Water intake and recurrent urinary tract infections prevention: economic impact analysis in seven countries.

BACKGROUND: To estimate the economic impact of preventing urinary tract infections (UTI) by increasing water intake among women with recurrent UTI and low fluid intake across seven countries: France, United Kingdom, Spain, United States of America, Mexico, China and Australia. METHODS: A Markov model was developed to compare costs and outcomes of UTIs associated with low fluid intake in women versus a strategy of primary prevention by increasing water intake. Model inputs were based on randomized controlled trial data which found that increasing water intake by 1.5 L/day decreased the risk of developing cystitis by 48% in women with low fluid intake and recurrent UTI. A time horizon of 10 years was used; outcomes were from the payer perspective and included both direct and indirect costs, reported in 2019 United States dollars ($). Discounting rates varied by country. Scenarios of increasing levels of compliance to the increased water intake strategy were evaluated. RESULTS: The total cost of one UTI episode, including diagnostics, treatment and complications, ranged from $2164 (Mexico) to $7671 (Australia). Assuming 80% compliance with the increased water intake strategy over a 10-year time horizon, the number of UTIs prevented ranged from 435,845 (Australia) to 24150,272 (China), resulting in total savings of 286 million (Australia) to $4.4 billion (China). Across all countries, increased water intake resulted in lower cost and fewer UTIs compared with low water intake. CONCLUSION: Preventing recurrent UTIs by increasing water intake would reduce both the clinical and economic burden associated with UTI. Public, healthcare professionals and patients should be made aware about the preventive positive impact of appropriate water intake on UTIs.

Fluid Intake Management in Maintenance Hemodialysis Using a Smartphone-Based Application: A Pilot Study.

Rationale & Objective: Increased interdialytic weight gain (IDWG) has been associated with increased morbidity and mortality. We evaluated the usefulness and safety of a mobile application (app) that allows patients receiving maintenance hemodialysis to self-monitor their daily fluid intake. Study Design: Within group comparison before or during intervention. Setting & Participants: Patients receiving maintenance hemodialysis with mean IDWG of <4%. Exposure: Participants were trained to use a smartphone-based app, FiApp that allowed them to record fluid intake and compare with individual targeted daily fluid intake determined by the nephrologist. Outcomes: The primary study outcome was the association between IDWG and fluid intake recorded in the FiApp. Secondary outcomes included FiApp safety and usage. Patient interviews were performed at weeks 1 and 4 to collect information regarding FiApp usability and recommendations for app improvements. Analytical Approach: Mean, median, and standard deviation. Results: Eighteen of 25 patients completed the full 4-week study, provided all app data, and completed 2 patient interviews. The mean 4-week IDWG during app use was similar to the baseline mean 4-week IDWG before app use; however, 61% of the participants had a decrease in IDWG when using the app compared with IDWG at baseline. Of the 18 participants who completed the study, only 1 had a mean 4-week IDWG that was 20% higher than that at baseline. The app was used on ≥80% of the days by 13 (72%) of 18 participants, and was used every day in 7 (39%) of 18 participants. The mean relationship between fluid reported in the app and fluid consumed was 40%. Limitations: This safety study recruited patients who had IDWG of <4%. Conclusions: A smartphone-based app can be safely used to help patients receiving maintenance hemodialysis track and control fluid intake. Motivated patients were able to decrease IDWG despite baseline IDWG being <4% of the body weight. Trial Registration: NCT03759847. Plain-Language Summary: Patients receiving maintenance hemodialysis struggle to limit fluid intake. Excess fluid intake can lead to adverse cardiovascular events. We developed a smartphone app to help patients receiving dialysis self-monitor their fluid intake. In this safety study in patients receiving dialysis with an interdialytic weight gain of <4% of the body weight, more than half of the patients were able to decrease their interdialytic fluid intake while using the app, and only 1 patient had an increase in interdialytic weight gain of >20% while using the app. Information gleaned from structured patient interviews will be used to refine this app.

Urine osmolality predicts calcium-oxalate crystallization risk in patients with recurrent urolithiasis.

Our aim was to investigate the validity of osmolality from 24-h urine collection in examining the risk for calcium-oxalate (CaOx) kidney stone formation in patients with recurrent urolithiasis. Three hundred and twelve subjects (males/females: 184/128) from France with a history of recurrent kidney stones from confirmed or putative CaOx origin were retrospectively included in the study (46 ± 14 years, BMI: 25.3 ± 5.0 kg·m-2). Tiselius' crystallization risk index (CRI) was calculated based on urinary calcium, oxalate, citrate, magnesium, and volume from 24-h samples. The diagnostic ability of 24-h urine osmolality to classify patients as high risk for kidney stone crystallization was examined through the receivers operating characteristics analysis. High risk for CaOx crystallization was defined as CRI > 1.61 and > 1.18, for males and females, respectively. The accuracy of urine osmolality to diagnose risk of CaOx stone formation (AUC, area under the curve) for females was 84.6%, with cut-off point of 501 mmol·kg-1 (sensitivity: 83.3%, specificity: 76.0%). Males had AUC of 85.8% with threshold of 577 mmo·kg-1 (sensitivity: 85.5%, specificity: 77.6%). A negative association was found between 24-h urine volume and osmolality (r = - 0.63, P < 0.001). Also, a positive association was found between 24-h urine osmolality and CRI (r = 0.65, P < 0.001), as well as urea excretion with CRI (r = 0.37, P < 0.001). In conclusion, urine osmolality > 501 and > 577 mmol·kg-1, in female and in male, respectively, was associated with a risk for CaOx kidney stone formation in patients with a history of recurrent urolithiasis. Thus, when CaOx origin is confirmed or suspected, 24-h urine osmolality provides a simple way to define individualized target of urine dilution to prevent urine crystallization and stone formation.

