Etiology
- Increased Dietary Phosphate Intake
- Acute Kidney Injury (AKI)/Chronic Kidney Disease (CKD)
- IV Phosphate Administration
- Total Parenteral Nutrition (TPN)
- Oral Phosphate Administration
- Rectal Phosphate Administration
Physiology
Dietary Phosphorous
- Organic Phophorous
- Found naturaly in foods
- Usually bound to proteins (such as phytate) that limit their intetsinal absorption
- Organic phosphate is hydrolyzed in intestinal lumen, releasing inorganic phosphate, which is then absorbed
- Only 60% of intestinal organic phospphate is absorbed
- Vitamine D compounds (such as calcitriol): increase intestinal phosphate absorption
- Inorganic Phosphorous
- Inorganic phosphorus is commonly used as a food additive in many processed foods (chicken nuggets, hot dogs, spreadable cheeses, etc): extends shelf life, enhances flavor, improves color, retains moisture, acts as an emulsifier, etc
- Inorganic phosphorus is not protein-bound
- Approximately 90-100% of inorganic phosphorus is absorbed
Effects of Hyperphosphatemia
- The potential adverse effects of high serum phosphorus (and/or phosphorus accumulation( are observed in end-stage renal disease (CKD-5), CKD-2 to CKD-4, and in the general population
Clinical Manifestations
Renal Manifestations
- Acute Kidney Injury (AKI) (see Acute Kidney Injury, [[Acute Kidney Injury]])
- Associated with hypocalcemia
- Acute Phosphate Nephropathy
- xxx
Other Manifestations
- Parathyroid Hyperplasia/Hyperparathyroidism
- Vascular Calcification
- Cardiovascular Disease
- Loss of Bone Strength and Bone Mass/Risk of Bone fractures
Treatment
General Commnets
- K/DOQI Guidelines: maintaon phosphate 3.5 to 5.5 mg/dL
Limitation of Dietary Phosphorous
Phosphate Binders
- Phosphate Binder Agents
- Aluminium Hydroxide (Alucaps, Basaljel)
- Calcium Carbonate (Calcichew, Titralac) (see Calcium Carbonate, [[Calcium Carbonate]])
- Calcium Acetate (Lenal Ace, PhosLo) (see Calcium Acetate, [[Calcium Acetate]])
- Lanthanum Carbonate (Fosrenol) (see Lanthanum Carbonate, [[Lanthanum Carbonate]])
- Sevelamer (Renagel, Renvela) (see Sevelamer, [[Sevelamer]])
- Calcium Acetate/Magnesium Carbonate (Osvaren, Lenal Ace, Renepho)
- Indications
- COSMOS Trial ([MEDLINE]
- Study: multicenter, open-cohort, observational prospective study in 227 dialysis centers from 20 European countries (n = 6797)
- Main Findings
- Use of phosphate-binding agents -> 29% lower all-cause mortality
- Use of phosphate-binding agents -> 22% lower cardiovascular mortality
- All single and combined therapies with phosphate-binding agents (except aluminum salts) showed a beneficial association with survival
References
- K/DOQI clinical practice guidelines for nutrition in chronic kidney failure. K/DOQI, National Kidney Foundation. Am J Kidney Dis. 2000;35(6)(suppl 2):S17–S104
- The dialysis outcomes and practice patterns study (DOPPS): An international hemodialysis study. Kidney Int. 2000;57(suppl 74):S74–S81
- Mortality risk in hemodialysis patients and changes in nutritional indicators: DOPPS. Kidney Int. 2002;62:2238–2245
- Hidden sources of phosphorus in the typical American diet: does it matter in nephrology? Semin Dial. 2003;16(3):186–188
- K/DOQI clinical practice guidelines for bone metabolism and disease in chronic kidney disease. Am J Kid Dis. 2003;42(4):S1–S201
- Hidden phosphorus: where do we go from here? J Ren Nutr. 2007;17(4):e31–e36
- Is controlling phosphorous by decreasing dietary protein intake beneficial or harmful in persons with chronic kidney disease. Am J Clin Nutr. 2008;88:1511–1518
- Mortality risk for dialysis patients with different levels of serum calcium, phosphorus, and PTH: the Dialysis Outcomes and Practice Patterns Study (DOPPS). Am J Kidney Dis. 2008;52(3):519–530
- Understanding sources of dietary phosphorous in the treatment of patients with chronic kidney disease. Clin J Am Soc Nephrol. 2010;5:519–530
- Use of phosphate-binding agents is associated with lower risk of mortality. Kidney Int. Published online 3 July 2013; doi:10.1038/ki.2013.185 [MEDLINE]