The French Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort study

Chronic Kidney Disease, Gender, and Access to Care: A Global Perspective

Little is known regarding the ways in which chronic kidney disease (CKD) prevalence and progression differ between the sexes. Still less is known regarding how social disparities between men and women may affect access to care for CKD. In this review, we briefly describe biological sex differences, noting how these differences currently do not influence CKD management recommendations. We then describe what is known within the published literature regarding differences in CKD epidemiology between sexes; namely prevalence, progression, and access to treatment throughout the major world regions. We highlight that health care expenditure and social gender disparities ultimately may determine whether women have equitable access to care for CKD and end-stage kidney disease. Among many high- and low-income settings, women more often donate and are less likely to receive kidney transplants when compared with men. Research is needed urgently to elucidate the reasons behind these disparities, as well as to develop CKD treatment strategies tailored to women's unique health care needs.

Impact of sex and glucose-lowering treatments on hypoglycaemic symptoms in people with type 2 diabetes and chronic kidney disease. The French Chronic Kidney Disease - Renal Epidemiology and Information Network (CKD-REIN) Study

AIM

To describe current practices of glucose-lowering treatments in people with diabetes and chronic kidney disease (CKD), the associated glucose control and hypoglycaemic symptoms, with an emphasis on sex differences.

METHODS

Among the 3033 patients with CKD stages 3-5 recruited into the French CKD-REIN study, 645 men and 288 women had type 2 diabetes and were treated by glucose-lowering drugs.

RESULTS

Overall, 31% were treated only with insulin, 28% with combinations of insulin and another drug, 42% with non-insulin glucose-lowering drugs. In CKD stage 3, 40% of patients used metformin, 12% at stages 4&5, similar for men and women; in CKD stage 3, 53% used insulin, similar for men and women, but at stages 4&5, 59% of men and 77% of women used insulin. Patients were reasonably well controlled, with a median HbA1c of 7.1% (54mmol/mol) in men, 7.4% (57mmol/mol) in women (P=0.0003). Hypoglycaemic symptoms were reported by 40% of men and 59% of women; they were not associated with the estimated glomerular filtration rate, nor with albuminuria or with HbA1c in multivariable analyses, but they were more frequent in people treated with insulin, particularly with fast-acting and pre-mixed insulins.

CONCLUSION

Glucose-lowering treatment, HbA1c and hypoglycaemic symptoms were sex dependent. Metformin use was similar in men and women, but unexpectedly low in CKD stage 3; its use could be encouraged rather than resorting to insulin. Hypoglycaemic symptoms were frequent and need to be more closely monitored, with appropriate patient-education, especially in women.

Validation of the nursing interventions and activities for patients on hemodialytic therapy

OBJECTIVE

To validate interventions and nursing activities proposed by the Nursing Interventions Classification for patients with acute renal failure or acute chronic renal disease in hemodialysis therapy with the Excess Fluid Volume and Risk for Imbalanced Fluid Volume nursing diagnoses.

METHODS

Validation of content with 19 expert nurses from a university hospital. The data collection was made from September to November 2011 through instruments that contained the interventions and nursing activities in study. The data analysis considered the average of scores obtained in the validation process.

RESULTS

The Fluid Management was validated as a priority intervention (mean ≥ 0.8), with eight main activities for the Excess Fluid Volume nursing diagnosis and eight for the Risk for Imbalanced Fluid Volume nursing diagnosis.

CONCLUSION

The validated intervation of the Fluid Management enables the monitoring of the hydric balance and facilitates the prevention of complications, which are important activities in the nursing care of the patients in hemodialysis therapy.

A Prospective Cohort Study in Patients with Type 2 Diabetes Mellitus for Validation of Biomarkers (PROVALID) - Study Design and Baseline Characteristics

BACKGROUND/AIMS

The prevalence of diabetes mellitus type 2 and kidney disease in these patients varies widely between European countries.

METHODS

In addition to store bio-samples the "Prospective cohort study in patients with type 2 diabetes mellitus for validation of biomarkers" collects information on history, physical status, laboratory measurements and medication in 4000 patients with diabetes mellitus type 2, being taken care of at the primary level of healthcare in 5 European countries (Austria, Hungary, Netherlands, Poland and Scotland). Next to comparing the rate of loss of eGFR between the countries, a further objective of the PROVALID study is to determine the 5-year cumulative incidence of renal and cardiovascular outcomes.