Hydration for health hypothesis: a narrative review of supporting evidence.

PURPOSE: An increasing body of evidence suggests that excreting a generous volume of diluted urine is associated with short- and long-term beneficial health effects, especially for kidney and metabolic function. However, water intake and hydration remain under-investigated and optimal hydration is poorly and inconsistently defined. This review tests the hypothesis that optimal chronic water intake positively impacts various aspects of health and proposes an evidence-based definition of optimal hydration. METHODS: Search strategy included PubMed and Google Scholar using relevant keywords for each health outcome, complemented by manual search of article reference lists and the expertise of relevant practitioners for each area studied. RESULTS: The available literature suggest the effects of increased water intake on health may be direct, due to increased urine flow or urine dilution, or indirect, mediated by a reduction in osmotically -stimulated vasopressin (AVP). Urine flow affects the formation of kidney stones and recurrence of urinary tract infection, while increased circulating AVP is implicated in metabolic disease, chronic kidney disease, and autosomal dominant polycystic kidney disease. CONCLUSION: In order to ensure optimal hydration, it is proposed that optimal total water intake should approach 2.5 to 3.5 L day-1 to allow for the daily excretion of 2 to 3 L of dilute (< 500 mOsm kg-1) urine. Simple urinary markers of hydration such as urine color or void frequency may be used to monitor and adjust intake.

Immunosuppressive agents for treating IgA nephropathy.

BACKGROUND: IgA nephropathy is the most common glomerulonephritis world-wide. IgA nephropathy causes end-stage kidney disease (ESKD) in 15% to 20% of affected patients within 10 years and in 30% to 40% of patients within 20 years from the onset of disease. This is an update of a Cochrane review first published in 2003 and updated in 2015. OBJECTIVES: To determine the benefits and harms of immunosuppression strategies for the treatment of IgA nephropathy. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to 9 September 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs of treatment for IgA nephropathy in adults and children and that compared immunosuppressive agents with placebo, no treatment, or other immunosuppressive or non-immunosuppressive agents. DATA COLLECTION AND ANALYSIS: Two authors independently assessed study risk of bias and extracted data. Estimates of treatment effect were summarised using random effects meta-analysis. Treatment effects were expressed as relative risk (RR) and 95% confidence intervals (95% CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes. Risks of bias were assessed using the Cochrane tool. Evidence certainty was evaluated using GRADE methodology. MAIN RESULTS: Fifty-eight studies involving 3933 randomised participants were included. Six studies involving children were eligible. Disease characteristics (kidney function and level of proteinuria) were heterogeneous across studies. Studies evaluating steroid therapy generally included patients with protein excretion of 1 g/day or more. Risk of bias within the included studies was generally high or unclear for many of the assessed methodological domains. In patients with IgA nephropathy and proteinuria > 1 g/day, steroid therapy given for generally two to four months with a tapering course probably prevents the progression to ESKD compared to placebo or standard care (8 studies; 741 participants: RR 0.39, 95% CI 0.23 to 0.65; moderate certainty evidence). Steroid therapy may induce complete remission (4 studies, 305 participants: RR 1.76, 95% CI 1.03 to 3.01; low certainty evidence), prevent doubling of serum creatinine (SCr) (7 studies, 404 participants: RR 0.43, 95% CI 0.29 to 0.65; low certainty evidence), and may lower urinary protein excretion (10 studies, 705 participants: MD -0.58 g/24 h, 95% CI -0.84 to -0.33;low certainty evidence). Steroid therapy had uncertain effects on glomerular filtration rate (GFR), death, infection and malignancy. The risk of adverse events with steroid therapy was uncertain due to heterogeneity in the type of steroid treatment used and the rarity of events. Cytotoxic agents (azathioprine (AZA) or cyclophosphamide (CPA) alone or with concomitant steroid therapy had uncertain effects on ESKD (7 studies, 463 participants: RR 0.63, 95% CI 0.33 to 1.20; low certainty evidence), complete remission (5 studies; 381 participants: RR 1.47, 95% CI 0.94 to 2.30; very low certainty evidence), GFR (any measure), and protein excretion. Doubling of serum creatinine was not reported. Mycophenolate mofetil (MMF) had uncertain effects on the progression to ESKD, complete remission, doubling of SCr, GFR, protein excretion, infection, and malignancy. Death was not reported. Calcineurin inhibitors compared with placebo or standard care had uncertain effects on complete remission, SCr, GFR, protein excretion, infection, and malignancy. ESKD and death were not reported. Mizoribine administered with renin-angiotensin system inhibitor treatment had uncertain effects on progression to ESKD, complete remission, GFR, protein excretion, infection, and malignancy. Death and SCr were not reported. Leflunomide followed by a tapering course with oral prednisone compared to prednisone had uncertain effects on the progression to ESKD, complete remission, doubling of SCr, GFR, protein excretion, and infection. Death and malignancy were not reported. Effects of other immunosuppressive regimens (including steroid plus non-immunosuppressive agents or mTOR inhibitors) were inconclusive primarily due to insufficient data from the individual studies in low or very low certainty evidence. The effects of treatments on death, malignancy, reduction in GFR at least of 25% and adverse events were very uncertain. Subgroup analyses to determine the impact of specific patient characteristics such as ethnicity or disease severity on treatment effectiveness were not possible. AUTHORS' CONCLUSIONS: In moderate certainty evidence, corticosteroid therapy probably prevents decline in GFR or doubling of SCr in adults and children with IgA nephropathy and proteinuria. Evidence for treatment effects of immunosuppressive agents on death, infection, and malignancy is generally sparse or low-quality. Steroid therapy has uncertain adverse effects due to a paucity of studies. Available studies are few, small, have high risk of bias and generally do not systematically identify treatment-related harms. Subgroup analyses to identify specific patient characteristics that might predict better response to therapy were not possible due to a lack of studies. There is no evidence that other immunosuppressive agents including CPA, AZA, or MMF improve clinical outcomes in IgA nephropathy.

