Pathophysiology of calcium and phosphorus disorders

Hypocalcemia and hypophosphatemia are relatively common in periparturient cows. This article reviews the etiologic factors that contribute to the development of these conditions. The physiologic role of magnesium in calcium homeostasis and the physiologic effect of dietary cation-anion difference at the cellular level are discussed in depth. A theory to explain the development of periparturient hypophosphatemia is developed.

The refeeding syndrome and hypophosphatemia

The refeeding syndrome is an underappreciated entity characterized by acute electrolyte derangements--notably hypophosphatemia--that occur during nutritional repletion of patients with significant suboptimal caloric intake. Adverse effects of hypophosphatemia include cardiac failure, muscle weakness, immune dysfunction, and death. Hypokalemia and hypomagnesemia commonly complicate refeeding syndrome as well; however, this report briefly reviews the clinical manifestations of refeeding-induced hypophosphatemia.

The efficacy and safety comparison between tenofovir and entecavir in treatment of chronic hepatitis B and HBV related cirrhosis: A systematic review and Meta-analysis

BACKGROUND

The purpose of this study was to assess the efficacy and safety between tenofovir and entecavir in the treatment of CHB and HBV related cirrhosis through Meta-analysis. Methods The electronic databases of PubMed, the Cochrane Library, Nature, CNKI and WanFang data were searched. The key words were: ("tenofovir", "entecavir") and ("Chronic Hepatitis B" or "CHB") and "Liver cirrhosis". Heterogeneity and report bias were analyzed.

RESULTS

There was significant difference of ALT norm level in the short-term period of 3months (RR=1.43, 95%CI: 1.06-1.94, P<0.017) and 6months (RR=0.89, 95%CI: 0.81-0.97, P<0.017), and significant difference of undetectable HBV-DNA only in 3months follow-up period (RR=1.59, 95%CI: 1.04-2.42, P<0.017) between TDF and ETV, but no significant difference in the long-term period. There is significant difference between TDF and ETV in eGFR level (RR=1.601, 95%CI: 1.035-2.478, P=0.0034) and hypophosphatemia incidence (RR=4.008, 95%CI: 1.485-10.820, P=0.006).

CONCLUSION

TDF has a better efficacy than ETV in 3months treatment duration, but intriguingly, TDF might not better than ETV during the 6months treatment period in the viral suppression and liver function improvement. There's no significant difference between TDF and ETV in the long-term treatment duration and in the treatment of HBV related liver cirrhosis. Both TDF and ETV could influence renal function but patients under TDF therapy may have more risk to suffer from renal damage and hypophosphatemia.

Phosphate-containing dialysis solution prevents hypophosphatemia during continuous renal replacement therapy

BACKGROUND

hypophosphatemia occurs in up to 80% of the patients during continuous renal replacement therapy (CRRT). Phosphate supplementation is time-consuming and the phosphate level might be dangerously low before normophosphatemia is re-established. This study evaluated the possibility to prevent hypophosphatemia during CRRT treatment by using a new commercially available phosphate-containing dialysis fluid.

METHODS

forty-two heterogeneous intensive care unit patients, admitted between January 2007 and July 2008, undergoing hemodiafiltration, were treated with a new Gambro dialysis solution with 1.2 mM phosphate (Phoxilium) or with standard medical treatment (Hemosol B0). The patients were divided into three groups: group 1 (n=14) receiving standard medical treatment and intravenous phosphate supplementation as required, group 2 (n=14) receiving the phosphate solution as dialysate solution and Hemosol B0 as replacement solution and group 3 (n=14) receiving the phosphate-containing solution as both dialysate and replacement solutions.

RESULTS

standard medical treatment resulted in hypophosphatemia in 11 of 14 of the patients (group 1) compared with five of 14 in the patients receiving phosphate solution as the dialysate solution and Hemosol B0 as the replacement solution (group 2). Patients treated with the phosphate-containing dialysis solution (group 3) experienced stable serum phosphate levels throughout the study. Potassium, ionized calcium, magnesium, pH, pCO(2) and bicarbonate remained unchanged throughout the study.

