Association of Serum Phosphorus Concentration with Mortality and Graft Failure among Kidney Transplant Recipients

[Pattern of biochemical markers of mineral and bone disorders in kidney transplant recipients: real-world data]

BACKGROUND

There is a lack of studies providing comprehensive data on the prevalence of mineral and bone disorders (MBD) laboratory abnormalities after kidney transplantation in Russia.

AIM

to obtain real-world data on the prevalence of the main mineral abnormalities among kidney transplant recipients and to revise their concomitant MBD therapy.

METHOD

This cross-sectional study included 236 patients with successful kidney transplantation. Their serum intact parathyroid hormone (iPTH), total calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP) levels were measured.

RESULTS

Only 6.2% of our cohort had all laboratory parameters within the target range, whereas persistent HPT along with hypercalcemia was noted in almost one third of the patients (31%). Normal iPTH levels were observed in 13% cases; 84% of the patients had hyperparathyroidism. The fraction of patients with target iPTH did not differ between the groups with normal and decreased estimated glomerular filtration rate (eGFR) (p=0.118). Hypercalcemia was observed in 29% cases. The serum P level varied significantly in groups with different eGFR (p<0.0001), increasing with declining graft function. Furthermore, 40.7% of patients had ALP above the target range. While 123 patients received active vitamin D (alfacalcidol), 33 received monotherapy with inactive vitamin D (cholecalciferol). The control group consisted of 57 medication-naïve patients. The serum total Ca level varied significantly between the groups (p=0.0006), being higher in patients supplemented with cholecalciferol. The fraction of patients with normocalcemia was lowest in the cholecalciferol group (chi-square, р=0.0018).

CONCLUSION

The prevalence of biochemical abnormalities after kidney transplantation is high. Alfacalcidol usage may be safer than using cholecalciferol to prevent hypercalcemia development.

Clinical factors associated with severe hypophosphataemia after kidney transplant

BACKGROUND

The mechanism by which hypophosphataemia develops following kidney transplantation remains debated, and limited research is available regarding risk factors. This study aimed to assess the association between recipient and donor variables, and the severity of post-transplantation hypophosphataemia.

METHODS

We performed a single-centre retrospective observational study. We assessed the association between demographic, clinical and biochemical variables and the development of hypophosphataemia. We used linear regression analysis to assess association between these variables and phosphate nadir.

RESULTS

87.6% of patients developed hypophosphataemia. Patients developing hypophosphataemia were younger, had a shorter time on renal replacement therapy, were less likely to have had a parathyroidectomy or to experience delayed graft function, were more likely to have received a living donor transplant, from a younger donor. They had higher pre-transplantation calcium levels, and lower alkaline phosphatase levels. Receipt of a living donor transplant, lower donor age, not having had a parathyroidectomy, receiving a transplant during the era of tacrolimus-based immunosuppression, not having delayed graft function, higher pre-transplantation calcium, and higher pre-transplantation phosphate were associated with lower phosphate nadir by multiple linear regression.

CONCLUSIONS

This analysis demonstrates an association between variables relating to better graft function and hypophosphataemia. The links with biochemical measures of mineral-bone disease remain less clear.

Machine Learning Approach Using Routine Immediate Postoperative Laboratory Values for Predicting Postoperative Mortality

Background: Several prediction models have been proposed for preoperative risk stratification for mortality. However, few studies have investigated postoperative risk factors, which have a significant influence on survival after surgery. This study aimed to develop prediction models using routine immediate postoperative laboratory values for predicting postoperative mortality. Methods: Two tertiary hospital databases were used in this research: one for model development and another for external validation of the resulting models. The following algorithms were utilized for model development: LASSO logistic regression, random forest, deep neural network, and XGBoost. We built the models on the lab values from immediate postoperative blood tests and compared them with the SASA scoring system to demonstrate their efficacy. Results: There were 3817 patients who had immediate postoperative blood test values. All models trained on immediate postoperative lab values outperformed the SASA model. Furthermore, the developed random forest model had the best AUROC of 0.82 and AUPRC of 0.13, and the phosphorus level contributed the most to the random forest model. Conclusions: Machine learning models trained on routine immediate postoperative laboratory values outperformed previously published approaches in predicting 30-day postoperative mortality, indicating that they may be beneficial in identifying patients at increased risk of postoperative death.

Mediterranean Diet Adherence and Nutritional Status in Dalmatian Kidney Transplant Recipients-Are They Related?

