The Effectiveness of a Mindfulness-Based Intervention Integrated with Physical Therapy (MIND-PT) for Postsurgical Rehabilitation After Lumbar Surgery: A Protocol for a Randomized Controlled Trial as Part of the Back Pain Consortium (BACPAC) Research Program.

BACKGROUND: Improving pain management for persons with chronic low back pain (LBP) undergoing surgery is an important consideration in improving patient-centered outcomes and reducing the risk of persistent opioid use after surgery. Nonpharmacological treatments, including physical therapy and mindfulness, are beneficial for nonsurgical LBP through complementary biopsychosocial mechanisms, but their integration and application for persons undergoing surgery for LBP have not been examined. This study (MIND-PT) is a multisite randomized trial that compares an enriched pain management (EPM) pathway that integrates physical therapy and mindfulness vs usual-care pain management (UC) for persons undergoing surgery for LBP. DESIGN: Participants from military treatment facilities will be enrolled before surgery and individually randomized to the EPM or UC pain management pathways. Participants assigned to EPM will receive presurgical biopsychosocial education and mindfulness instruction. After surgery, the EPM group will receive 10 sessions of physical therapy with integrated mindfulness techniques. Participants assigned to the UC group will receive usual pain management care after surgery. The primary outcome will be the pain impact, assessed with the Pain, Enjoyment, and General Activity (PEG) scale. Time to opioid discontinuation is the main secondary outcome. SUMMARY: This trial is part of the National Institutes of Health Helping to End Addiction Long-term (HEAL) initiative, which is focused on providing scientific solutions to the opioid crisis. The MIND-PT study will examine an innovative program combining nonpharmacological treatments designed to improve outcomes and reduce opioid overreliance in persons undergoing lumbar surgery.

Rationale, design, demographics and baseline characteristics of the randomized, controlled, Phase 2b SAPPHIRE study of verinurad plus allopurinol in patients with chronic kidney disease and hyperuricaemia.

BACKGROUND: Verinurad is a human uric acid (UA) transporter (URAT1) inhibitor known to decrease serum UA (sUA) levels and that may reduce albuminuria. In a Phase 2a study (NCT03118739), treatment with verinurad + febuxostat lowered urine albumin-to-creatinine ratio (UACR) at 12 weeks by 39% (90% confidence interval 4-62%) among patients with Type 2 diabetes mellitus, hyperuricaemia and albuminuria. The Phase 2b, randomized, placebo-controlled Study of verinurAd and alloPurinol in Patients with cHronic kIdney disease and hyperuRicaEmia (SAPPHIRE; NCT03990363) will examine the effect of verinurad + allopurinol on albuminuria and estimated glomerular filtration rate (eGFR) slope among patients with chronic kidney disease (CKD) and hyperuricaemia. METHODS: Adults (≥18 years of age) with CKD, eGFR ≥25 mL/min/1.73 m2, UACR 30-5000 mg/g and sUA ≥6.0 mg/dL will be enrolled. Approximately 725 patients will be randomized 1:1:1:1:1 to 12, 7.5 or 3 mg verinurad + allopurinol, allopurinol or placebo. An 8-week dose-titration period will precede a 12-month treatment period; verinurad dose will be increased to 24 mg at Month 9 in a subset of patients in the 3 mg verinurad + allopurinol arm. The primary efficacy endpoint the is change from baseline in UACR at 6 months. Secondary efficacy endpoints include changes in UACR, eGFR and sUA from baseline at 6 and 12 months. CONCLUSIONS: This study will assess the combined clinical effect of verinurad + allopurinol on kidney function in patients with CKD, hyperuricaemia and albuminuria, and whether this combination confers renoprotection beyond standard-of-care.

A Sequential Multiple-Assignment Randomized Trial (SMART) for Stepped Care Management of Low Back Pain in the Military Health System: A Trial Protocol.