CONCLUSION

the new phosphate-containing replacement and dialysis solution reduces the variability of serum phosphate levels during CRRT and eliminates the incidence of hypophosphatemia.

A comparison of clinically useful phosphorus binders for patients with chronic kidney failure

A comparison of clinically useful phosphorus binders for patients with chronic kidney failure. Over the past 30 years it has become apparent that hyperphosphatemia plays a major causative role across the entire spectrum of morbidity associated with advancing kidney dysfunction and failure. A large fraction (60% to 70%) of dietary phosphorus is absorbed and normally excreted by the kidneys. Ideally, as kidney function deteriorates, the net quantity of phosphorus absorbed from the GI tract should be proportionally reduced to match the decrease in kidney function. After initiation of chronic dialysis therapy, the absorbed phosphorus load should match the amount of phosphorus removed via dialysis plus any excreted by residual kidney function. Because it is very difficult to reduce dietary phosphorus to these levels, a variety of oral phosphorus binders have been employed. Currently available binders include alkaline aluminum, magnesium, and calcium salts (primarily calcium carbonate and calcium acetate), various iron salts, and the binding resin sevelamer hydrochloride. Lanthanum carbonate is the newest agent and will probably be released shortly. This review compares the theoretic and in vitro chemistry of these drugs with in vivo data obtained in both normal patients, and in patients with kidney failure. The clinical potency and potential toxicity of the binding agents are compared, and optimal drug administration strategies are also reviewed.

A New Graduated Dosing Regimen for Phosphorus Replacement in Patients Receiving Nutrition Support

BACKGROUND

Hypophosphatemia is a common metabolic complication in patients receiving specialized nutrition support. We changed our previously reported dosing algorithm because the low dose no longer appeared to be effective at increasing serum phosphorus concentrations. The purpose of this study was to evaluate the safety and efficacy of a revised weight-based phosphorus-dosing algorithm in critically ill trauma patients receiving specialized nutrition support.

METHODS

Seventy-nine adult trauma patients with hypophosphatemia (serum phosphorus concentration < or = 0.96 mmol/L) receiving nutrition support received an IV dose of phosphorus on day 1 according to the serum concentration of phosphorus: 0.73-0.96 mmol/L (0.32 mmol/kg, low dose), 0.51-0.72 mmol/L (0.64 mmol/kg, moderate dose), and < or = 0.5 mmol/L (1 mmol/kg, high dose). The IV phosphorus bolus dose was administered at 7.5 mmol/hour. Generally, patients with a serum potassium concentration <4 mmol/L received potassium phosphate and patients with a serum potassium concentration > or = 4 mmol/L received sodium phosphate. Patients who still had hypophosphatemia on day 2 were dosed using the new dosing algorithm by the nutrition support service according to that day's serum concentration of phosphorus, or empirically by the trauma service.

RESULTS

Of the 79 patients studied, 57 were male and 22 were female with a mean age of 44.8 +/- 20.6 years. Mean Injury Severity Scores and APACHE-II scores were 27.1 +/- 11.6 and 15.2 +/- 6.8, respectively. There was no difference in baseline characteristics among the 3 dosing groups. Of the 79 patients, 34 received the low dose, 30 received the moderate dose, and 15 received the high dose of phosphorous. Mean serum phosphorous concentrations on day 2 were significantly increased in the moderate-dosed group (0.64 +/- 0.06 to 0.77 +/- 0.22 mmol/L, p < .05) and high-dosed group (0.38 +/- 0.06 to 0.93 +/- 0.32 mmol/L, p < .01), respectively, when compared with day 1. Mean serum phosphorus concentrations were normal in all 3 groups on day 3. Serum concentrations of magnesium, sodium, and potassium, as well as arterial pH, were stable across the study. Mean concentrations of ionized calcium were not significantly different in any of the 3 dosing groups across the study period.