The aim of this study was to evaluate adherence to Mediterranean diet (MeDi) and possible correlation of MeDi adherence and nutritional status parameters in Dalmatian kidney transplant recipients (KTRs). One hundred and sixteen KTRs were included in this study. Data about Mediterranean Diet Serving Score (MDSS), body mass composition, anthropometric parameters, clinical and laboratory parameters were collected for each study participant. The results showed 25% adherence to the MeDi in Dalmatian KTRs. MDSS showed association with higher serum albumin and phosphorus level and higher skeletal muscle mass. Also, significant association between diabetic status and MDSS was found. Adherence to olive oil intake suggested by the MeDi showed significant association with lower level of triglycerides and adherence to nuts suggestions was associated with lower level of fat mass. Following MeDi recommendations for consumption of other foods (cereals, potato, eggs, vegetables, fruits and dairy) were also associated with body mass composition parameters and laboratory findings. In conclusion, low adherence to the MeDi in Dalmatian KTRs raises high concerns. The results showed that MeDi can have favorable effects on nutritional status in KTRs. A structured nutritional approach is needed to enhance adherence to the MeDi and prevent possible adverse effects in this patient population.

Defining a minimal clinically meaningful difference in 12-month estimated glomerular filtration rate for clinical trials in deceased donor kidney transplantation

BACKGROUND

A Minimal Clinically Meaningful Difference (MCMD) has not been defined for Estimated glomerular filtration rate (eGFR). Our goal was to define the MCMD for eGFR anchored to kidney graft failure.

METHODS

A systematic review of studies with 12-month eGFR and subsequent renal graft failure was conducted. For observational studies, we calculated hazard ratio (HR) differences between adjacent eGFR intervals weighted by population distribution. Interventional trials yielded therapeutically induced changes in eGFR and failure risk. OPTN data analysis divided 12-month eGFR into bands for Cox regressions comparing adjacent eGFR bands with a death-censored graft survival outcome.

RESULTS

Observational studies indicated that lower eGFR was associated with increased death-censored graft failure risk; each 5 ml/min/1.73 m2 12-month eGFR band associated with a weighted incremental HR = 1.12 to 1.23. Clinical trial data found a 5 ml/min/1.73 m2 difference was associated with incremental HR = 1.16 to 1.35. OPTN analyses showed weighted mean HRs across 10, 7, and 5 ml/min/1.73 m2 bands of 1.47, 1.30, and 1.19.

CONCLUSIONS

A 5 ml/min/1.73 m2 difference in 12-month eGFR was consistently associated with ~20% increase in death-censored graft failure risk. The magnitude of effect has been interpreted as clinically meaningful in other disease states and should be considered the MCMD in renal transplantation clinical trials.

A Narrative Review of Dietary Approaches for Kidney Transplant Patients

A healthy eating pattern has proven to lower the risk of metabolic and cardiovascular diseases. However, there are sparse dietary recommendations for kidney transplant recipients, and the ones available focus only on single nutrients intake, such as sodium, potassium, and proteins, and not on the overall eating pattern. Considering that individuals do not typically consume nutrients in isolation, but as part of a complete dietary pattern, it is challenging for the average transplanted patient to understand and implement specific dietary recommendations. Also, single-nutrient interventions demonstrate largely inconclusive effects, and it seems improbable that they could have a strong enough impact on transplant outcomes. Dietary trends such as plant-based diets, intermittent fasting, low-carb diet/keto-diet, and juicing, have gained major attention from the media. Herein, we review the potential risks and benefits of these diets in kidney transplant recipients and provide an updated dietary recommendation for this population with consideration of current nutritional trends. Overall, the Mediterranean and DASH diets have demonstrated to be the most beneficial dietary patterns to the post kidney transplant population by focusing on less meat and processed foods, while increasing the intake of fresh foods and plant-based choices. We believe that to maintain a healthy lifestyle posttransplant, patients should be educated about the scientific evidence of different diets and choose a dietary pattern that is sustainable long-term.

Optimizing Diet to Slow CKD Progression

Due to the unique role of the kidney in the metabolism of nutrients, patients with chronic kidney disease (CKD) lose the ability to excrete solutes and maintain homeostasis. Nutrient intake modifications and monitoring of nutritional status in this population becomes critical, since it can affect important health outcomes, including progression to kidney failure, quality of life, morbidity, and mortality. Although there are multiple hemodynamic and metabolic factors involved in the progression and prognosis of CKD, nutritional interventions are a central component of the care of patients with non-dialysis CKD (ND-CKD) and of the prevention of overweight and possible protein energy-wasting. Here, we review the reno-protective effects of diet in adults with ND-CKD stages 3-5, including transplant patients.