RESULTS

The mean age of the population recruited is 62.9±10 years, 54.6% are male and the mean BMI is 30.9±5.4 kg/m2. Metabolic control (median HBA1c 6.8 % (6.2; 7.5)) is achieved via administration of metformin in 67.4% of the patients and insulin in 30.3%. Median systolic and diastolic blood pressure at recruitment is 135 (125; 146) and 80 (72; 85) mmHg, 65.4% of subjects received RAAS blocking agents. Mean eGFR is 80.7±29.2 ml/min/1.73m2 and median baseline albumin/creatinine ratio 8.3 mg (IQR: 3.8 and 25.1).

CONCLUSION

PROVALID will provide information on incidence and progression of renal and cardiovascular disease and therapy in patients with type 2 diabetes mellitus in different European countries. Thus, in contrast to many other cohort studies we will be able to associate national clinical practise pattern with outcome in this highly vulnerable patient population.

Spectrum (characteristics) of patients with chronic kidney disease (CKD) with increasing age in a major metropolitan renal service

Background

Aim of our study is to describe, in people with CKD, the demographic and clinical characteristics and outcomes with increasing age. The prevalence of CKD in Western populations, where longevity is the norm, is about 10–15%, but how age influence different characteristics of patients with CKD is largely not known.

Methods

One thousand two hundred sixty-five patients enrolled in the CKD.QLD registry at the Royal Brisbane and Women’s Hospital were grouped according to age at consent i.e. <35, 35–44, 45–54, 55–64, 65–74, 75–84, 85+ years age groups, and were followed till start of renal replacement therapy (RRT), death, discharge or the censor date of September 2015.

Results

Age ranged from 17.6 to 98.5 years with medians of 70.1 and 69.9 years for males and females respectively: 7% were <35 years of age, with the majority (63%) >65 years old. The leading renal diagnoses changed from genetic real disease (GRD) and glomerulonephritis (GN) in the younger patients to renovascular disease (RVD) and hypertension (HTN) in older patients. With increasing age, there were often multiple renal disease diagnoses, more advanced stages of CKD, greater number of comorbidities, more frequent and more costly hospitalizations, and higher death rates. The rates of initiation of renal replacement therapy (RRT) rose from 4.5 per 100 person years in those age < 35 years to a maximum of 5.5 per 100 person years in 45–54 years age group and were lowest, at 0.5 per 100 person years in those >85 years. Mortality rates increased by age group from 1.3 to 17.0 per 100 person years in 35–44 year and 85+ year age groups respectively. Rates of hospitalization, length of stay and cost progressively increased from the youngest to eldest groups. Patients with diabetic nephropathy had highest incidence rate of RRT and death. The proportion of patients who lost more than 5mls/min/1.73m² of eGFR during at least 12 months follow up increased from 13.3% in the youngest age group to 29.2% in the eldest.

Conclusion

This is the first comprehensive view, with no exclusions, of CKD patients seen in a public renal specialty referral practice, in Australia. The age distribution of patients encompasses the whole of adult life, with a broader range and higher median value than patients receiving RRT. Health status ranged from a single system (renal) disease in young adults through, with advancing age, renal impairment as a component of, or accompanying multisystem diseases, to demands and complexities of support of frail or elderly people approaching end of life. This great spectrum demands a broad understanding and capacity of renal health care providers, and dictates a need for a wider scope of health services provision incorporating multiple models of care.

[Management of bone and mineral metabolism disorders before the dialysis stage remains still perfectible. Data from the French Phosphorus and Calcium Survey Photo-Graphe]