A Role for Both V1a and V2 Receptors in Renal Heat Stress Injury Amplified by Rehydration with Fructose.

Chronic vasopressin secretion induced by recurrent mild heat stress exposure is significantly enhanced by limited rehydration with a fructose-containing beverage both in rodents and in humans. Moreover, this effect has been associated with upregulation of the polyol-fructokinase pathway and increased renal oxidative stress. Previously, we have shown that pharmacological inhibition of both V1a and V2 vasopressin receptors with conivaptan improved such renal alterations. The aim of this study was to evaluate the independent contributions of V1a and V2 receptors to the renal damage caused by mild heat stress and limited rehydration with a fructose-containing beverage. Osmotic minipumps were used to deliver either relcovaptan (0.64 mg/day) or tolvaptan (0.25 mg/day) in male Wistar rats for two weeks. Corresponding dilution vehicles were used as controls. To induce dehydration, rats were exposed to mild heat stress (37 °C for 1 h, Monday to Friday). All groups received a 10% fructose solution as a rehydration fluid for 2 h after mild heat stress. For the remainder of the day and on weekends, rats received tap water. The independent blockade of either the V1a or the V2 receptor prevented renal damage, reduced oxidative stress, and decreased plasma cortisol and systemic inflammation. However, the beneficial effects were regulated by different mechanisms. Tolvaptan inhibited polyol-fructokinase pathway overactivation, while relcovaptan prevented upregulation of the renin-angiotensin system and SGK1 expression. These data suggest that both V1a and V2 receptors participate in renal damage caused by heat stress-induced dehydration when fructose-containing beverages are used as rehydration fluids.

Antioxidant supplements as a novel mean for blocking recurrent heat stress-induced kidney damage following rehydration with fructose-containing beverages.

Recently repeated heat stress and dehydration have been reported to cause oxidative stress and kidney damage that is enhanced by rehydrating with fructose solutions. We hypothesized that antioxidants might provide a novel way to prevent kidney damage. To test this hypothesis, mild heat stress was induced by exposing rats to 37 °C during 1 h in a closed chamber. The supplementation with water-soluble antioxidants (Antiox), ascorbic acid 1% plus N-acetyl cysteine 600 mg/L was done either in the 10% fructose 2 h rehydration fluid immediately after heat stress (Fructose 10% + Antiox), and/or in the tap water (Water + Antiox) for the remainder of the day, or in both fluids. After 4 weeks, control rats exposed to heat with fructose rehydration developed impaired renal function, tubular injury, intrarenal oxidative stress, a reduction in Nrf2-Keap1 antioxidant pathway, stimulation of vasopressin and the intrarenal polyol-fructokinase pathway. In contrast, dosing the antioxidants in the tap water (i.e., before the heat exposure and rehydration with fructose) preserved renal function, prevented renal tubule dysfunction and avoided the increase in systemic blood pressure. These effects were likely due to the amplification of the antioxidant defenses through increased Nrf2 nuclear translocation stimulated by the antioxidants and by the prevention of polyol fructokinase pathway overactivation. More studies to understand the mechanisms implicated in this pathology are warranted as there is recent evidence that they may be operating in humans as well.

The Long-Term Impact of Renin-Angiotensin System (RAS) Inhibition on Cardiorenal Outcomes (LIRICO): A Randomized, Controlled Trial.

BACKGROUND: The comparative effectiveness of treatment with angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), or their combination in people with albuminuria and cardiovascular risk factors is unclear. METHODS: In a multicenter, randomized, open label, blinded end point trial, we evaluated the effectiveness on cardiovascular events of ACE or ARB monotherapy or combination therapy, targeting BP<130/80 in patients with moderate or severe albuminuria and diabetes or other cardiovascular risk factors. End points included a primary composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and hospitalization for cardiovascular causes and a revised end point of all-cause mortality. Additional end points included ESRD, doubling of serum creatinine, albuminuria, eGFR, BP, and adverse events. RESULTS: Because of slow enrollment, the trial was modified and stopped 41% short of targeted enrollment of 2100 participants, corresponding to 35% power to detect a 25% reduced risk in the primary outcome. Our analysis included 1243 adults, with median follow-up of 2.7 years. Efficacy outcomes were similar between groups (ACE inhibitor versus ARB, ACE inhibitor versus combination, ARB versus combination) as were rates of serious adverse events. The rate of permanent discontinuation for ARB monotherapy (6.3%) was significantly lower than for ACE inhibitor monotherapy (15.7%) or combined therapy (18.3%). CONCLUSIONS: Patients may tolerate ARB monotherapy better than ACE inhibitor monotherapy. However, data from this trial and similar trials, although as yet inconclusive, show no trend suggesting differences in mortality and renal outcomes with ACE inhibitors or ARBs as dual or monotherapy in patients with albuminuria and diabetes or other cardiovascular risk factors.

Effect of Increased Daily Water Intake in Premenopausal Women With Recurrent Urinary Tract Infections: A Randomized Clinical Trial.