Long-term outcomes after kidney transplant failure and variables related to risk of death and probability of retransplant: Results from a single-center cohort study in Brazil

Background

Returning to dialysis after kidney graft loss (GL) is associated with a high risk of mortality, mainly in the first 3–6 months. The follow-up of patients with GL should be extended to better understand crude patient outcomes, mainly in emerging countries, where the transplantation activity has increased.

Methods

This is a historical single-center cohort study conducted in an emerging country (Brazil) that included 115 transplant patients with kidney allograft failure who were followed for 44.1 (21.4; 72.6) months after GL. The outcomes were death or retransplantation after GL calculated by Kaplan-Meier and log-rank tests. Proportional hazard ratios for death and retransplantation were assessed by Cox regression.

Results

The 5-year probability of retransplantation was 38.7% (95% CI: 26.1%-51.2%) and that of death was 37.7% (95% CI: 24.9%-50.5%); OR = 1.03 (95% CI: 0.71–1.70) and P = 0.66. The likelihood of retransplantation was higher in patients who resumed dialysis with higher levels of hemoglobin (HR = 1.22; 95% CI = 1.04–1.43; P = 0.01) and lower in blood type O patients (HR = 0.48; 95% CI = 0.25–0.93; P = 0.03), which was associated with a lower frequency of retransplantation with a subsequent living-donor kidney. On the other hand, the risk of death was significantly associated with Charlson comorbidity index (HR for each point = 1.37; 95% CI 1.19–1.50; P<0.001), and residual eGFR at the time when patients had resumed to dialysis (HR for each mL = 1.14; 95% CI = 1.05–1.25; P = 0.002). The trend toward a lower risk of death when patients had resumed to dialysis using AV fistula access was observed (HR = 0.50; 95% CI 0.25–1.02; P = 0.06), while a higher risk seems to be associated with the number of previous engraftment (HR = 2.01; 95% CI 0.99–4.07; P = 0.05).

Conclusions

The 5-year probability of retransplantation was not less than that of death. Variables related to the probability of retransplantation were hemoglobin level before resuming dialysis and ABO blood type, while the risk of death was associated with comorbidities and residual eGFR.

The Relationship Between Simple Renal Cysts and Renal Function in Patients With Type 2 Diabetes

Introduction: Simple renal cysts (SRCs) are the most common acquired cystic kidney disease, but the relationship between SRCs and renal function has not been clarified in patients with type 2 diabetes mellitus (T2DM).

Methods: A retrospective study was conducted to analyze the clinical features of renal cysts and ultrasound data of the kidney in 4,304 patients with T2DM.

Results: The prevalence of SRCs in patients with T2DM was 21.1%. Compared to patients with no SRCs, patients with SRCs had worse renal function (estimated glomerular filtration rate: 108.65 ± 40.93 vs. 92.38 ± 42.1 ml/min/1.73 m², p < 0.05). After adjusting the confounders, SRC was related to estimated glomerular filtration rate in patients with T2DM [odds ratio = 1.49, 95% confidence interval (1.24, 1.79), p < 0.01]. Age, gout, proteinuria, cerebrovascular disease (CVD), and increased serum phosphorus levels were associated with SRCs in patients with T2DM.

Conclusion: SRCs are associated with worse renal function in patients with T2DM. More attention should be paid to gout, proteinuria, CVD, serum phosphorus levels, and renal function in T2DM patients with SRCs.

Serum phosphate levels modify the impact of parathyroid hormone levels on renal outcomes in kidney transplant recipients

Separate assessment of mineral bone disorder (MBD) parameters including calcium, phosphate, parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D (1,25D) predict renal outcomes in kidney transplant recipients (KTRs), with conflicting results. To date, data simultaneously evaluating these parameters and interwoven relations on renal outcomes are scarce. We conducted a prospective long-term follow-up cohort study included 263 KTRs with grafts functioning at least 1 year after transplantation. The outcome was a composite of estimated GFR halving and graft loss. Cox regression analyses were employed to evaluate associations between a panel of six MBD parameters and renal outcomes. The outcome occurred in 98 KTRs during a median follow-up of 10.7 years. In a multivariate Cox analysis, intact PTH (iPTH), phosphate, and 1,25D levels were associated with the outcome (hazard ratio, 1.60 per log scale; 95% confidence interval, 1.19–2.14, 1.60 per mg/dL; 1.14–2.23 and 0.82 per 10 pg/mL; 0.68–0.99, respectively). Competing risk analysis with death as a competing event yielded a similar result. After stratification into four groups by iPTH and phosphate medians, high risks associated with high iPTH was not observed in KTRs with low phosphate levels (P-interaction < 0.1). Only KTRs not receiving active vitamin D, poor 1,25D status predicted the worse outcome (P-interaction < 0.1). High iPTH, phosphate, and low 1,25D, but not FGF23, levels predicted poor renal outcomes. Simultaneous evaluation of PTH and phosphate levels may provide additional information regarding renal allograft prognosis.