CONCLUSIONS

This weight-based phosphorus-dosing algorithm is safe for use in critically ill patients receiving nutrition support. The moderate and severe-dose regimens effectively increase serum phosphorus concentrations.

Metabolic complications of total parenteral nutrition: effects of a nutrition support service

BACKGROUND

The effectiveness of Nutrition Support Services in optimizing parenteral nutrition has not been evaluated since the 1980s.

METHODS

We prospectively monitored medical and surgical patients on total parenteral nutrition (TPN) in a university hospital who did not receive Nutrition Support Service recommendations to compare the incidence of metabolic complications in 1979 (group 1, n = 100) with that in 1992 (group 2, n = 106). The Service provided automatic recommendations on a subsequent group of medical service patients (group 3, n = 128) and compared them with the patients in group 2 who were on the medical service (group 2B, n = 29).

RESULTS

Statistically significant changes between 1979 and 1992 included a decline in the incidence of hyperglycemia from 47% to 22% and in hypokalemia from 12% to 3% of surgical patients and an increase in hypomagnesemia from 0% to 23% of surgical patients and from 2% to 14% of medical patients. The incidence of hypophosphatemia remained > 20% in both medical and surgical patients. Within 1992, the addition of automatic recommendations had little impact on metabolic abnormalities and was associated with slightly but insignificantly lower TPN costs (not counting Service personnel costs).

CONCLUSIONS

Factors such as the general integration of parenteral nutrition into tertiary medical care, standard protocols and order forms, automatic Nutrition Support Service consultations in an affiliated hospital, and nutrition curricula may be responsible for the improvements seen since 1979. However, the addition of automatic Service consultation in 1992 had only a marginal effect on metabolic complications and costs of parenteral nutrition.

A comparison of renal phosphorus regulation in thermally injured and multiple trauma patients receiving specialized nutrition support

To compare phosphorus intake and renal phosphorus regulation between thermally injured patients and multiple trauma patients, 40 consecutive critically ill patients, 20 with thermal injury and 20 with multiple trauma, who required enteral tube feeding were evaluated. Phosphorus intakes were recorded for 14 days from the initiation of tube feeding which was started 1 to 3 days postinjury. Serum for determination of phosphorus concentrations was collected at days 1, 3, 7, and 14 of the study period. A 24-hour urine collection was obtained during the first and second weeks of nutrition support for urinary phosphorus excretion, fractional excretion of phosphorus, renal threshold phosphate concentration, and phosphorus clearance. Average total daily phosphorus intake during the 14-day study for thermally injured patients and multiple trauma patients was 0.99+/-0.26 mmol/kg/d vs 0.58+/-0.21 mmol/kg/d, respectively, p < .001. Serum phosphorus concentration on the third day of observation was significantly lower in the thermally injured group than those with multiple trauma (1.9+/-0.8 mg/dL vs 3.0+/-0.8 mg/dL, p < or = .01). A trend toward hypophosphatemia in the thermally injured group persisted by the seventh day of feeding (2.7+/-1.2 mg/dL vs 3.3+/-0.6 mg/dL, p < or = .04). Differences in urinary phosphorus excretion was not statistically significant between the thermally injured and multiple trauma groups (271+/-213 mg/d vs 171+/-181 mg/d for week 1, and 320+/-289 mg/d vs 258+/-184 mg/d for week 2, respectively). Urinary phosphorus clearance, fractional excretion of phosphorus, or renal threshold phosphate concentrations were also not significantly different between thermally injured and multiple trauma patients. During nutrition support, serum phosphorus concentrations are lower in thermally injured patients compared with multiple trauma patients despite receiving a significantly greater intake of phosphorus. Renal phosphorus regulation does not significantly contribute to the profound hypophosphatemia observed in thermally injured patients when compared with multiple trauma patients during nutrition support.

