10⁹/L) (P for interaction > 0.05).

Conclusions

Serum ALP was noted as an independent risk factor for a poor 3-month prognosis of AIS patients with preserved renal function. ALP levels higher than 90 U/L could cause an increased risk of a poor 3-month prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02779-y.

Risk factors affecting the 1-year outcomes of minor ischemic stroke: results from Xi'an stroke registry study of China

BACKGROUND

The prevalence of stroke recurrence, disability, and all-cause mortality of patients with minor ischemic stroke (MIS) remains problematic. The aim of the present study was to identify risk factors associated with adverse outcomes at 1 year after MIS in the Xi'an region of China.

METHODS

This prospective cohort study included MIS patients above 18 years old with National Institutes of Health Stroke Scale (NIHSS) score ≤ 3 who were treated in any of four hospitals in Xi'an region of China between January and December 2015. The 1-year prevalence of stroke recurrence, disability, and all-cause mortality were evaluated, respectively. Multivariate logistic regression analysis was performed to assess the association between the identified risk factors and clinical outcomes.

RESULTS

In this study, 131(10.5%, 131/1252) patients were lost to follow-up at 1 year. A total of 1121 patients were included for analysis, the prevalence of stroke recurrence, disability, and all-cause mortality at 1 year after MIS were 3.4% (38/1121), 9.3% (104/1121), and 3.3% (37/1121), respectively. Multivariate logistic regression analysis identified age, current smoking, and pneumonia as independent risk factors for stroke recurrence. Age, pneumonia, and alkaline phosphatase were independent risk factors for all-cause mortality. Independent risk factors for disability were age, pneumonia, NIHSS score on admission, and leukocyte count.

CONCLUSIONS

The 1-year outcomes of MIS in Xi'an region of China were not optimistic, especially with a high prevalence of disability. The present study indicated that age and pneumonia were the common independent risk factors affecting the 1-year outcomes of MIS in Xi'an region of China.

Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD): Current Perspectives

Despite the availability of global and regional guidelines to curtail the adverse clinical outcomes associated with chronic kidney disease–mineral and bone disorder (CKD-MBD), most CKD patients are still affected by the consequences of abnormalities of CKD-MBD. This important clinical complication of CKD continues to be studied, in order to improve the understanding and management of CKD-MBD. Some notable discoveries include the role of fibroblast growth factor 23 (FGF23) in the pathogenesis of CKD-MBD, leading to a shift from the previous well-established classic trade-off hypothesis to the updated trade-off hypothesis. More recently, there has been a shift from the treatment of CKD-MBD based on a single level of biomarkers to serial measurements of calcium, phosphate and parathyroid hormone (PTH). Furthermore, some clinical trials have emerged after the 2009 Kidney Disease-Improving Global Outcomes (KDIGO) Guidelines, leading to the 2017 KDIGO updated recommendations. Hence, this review gives an overview of the rapidly evolving trends in CKD-MBD, linking the past and current concepts of CKD-MBD.

Associations of plasma fibroblast growth factor 23 and other markers of chronic kidney disease-Mineral and bone disorder with all-cause mortality in South African patients on maintenance dialysis: A 3-year prospective cohort study

INTRODUCTION

Few studies have linked high levels of plasma C-terminal fibroblast growth factor 23 (FGF23) with poor clinical outcomes in patients on maintenance haemodialysis (MHD), while the association between intact FGF23 and mortality in this group of patients remains inconclusive. Therefore, the aim of this study was to evaluate the association between plasma levels of intact FGF23 and mortality in dialysis patients.

METHODS

A prospective multicenter study involving patients undergoing dialysis at three dialysis centers in Johannesburg was undertaken between 1st October 2014 and 31st December 2017.

RESULTS

The study comprised 165 chronic dialysis patients (111 blacks, 54 whites) with a mean age of 46.6 ±14.2 years. During a three year follow up period, there were 46 deaths (1.03 per 100 person-years). The median plasma FGF 23 level was 382 pg/ml (interquartile range [IQR], 145-2977). In adjusted multivariable analyses, there was a non-statistically significant increase in the risk of mortality with higher quartiles of FGF 23 levels: the adjusted hazard ratios (HR) for the second, third and fourth quantiles were HR 3.20 (95% CI, 0.99-10.35; P = 0.052), HR 2.43(95% CI,0.65-9.09; P = 0.19), and HR 2.09 (95% CI, 0.66-7.32; P = 0.25),respectively. Corrected serum calcium 2.38-2.5 mmol/l [HR 2.98 (95% CI, 1.07-8.29; P = 0.04] and > 2.50 mmol/l [HR 5.50 (95% CI, 1.84-16.48; P = 0.002] were independently associated with increased risk of death. Likewise, patients with intact parathyroid hormone > 600 pg/ml had a 3.46-fold higher risk of death (HR 3.46, 95% CI, 1.22-9.82 P = 0.019). These findings persisted in time -dependent analyses.

CONCLUSION

Higher levels of intact FGF 23 appear not to be independently associated with all-cause mortality in our dialysis patients, while hypercalcaemia and severe hyperparathyroidism were found to be independent predictors of mortality in this cohort of patients.