Importance: Increased hydration is often recommended as a preventive measure for women with recurrent cystitis, but supportive data are sparse. Objective: To assess the efficacy of increased daily water intake on the frequency of recurrent cystitis in premenopausal women. Design, Setting, and Participants: Randomized, open-label, controlled, 12-month trial at a clinical research center (years 2013-2016). Among 163 healthy women with recurrent cystitis (≥3 episodes in past year) drinking less than 1.5 L of fluid daily assessed for eligibility, 23 were excluded and 140 assigned to water or control group. Assessments of daily fluid intake, urinary hydration, and cystitis symptoms were performed at baseline, 6- and 12-month visits, and monthly telephone calls. Interventions: Participants were randomly assigned to drink, in addition to their usual fluid intake, 1.5 L of water daily (water group) or no additional fluids (control group) for 12 months. Main Outcomes and Measures: Primary outcome measure was frequency of recurrent cystitis over 12 months. Secondary outcomes were number of antimicrobial regimens used, mean time interval between cystitis episodes, and 24-hour urinary hydration measurements. Results: The mean (SD) age of the 140 participants was 35.7 (8.4) years, and the mean (SD) number of cystitis episodes in the previous year was 3.3 (0.6). During the 12-month study period, the mean (SD) number of cystitis episodes was 1.7 (95% CI, 1.5-1.8) in the water group compared with 3.2 (95% CI, 3.0-3.4) in the control group, with a difference in means of 1.5 (95% CI, 1.2-1.8; P < .001). Overall, there were 327 cystitis episodes, 111 in the water group and 216 in the control group. The mean number of antimicrobial regimens used to treat cystitis episodes was 1.9 (95% CI, 1.7-2.2) and 3.6 (95% CI, 3.3-4.0), respectively, with a difference in means of 1.7 (95% CI, 1.3-2.1; P < .001). The mean time interval between cystitis episodes was 142.8 (95% CI, 127.4-160.1) and 84.4 (95% CI, 75.4-94.5) days, respectively, with a difference in means of 58.4 (95% CI, 39.4-77.4; P < .001). Between baseline and 12 months, participants in the water group, compared with those in the control group, had increased mean (SD) urine volume (1.4 [0.04] vs 0.1 [0.04] L; P < .001) and voids (2.4 [0.2] vs -0.1 [0.2]; P < .001) and decreased urine osmolality (-402.8 [19.6] vs -24.0 [19.5] mOsm/kg; P < .001). Conclusions and Relevance: Increased water intake is an effective antimicrobial-sparing strategy to prevent recurrent cystitis in premenopausal women at high risk for recurrence who drink low volumes of fluid daily. Trial Registration: ClinicalTrials.gov identifier: NCT02444975.

Phosphate binders for preventing and treating chronic kidney disease-mineral and bone disorder (CKD-MBD).