Enteral supplementation of phosphate does not prevent hypophosphatemia during refeeding of cachectic patients

Hypophosphatemia due to parenteral nutrition has been described frequently. It was attributed to the lack of phosphorus content in parenteral nutrition solutions. With modern parenteral nutrition regimens containing phosphorus, this problem has been virtually eliminated. Enteral nutrition solutions contain adequate phosphate for patients with normal phosphate stores. Hypophosphatemia has therefore rarely been reported in enteral nutrition. We describe two patients with protein-energy malnutrition who developed severe hypophosphatemia during tube feeding with phosphorus-containing formula diets. Chronic alcoholism and vitamin D deficiency due to malabsorption because of Crohn's disease were additional risk factors in these two patients. Patients with depleted phosphate stores and high metabolic demand have a higher daily requirement for phosphorus than is available in routine isotonic enteral formulas. This case report emphasizes the importance of monitoring serum phosphate concentration daily during the first week of refeeding.

Refeeding syndrome in cancer patients

BACKGROUND

Refeeding syndrome (RFS) is a common, yet underappreciated, constellation of electrolyte derangements that typically occurs in acutely ill, malnourished hospitalised patients who are administered glucose solutions or other forms of intravenous or enteral nutrition.

DISCUSSION

The hallmark of RFS is hypophosphataemia, but hypokalaemia and hypomagnesaemia are also common. Patients with various types of malignancies are at-risk for RFS, but very little exists in the oncologic literature about this disorder.

CONCLUSIONS

As RFS can have many adverse metabolic, cardiovascular, haematologic and neurologic complications, practicing oncologist needs to be aware of the pathophysiology, risk factors and clinical manifestations to promptly recognise this important, and potentially fatal, metabolic disorder.

The Role of Phosphate in Alcohol-Induced Experimental Pancreatitis

BACKGROUND & AIMS

Heavy alcohol consumption is a common cause of acute pancreatitis; however, alcohol abuse does not always result in clinical pancreatitis. As a consequence, the factors responsible for alcohol-induced pancreatitis are not well understood. In experimental animals, it has been difficult to produce pancreatitis with alcohol. Clinically, alcohol use predisposes to hypophosphatemia, and hypophosphatemia has been observed in some patients with acute pancreatitis. Because of abundant protein synthesis, the pancreas has high metabolic demands, and reduced mitochondrial function leads to organelle dysfunction and pancreatitis. We proposed, therefore, that phosphate deficiency might limit adenosine triphosphate synthesis and thereby contribute to alcohol-induced pancreatitis.

METHODS

Mice were fed a low-phosphate diet (LPD) before orogastric administration of ethanol. Direct effects of phosphate and ethanol were evaluated in vitro in isolated mouse pancreatic acini.

RESULTS

LPD reduced serum phosphate levels. Intragastric administration of ethanol to animals maintained on an LPD caused severe pancreatitis that was ameliorated by phosphate repletion. In pancreatic acinar cells, low-phosphate conditions increased susceptibility to ethanol-induced cellular dysfunction through decreased bioenergetic stores, specifically affecting total cellular adenosine triphosphate and mitochondrial function. Phosphate supplementation prevented ethanol-associated cellular injury.

CONCLUSIONS

Phosphate status plays a critical role in predisposition to and protection from alcohol-induced acinar cell dysfunction and the development of acute alcohol-induced pancreatitis. This finding may explain why pancreatitis develops in only some individuals with heavy alcohol use and suggests a potential novel therapeutic approach to pancreatitis. Finally, an LPD plus ethanol provides a new model for studying alcohol-associated pancreatic injury.

Raising plasma phosphorus levels by phosphorus-enriched, bicarbonate-containing dialysate in hemodialysis patients

In 6 hemodialysis patients, enriching the "base concentrate" of a bicarbonate-containing dialysate-generating system with phosphorus succeeded in raising plasma phosphorus levels.

Phosphorus-enriched hemodialysis for the treatment of patients with severe methanol intoxication

Severe methanol poisoning requires treatment with prolonged and intensive hemodialytic therapy. Such treatment can engender either the de novo development of hypophosphatemia or the worsening of pre-existing hypophosphatemia. Phosphorus-enriched hemodialysis therapy can prevent the occurrence of this complication. We report three patients with severe methanol poisoning who were treated with phosphorus-enriched hemodialysis. Prevention or treatment of hypophosphatemia was successfully achieved with this dialytic technique.