BACKGROUND: The Defense Health Agency has prioritized system-level pain management initiatives within the Military Health System (MHS), with low back pain as one of the key focus areas. A stepped care model focused on nonpharmacologic treatment to promote self-management is recommended. Implementation of stepped care is complicated by lack of information on the most effective nonpharmacologic strategies and how to sequence and tailor the various available options. The Sequential Multiple-Assignment Randomization Trial for Low Back Pain (SMART LBP) is a multisite pragmatic trial using a SMART design to assess the effectiveness of nonpharmacologic treatments for chronic low back pain. DESIGN: This SMART trial has two treatment phases. Participants from three military treatment facilities are randomized to 6 weeks of phase I treatment, receiving either physical therapy (PT) or Army Medicine's holistic Move2Health (M2H) program in a package specific to low back pain. Nonresponders to treatment in phase I are again randomized to phase II treatment of combined M2H + PT or mindfulness-based treatment using the Mindfulness-Oriented Recovery Enhancement (MORE) program. The primary outcome is the Patient-Reported Outcomes Measurement Information System pain interference computer-adapted test score. SUMMARY: This trial is part of an initiative funded by the National Institutes of Health, Veterans Affairs, and the Department of Defense to establish a national infrastructure for effective system-level management of chronic pain with a focus on nonpharmacologic treatments. The results of this study will provide important information on nonpharmacologic care for chronic LBP in the MHS embedded within a stepped care framework.

The OPTIMIZE study: protocol of a pragmatic sequential multiple assessment randomized trial of nonpharmacologic treatment for chronic, nonspecific low back pain.

BACKGROUND: Low back pain is a prevalent condition that causes a substantial health burden. Despite intensive and expensive clinical efforts, its prevalence is growing. Nonpharmacologic treatments are effective at improving pain-related outcomes; however, treatment effect sizes are often modest. Physical therapy (PT) and cognitive behavioral therapy (CBT) have the most consistent evidence of effectiveness. Growing evidence also supports mindfulness-based approaches. Discussions with providers and patients highlight the importance of discussing and trying options to find the treatment that works for them and determining what to do when initial treatment is not successful. Herein, we present the protocol for a study that will evaluate evidence-based, protocol-driven treatments using PT, CBT, or mindfulness to examine comparative effectiveness and optimal sequencing for patients with chronic low back pain. METHODS: The Optimized Multidisciplinary Treatment Programs for Nonspecific Chronic Low Back Pain (OPTIMIZE) Study will be a multisite, comparative effectiveness trial using a sequential multiple assessment randomized trial design enrolling 945 individuals with chronic low back pain. The co-primary outcomes will be disability (measured using the Oswestry Disability Index) and pain intensity (measured using the Numerical Pain Rating Scale). After baseline assessment, participants will be randomly assigned to PT or CBT. At week 10, participants who have not experienced at least 50% improvement in disability will be randomized to cross-over phase-1 treatments (e.g., PT to CBT) or to Mindfulness-Oriented Recovery Enhancement (MORE). Treatment will consist of 8 weekly sessions. Long-term outcome assessments will be performed at weeks 26 and 52. DISCUSSION: Results of this study may inform referring providers and patients about the most effective nonoperative treatment and/or sequence of nonoperative treatments to treat chronic low back pain. TRIAL REGISTRATION: This study was prospectively registered on March 1, 2019, with Clinicaltrials.gov under the registration number NCT03859713 (https://clinicaltrials.gov/ct2/show/NCT03859713).

Neonatal Magnesium Levels Between 24 and 48 Hours of Life and Outcomes for Epilepsy and Motor Impairment in Premature Infants.

