Serum Alkaline Phosphatase Levels are Not Associated with Increased Death Risk in Prevalent Hemodialysis Patients: 5-Year Experience in a Single Hemodialysis Center

Abstract

Background/Aims: Although high serum alkaline phosphatase (ALP) levels were reported as predictive factors for death risk in dialysis patients on the basis of large databank analyses, the real scenario in a single hemodialysis (HD) center is unknown. Methods: In this study, a 5-year cohort of 1126 prevalent HD patients in the largest HD center in Taiwan was studied. The associations of ALP levels expressed as baseline, time-average, and time-dependent with all-cause mortality and cardiovascular mortality were evaluated by using adjusted Cox regression models. Results: At baseline, levels of serum parathyroid hormone, calcium, and liver enzymes are increased in parallel with ALP quartiles. The hazard ratio (HR) for all-cause mortality was significantly increased in time-average and time-dependent ALP quartile in the unadjusted Cox analysis. The significance disappeared when multivariate adjusted Cox analysis was used. Similarly, HR was not significantly increased for cardiovascular mortality with ALP quartile expressed as baseline, time-average, and time-dependent in three models of Cox analyses. Conclusion: Our study demonstrated that serum ALP levels were not associated with increased death risk in prevalent HD patients over a 5-year interval.

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

“…Subsequently, 134 articles were excluded after applying our predefined inclusion criteria. Thus, 12 studies 8 – 17 , 20 , 21 with 393,200 patients on dialysis were finally included in the meta-analysis. Table 1 presents a summary of the general characteristics of the included studies.…”

“…Table 1 presents a summary of the general characteristics of the included studies. These included studies were mainly conducted in the United States 8 – 10 , 12 , 13 , mainland China 14 , Japan 11 , 15 , South Africa 17 , and Taiwan 16 , 20 , 21 . One study 10 was a retrospective analysis of a randomized controlled trial, and others were retrospective cohort designs.…”

“…One study 10 was a retrospective analysis of a randomized controlled trial, and others were retrospective cohort designs. Eight studies 8 – 11 , 15 – 17 , 20 enrolled patients on hemodialysis, three studies 13 , 14 , 21 enrolled patients on peritoneal dialysis, and one study 12 comprised both patients on hemodialysis and peritoneal dialysis. Individual study sample sizes varied from 90 to 185,277, and the follow-up duration ranged from 1.0 year to 7.0 years.…”

“…The mean reported age of patients was between 47.5 and 66 years. Six studies 8 , 9 , 12 , 15 , 16 , 20 with 7 to 8 Newcastle–Ottawa Scale (NOS) stars were grouped as good quality, and the others 10 , 11 , 13 , 14 , 17 , 21 achieved 5–6 stars.

Figure 1 Flowchart of the study selection process.

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“…ALP usually originates from the liver or bone and concentrates in the bone, liver, placenta, and kidney. Several 8 – 18 but not all 19 , 20 epidemiologic studies reported that elevated serum levels of ALP are associated with increased all-cause mortality among patients on hemodialysis and peritoneal dialysis. Nonetheless, for cardiovascular mortality, studies 10 , 14 , 15 , 20 have yielded contradicting results.…”