Cost reduction strategies in burn nutrition services: adjustments in dietary treatment of patients with hyponatremia and hypophosphatemia

Two clinically effective adjustments in diet therapy were tested at a burn center as strategies to lower clinical care costs. The use of adult enteral formulas for pediatric burn patients reduced the incidence of hyponatremia and the need for costly sodium supplements. The prophylactic administration of oral phosphate during the first days of hospitalization may lessen the decline in serum phosphate and save costs for the treatment of hypophosphatemia of severely burned patients.

Hypophosphatemia and refeeding: a corrective or a preventive attitude?

Hypophosphatemia is a rare but potentially lethal complication of the refeeding of cachectic patients. Up until now a careful monitoring of the serum phosphor level was recommended and the deficit was corrected as needed. Illustrated by two case reports we propose the use of a preventive schedule in patients with a normal renal function. We show that preventively treated patients do not develop hypophosphatemia and thereby avoid serious complications such as sudden death. In the presence of normal kidney function we propose to administer phosphor at 2 x 10 mmol/day orally or between 10 and 30 mmol IV depending on the initial phosphor levels. Further treatment is then adapted to measured levels. In the presence of kidney malfunction we propose to keep the corrective schedule.

Prophylactic supplementation of phosphate, magnesium, and potassium for the prevention of refeeding syndrome in hospitalized individuals with anorexia nervosa

Medical stabilization, nutrition rehabilitation, and weight restoration, while minimizing risk for the potentially fatal complication of refeeding syndrome, are the primary goals for the treatment of hospitalized individuals with anorexia nervosa and other restrictive-type eating disorders. The purpose of this review was to examine the literature exploring the prophylactic supplementation of phosphate, magnesium, and potassium, in addition to routine thiamin and multivitamin supplementation, for the prevention of refeeding syndrome in adolescents and adults with anorexia nervosa. Through evaluation of outcomes (including serum electrolyte levels and clinical signs and symptoms such as respiratory failure, cardiac failure, peripheral edema, rhabdomyolysis, and encephalopathy), three studies found that prophylactic supplementation of potassium, magnesium, and/or phosphate were effective in preventing refeeding syndrome or refeeding hypophosphatemia (a characteristic of refeeding syndrome). Although all studies found that prophylactic supplementation was effective in preventing refeeding syndrome, refeeding approaches (including the method, amount, and duration of nutrient delivery) as well as the populations studied varied considerably, making it difficult to arrive at specific recommendations for practice. Randomized controlled trials are needed to further examine the safety and effectiveness of prophylactic supplementation of phosphate, magnesium, and potassium on the prevention of refeeding syndrome, utilizing similar feeding and supplementation protocols.

Corn-Soy-Blend Fortified with Phosphorus to Prevent Refeeding Hypophosphatemia in Undernourished Piglets

BACKGROUND

Phosphorus (P) levels in refeeding diets are very important as undernourished children are at risk of hypophosphatemia during refeeding. For this reason, conventional corn-soy-blends (CSB) have been reformulated by the World Food Programme to obtain a mono-calcium-phosphate fortified product (CSB+) and a product further fortified with skim milk powder (CBS++).

METHODS

Using a piglet model of undernourished children, we hypothesized that feeding of CSB+, CSB++ or CSB+ with added whey permeate (CSB+/wp) would help to prevent refeeding hypophosphatemia. Pigs were weaned at 4 weeks of age and undernutrition was induced with a nutritionally inadequate pure maize diet for 7 weeks, after which they were refed for 3 weeks with either CSB+ (n = 10), CSB++ (n = 10) or CSB+/wp (n = 10). For reference, a fourth group continued on the maize diet (REF, n = 10).