OBJECTIVE: Elevated rates of epilepsy and motor impairments including cerebral palsy are observed in children who were born prematurely. Maternal antenatal magnesium supplementation has been associated with decreased rates of cerebral palsy in infants born prematurely. Our objective was to determine whether the neonatal serum magnesium level between 24 and 48 hours after birth is associated with better long-term neurodevelopmental outcomes (epilepsy, motor impairment) in premature infants. METHODS: We performed a retrospective cohort analysis in infants born less than 37-weeks gestation over a ten-year period. Prenatal, perinatal, and postnatal clinical and demographic information was collected. Crude and adjusted odds ratios were estimated under generalized linear models with generalized estimating equations to examine the association of the neonatal serum magnesium level between 24 and 48 hours after birth with the risk of epilepsy and/or motor impairment (spasticity; hypotonia; cerebral palsy). RESULTS: The final cohort included 5461 infants born less than 37-weeks gestation from 2002 to 2011. The adjusted relative risk ratio for the combined outcomes of epilepsy and/or motor impairment, controlling for gestational age, current age, maternal magnesium supplementation, maternal steroid administration, five-minute Apgar score, neonatal infection, need for vasopressor use, and birth weight and with serum magnesium level as the main independent variable, was 0.85 (P = 0.24). Stratified analyses by gestational age less than 32 or greater than 32 weeks were not significantly associated with adverse neurodevelopmental outcome (risk ratio = 0.79 and 1.2, P = 0.12 and 0.49, respectively). A multivariate analysis for the risk of motor impairment alone had a risk ratio of 0.94 (P = 0.72). CONCLUSION: This study demostrates that the neonatal magnesium level between 24 and 48 hours of life in premature infants is not significantly associated with the risk for developing epilepsy or motor impairment.

Supervised oral protein supplementation during dialysis in patients with elevated C-reactive protein levels: a two phase, longitudinal, single center, open labeled study.

BACKGROUND: Inflammation is considered one of the major causes of protein-energy wasting in maintenance hemodialysis (MHD) patients. It is unclear whether dietary interventions can impact nutritional status and quality of life in MHD patients with elevated C-reactive protein (CRP) levels. Therefore, we examined the hypothesis that supervised intra-dialysis protein supplementation in MHD patients with elevated plasma CRP will improve protein stores and quality of life. METHODS: A 24 week, two phase, longitudinal, single center, open labeled study of 50 MHD patients with plasma CRP > 3 mg/L was conducted. During the 12-week observation phase dietary advice was provided to increase protein intake to 1.2 g/kg/day. In the 12-week treatment phase 45 g of liquid protein supplement was provided at each dialysis treatment. Protein nitrogen appearance (PNA), mid-arm muscle circumference (MAMC), serum albumin, body mass index (BMI) and quality of life (assessed by Short Form-12 questionnaire) were measured at baseline, 12 and 24 weeks. RESULTS: Median plasma CRP at baseline was 16.0 (IQR 7.7 to 25.1) mg/L. The mean MAMC was 26.5 ± 3.9 cm, BMI 29.2 ± 6.9 kg/m(2) and plasma albumin 3.8 ± 0.3 g/dl. During the intervention period, mean PNA increased by 0.13 g/kg/d (p = 0.01) under a mixed effects model. However, there were no clinically or statistically significant effects on MAMC (p = 0.87), plasma albumin (p = 0.70), BMI (p = 0.09), physical (p = 0.32) or mental (p = 0.96) composite scores. CONCLUSIONS: In MHD patients with elevated plasma CRP but otherwise mostly normal nutritional parameters, intra-dialytic oral protein supplement was effective in increasing protein intake but did not provide a detectable impact on nutritional status or quality of life.

Ferric citrate controls phosphorus and delivers iron in patients on dialysis.

Patients on dialysis require phosphorus binders to prevent hyperphosphatemia and are iron deficient. We studied ferric citrate as a phosphorus binder and iron source. In this sequential, randomized trial, 441 subjects on dialysis were randomized to ferric citrate or active control in a 52-week active control period followed by a 4-week placebo control period, in which subjects on ferric citrate who completed the active control period were rerandomized to ferric citrate or placebo. The primary analysis compared the mean change in phosphorus between ferric citrate and placebo during the placebo control period. A sequential gatekeeping strategy controlled study-wise type 1 error for serum ferritin, transferrin saturation, and intravenous iron and erythropoietin-stimulating agent usage as prespecified secondary outcomes in the active control period. Ferric citrate controlled phosphorus compared with placebo, with a mean treatment difference of -2.2±0.2 mg/dl (mean±SEM) (P<0.001). Active control period phosphorus was similar between ferric citrate and active control, with comparable safety profiles. Subjects on ferric citrate achieved higher mean iron parameters (ferritin=899±488 ng/ml [mean±SD]; transferrin saturation=39%±17%) versus subjects on active control (ferritin=628±367 ng/ml [mean±SD]; transferrin saturation=30%±12%; P<0.001 for both). Subjects on ferric citrate received less intravenous elemental iron (median=12.95 mg/wk ferric citrate; 26.88 mg/wk active control; P<0.001) and less erythropoietin-stimulating agent (median epoetin-equivalent units per week: 5306 units/wk ferric citrate; 6951 units/wk active control; P=0.04). Hemoglobin levels were statistically higher on ferric citrate. Thus, ferric citrate is an efficacious and safe phosphate binder that increases iron stores and reduces intravenous iron and erythropoietin-stimulating agent use while maintaining hemoglobin.