BACKGROUND: Phosphate binders are used to reduce positive phosphate balance and to lower serum phosphate levels for people with chronic kidney disease (CKD) with the aim to prevent progression of chronic kidney disease-mineral and bone disorder (CKD-MBD). This is an update of a review first published in 2011. OBJECTIVES: The aim of this review was to assess the benefits and harms of phosphate binders for people with CKD with particular reference to relevant biochemical end-points, musculoskeletal and cardiovascular morbidity, hospitalisation, and death. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to 12 July 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: We included randomised controlled trials (RCTs) or quasi-RCTs of adults with CKD of any GFR category comparing a phosphate binder to another phosphate binder, placebo or usual care to lower serum phosphate. Outcomes included all-cause and cardiovascular death, myocardial infarction, stroke, adverse events, vascular calcification and bone fracture, and surrogates for such outcomes including serum phosphate, parathyroid hormone (PTH), and FGF23. DATA COLLECTION AND ANALYSIS: Two authors independently selected studies for inclusion and extracted study data. We applied the Cochrane 'Risk of Bias' tool and used the GRADE process to assess evidence certainty. We estimated treatment effects using random-effects meta-analysis. Results were expressed as risk ratios (RR) for dichotomous outcomes together with 95% confidence intervals (CI) or mean differences (MD) or standardised MD (SMD) for continuous outcomes. MAIN RESULTS: We included 104 studies involving 13,744 adults. Sixty-nine new studies were added to this 2018 update.Most placebo or usual care controlled studies were among participants with CKD G2 to G5 not requiring dialysis (15/25 studies involving 1467 participants) while most head to head studies involved participants with CKD G5D treated with dialysis (74/81 studies involving 10,364 participants). Overall, seven studies compared sevelamer with placebo or usual care (667 participants), seven compared lanthanum to placebo or usual care (515 participants), three compared iron to placebo or usual care (422 participants), and four compared calcium to placebo or usual care (278 participants). Thirty studies compared sevelamer to calcium (5424 participants), and fourteen studies compared lanthanum to calcium (1690 participants). No study compared iron-based binders to calcium. The remaining studies evaluated comparisons between sevelamer (hydrochloride or carbonate), sevelamer plus calcium, lanthanum, iron (ferric citrate, sucroferric oxyhydroxide, stabilised polynuclear iron(III)-oxyhydroxide), calcium (acetate, ketoglutarate, carbonate), bixalomer, colestilan, magnesium (carbonate), magnesium plus calcium, aluminium hydroxide, sucralfate, the inhibitor of phosphate absorption nicotinamide, placebo, or usual care without binder. In 82 studies, treatment was evaluated among adults with CKD G5D treated with haemodialysis or peritoneal dialysis, while in 22 studies, treatment was evaluated among participants with CKD G2 to G5. The duration of study follow-up ranged from 8 weeks to 36 months (median 3.7 months). The sample size ranged from 8 to 2103 participants (median 69). The mean age ranged between 42.6 and 68.9 years.Random sequence generation and allocation concealment were low risk in 25 and 15 studies, respectively. Twenty-seven studies reported low risk methods for blinding of participants, investigators, and outcome assessors. Thirty-one studies were at low risk of attrition bias and 69 studies were at low risk of selective reporting bias.In CKD G2 to G5, compared with placebo or usual care, sevelamer, lanthanum, iron and calcium-based phosphate binders had uncertain or inestimable effects on death (all causes), cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification. Sevelamer may lead to constipation (RR 6.92, CI 2.24 to 21.4; low certainty) and lanthanum (RR 2.98, CI 1.21 to 7.30, moderate certainty) and iron-based binders (RR 2.66, CI 1.15 to 6.12, moderate certainty) probably increased constipation compared with placebo or usual care. Lanthanum may result in vomiting (RR 3.72, CI 1.36 to 10.18, low certainty). Iron-based binders probably result in diarrhoea (RR 2.81, CI 1.18 to 6.68, high certainty), while the risks of other adverse events for all binders were uncertain.In CKD G5D sevelamer may lead to lower death (all causes) (RR 0.53, CI 0.30 to 0.91, low certainty) and induce less hypercalcaemia (RR 0.30, CI 0.20 to 0.43, low certainty) when compared with calcium-based binders, and has uncertain or inestimable effects on cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification. The finding of lower death with sevelamer compared with calcium was present when the analysis was restricted to studies at low risk of bias (RR 0.50, CI 0.32 to 0.77). In absolute terms, sevelamer may lower risk of death (all causes) from 210 per 1000 to 105 per 1000 over a follow-up of up to 36 months, compared to calcium-based binders. Compared with calcium-based binders, lanthanum had uncertain effects with respect to all-cause or cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification and probably had reduced risks of treatment-related hypercalcaemia (RR 0.16, CI 0.06 to 0.43, low certainty). There were no head-to-head studies of iron-based binders compared with calcium. The paucity of placebo-controlled studies in CKD G5D has led to uncertainty about the effects of phosphate binders on patient-important outcomes compared with placebo.It is uncertain whether the effects of binders on clinically-relevant outcomes were different for patients who were and were not treated with dialysis in subgroup analyses. AUTHORS' CONCLUSIONS: In studies of adults with CKD G5D treated with dialysis, sevelamer may lower death (all causes) compared to calcium-based binders and incur less treatment-related hypercalcaemia, while we found no clinically important benefits of any phosphate binder on cardiovascular death, myocardial infarction, stroke, fracture or coronary artery calcification. The effects of binders on patient-important outcomes compared to placebo are uncertain. In patients with CKD G2 to G5, the effects of sevelamer, lanthanum, and iron-based phosphate binders on cardiovascular, vascular calcification, and bone outcomes compared to placebo or usual care, are also uncertain and they may incur constipation, while iron-based binders may lead to diarrhoea.

Prevention of Cystitis: Travelling between the Imaginary and Reality.

As a preventive strategy, increased water intake is often recommended to women affected by recurrent cystitis; however, clinical data are sparse and conflicting. This review evaluates the preventive approaches used as alternatives to obtain relief from the burden of cystitis and focuses on the effect of fluid intake on urinary tract infection.

Effect of increased water intake on plasma copeptin in healthy adults.

PURPOSE: Inter-individual variation in median plasma copeptin is associated with incident type 2 diabetes mellitus, progression of chronic kidney disease, and cardiovascular events. In this study, we examined whether 24-h urine osmolality was associated with plasma copeptin and whether increasing daily water intake could impact circulating plasma copeptin. METHODS: This trial was a prospective study conducted at a single investigating center. Eighty-two healthy adults (age 23.6 ± 2.9 years, BMI 22.2 ± 1.5 kg/m2, 50% female) were stratified based upon habitual daily fluid intake volumes: arm A (50-80% of EFSA dietary reference values), arm B (81-120%), and arm C (121-200%). Following a baseline visit, arms A and B increased their water intake to match arm C for a period of 6 consecutive weeks. RESULTS: At baseline, plasma copeptin was positively and significantly associated with 24-h urine osmolality (p = 0.002) and 24-h urine specific gravity (p = 0.003) but not with plasma osmolality (p = 0.18), 24-h urine creatinine (p = 0.09), and total fluid intake (p = 0.52). Over the 6-week follow-up, copeptin decreased significantly from 5.18 (3.3;7.4) to 3.90 (2.7;5.7) pmol/L (p = 0.012), while urine osmolality and urine specific gravity decreased from 591 ± 206 to 364 ± 117 mOsm/kg (p < 0.001) and from 1.016 ± 0.005 to 1.010 ± 0.004 (p < 0.001), respectively. CONCLUSIONS: At baseline, circulating levels of copeptin were positively associated with 24-h urine concentration in healthy young subjects with various fluid intakes. Moreover, this study shows, for the first time, that increased water intake over 6 weeks results in an attenuation of circulating copeptin. CLINICAL TRIAL REGISTRATION NUMBER: NCT02044679.

Glucose targets for preventing diabetic kidney disease and its progression.