Nutrition Trends in Patients Over the Long Term After Kidney Transplantation

OBJECTIVES

Nutritional behaviors may exert important influence on morbidity and graft function in patients after kidney transplantation (KT). Nutritional status is closely related to potential risk factors of developing posttransplant complications, including diabetes mellitus, weight gain, and negative effects on immunosuppressive therapy. The aim of this study was to assess the dietary intake in patients after KT.

DESIGN AND METHODS

Nutritional intake of 154 (61 women and 93 men) patients was assessed based on a questionnaire regarding food intake (proteins, fats, carbohydrates, cholesterol, sugar, phosphorus, calorific value) within 3 working days preceding the routine outpatient posttransplant visit. Patient medical history, concomitant medications, and estimated glomerular filtration rate (eGFR) was obtained from medical charts.

RESULTS

The mean age (years) ± SD of patients was 51.9 ± 14.1. The patients were evaluated 94 ± 67 months after KT, with a median eGFR of 53 (range, 41.2-64.1) mL/min/1.73 m². Sixty-two percent of patients had increased body mass index values. The mean total energy intake was 2159.4 ± 551.9 kcal/day. The patients reported elevated salt (8.5 ± 2.4 g per day) and fat intake (99.4 ± 3.2 g per day) including 57% saturated fatty acids. The patients consumed products containing high amounts of sugars (108.2 ± 107.0 g per day), carbohydrates (238.3 ± 64.3 g per day), and cholesterol (303.6 ± 11.1 mg per day). The diet among kidney recipients consisted predominantly of fats, meat, cured meat, and sweets.

CONCLUSIONS

The nutritional behaviors of patients after KT are in most cases poor. Improvement of eating habits in these patients seems to be a simple method to preserve kidney function over the long term.

Calcium and phosphate levels after kidney transplantation and long-term patient and allograft survival

Background

Non-traditional cardiovascular risk factors, including calcium and phosphate derangement, may play a role in mortality in renal transplant. The data regarding this effect are conflicting. Our aim was to assess the impact of calcium and phosphate derangements in the first 90 days post-transplant on allograft and recipient outcomes.

Methods

We performed a retrospective cohort review of all-adult, first renal transplants in the Republic of Ireland between 1999 and 2015. We divided patients into tertiles based on serum phosphate and calcium levels post-transplant. We assessed their effect on death-censored graft survival and all-cause mortality. We used Stata for statistical analysis and did survival analysis and spline curves to assess the association.

Results

We included 1525 renal transplant recipients. Of the total, 86.3% had hypophosphataemia and 36.1% hypercalcaemia. Patients in the lowest phosphate tertile were younger, more likely female, had lower weight, more time on dialysis, received a kidney from a younger donor, had less delayed graft function and better transplant function compared with other tertiles. Patients in the highest calcium tertile were younger, more likely male, had higher body mass index, more time on dialysis and better transplant function. Adjusting for differences between groups, we were unable to show any difference in death-censored graft failure [phosphate = 1.14, 95% confidence interval (CI) 0.92–1.41; calcium = 0.98, 95% CI 0.80–1.20] or all-cause mortality (phosphate = 1.10, 95% CI 0.91–1.32; calcium = 0.96, 95% CI 0.81–1.13) based on tertiles of calcium or phosphate in the initial 90 days.

Conclusions

Hypophosphataemia and hypercalcaemia are common occurrences post-kidney transplant. We have identified different risk factors for these metabolic derangements. The calcium and phosphate levels exhibit no independent association with death-censored graft failure and mortality.