RESULTS

Following induction of undernutrition, body weight and length were 29±5% and 67±4% (means±SD) of values in age-matched pigs fed a nutritionally adequate diet, and the mean serum P level was 1.77±0.34 mmol/l. During the first week of refeeding, P levels in the CSB+ pigs decreased to 55% of values before refeeding (P < 0.05) while values in the CSB++ and CSB+/wp pigs were able to maintain their plasma phosphate at a similar level as before refeeding.

CONCLUSION

We conclude that fortification of CSB with only monocalcium-phosphate does not prevent hypophosphatemia. Dairy products like skim milk powder or whey permeate may represent relevant sources of phosphorus during refeeding. The content and form of phosphorus in such diets need to be carefully evaluated, and the undernourished piglet may be used to test the efficacy of such diets.

Hypophosphatemia in postoperative patients with total parenteral nutrition: influence of nutritional support teams

PURPOSE, SETTING AND SUBJECTS: We conducted a prospective, descriptive study of postoperative patients under total parenteral nutrition controlled by a Multidisciplinary Nutritional Support Team in a tertiary care hospital. Between january 2002 and november 2003. Data of nutritional status, nutritional support, hypophosphatemia, electrolyte and metabolic complications were reviewed.

RESULTS

215 postoperative patients (63.3% male, 68 +/- 13.9 years old, 47.4% neoplasia). were included. Nutritional support according nutritional needs was made during fasting 14.2 +/- 18.4 days. Mild-moderate initial malnutrition was present in 58% of patients. 18.1% developed postoperative hypophosphatemia 96 hours after starting total parenteral nutrition containing phosphate. 37.7% patients showed moderated and 6.5% severe hypophosphatemia. Nutritional intervention corrected hypophosphatemia (p < 0.001). Factors related to hypophosphatemia were hypokalemia, hypomagnesemia, hypercalcemia, female sex, neoplasia, 96-hour postoperative period and duration of nutrition.

CONCLUSIONS

Prevalence of hypophosphatemia in postoperative patients with total parenteral nutrition is high and needs timely monitoring. The intervention of Multidisciplinary Nutritional Support Team is effective detecting and correcting postoperative hypophosphatemia.

[Hypophosphatemia in parenteral nutrition: prevention and associated risks factors]

AIM

To determine the incidence of hypophosphatemia in parenterally fed patients, the phosphate amount necessary to prevent this complication and associated risks factors.

SETTING

Observational study, not controlled, in a third level hospital.

PATIENTS

In-patients with parenteral nutrition with at least a complete laboratory work-up.

INTERVENTION

For a complete year, days on parenteral nutrition, administered phosphate and plasmatic ionised calcium levels, y-glutamiltranspeptidase, glucose, phosphate, pre-albumin, urea, and leukocytes were recorded. A multiple stepwise regression analysis and logistic regression are used for data analysis.

RESULTS

Eight hundred and twenty seven determinations, corresponding to 401 patients, were included. Significant variables (p < 0.05) were: administered phosphate and ionised calcium serum levels, glucose, pre-albumin, and urea; regression coefficients were 0.004 (95%CI: 0.002 to 0.006), -0.156 (95%CI: -0.270 to 0.037), -0.014 (95%IC: -0.022 to 0.009), 0.005 (95%CI: 0.002 to 0.009) and 0.019 (95%CI: 0.016 to 0.022), respectively; the constant was 1.0735 (95%CI: 0.939 to 1.2079). The risk for developing hypophosphatemia decreased from 0.65 (95%CI: 0.33 to 1.26) to 0.16 (95%CI: 0.078 to 0.35) when administered phosphate varied from the span 7.5-17.5 mmol to values higher than 27.5 mmol.

CONCLUSIONS

It is necessary to routinely supplement nutrition with phosphate since its content in commercially available lipidic emulsions is not sufficient to prevent hypophosphatemia in the majority of patients with parenteral nutrition. Phosphate intake must be sufficient to restore the intracellular phosphate deficit and to compensate for the plasmatic phosphate fall, with special attention to poorly nourished, hyperglycaemic or with renal failure patients. Phosphate intakes around 27-37 mmol dramatically decrease the incidence of hypophosphatemia in studied patients, with no recorded cases of severe hypophosphatemia.