Only limited data is available on the management of the chronic kidney disease-associated bone and mineral metabolism disorder (CKD-MBD) in the pre-dialysis stages of CKD in France. A better knowledge of current management habits could lead to an improvement in the implementation of international recommendations (KDIGO). The 3rd version of the French Phosphorus and Calcium Survey Photo-Graphe (Sanofi) included a cohort of CKD stages 4 and 5 patients, whose aim was to examine the prevalence of CKD-MBD and the quality of its management in patients under the care of 62 nephrologists from over 20 geographical regions in France. The study started in October 2011, i.e. one year after patient enrollment. We examined in particular the percentage of patients presenting with laboratory parameter abnormalities indicative of CKD-MBD who were not receiving adequate treatment. A total of 456 patients with CKD stage 4 and 154 with CKD stage 5 were studied. Their mean age was 72.9±14.2 years, and male/female ratio was 58/42. KDIGO targets of serum PTH for CKD stages 4 and 5 were not achieved in respectively 80 and 84% of the patients, for serum calcium in 8 and 22% and for serum phosphate in 12 and 46%. As a potential explanation, insufficient therapy was estimated to account for respectively 45 and 60% of insufficiently controlled secondary hyperparathyroidism, and for 36% of persistent hyperphosphatemia in stage 5. It should be noted that 55.5 and 57.5% of patients were receiving native vitamin D. In this national observatory, the management of CKD-MBD stages 4 and 5 appears suboptimal, especially as regards the control of secondary hyperparathyroidism, which remained untreated in nearly 50% of the patients. Hyperphosphatemia was also common and inadequately controlled in CKD stage 5. To improve the management of CKD-MBD, nephrologists need to be more aware of the importance of aiming for recommended laboratory targets and how this can be achieved.

Predictors of nonfunctional arteriovenous access at hemodialysis initiation and timing of access creation: A registry-based study

Determinants of nonfunctional arteriovenous (AV) access, including timing of AV access creation, have not been sufficiently described. We studied 29 945 patients who had predialysis AV access placement and were included in the French REIN registry from 2005 through 2013. AV access was considered nonfunctional when dialysis began with a catheter. We estimated crude and adjusted odds ratio (OR) with 95% confidence intervals (CI) of nonfunctional versus functional AV access associated with case-mix, facility characteristics, and timing of AV access creation. Analyses were stratified by dialysis start condition (planned or as an emergency) and comorbidity profile. Overall, 18% patients had nonfunctional AV access at hemodialysis initiation. In the group with planned dialysis start, female gender (OR 1.43, 95% CI 1.32–1.56), diabetes (OR 1.28, 95% CI 1.15–1.44), and a higher number of cardiovascular comorbidities (OR 1.27, 95% CI 1.09–1.49, and 1.31, 1.05–1.64, for 3 and >3 cardiovascular comorbidities versus none, respectively) were independent predictors of nonfunctional AV access. A higher percentage of AV access creation at the region level was associated with a lower rate of nonfunctional AV access (OR 0.98, 95% CI 0.98–0.99 per 1% increase). The odds of nonfunctional AV access decreased as time from creation to hemodialysis initiation increased up to 3 months in nondiabetic patients with fewer than 2 cardiovascular comorbidities and 6 months in patients with diabetes or 2 or more such comorbidities. In conclusion, both patient characteristics and clinical practices may play a role in successful AV access use at hemodialysis initiation. Adjusting the timing of AV access creation to patients’ comorbidity profiles may improve functional AV access rates.

Pilot non dialysis chronic renal insufficiency study (P-ND-CRIS): a pilot study of an open prospective hospital-based French cohort

BACKGROUND

Before establishing a prospective cohort, an initial pilot study is recommended. However, there are no precise guidelines on this subject. This paper reports the findings of a French regional pilot study carried out in three nephrology departments, before realizing a major prospective Non Dialysis Chronic Renal Insufficiency study (ND-CRIS).

METHODS

We carried out an internal pilot study. The objectives of this pilot study were to validate the feasibility (regulatory approval, providing patients with information, availability of variables, refusal rate of eligible patients) and quality criteria (missing data, rate of patients lost to follow-up, characteristics of the patients included and non-included eligible patients, quality control of the data gathered) and estimate the human resources necessary (number of clinical research associates required).

RESULTS

The authorizations obtained (CCTIRS - CNIL) and the contracts signed with hospitals have fulfilled the regulatory requirements. After validating the information on the study provided to patients, 1849 of them were included in three centres (university hospital, intercommunal hospital, town hospital) between April 2012 and September 2015. The low refusal rate (51 patients) and the characteristics of non-included patients have confirmed the benefit for patients of participating in the study and provide evidence of the feasibility and representativeness of the population studied. The lack of missing data on the variables studied, the quality of the data analyzed and the low number of patients lost to follow-up are evidence of the quality of the study. By taking into account the time spent by CRAs to enter data and to travel, as well as the annual patient numbers in each hospital, we estimate that five CRAs will be required in total.