Effect of decreased parenteral soybean lipid emulsion on hepatic function in infants at risk for parenteral nutrition-associated liver disease: a pilot study.

PURPOSE: We performed a pilot trial to compare reduced dose versus standard soybean lipid emulsion in neonates at risk for parenteral nutrition-associated liver disease. METHODS: A prospective randomized controlled trial was performed (2009-2011) enrolling surgical patients ≥ 26 weeks' gestation anticipated to require >50% of daily caloric intake from parenteral nutrition (PN) for at least 4 weeks. Randomization occurred into either reduced (1.0 g/kg/day) or standard (3g/kg/day) groups. Co-primary outcomes for interpretation of the results were conjugated bilirubin and total bile acids. Additional outcomes included ALT, AST, GGT, alkaline phosphatase, growth, and essential fatty acid levels. Outcomes were compared between treatment groups using Wilcoxon rank sums tests. RESULTS: Twenty-eight patients (47% enrollment rate) were included in the study with an average treatment duration of 5.4 weeks. Groups had similar PN calories and protein intake throughout the study. Total increase from baseline was smaller in the reduced vs. standard group for conjugated bilirubin (p=0.04) and total bile acids (p=0.02). Weight z-score increased more in the standard group, and no patient experienced essential fatty acid deficiency. CONCLUSION: Markers of cholestasis rose at a slower rate using reduced lipid doses. This pilot study demonstrates feasibility and need for a larger study evaluating the effects of reduced lipids in patients at risk for developing parenteral nutrition-associated liver disease.

The safety and tolerability of ferric citrate as a phosphate binder in dialysis patients.

BACKGROUND: A phase II open-label study was conducted in hemodialysis patients evaluating the short-term safety, tolerability, and iron absorption with ferric citrate when used as a phosphate binder. METHODS: Enrollment occurred in two periods. Period 1 recruited patients taking 6-15 pills/day of binder with phosphorus of ≥2.5 mg/dl. Period 2 recruited patients taking ≥12 pills/day of binder with phosphorus of ≥3.5 mg/dl. Participants with ferritin ≥1,000 µg/l or transferrin iron saturation (TSAT) ≥50% at screening were excluded. Subjects discontinued their previous binders and started 4.5 g/day of ferric citrate (period 1) or 6 g/day (period 2) and were titrated for 4 weeks to maintain a phosphorus of 3.5-5.5 mg/dl. Chemistries and complete blood count were obtained weekly and a gastrointestinal questionnaire was administered at drug initiation and final visit. Iron therapy was permitted if the ferritin was <500 µg/l and TSAT <30%. RESULTS: Fifty-five subjects were enrolled. Four serious adverse events were reported; none were related to the study drug. Findings from the gastrointestinal questionnaire included stool discoloration (69%), constipation (15%), and bloating (7%). Mean iron parameters at the beginning of the study were ferritin 554 ± 296 µg/l, iron 68 ± 21 µg/dl, and iron saturation 30 ± 7.8%. At the end of study, mean ferritin was 609 ± 340 µg/l (p = 0.02), iron 75 ± 27 µg/dl (p = 0.04), and TSAT was 35 ± 13% (p = 0.001). Mean phosphorus and calcium levels were unchanged from baseline at the end of study. CONCLUSION: Ferric citrate was well tolerated by patients after 4 weeks with no significant clinical or biochemical adverse events related to exposure.

Effects of frequent hemodialysis on measures of CKD mineral and bone disorder.