BACKGROUND: Diabetes is the leading cause of end-stage kidney disease (ESKD) around the world. Blood pressure lowering and glucose control are used to reduce diabetes-associated disability including kidney failure. However there is a lack of an overall evidence summary of the optimal target range for blood glucose control to prevent kidney failure. OBJECTIVES: To evaluate the benefits and harms of intensive (HbA1c < 7% or fasting glucose levels < 120 mg/dL versus standard glycaemic control (HbA1c ≥ 7% or fasting glucose levels ≥ 120 mg/dL for preventing the onset and progression of kidney disease among adults with diabetes. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Specialised Register up to 31 March 2017 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials evaluating glucose-lowering interventions in which people (aged 14 year or older) with type 1 or 2 diabetes with and without kidney disease were randomly allocated to tight glucose control or less stringent blood glucose targets. DATA COLLECTION AND ANALYSIS: Two authors independently assessed studies for eligibility and risks of bias, extracted data and checked the processes for accuracy. Outcomes were mortality, cardiovascular complications, doubling of serum creatinine (SCr), ESKD and proteinuria. Confidence in the evidence was assessing using GRADE. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. MAIN RESULTS: Fourteen studies involving 29,319 people with diabetes were included and 11 studies involving 29,141 people were included in our meta-analyses. Treatment duration was 56.7 months on average (range 6 months to 10 years). Studies included people with a range of kidney function. Incomplete reporting of key methodological details resulted in uncertain risks of bias in many studies. Using GRADE assessment, we had moderate confidence in the effects of glucose lowering strategies on ESKD, all-cause mortality, myocardial infarction, and progressive protein leakage by kidney disease and low or very low confidence in effects of treatment on death related to cardiovascular complications and doubling of serum creatinine (SCr).For the primary outcomes, tight glycaemic control may make little or no difference to doubling of SCr compared with standard control (4 studies, 26,874 participants: RR 0.84, 95% CI 0.64 to 1.11; I2= 73%, low certainty evidence), development of ESKD (4 studies, 23,332 participants: RR 0.62, 95% CI 0.34 to 1.12; I2= 52%; low certainty evidence), all-cause mortality (9 studies, 29,094 participants: RR 0.99, 95% CI 0.86 to 1.13; I2= 50%; moderate certainty evidence), cardiovascular mortality (6 studies, 23,673 participants: RR 1.19, 95% CI 0.73 to 1.92; I2= 85%; low certainty evidence), or sudden death (4 studies, 5913 participants: RR 0.82, 95% CI 0.26 to 2.57; I2= 85%; very low certainty evidence). People who received treatment to achieve tighter glycaemic control probably experienced lower risks of non-fatal myocardial infarction (5 studies, 25,596 participants: RR 0.82, 95% CI 0.67 to 0.99; I2= 46%, moderate certainty evidence), onset of microalbuminuria (4 studies, 19,846 participants: RR 0.82, 95% CI 0.71 to 0.93; I2= 61%, moderate certainty evidence), and progression of microalbuminuria (5 studies, 13,266 participants: RR 0.59, 95% CI 0.38 to 0.93; I2= 75%, moderate certainty evidence). In absolute terms, tight versus standard glucose control treatment in 1,000 adults would lead to between zero and two people avoiding non-fatal myocardial infarction, while seven adults would avoid experiencing new-onset albuminuria and two would avoid worsening albuminuria. AUTHORS' CONCLUSIONS: This review suggests that people who receive intensive glycaemic control for treatment of diabetes had comparable risks of kidney failure, death and major cardiovascular events as people who received less stringent blood glucose control, while experiencing small clinical benefits on the onset and progression of microalbuminuria and myocardial infarction. The adverse effects of glycaemic management are uncertain. Based on absolute treatment effects, the clinical impact of targeting an HbA1c < 7% or blood glucose < 6.6 mmol/L is unclear and the potential harms of this treatment approach are largely unmeasured.

Fluid Intake and Vasopressin: Connecting the Dots.

In the last decade, cross-sectional and multiple cohort studies have associated total fluid intake or water intake with the risk for chronic kidney disease (CKD) and even the risk of developing hyperglycemia. Urine biomarkers have also been linked to the risk of CKD and lithiasis, and these biomarkers respond quickly to variations in fluid intake. High circulating copeptin levels, a surrogate marker of arginine vasopressin, have been associated with metabolic syndrome, renal dysfunction and increased risk for diabetes mellitus, cardiovascular disease and death. The aim of this paper was to explore how the various findings on water intake, hydration and health are interconnected, to highlight current gaps in our understanding and to propose a model that links water intake, homeostatic mechanisms to maintain water balance and health outcomes. Since plasma copeptin and vasopressin have been demonstrated to be sensitive to changes in water intake, inversely associated with 24-hour urine volume, and associated with urine biomarkers and fluid intake, vasopressin is proposed as the central player in this theoretical physiological model.