CONCLUSION

With no specific guidelines on how to realize a pilot study before implementing a major prospective cohort, we considered it pertinent to report our experience of P-ND-CRIS. This experience confirms that i) feasibility, ii) quality of data and iii) evaluating the resources required must be validated before carrying out a large prospective cohort study such as ND-CRIS.

International Network of Chronic Kidney Disease cohort studies (iNET-CKD): a global network of chronic kidney disease cohorts

Background

Chronic kidney disease (CKD) is a global health burden, yet it is still underrepresented within public health agendas in many countries. Studies focusing on the natural history of CKD are challenging to design and conduct, because of the long time-course of disease progression, a wide variation in etiologies, and a large amount of clinical variability among individuals with CKD. With the difference in health-related behaviors, healthcare delivery, genetics, and environmental exposures, this variability is greater across countries than within one locale and may not be captured effectively in a single study.

Methods

Studies were invited to join the network. Prerequisites for membership included: 1) observational designs with a priori hypotheses and defined study objectives, patient-level information, prospective data acquisition and collection of bio-samples, all focused on predialysis CKD patients; 2) target sample sizes of 1,000 patients for adult cohorts and 300 for pediatric cohorts; and 3) minimum follow-up of three years. Participating studies were surveyed regarding design, data, and biosample resources.

Results

Twelve prospective cohort studies and two registries covering 21 countries were included. Participants age ranges from >2 to >70 years at inclusion, CKD severity ranges from stage 2 to stage 5. Patient data and biosamples (not available in the registry studies) are measured yearly or biennially. Many studies included multiple ethnicities; cohort size ranges from 400 to more than 13,000 participants. Studies’ areas of emphasis all include but are not limited to renal outcomes, such as progression to ESRD and death.

Conclusions

iNET-CKD (International Network of CKD cohort studies) was established, to promote collaborative research, foster exchange of expertise, and create opportunities for research training. Participating studies have many commonalities that will facilitate comparative research; however, we also observed substantial differences. The diversity we observed across studies within this network will be able to be leveraged to identify genetic, behavioral, and health services factors associated with the course of CKD. With an emerging infrastructure to facilitate interactions among the investigators of iNET-CKD and a broadly defined research agenda, we are confident that there will be great opportunity for productive collaborative investigations involving cohorts of individuals with CKD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0335-2) contains supplementary material, which is available to authorized users.

Budget impact of secondary hyperparathyroidism treatment in chronic kidney disease in an Ecuadorian social security hospital

BACKGROUND

Chronic kidney disease (CKD) is a disorder with high morbidity and mortality worldwide whose complications generate multiple costs. In Ecuador, only a few healthcare institutions have implemented management protocols aimed to reduce costs and to improve the quality of life of patients. The aim of this study is to evaluate the short-term (1-year) and long-term (5-year) costs and savings in the management of secondary hyperparathyroidism (SHPT) of hemodialyzed CKD patients by comparing calcitriol and paricalcitol in a large social security hospital in Quito, Ecuador.

METHODS

The estimation model assessed the resources used in the management of SHPT by comparing prospectively the cost savings within 1-year and 5-year time horizon with calcitriol and paricalcitol. Hospitalization, erythropoietin (EPO), treatment doses, intravenous iron consumption, and medical supplies were estimated according international references, based on the initial parathormone level (iPTH) of patients. The Ecuadorian National Reference costs (2014-2015) and institutional costs were used to calculate treatment costs. A statistical sensitivity analysis was also performed.

RESULTS

The study was based on data from 354 patients of whom 147 (41.4 %) had a value of iPTH in the range 300-600 pg/ml, 45 (12.8 %) in the range 601-800 pg/ml, and 162 (45.7 %) over 800 pg/ml. The 1-year estimated costs per patient for calcitriol and paricalcitol, respectively, were: medication, 63.88 USD and 1,123.44 USD; EPO, 19,522.95 USD and 16,478 USD; intravenous iron 143.21 USD and 187.76 USD. Yearly hospitalization costs per patient were 11,647.99 USD with calcitriol and 8,019.41 USD with paricalcitol. Total yearly costs per patient amounted to 31,378.02 USD with calcitriol and 25,809.50 USD with paricalcitol. Total savings using paricalcitol were 5,568.52 USD per patient compared with calcitriol. The 5-year cumulative medication costs were 319 USD for calcitriol and 2,403 USD for paricalcitol; EPO with calcitriol was 97,615 USD and with paricalcitol 82,394 USD; intravenous iron with calcitriol was 716 USD and paricalcitol 939 USD. Hospitalization costs for patients with calcitriol and paricalcitol were 43,095 USD and 62,595 USD, respectively. Total savings using paricalcitol amounted 32,414 USD per patient compared with calcitriol.