More frequent hemodialysis sessions and longer session lengths may offer improved phosphorus control. We analyzed data from the Frequent Hemodialysis Network Daily and Nocturnal Trials to examine the effects of treatment assignment on predialysis serum phosphorus and on prescribed dose of phosphorus binder, expressed relative to calcium carbonate on a weight basis. In the Daily Trial, with prescribed session lengths of 1.5-2.75 hours six times per week, assignment to frequent hemodialysis associated with both a 0.46 mg/dl decrease (95% confidence interval [95% CI], 0.13-0.78 mg/dl) in mean serum phosphorus and a 1.35 g/d reduction (95% CI, 0.20-2.50 g/d) in equivalent phosphorus binder dose at month 12 compared with assignment to conventional hemodialysis. In the Nocturnal Trial, with prescribed session lengths of 6-8 hours six times per week, assignment to frequent hemodialysis associated with a 1.24 mg/dl decrease (95% CI, 0.68-1.79 mg/dl) in mean serum phosphorus compared with assignment to conventional hemodialysis. Among patients assigned to the group receiving six sessions per week, 73% did not require phosphorus binders at month 12 compared with only 8% of patients assigned to sessions three times per week (P<0.001). At month 12, 42% of patients on nocturnal hemodialysis required the addition of phosphorus into the dialysate to prevent hypophosphatemia. Frequent hemodialysis did not have major effects on calcium or parathyroid hormone concentrations in either trial. In conclusion, frequent hemodialysis facilitates control of hyperphosphatemia and extended session lengths could allow more liberal diets and freedom from phosphorus binders.

Serum alkaline phosphatase and mortality in African Americans with chronic kidney disease.

BACKGROUND AND OBJECTIVES: Serum alkaline phosphatase has been associated with increased mortality in hemodialysis patients but its associations with mortality in chronic kidney disease (CKD) stages III and IV are unknown. Design, settings, participants & measurements: In 1094 participants in the African-American Study of Kidney Disease and Hypertension (AASK) database, the associations of serum alkaline phosphatase with mortality and cardiovascular events were examined in Cox models. RESULTS: The mean (+/-SD) age was 54 +/- 11 yr, and 61% were men. The median alkaline phosphatase was 80 IU/L, and interquartile range was 66 to 97 IU/L. The mean follow-up was 4.6 yr. There were 105 (9.6%) all-cause deaths and 149 (13.6%) cardiovascular events. Each doubling of serum alkaline phosphatase was significantly associated with increased hazard [hazard ratio (HR) 1.60, 95% confidence interval (CI) 1.08 -2.36] of all-cause mortality adjusted for demographics, drug and blood pressure groups, and comorbidity. With further adjustment for liver function tests as well as serum calcium and phosphorus, each doubling of serum alkaline phosphatase remained significantly associated with increased mortality (HR 1.55, 95% CI 1.03 to 2.33). Serum alkaline phosphatase was not significantly associated with increased risk of cardiovascular events. CONCLUSIONS: Independent of liver function tests and serum calcium and phosphorus, higher levels of serum alkaline phosphatase are associated with increased mortality in the CKD population. Further studies are warranted to identify the potential mechanisms for this association.

Effect of a very low-protein diet on outcomes: long-term follow-up of the Modification of Diet in Renal Disease (MDRD) Study.