Immunosuppressive agents for treating IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) is the most common glomerulonephritis world-wide and a cause of end-stage kidney disease (ESKD) in 15% to 20% of patients within 10 years and in 30% to 40% of patients within 20 years from the onset of disease. This is an update of a review first published in 2003. OBJECTIVES: To determine the benefits and harms of immunosuppression for the treatment of IgAN. SEARCH METHODS: For this review update we searched the Specialised Register to 19 February 2015 through contact with the Trials Search Co-ordinator using search terms relevant to this review. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs of treatment for IgAN in adults and children and that compared immunosuppressive agents with placebo, no treatment, or other immunosuppressive or non-immunosuppressive agents. DATA COLLECTION AND ANALYSIS: Two authors independently assessed study risk of bias and extracted data for population characteristics, interventions and outcomes including mortality, infection, hospitalisation, ESKD requiring renal replacement therapy (dialysis or kidney transplantation), doubling of serum creatinine, remission of proteinuria, and end of treatment urinary protein excretion, serum creatinine, and glomerular filtration rate.Estimates of treatment effect and hazards were summarised using random effects meta-analysis. Treatment effects were expressed as relative risk (RR) and 95% confidence intervals (95% CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes. MAIN RESULTS: We included 32 studies comprising 1781 participants. Risk of bias within the included studies was generally high: 22 studies (69%) did not describe the method used to generate the randomisation sequence; 24 (75%) did not describe the methods used to conceal allocation; performance bias was not reported or high in 30 studies (94%); detection bias was unclear in 31 studies (97%); attrition bias was low in 14 studies (44%), unclear in eight (25%) and high in 12 studies (38%); reporting bias was low in 21 studies (67%) and high in 10 studies (31%); and four studies received industry funding or were terminated early (13%).Steroids lowered risks of progression to ESKD (6 studies, 341 participants: RR 0.44, 95% CI 0.25 to 0.80), and doubling of serum creatinine (6 studies, 341 participants: RR 0.45, 95% CI 0.29 to 0.69), lowered urinary protein excretion (6 studies, 263 participants: MD -0.49 g/24 h, 95% CI -0.72 to -0.25); and preserved glomerular filtration rate (4 studies, 138 participants: MD 17.87 mL/min/1.73 m(2), 95% CI 4.93 to 30.82) compared to no treatment or placebo. Combining steroids plus renin-angiotensin-system (RAS) inhibitors lowered the risk of progression to ESKD (2 studies, 160 participants: RR 0.16, 95% CI 0.04 to 0.59) and reduced urinary protein excretion (1 study, 38 participants: MD -0.20 g/24 h, 95% CI -0.26 to -0.14) compared with RAS inhibitors or steroids alone. Cytotoxic agents (azathioprine) plus steroid regimens plus dipyridamole increased remission of proteinuria (1 study, 78 participants: RR 1.24, 95% CI 1.01 to 1.52) compared to steroids alone but had uncertain effects on other outcomes.Mycophenolate mofetil plus RAS inhibitors lowered the risk of progression to ESKD (1 study, 40 participants: RR 0.22, 95% CI 0.05 to 0.90), improved remission of proteinuria (1 study, 40 participants: RR 2.67, 95% CI 1.32 to 5.39) and reduced urinary protein excretion (1 study, 40 participants: MD -1.26 g/24 h, 95% CI -1.46 to -1.06). Effects of other immunosuppressive regimens (including cyclosporin, leflunomide) were inconclusive primarily due to insufficient data from the individual studies. Subgroup analyses to determine the impact of patient characteristics on treatment effectiveness were not possible. AUTHORS' CONCLUSIONS: The optimal management of IgAN remains uncertain although corticosteroid therapy may lower the risks of kidney disease progression and need for dialysis or transplantation. Evidence for treatment effects of immunosuppressive agents on mortality, infection, and cancer is generally sparse or low-quality and insufficient to guide clinical practice. Available RCTs are few, small, have high risk of bias - particularly selective reporting - and generally do not systematically identify treatment-related harms. Subgroup analyses to identify specific patient characteristics that might predict better response to therapy were not possible. Larger placebo-controlled studies of corticosteroid therapy or mycophenolate mofetil which are sufficiently powered to evaluate patient-relevant end points including adverse events and that examine the optimal duration of treatment are now required in populations with IgAN with a range of kidney function.

Haemodiafiltration, haemofiltration and haemodialysis for end-stage kidney disease.

BACKGROUND: Convective dialysis modalities (haemofiltration (HF), haemodiafiltration (HDF), and acetate-free biofiltration (AFB)) removed excess body fluid across the dialysis membrane with positive pressure and accumulated middle- and larger-size accumulated solutes more efficiently than haemodialysis (HD). This increased larger solute removal combined with use of ultra-pure dialysis fluid in convective dialysis is hypothesised to reduce the frequency and severity of symptoms during dialysis as well as improve clinical outcomes. Convective dialysis therapies (HDF and HF) are associated with lower mortality compared to diffusive therapy (HD) in observational studies. This is an update of a review first published in 2006. OBJECTIVES: To compare convective (HF, HDF, or AFB) with diffusive (HD) dialysis modalities on clinical outcomes (mortality, major cardiovascular events, hospitalisation and treatment-related adverse events) in men and women with end-stage kidney disease (ESKD). SEARCH METHODS: We searched the Cochrane Renal Group's Specialised Register (to 18 February 2015) through contact with a Trials' Search Co-ordinator using search terms relevant to this review. SELECTION CRITERIA: We included randomised controlled trials comparing convective therapy (HF, HDF, AFB) with another convective therapy or diffusive therapy (HD) for treatment of ESKD. DATA COLLECTION AND ANALYSIS: Two independent authors identified studies, extracted data and assessed study risk of bias. We summarised treatment effects using the random effects model. We reported results as a risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous data together with 95% confidence intervals (CI). We assessed for heterogeneity using the Chi(2) test and explored the amount of variation in treatment estimates beyond that expected by chance using the I(2) statistic. MAIN RESULTS: Twenty studies comprising 667 participants were included in the 2006 review. In that review, there was insufficient evidence of treatment effects on major clinical outcomes to draw clinically meaningful conclusions. Searching to February 2015 identified 40 eligible studies comprising 3483 participants overall. In total, 35 studies (4039 participants) compared HF, HDF or AFB with HD, three studies (54 participants) compared AFB with HDF, and three studies (129 participants) compared HDF with HF.Risks of bias in all studies were generally high resulting in low confidence in estimated treatment effects. Convective dialysis had no significant effect on all-cause mortality (11 studies, 3396 participants: RR 0.87, 95% CI 0.72 to 1.05; I(2) = 34%), but significantly reduced cardiovascular mortality (6 studies, 2889 participants: RR 0.75, 95% CI 0.61 to 0.92; I(2) = 0%). One study reported no significant effect on rates of nonfatal cardiovascular events (714 participants: RR 1.14, 95% CI 0.86 to 1.50) and two studies showed no significant difference in hospitalisation (2 studies, 1688 participants: RR 1.23, 95% CI 0.93 to 1.63; I(2) = 0%). One study reported rates of hypotension during dialysis were significantly reduced with convective therapy (906 participants: RR 0.72, 95% CI 0.66 to 0.80). Adverse events were not systematically evaluated in most studies and data for health-related quality of life were sparse. Convective therapies significantly reduced predialysis levels of B2 microglobulin (12 studies, 1813 participants: MD -5.55 mg/dL, 95% CI -9.11 to -1.98; I(2) = 94%) and increased dialysis dose (Kt/V urea) (14 studies, 2022 participants: MD 0.07, 95% CI -0.00 to 0.14; I(2) = 90%) compared to diffusive therapy, but results across studies were very heterogeneous. Sensitivity analyses limited to studies comparing HDF with HD showed very similar results. Directly comparative data for differing types of convective dialysis were insufficient to draw conclusions.Studies had important risks of bias leading to low confidence in the summary estimates and were generally limited to patients who had adequate dialysis vascular access. AUTHORS' CONCLUSIONS: Convective dialysis may reduce cardiovascular but not all-cause mortality and effects on nonfatal cardiovascular events and hospitalisation are inconclusive. However, any treatment benefits of convective dialysis on all patient outcomes including cardiovascular death are unreliable due to limitations in study methods and reporting. Future studies which assess treatment effects of convection dose on patient outcomes including mortality and cardiovascular events would be informative.