CONCLUSIONS

Paricalcitol use generated more cost savings than calcitriol after 1 and 5 years.

The Non-Dialysis Chronic Renal Insufficiency study (ND-CRIS): an open prospective hospital-based cohort study in France

BACKGROUND

Chronic kidney disease (CKD) amounts to a heavy burden for health services. There is no long-running epidemiological tool for CKD before dialysis. We here present the protocol for a cohort of patients with "non-dialysis" CKD receiving care in the Bourgogne-Franche-Comté region of France. The aim of this cohort was to periodically describe the characteristics of patients included and their care provision, to analyse evolution in care and patients' kidney function outcomes.

METHODS

The ND-CRIS cohort is prevalent and incident. Patients are included in the cohort if over 18, with a glomerula filtration rate (GFR) <60 ml/min/1.73 m2, non-dialysed, informed on the research and not having opposed it, and followed by a nephrologist in one of the 9 centres in the region, (3 pilot centres joined by 6 others in 2015). All the patients are followed up, with varying time lapses according to the degree of GFR deterioration. Data is collected by clinical research assistants (CRAs) using a dedicated computerised case-report form (CRF). Professional practices are assessed using indicators defined by the French Health Authority. The follow-up of patients included should enable assessment of the evolution of their GFR and co-morbidities. The periodic descriptions should give insight into evolution in epidemiological terms.

DISCUSSION

The ND-CRIS meets a need in epidemiological tools in France for CKD. The cohort does claim to be representative, of ND-CKD patients receiving care from nephrologists. The open and incident nature of the cohort and the number of patients included in the ND-CRIS should provide answers to questions that cannot be answered by smaller solely prevalent cohorts. The numbers of patients included over the study period (2391 patients in 3 centres in 3 years) suggests that the figure of 5000 patients should be reached by 2017. The participation of nephrologists and the rate of inclusions point to the feasibility of the implementation of this cohort. Beyond the information to be found in the CRFs, this cohort should also enable ad hoc studies, in particular in the area of pharmaco-epidemiology, and it could later serve as a research platform and as a public health surveillance tool.

Renal PET-imaging with (11)C-metformin in a transgenic mouse model for chronic kidney disease

Background

Organic cation transporters (OCTs) in the renal proximal tubule are important for the excretion of both exo- and endogenous compounds, and chronic kidney disease (CKD) alter the expression of OCT. Metformin is a well-known substrate for OCT, and recently, we demonstrated that positron emission tomography (PET) with 11C-labelled metformin (¹¹C-metformin) is a promising approach to evaluate the function of OCT. The aim of this study is therefore to examine renal pharmacokinetics of ¹¹C-metformin and expression of OCTs in a transgenic (RenTGF-β1) mouse model of CKD.

Methods

Age- and sex-matched RenTGF-β1 (Tg) and wildtype (WT) mice were used (5–8/group). Animals received an iv bolus of ¹¹C-metformin followed by 90-min dynamic PET and MRI scan. PET data were analysed using a one-tissue compartment model. Renal protein abundance of OCT2 (by Western blot) as well as OCT1, OCT2, and MATE1 messenger RNA (mRNA) (by RT-PCR) was examined.

Results

Protein expression of the basolateral uptake transporter OCT2 was 1.5-fold lower in Tg mice compared to WT mice while OCT1 and MATE1 mRNA expression did not differ between the two groups. The influx rate constant of ¹¹C-metformin in renal cortex (K₁) was 2.2-fold lower in transgenic mice whereas the backflux rate constant (k₂) was similar in the two groups, consistent with protein expression. Total body clearance (TBC) correlated within each group linearly with K₁.

Conclusions

In conclusion, this study demonstrates that both renal OCT2 expression and ¹¹C-metformin uptake are reduced in CKD mice. This potentially makes ¹¹C-metformin valuable as a PET probe to evaluate kidney function.