BACKGROUND: The long-term effect of a very low-protein diet on the progression of kidney disease is unknown. We examined the effect of a very low-protein diet on the development of kidney failure and death during long-term follow-up of the Modification of Diet in Renal Disease (MDRD) Study. STUDY DESIGN: Long-term follow-up of study B of the MDRD Study (1989-1993). SETTING & PARTICIPANTS: The MDRD Study examined the effects of dietary protein restriction and blood pressure control on progression of kidney disease. This analysis includes 255 trial participants with predominantly stage 4 nondiabetic chronic kidney disease. INTERVENTION: A low-protein diet (0.58 g/kg/d) versus a very low-protein diet (0.28 g/kg/d) supplemented with a mixture of essential keto acids and amino acids (0.28 g/kg/d). OUTCOMES: Kidney failure (initiation of dialysis therapy or transplantation) and all-cause mortality until December 31, 2000. RESULTS: Kidney failure developed in 227 (89%) participants, 79 (30.9%) died, and 244 (95.7%) reached the composite outcome of either kidney failure or death. Median duration of follow-up until kidney failure, death, or administrative censoring was 3.2 years, and median time to death was 10.6 years. In the low-protein group, 117 (90.7%) participants developed kidney failure, 30 (23.3%) died, and 124 (96.1%) reached the composite outcome. In the very low-protein group, 110 (87.3%) participants developed kidney failure, 49 (38.9%) died, and 120 (95.2%) reached the composite outcome. After adjustment for a priori-specified covariates, hazard ratios were 0.83 (95% confidence interval, 0.62 to 1.12) for kidney failure, 1.92 (95% confidence interval, 1.15 to 3.20) for death, and 0.89 (95% confidence interval, 0.67 to 1.18) for the composite outcome in the very low-protein diet group compared with the low-protein diet group. LIMITATIONS: Lack of dietary protein measurements during follow-up. CONCLUSION: In long-term follow-up of the MDRD Study, assignment to a very low-protein diet did not delay progression to kidney failure, but appeared to increase the risk of death.

Baseline predictors of renal disease progression in the African American Study of Hypertension and Kidney Disease.

Patients with chronic kidney disease have an increased risk for progression to ESRD. The purpose of this study was to examine factors that predict increased risk for adverse renal outcomes. Cox regression was performed to assess the potential of 38 baseline risk factors to predict the clinical renal composite outcome of 50% or 25-ml/min per 1.73 m(2) GFR decline or ESRD among 1094 black patients with hypertensive nephrosclerosis (GFR 20 to 65 ml/min per 1.73 m(2)). Patients were trial participants who had been randomly assigned to one of two BP goals and to one of three antihypertensive regimens and followed for a range of 3 to 6.4 yr. In unadjusted and adjusted analyses, baseline proteinuria was consistently associated with an increased risk for adverse renal outcomes, even at low levels of proteinuria. The relationship of proteinuria with adverse renal outcomes also was evident in analyses that were stratified by level of GFR, which itself was associated with adverse renal outcomes but only at levels <40 ml/min. Other factors that were significantly associated with increased renal events after adjustment for baseline GFR, age, and gender, both with and without adjustment for baseline proteinuria, included serum creatinine, urea nitrogen, and phosphorus. In black patients with hypertensive nephrosclerosis, increased proteinuria, reduced GFR, and elevated levels of serum creatinine, urea nitrogen and phosphorus were directly associated with adverse clinical renal events. These findings identify a subset of this high-risk population that might benefit from even more aggressive treatment.

Effect of dietary protein intake on serum total CO2 concentration in chronic kidney disease: Modification of Diet in Renal Disease study findings.

Metabolic acidosis is a feature of chronic kidney disease (CKD), but whether serum bicarbonate concentration is influenced by variations in dietary protein intake is unknown. For assessing the effect of diet, data that were collected in the Modification of Diet in Renal Disease study were used. In this study, patients with CKD were enrolled into a baseline period, then randomly assigned to follow either a low- or a usual-protein diet (study A, entry GFR 25 to 55 ml/min) or a low- or very low-protein diet, the latter supplemented with ketoanalogs of amino acids (study B, entry GFR 13 to 24 ml/min). Serum [total CO2] and estimated protein intake (EPI) were assessed at entry (n = 1676) and again at 1 yr after randomization, controlling for changes in GFR and other key covariates (n = 723). At entry, serum [total CO2] was inversely related to EPI (1.0 mEq/L lower mean serum [total CO2]/g per kg body wt increase in protein intake/d; P = 0.009). In an intention-to-treat analysis, the reduction in mean EPI in the low-protein group as compared with the usual-protein group (0.41 g/kg body wt per d) was independently associated with a 0.9-mEq/L increase in serum [total CO2], after adjustment for covariates (P < 0.001). No such effect was evident in study B, in which the very low-protein diet group received dietary supplements. Serum [total CO2] is inversely correlated with dietary protein intake in patients with CKD. A reduction in protein intake results in an increase in serum [total CO2].

Relationship of phosphorus and calcium-phosphorus product with mortality in CKD.