Alkaline Phosphatase and Outcomes in Patients With Preserved Renal Function

Background and Purpose—

Alkaline phosphatase (ALP) is associated with risk of adverse cardiovascular events in patients with kidney failure. However, there is little data about effects of ALP on stroke outcomes in patients with preserved kidney function. The study aimed to explore the association between serum ALP level and clinical outcomes after stroke in patients with preserved kidney function.

Methods—

We included 16 367 stroke patients with preserved kidney function from the China National Stroke Registry for current analysis. Serum ALP levels were tested by automated enzymatic method using unfrozen samples in each center. Participants were divided into 5 groups according to ALP quintiles. Composite end point comprised of recurrent stroke, myocardial infarction, other ischemic vascular events, and all-cause mortality. Poor functional outcome is defined as modified Rankin Scale score of 3 to 6. Multivariable logistic regression was used to evaluate the independent association of serum ALP with 1-year all-cause mortality, recurrent stroke, composite end point, and poor functional outcome.

Results—

The mean age of the included 16 367 patients was 63.9 years, and 63.3% of them were men. Among the top ALP quintile (>98.0 U/L), 1-year incidences of all-cause mortality, recurrent stroke, composite end point, and poor functional outcome were 12.6%, 5.7%, 14.4%, and 27.0%, respectively. Compared with the lowest ALP quintile (≤59.0 U/L), the adjusted odds ratios of the top quintile were 1.36 (1.10–1.68) for all-cause mortality, 1.45 (1.11–1.90) for stroke recurrence, 1.35 (1.12–1.63) for composite end point, and 1.36 (1.17–1.60) for poor functional outcome. There was no significant interaction between age, sex, or alcohol consumption and ALP ( P for interaction ≥0.10) for all outcomes.

Conclusions—

In patients with preserved kidney function, ALP may be an independent predictor of all-cause mortality, stroke recurrence, composite end point, and poor functional outcome after stroke.

Influence of vitamin D receptor polymorphisms on biochemical markers of mineral bone disorders in South African patients with chronic kidney disease

BACKGROUND

It remains unclear whether genetic factors may explain the reported variation in the levels of biochemical markers of chronic kidney disease mineral and bone disorders (CKD- MBD) across ethnic groups. Therefore, the aim of this study was to examine the influence of vitamin D receptor (VDR) polymorphisms on secondary hyperparathyroidism and its association with vitamin D levels in black and white South African study participants.

METHODS

This was a cross sectional study involving 272 CKD stage 3- 5D patients and 90 healthy controls. The four major VDR polymorphisms (Bsm 1, Fok 1, Taq 1, and Apa1) were genotyped using the polymerase chain reaction- restriction fragment length polymorphism (PCR -RFLP) method. In addition, biochemical markers of CKD-MBD were measured to determine their associations with the four VDR polymorphisms.

RESULTS

With the exception of Taq I polymorphism, the distribution of the VDR polymorphisms differed significantly between blacks and whites. In hemodialysis patients, the Bb genotype was significantly associated with moderate secondary hyperparathyroidism (OR, 3.88; 95 CI 1.13-13.25, p = 0.03) and severe hyperparathyroidism (OR, 2.54; 95 CI 1.08-5.96, p = 0.03). This was consistent with the observed higher levels of median parathyroid hormone, fibroblast growth factor 23 and mean phosphate in patients with Bb genotype. This candidate risk genotype (Bb) was over represented in blacks compared to whites (71.0% versus 55.6%, p < 0.0001). In an unadjusted regression model, FokFf genotype was found to be significantly associated with the risk of developing severe vitamin D deficiency < 15 ng/ml (OR, 1.89; 95 CI 1.17-3.07, p = 0.01).

CONCLUSION

The VDR Bb genotype is an independent predictor of developing secondary hyperparathyroidism in patients with end stage kidney disease. In addition, study participants with FokFf genotype are at increased of developing severe 25 -hydroxyvitamin D [25(OH)D] deficiency.

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

Studies on serum alkaline phosphatase (ALP) and mortality risk in patients with end-stage renal disease (ESRD) undergoing dialysis have yielded conflicting results. This meta-analysis was designed to assess the association of serum ALP levels with cardiovascular or all-cause mortality risk among patients on dialysis. PubMed and Embase databases were searched until March 2017 for studies evaluating the association of serum ALP levels and cardiovascular or all-cause mortality risk in adult patients with ESRD undergoing maintenance hemodialysis or chronic peritoneal dialysis. Twelve studies enrolling 393,200 patients on dialysis were included. Compared with the reference low serum ALP category, pooled adjusted hazard risk (HR) of all-cause mortality was 1.46 (95% confidence interval [CI] 1.30–1.65) for patients on hemodialysis and 1.93 (95% CI 1.71–2.17) for peritoneal patients on dialysis. In addition, elevated serum ALP significantly increased cardiovascular mortality among patients on peritoneal dialysis (HR 2.39; 95% CI 1.23–4.65) but not in patients on hemodialysis (HR 1.08; 95% CI 0.84–1.40). Elevated serum ALP was an independent risk factor for all-cause mortality among patients on hemodialysis or peritoneal dialysis. Further well-designed prospective studies are needed to investigate the association of high serum ALP levels with cardiovascular mortality among patients on dialysis.