Refeeding syndrome

Refeeding syndrome can occur when nutrition is reinstituted in a starved patient and, if abnormalities are not corrected, can be lethal. This article describes metabolic adaptations to starvation, risk factors for the development of refeeding syndrome, and causes as well as symptoms of refeeding syndrome. Adverse consequences of hypophosphatemia, hypomagnesemia, and hypokalemia are described. Nursing implications to prevent refeeding syndrome are outlined.

Ferric carboxymaltose with or without phosphate substitution in iron deficiency or iron deficiency anemia before elective surgery - The DeFICIT trial

BACKGROUND

Iron deficiency anemia in the perioperative setting is treated predominantly with intravenous iron formulation, of which ferric carboxymaltose may induce hypophosphatemia by modulating fibroblast growth factor 23.

METHODS

In this single-center, prospective, randomized, double-blind trial, we consented 92 adult patients scheduled for elective major abdominal or thoracic surgery. These patients either had isolated iron deficiency (plasma ferritin <100 ng/mL or transferrin saturation < 20 %) or iron deficiency anemia (hemoglobin (Hb) 100-130 g/L with plasma ferritin <100 ng/mL or transferrin saturation < 20 %). Preoperatively, participants received a single preoperative intravenous dose of ferric carboxymaltose and were then randomly assigned to receive either phosphate or placebo, administered orally three times a day for 30 days corresponding to an 18 mmol dose of daily phosphate supplementation in the intervention group. The primary endpoint was the minimum serum phosphate concentration during follow-up visits. The key secondary efficacy endpoint was mean perioperative hemoglobin concentration of postoperative days 0, 2 and 4, assessing the non-inferiority of additional phosphate supplementation.

RESULTS

We randomly consented 46 patients in each group (mean ± SD age 56 ± 17 years, 57 % female). Minimal phosphate concentration was 0.49 ± 0.21 mmol/L in the treatment group and 0.42 ± 0.17 mmol/L in the placebo group (p = 0.12, two-sided p-value). Average mean hemoglobin was 110 ± 16 g/L in the treatment and 113 ± 13 g/L in the placebo group (p = 0.023, one-sided p-value for non-inferiority). Hypophosphatemia occurred in 32 patients (70 %) of the treatment group and in 39 patients (85 %) of the placebo group (odds ratio 0.15, 95 % CI from 0.02 to 0.77, p = 0.014). Secondary outcomes, such as rescue medication use, core muscle strength and MOCA test scores, did not differ between groups.

CONCLUSION

Co-administration of oral phosphate supplementation to ferric carboxymaltose cannot prevent hypophosphatemia. However, hypophosphatemia occurs in fewer patients. Phosphate co-administration did not impede the treatment of iron deficiency anemia with ferric carboxymaltose.

Refeeding syndrome: an important aspect of supportive oncology

Refeeding syndrome (RFS) is an underappreciated, yet common and potentially dangerous, constellation of metabolic derangements that can occur upon reinstitution of any type of nutritional intervention. The typical patient who experiences RFS has been malnourished for days to weeks and develops hypophosphatemia and, occasionally, hypokalemia and hypomagnesemia when administered a carbohydrate load in the form of glucose-containing fluids, total parenteral nutrition (TPN), tube feedings, or an oral diet. The pathophysiology of RFS is complex but mainly results from an acute intracellular shift in electrolytes, increased phosphate demand during tissue anabolism, and formation of high-energy phosphate bonds. Potential complications of RFS include fatal cardiac arrhythmia, systolic heart failure, respiratory insufficiency, and hematologic derangements. Because supportive care of the cancer patient often involves nutritional and metabolic support, any clinician involved with providing acute or palliative oncologic care should be familiar with the risks, manifestations, and treatment of RFS.