BACKGROUND: Abnormalities of mineral metabolism are prevalent in patients with kidney failure and are associated with increased risk for cardiovascular events. There are limited data investigating relationships of phosphorus and calcium-phosphorus product with outcomes in patients with chronic kidney disease (CKD) stages 3 to 4. METHODS: Serum phosphorus and calcium were measured at baseline in 840 participants from the randomized cohort of the Modification of Diet in Renal Disease Study. Survival status until December 31, 2000, was obtained from the National Death Index. Cox models were performed to assess the relationship of serum phosphorus level and calcium-phosphorus product with all-cause and cardiovascular disease (CVD) mortality. RESULTS: Mean serum phosphorus level was 3.8 +/- 0.7 mg/dL (1.23 +/- 0.23 mmol/L), calcium-phosphorus product was 34.7 +/- 6.3 mg2/dL2, and glomerular filtration rate (GFR) was 33 +/- 12 mL/min/1.73 m2 (0.55 +/- 0.20 mL/s/1.73 m2). All-cause and CVD mortality rates were 25% and 15%. Serum phosphorus level was not related to all-cause mortality in multivariable models (P = 0.46). In unadjusted analysis, serum phosphorus level was associated with (hazard ratio [HR] per 1 mg/dL increase, 1.34; 95% confidence interval [CI], 1.05 to 1.71; P = 0.02) increased risk for CVD mortality, but this association was partly attenuated and not statistically significant after adjustment for GFR and other confounders (HR, 1.27; 95% CI, 0.94 to 1.73; P = 0.12). Calcium-phosphorus product was not associated with all-cause mortality in unadjusted (P = 0.23) or multivariate analysis (P = 0.35). Calcium-phosphorus product was related to CVD mortality in unadjusted (HR per 10 mg2/dL2 increase, 1.30; 95% CI, 1.01 to 1.69; P = 0.04) analysis, but this association was not statistically significant after adjustment for GFR and other confounders (HR, 1.22; 95% CI, 0.89 to 1.66; P = 0.23). CONCLUSION: In the Modification of Diet in Renal Disease Study cohort, serum phosphorus level and calcium-phosphorus product were not statistically associated with all-cause or CVD mortality after adjustment for GFR; however larger studies with additional statistical power are needed to evaluate these relationships, especially in the context of current practice patterns in patients with CKD.

Homocysteine in chronic kidney disease: Effect of low protein diet and repletion with B vitamins.

BACKGROUND: Data are limited on the determinants of homocysteine (tHcy) and its relationship with nutritional indices, and dietary protein intake, in the earlier stages of chronic kidney disease (CKD). METHODS: Levels of tHcy were assayed at baseline (N= 804) and 1 year postrandomization (N= 678) in the Modification of Diet in Renal Disease (MDRD) Study [study A, glomerular filtration rate (GFR) 25 to 55 mL/min/1.73 m(2) and study B GFR 13 to 24 mL/min/1.73 m(2)]. Participants were randomly assigned to different blood pressure targets and protein diets and all subjects received a multivitamin supplement containing 1 mg of folic acid, 10 mg pyridoxal 5'-phosphate (PLP) and 6 mug of vitamin B(12). Multivariable analyses were used to evaluate determinants of tHcy at baseline and 1 year. RESULTS: The prevalence of hyperhomocysteinemia (tHcy >15 mumol/L) at baseline was 56% in study A and 85% in study B. Baseline tHcy was negatively correlated with measures of body fat and dietary protein intake. Folate, vitamin B(12), and GFR were the major determinants of tHcy levels. Of the patients with hyperhomocysteinemia at baseline, 49% and 24% reduced their tHcy levels at 1 year to < or =15 micromol/L in study A and study B, respectively. There was no association between dietary protein intake and odds of developing hyperhomocysteinemia at 1 year in study A (P= 0.94) or study B (P= 0.10). CONCLUSION: Hyperhomocysteinemia is partly amenable to correction by vitamin supplementation in CKD stages 3 and 4. There is insufficient evidence to suggest that low tHcy is associated with poor nutritional status in the MDRD Study cohort. B vitamins and GFR, but not dietary protein, are the major determinants of tHcy in this patient population.