Phosphate Transport in Epithelial and Nonepithelial Tissue

Phosphate is an essential nutrient for life and is a critical component of bone formation, a major signaling molecule, and structural component of cell walls. Phosphate is also a component of high-energy compounds (i.e., AMP, ADP, and ATP) and essential for nucleic acid helical structure (i.e., RNA and DNA). Phosphate plays a central role in the process of mineralization, normal serum levels being associated with appropriate bone mineralization, while high and low serum levels are associated with soft tissue calcification. The serum concentration of phosphate and the total body content of phosphate are highly regulated, a process that is accomplished by the coordinated effort of two families of sodium-dependent transporter proteins. The three isoforms of the SLC34 family (SLC34A1-A3) show very restricted tissue expression and regulate intestinal absorption and renal excretion of phosphate. SLC34A2 also regulates the phosphate concentration in multiple lumen fluids including milk, saliva, pancreatic fluid, and surfactant. Both isoforms of the SLC20 family exhibit ubiquitous expression (with some variation as to which one or both are expressed), are regulated by ambient phosphate, and likely serve the phosphate needs of the individual cell. These proteins exhibit similarities to phosphate transporters in nonmammalian organisms. The proteins are nonredundant as mutations in each yield unique clinical presentations. Further research is essential to understand the function, regulation, and coordination of the various phosphate transporters, both the ones described in this review and the phosphate transporters involved in intracellular transport.

Identification of U-shaped curve relation between proneurotensin and risk of coronary artery disease (CAD) in patients with premature CAD

BACKGROUND AND AIMS

Neurotensin (NT) is a gut hormone with broad effects on the cardiovascular system. Recent data suggested that circulating proneurotensin (pro-NT)-the stable precursor fragment of NT-could independently predict cardiovascular artery disease (CAD) development. However, serum pro-NT levels in patients with premature cardiovascular artery disease (PCAD) are still unknown. This study aims to determine serum pro-NT levels in patients with PCAD and investigate its relationship with PCAD risk.

METHODS AND RESULTS

A total of 490 subjects, including 364 with PCAD and 126 without PCAD (NPCAD), and 182 controls were enrolled in the study. Data of baseline clinical parameters and biochemical variables were collected. Serum pro-NT levels were measured by ELISA. Serum pro-NT levels were higher in patients with PCAD than in controls (59.42 ± 66.66 vs. 38.07 ± 48.48 pg/mL, P < 0.05), especially in patients with BMI<25 kg/m². Serum pro-NT levels were independently related to PCAD (β = 0.349, P < 0.001), and the association revealed a U-shaped curve characteristic between pro-NT tertiles and CAD risk in patients with premature CAD and controls. Subjects with low and high tertiles of pro-NT levels had 1.79-fold and 2.23-fold higher risks of PCAD, respectively, than subjects with median pro-NT levels (P < 0.05). After adjusting for age, gender, and BMI in Model 1 and other confounders in Model 2 and Model 3, the U-shaped relationship remained significant.

CONCLUSION

Serum pro-NT levels were significantly increased in patients with PCAD. The association between pro-NT levels and PCAD risk presents a U-shaped curve characteristic, which demonstrated that subjects with lower and higher pro-NT levels both were more likely to have PCAD.

Relative hypophosphatemia early after transplantation is a predictor of good kidney graft function

BACKGROUND

Phosphate level is a potent independent risk factor for cardiovascular disease and mortality in patients with chronic kidney disease. The association between hypophosphatemia and kidney function in kidney transplant patients is uncertain.

METHODS

In total, 90 kidney transplant recipients were divided into two groups: one group of patients with hypophosphatemia and the other group without hypophosphatemia. The recipients with hypophosphatemia were identified as having less than or equal to the lowest quartile of serum phosphate levels at 1-, 3-, and 12-month post-transplant. The cumulative kidney survival rates were calculated for each group using the Kaplan-Meier method, and the adjusted hazard ratio (HR) was calculated using the Cox regression model.

RESULTS

The mean age of patients was 47 years and the median follow-up period was 58 months. During the follow-up period, the following results were demonstrated in 90 transplant patients: graft loss (n = 6), mortality (n = 3). According to the Kaplan-Meier analysis results, the patients with hypophosphatemia demonstrated a significantly lower risk of 30% decline in eGFR compared to those without hypophosphatemia at 1- and 3-month post-transplant, but not at 12-month post-transplant. After adjusting for confounding factors, hypophosphatemia at 1- and 3-month post-transplant was an independent predictor of good kidney survival (HR 0.31, 95% CI 0.10-0.82 and HR 0.31, 95% CI 0.07-0.92, respectively).

CONCLUSIONS

Our findings suggest that hypophosphatemia during the first 3 months after kidney transplantation was associated with better kidney survival.