The Association between Nutritional Markers and Biochemical Parameters and Residual Renal Function in Peritoneal Dialysis Patients

Residual renal function (RRF) is an important prognostic factor for peritoneal dialysis patients as it influences the quality of life and mortality. This study was conducted to explore the potential factors correlated with RRF. A cross-sectional study was conducted by recruiting 155 patients with residual GFR more than 1mL/min per 1.73m2 at the initiation of peritoneal dialysis. We collected the demographic characteristics, nutritional markers and biochemical parameters of all participants, and analyzed the correlation between these variables and residual GFR as well. The odds ratio of RRF loss associated with each of the nutritional markers and biochemical parameters were estimated by logistic regression model. The residual GFR was negatively correlated with serum phosphate (ORQ3 = 2.67, 95%CI: 1.03-6.92; ORQ4 = 3.45, 95%CI: 1.35-9.04), magnesium (ORQ4 = 3.77, 95%CI: 1.48-3.63), and creatinine (ORQ3 = 2.93, 95%CI: 1.09-7.88; ORQ4 = 8.64 95%CI: 2.79-26.78), while positively associated with normalized protein catabolic rate (ORQ3 = 0.24, 95%CI: 0.09-0.65; ORQ4 = 0.11, 95%CI: 0.03-0.35), 24 hours urine volume(ORQ1 = 22.87, 95%CI: 2.76-189.24; ORQ3 = 0.08, 95%CI: 0.02-0.28) and serum chlorine concentrations (ORQ1 = 5.34, 95%CI: 1.94-14.68; ORQ4 = 0.28, 95%CI: 0.09-0.85), respectively. Our study suggested that the nutritional markers and biochemical parameters, though not all, but at least in part were closely correlated with RRF in peritoneal dialysis patients.

The CKD Outcomes and Practice Patterns Study (CKDopps): Rationale and Methods

BACKGROUND

Minimizing clinical complications in patients with advanced chronic kidney disease (CKD) and improving the transition to dialysis therapy and transplantation represents a challenge, requiring reliable evidence regarding the effects of CKD care on outcomes.

STUDY DESIGN

The CKD Outcomes and Practice Patterns Study (CKDopps) is a new international prospective cohort study designed to describe and evaluate variation in nephrologist-led CKD practices.

SETTING & PARTICIPANTS

CKDopps is underway in Brazil, France, Germany, Japan, and the United States. Diverse national samples of nephrology clinics are being recruited based on random selection stratified by geographic region and clinic characteristics. CKDopps aims to enroll 12,200 non-dialysis-dependent patients with CKD (75% and 25% with estimated glomerular filtration rates < 30 and 30-<60mL/min/1.73m(2), respectively) to be followed up for 3 to 5 years.

PREDICTORS

Demographic, comorbid condition, laboratory, and treatment-related variables are collected at 6-month intervals; patient-reported data are collected annually and more frequently near the transition to end-stage kidney disease; nephrologist practice surveys are collected annually.

OUTCOMES

Outcomes include mortality, end-stage kidney disease, other clinical events (eg, acute kidney injury, hospitalizations, infections, cardiovascular events, and transplant wait-listing), and patient-reported outcomes.

RESULTS

For the targeted sample size of 12,200 patients and 160 clinics, CKDopps has 80% power to detect HRs of 1.31 for mortality and 1.19 for mortality or transition to end-stage kidney disease.

LIMITATIONS

CKDopps does not capture care provided in settings outside nephrology clinics (eg, primary care) or patients with CKD not receiving medical care.

CONCLUSIONS

CKDopps is designed to characterize nephrology clinic practice variation and identify practices associated with better outcomes, with particular focus on advanced CKD, transition to end-stage kidney disease, and the patient experience. Because data will be collected during routine clinical care in real-world practice, analyses may yield practical readily implementable findings. CKDopps aims to establish a multinational infrastructure for research, collaboration, and ancillary investigation. Additional countries are encouraged to join.

