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

The correlation between serum alkaline phosphatase and grip strength in middle-aged and elderly people: NHANES 2011-2014

BACKGROUND

Serum alkaline phosphatase (ALP) plays a crucial role in bone and muscle health. Previous studies have demonstrated that serum alkaline phosphatase (ALP) is closely associated with muscle mass. Nevertheless, the association between serum alkaline phosphatase (ALP) and grip strength remains unclear. Therefore, the present study focused on exploring the association of serum ALP with grip strength in middle-aged and elderly people.

METHODS

We conducted a cross-sectional study using data from the National Health and Nutrition Examination Survey conducted from 2011 to 2014. A total of 3514 participants (1891 males and 1623 females) aged 40-80 years were included in this study. Serum ALP and pelvic grip strength were analyzed as independent and dependent variables, additional variables were the possible impact modifiers. weighted generalized linear models and stratified analysis by gender, age group, and race were applied to assess the relationship between serum ALP and grip strength. Smooth curve fitting and threshold effect analysis/saturation effect analysis were used to analyze the nonlinear relationship between the 2 variables.

RESULTS

In the gender-stratified subgroup analysis, we observed an inverse association between serum ALP and grip strength in both male and female. When stratified by age group, the association remained significant among participants 40-59 years of age, but not among those ≥ 60 years old. When stratified by race, the association remained significant among Non-Hispanic White and Non-Hispanic Black. It is noteworthy that serum ALP and grip strength showed a significant negative correlation among female aged 40-59 years, but not among female aged ≥ 60 years. Additionally, Smooth curve fitting showed that serum ALP had a nonlinear relationship with grip strength in male aged 40-59 years and male aged over 60 years, the inflection points are 54 IU and 97 IU respectively.

CONCLUSION

Our study revealed an inverse relationship between serum ALP and grip strength, this finding offers new insights and avenues for understanding how serum alkaline phosphatase affects skeletal muscle health.

Nutritional and Inflammatory Aspects of Low Parathyroid Hormone in Maintenance Hemodialysis Patients-A Longitudinal Study

BACKGROUND

Low serum parathyroid hormone (PTH) is an accepted marker for adynamic bone disease which is characterized by increased morbidity and mortality in maintenance hemodialysis (MHD) patients. In light of the known cross-sectional associations between PTH and malnutrition-inflammation syndrome, we aimed to examine the longitudinal associations between PTH with changes in nutritional and inflammatory parameters and clinical outcomes in MHD patients with low PTH.

METHODS

This historical prospective and longitudinal study analyzed a clinical database at a single hemodialysis center, containing the medical records of 459 MHD patients (mean age of 71.4 ± 12.9 years old, 171 women), treated between the years 2007-2020. Bone turnover, nutritional and inflammatory marker levels were recorded at 0, 6, 12, 18, 24, 30, and 36 months followed by a median of 24 additional months of clinical observations. According to previous use of vitamin D analogs and/or calcium-sensing receptor agonists, the study participants were divided into treatment-related and disease-related groups. A linear mixed effects model was adjusted for baseline demographics and clinical parameters.

RESULTS

Of 459 MHD patients, 81 (17.6%) had PTH lower than 150pg/mL. Among them, 30 patients had treatment-related and 51 had disease-related low PTH. At baseline, MHD patients with treatment-related low PTH had a higher rate of diabetes compared to the disease-related group. In a linear mixed effects model, increased PTH over time was associated with decreased levels of alkaline phosphatase and C-reactive protein and with increased hemoglobin and albumin, but not the geriatric nutritional risk index at 3-year follow-up. The survival rate did not differ between the groups, with the risk of hospitalizations due to fractures being higher (HR: 4.04 with 95% CI: 1.51-10.8) in the disease-related group. Statistical significance of this association was abolished after adding C-reactive protein or alkaline phosphatase to the multivariate models.

CONCLUSIONS

Low serum PTH in MHD patients behaves differently depending on its cause, with a higher risk of fractures in the disease-related group. This association is dependent on inflammation. Our results should be verified in larger epidemiological studies.

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.

Prognostic significance of albumin to alkaline phosphatase ratio in critically ill patients with acute kidney injury

OBJECTIVE

No epidemiological evidence has investigated the effect of albumin to alkaline phosphatase ratio (AAPR) on the prognosis among critically ill patients with acute kidney injury (AKI). We aimed to explore the prognostic value of AAPR in these patients.

METHODS

We extracted all clinical data from MIMIC III. ROC curve analysis was used to evaluate the discrimination of AAPR for predicting in-hospital mortality. A generalized additive model was applied to identify a nonlinear association between AAPR and in-hospital mortality. The Cox proportional hazards models were used to determine the association between AAPR and in-hospital and 30-day mortality.

RESULTS

A total of 6894 eligible subjects were enrolled in this study. The relationship between AAPR and in-hospital mortality was nonlinear. Multivariate analysis demonstrated that lower AAPR (AAPR < 0.35) was an independent predictor of in-hospital and 30-day mortality after adjusting for potential confounders (HR 1.74, 95% CI 1.72-2.20, P < 0.001; HR 1.89, 95% CI 1.66-2.14, P < 0.001, respectively).

CONCLUSIONS

AAPR may serve as a potential prognostic biomarker in critically ill patients with AKI and lower AAPR was associated with increased risk of in-hospital and 30-day mortality among these patients.

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.