Nutrition Trends in Kidney Transplant Recipients: the Importance of Dietary Monitoring and Need for Evidence-Based Recommendations

Many physiological properties of the renal system influence nutrient metabolism, elimination, and homeostasis. Kidney failure poses significant challenges to maintaining adequate nutrition, most of which transplantation ameliorates. Comprehensive recommendations for managing nutritional derangements for patients with chronic kidney disease and end stage renal disease exist; however, there are only sparse guidelines for post-transplant malnutrition and adverse outcomes. Not only are guidelines limited, but little is known about dietary trends of post-kidney transplant recipients. This review describes guidelines for prevalent metabolic and nutritional complications post-kidney transplantation and also evaluates changes in caloric intake and diet composition after transplantation. This topic is important because nutrition influences allograft function and a number of cardiovascular risk factors including blood pressure, dyslipidemia, weight, and diabetes. In addition, many dietary recommendations and modifiable lifestyle changes should be tailored for specific complications of transplant patients, namely immunosuppression side effects, dietary restrictions, and electrolyte imbalances.

Mineral and Bone Disorders After Kidney Transplantation

The risk of mineral and bone disorders among patients with chronic kidney disease is substantially elevated, owing largely to alterations in calcium, phosphorus, vitamin D, parathyroid hormone, and fibroblast growth factor 23. The interwoven relationship among these minerals and hormones results in maladaptive responses that are differentially affected by the process of kidney transplantation. Interpretation of conventional labs, imaging, and other fracture risk assessment tools are not standardized in the post-transplant setting. Post-transplant bone disease is not uniformly improved and considerable variation exists in monitoring and treatment practices. A spectrum of abnormalities such as hypophosphatemia, hypercalcemia, hyperparathyroidism, osteomalacia, osteopenia, and osteoporosis are commonly encountered in the post-transplant period. Thus, reducing fracture risk and other bone-related complications requires recognition of these abnormalities along with the risk incurred by concomitant immunosuppression use. As kidney transplant recipients continue to age, the drivers of bone disease vary throughout the post-transplant period among persistent hyperparathyroidism, de novo hyperparathyroidism, and osteoporosis. The use of anti-resorptive therapies require understanding of different options and the clinical scenarios that warrant their use. With limited studies underscoring clinical events such as fractures, expert understanding of MBD physiology, and surrogate marker interpretation is needed to determine ideal and individualized therapy.

Post-Transplant Hypophosphatemia and the Risk of Death-Censored Graft Failure and Mortality after Kidney Transplantation

BACKGROUND AND OBJECTIVES

Hypophosphatemia is common in the first year after kidney transplantation, but its clinical implications are unclear. We investigated the relationship between the severity of post-transplant hypophosphatemia and mortality or death-censored graft failure in a large cohort of renal transplant recipients with long-term follow-up.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a longitudinal cohort study in 957 renal transplant recipients who were transplanted between 1993 and 2008 at a single center. We used a large real-life dataset containing 28,178 phosphate measurements (median of 27; first to third quartiles, 23-34) serial measurements per patient) and selected the lowest intraindividual phosphate level during the first year after transplantation. The primary outcomes were all-cause mortality, cardiovascular mortality, and death-censored graft failure.

RESULTS

The median (interquartile range) intraindividual lowest phosphate level was 1.58 (1.30-1.95) mg/dl, and it was reached at 33 (21-51) days post-transplant. eGFR was the main correlate of the lowest serum phosphate level (model R2 =0.32). During 9 (5-12) years of follow-up, 181 (19%) patients developed graft failure, and 295 (35%) patients died, of which 94 (32%) deaths were due to cardiovascular disease. In multivariable Cox regression analysis, more severe hypophosphatemia was associated with a lower risk of death-censored graft failure (fully adjusted hazard ratio, 0.61; 95% confidence interval, 0.43 to 0.88 per 1 mg/dl lower serum phosphate) and cardiovascular mortality (fully adjusted hazard ratio, 0.37; 95% confidence interval, 0.22 to 0.62) but not noncardiovascular mortality (fully adjusted hazard ratio, 1.33; 95% confidence interval, 0.9 to 1.96) or all-cause mortality (fully adjusted hazard ratio, 1.15; 95% confidence interval, 0.81 to 1.61).

CONCLUSIONS

Post-transplant hypophosphatemia develops early after transplantation. These data connect post-transplant hypophosphatemia with favorable long-term graft and patient outcomes.