Body fluid peptide and protein signatures in diabetic kidney diseases

Body fluid protein-based biomarkers carry the hope of improving patient management in diabetes by enabling more accurate and earlier detection of diabetic kidney disease (DKD), but also of defining the most suitable therapeutic targets. We present the data on some of the best studied individual protein markers in body fluids and conclude that their potential in clinical application for assessing DKD is moderate. Proteome-based approaches aiming at the identification of panels of body fluid biomarkers might be a valid alternative. We discuss the past (first) clinical proteomics studies in DKD, stressing their drawbacks but also the lessons that could be learned from them, as well as the more recent studies that have a potential for actual clinical implementation. We also highlight relevant issues and current problems associated with clinical proteomics from discovery towards application, and give suggestions for solutions that may help guiding proteomic studies, thereby removing some of the current hurdles for implementation of potentially beneficial results.

A prospective, multi-centre, observational study to examine kidney disease progression in adults with chronic kidney disease - CKDOD - Study design and preliminary results

Background

The objective of this article is to describe the organisation of an international, clinical registry, the Chronic Kidney Disease Observational Database (CKDOD), the processes of enrolling patients and entering data and preliminary results to date.

Design

The Chronic Kidney Disease Observational Database (CKDOD) is designed to assess the association between different factors with a known influence on chronic kidney disease (CKD) progression as well as treatment strategies such as dietary modifications, blood pressure control and pharmacological interventions in Asian countries (India, China, Malaysia and Thailand). The only inclusion criterion is the presence of CKD stage 2 or higher as defined by the KDIGO guidelines. Demographic and clinical information are collected by a standardised electronic questionnaire, available in English and Chinese. The data are transferred to the CKDOD database either by e-mail or via web access. All data are checked for consistency and missing values.

Collection of data started in September 2011 and by April 2015, data on 1323 individual patients had been submitted. The mean age at inclusion was 57 ± 14 years, 67 % were male and 36 % were diabetic. The baseline estimated glomerular filtration rate was 26 ml/min/1.73 m². Of all enrolled patients, 324 (24 %) received ketoanalogue supplementation during at least one recorded visit.

Discussion

The CKDOD is a very large and comprehensive data repository, currently focused in subjects recruited from Asia. The database is expected to provide important long-term information on CKD progression, nutritional and metabolic derangements that accompany CKD progression and treatment strategies to ameliorate progression and complications of CKD.

Trial Registration

Clinical Trial Registry – India: CTRI/2012/06/002743; 25th July 2012

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0191-5) contains supplementary material, which is available to authorized users.

Pro: 'The usefulness of biomarkers in glomerular diseases'. The problem: moving from syndrome to mechanism--individual patient variability in disease presentation, course and response to therapy

The diagnosis and treatment decisions in glomerular disease are principally based on renal pathology and nonspecific clinical laboratory measurements such as serum creatinine and urine protein. Using these classification approaches, patients have marked variability in rate of progression and response to therapy, exposing a significant number of patients to toxicity without benefit. Additionally, clinical trials are at risk of not being able to detect an efficacious therapy in relevant subgroups as patients with shared clinical-pathologic diagnoses have heterogeneous underlying pathobiology. To change this treatment paradigm, biomarkers that reflect the molecular mechanisms underlying the clinical-pathologic diagnoses are needed. Recent progress to identify such biomarkers has been aided by advances in molecular profiling, large-scale data generation and multi-scalar data integration, including prospectively collected clinical data. This article reviews the evolving success stories in glomerular disease biomarkers across the genotype-phenotype continuum and highlights opportunities to transition to precision medicine in glomerular disease.

Metabolic biomarkers for chronic kidney disease

Chronic kidney disease (CKD) is an increasingly recognized burden for patients and health care systems with high (and growing) global incidence and prevalence, significant mortality, and disproportionately high treatment costs. Yet, the available diagnostic tools are either impractical in clinical routine or have serious shortcomings impeding a well-informed disease management although optimized treatment strategies with proven benefits for the patients have become available. Advances in bioanalytical technologies have facilitated studies that identified genomic, proteomic, and metabolic biomarker candidates, and confirmed some of them in independent cohorts. This review summarizes the CKD-related markers discovered so far, and focuses on compounds and pathways, for which there is quantitative data, substantiating evidence from translational research, and a mechanistic understanding of the processes involved. Also, multiparametric marker panels have been suggested that showed promising diagnostic and prognostic performance in initial analyses although the data basis from prospective trials is very limited. Large-scale studies, however, are underway and will provide the information for validating a set of parameters and discarding others. Finally, the path from clinical research to a routine application is discussed, focusing on potential obstacles such as the use of mass spectrometry, and the feasibility of obtaining regulatory approval for targeted metabolomics assays.