Twenty-four-hour urine osmolality as a physiological index of adequate water intake.

While associations exist between water, hydration, and disease risk, research quantifying the dose-response effect of water on health is limited. Thus, the water intake necessary to maintain optimal hydration from a physiological and health standpoint remains unclear. The aim of this analysis was to derive a 24 h urine osmolality (U(Osm)) threshold that would provide an index of "optimal hydration," sufficient to compensate water losses and also be biologically significant relative to the risk of disease. Ninety-five adults (31.5 ± 4.3 years, 23.2 ± 2.7 kg·m(-2)) collected 24 h urine, provided morning blood samples, and completed food and fluid intake diaries over 3 consecutive weekdays. A U(Osm) threshold was derived using 3 approaches, taking into account European dietary reference values for water; total fluid intake, and urine volumes associated with reduced risk for lithiasis and chronic kidney disease and plasma vasopressin concentration. The aggregate of these approaches suggest that a 24 h urine osmolality ≤500 mOsm·kg(-1) may be a simple indicator of optimal hydration, representing a total daily fluid intake adequate to compensate for daily losses, ensure urinary output sufficient to reduce the risk of urolithiasis and renal function decline, and avoid elevated plasma vasopressin concentrations mediating the increased antidiuretic effort.

Convective versus diffusive dialysis therapies for chronic kidney failure: an updated systematic review of randomized controlled trials.

BACKGROUND: Convective dialysis therapies (hemofiltration or hemodiafiltration) are associated with lower mortality compared to hemodialysis in observational studies. A previous meta-analysis of randomized trials comparing convective modalities with hemodialysis in 2006 was inconclusive due to insufficient data. Additional randomized trials recently have reported conflicting results. STUDY DESIGN: Systematic review and meta-analysis of randomized trials to February 27, 2013. SETTING & POPULATION: Patients with chronic kidney failure treated by hemodialysis, hemodiafiltration, hemofiltration, or biofiltration. SELECTION CRITERIA FOR STUDIES: Randomized controlled trials. INTERVENTION: Convective therapies (hemodiafiltration, hemofiltration, and acetate-free biofiltration) compared with hemodialysis. OUTCOMES: All-cause and cardiovascular mortality, nonfatal cardiovascular events, hospitalization, change in dialysis modality, health-related quality of life, adverse events, blood pressure, and clearances of urea and ß2-microglobulin. RESULTS: 35 trials (4,039 participants) were included. In low-quality evidence, convective dialysis had little or no effect on all-cause mortality (relative risk [RR], 0.87; 95% CI, 0.70-1.07) and may reduce cardiovascular mortality (RR, 0.75; 95% CI, 0.58-0.97) and hypotension (RR, 0.72; 95% CI, 0.66-0.80) during dialysis, but had uncertain effects on nonfatal cardiovascular events (RR, 1.14; 95% CI, 0.85-1.52) and hospitalization (RR, 1.21; 95% CI, 0.12-12.05). Adverse events were not reported systematically and health-related quality-of-life outcomes were sparse. Convective therapies reduced predialysis levels of ß2-microglobulin (mean difference, -5.77 [95% CI, -10.97 to -0.56]mg/dL) and increased dialysis dose (Kt/Vurea mean difference, 0.10; 95% CI, 0.02-0.19), but these effects were very heterogeneous. Sensitivity analyses limited to trials comparing hemodiafiltration with hemodialysis showed similar results. LIMITATIONS: Studies had important risks of bias leading to low confidence in the summary estimates and generally were limited to patients who had adequate dialysis vascular access. CONCLUSIONS: Treatment effects of convective dialysis are unreliable due to limitations in trial methods and reporting. Convective dialysis may reduce cardiovascular but not all-cause mortality, and effects on nonfatal cardiovascular events and hospitalization are inconclusive.