Renal function trajectory is more important than chronic kidney disease stage for managing patients with chronic kidney disease

Clinical Outcomes in Patients with CKD and Rapid or Non-rapid eGFR Decline: A Report from the DISCOVER CKD Retrospective Cohort

INTRODUCTION

This analysis examined the baseline characteristics and clinical outcomes of patients with chronic kidney disease (CKD) and rapid or non-rapid estimated glomerular filtration rate (eGFR) decline, using retrospective data from DISCOVER CKD (ClinicalTrials.gov, NCT04034992).

METHODS

Data (2008-2020) were extracted from UK Clinical Practice Research Datalink, US TriNetX, US Limited Claims and Electronic Health Record Dataset, and Japan Medical Data Vision. Patients with CKD (two consecutive eGFR measures < 75 mL/min/1.73 m2 recorded 90-730 days apart) were included. Rapid eGFR decline was defined as an annual decline of > 4 mL/min/1.73 m2 at 2 years post-index; non-rapid eGFR decline was defined as an annual decline of ≤ 4 mL/min/1.73 m2. Clinical outcomes assessed included all-cause mortality, kidney outcomes (composite risk of kidney failure [progression to CKD stage 5] or > 50% eGFR decline, and kidney failure alone), cardiovascular events-including major adverse cardiovascular events (MACE; non-fatal myocardial infarction/stroke and cardiovascular death)-and all-cause hospitalization.

RESULTS

Across databases, rapid eGFR decline occurred in 13.7% of 804,237 eligible patients. Mean annual eGFR decline ranged between - 6.21 and - 6.86 mL/min/1.73 m2 in patients with rapid eGFR decline versus between - 0.11 and - 0.77 mL/min/1.73 m2 in patients with non-rapid eGFR decline. Rapid eGFR decline was associated with increased comorbidity burden and medication prescriptions. Across databases, the composite risk of kidney failure or > 50% decline in eGFR was significantly greater in patients with rapid versus non-rapid eGFR decline (P < 0.01); all-cause mortality, kidney failure alone, MACE, and all-cause hospitalization each significantly increased in two databases (P < 0.01-0.05).

CONCLUSION

Understanding patient factors associated with rapid eGFR decline in patients with CKD may help identify individuals who would benefit from proactive management to minimize the risk of adverse outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04034992.

The Assessment of the Association of Proton Pump Inhibitor Usage with Chronic Kidney Disease Progression through a Process Mining Approach

Previous studies have suggested an association between Proton Pump Inhibitors (PPIs) and the progression of chronic kidney disease (CKD). This study aims to assess the association between PPI use and CKD progression by analysing estimated glomerular filtration rate (eGFR) trajectories using a process mining approach. We conducted a retrospective cohort study from 1 January 2006 to 31 December 2011, utilising data from the Stockholm Creatinine Measurements (SCREAM). New users of PPIs and H2 blockers (H2Bs) with CKD (eGFR < 60) were identified using a new-user and active-comparator design. Process mining discovery is a technique that discovers patterns and sequences in events over time, making it suitable for studying longitudinal eGFR trajectories. We used this technique to construct eGFR trajectory models for both PPI and H2B users. Our analysis indicated that PPI users exhibited more complex and rapidly declining eGFR trajectories compared to H2B users, with a 75% increased risk (adjusted hazard ratio [HR] 1.75, 95% confidence interval [CI] 1.49 to 2.06) of transitioning from moderate eGFR stage (G3) to more severe stages (G4 or G5). These findings suggest that PPI use is associated with an increased risk of CKD progression, demonstrating the utility of process mining for longitudinal analysis in epidemiology, leading to an improved understanding of disease progression.

Evaluation of Hepatic/Renal and Splenic/Renal Echointensity Ratio Using Ultrasonography in Diabetic Nephropathy

The objective of this study is to assess the hepatic/renal and splenic/renal echointensity ratios in ultrasonography in patients with and without diabetic nephropathy. This retrospective study included patients with diabetes mellitus who underwent ultrasound examinations at our hospital between January 2023 and May 2023. Ultrasound examinations were conducted using renal cortical echogenicity and corticomedullary differentiation by using B-mode ultrasonography. The hepatic/renal and splenic/renal echo intensity ratios were compared among study groups (diabetic patients with diabetic nephropathy and without nephropathy). The diabetic nephropathy group exhibited significantly higher right renal echointensity and left renal echointensity compared to the non-nephropathic group. Additionally, the splenic/renal echointensity ratio and hepatic/renal echointensity ratio were significantly lower in the diabetic nephropathy group. Urinary microalbumin levels were significantly correlated with right renal echointensity (r = 0.65, p < 0.001) and left renal echointensity (r = 0.69, p < 0.001). There was also a significant inverse correlation between the urinary albumin and splenic/renal echointensity ratio (r = -0.58, p < 0.001). Ultrasonography, specifically the assessment of hepatic/renal and splenic/renal echointensity ratios, shows promise as a noninvasive and cost-effective method for evaluating morphological changes in the kidneys in patients with diabetic nephropathy. These findings suggest that ultrasonography can be a valuable tool for monitoring the progression of diabetic nephropathy and contributing to its early detection and management.

Quality of Life and Kidney Function in Older Adults: Prospective Data of the SCOPE Study

A longitudinal alteration in health-related quality of life (HRQoL) over a two-year period and its association with early-stage chronic kidney disease (CKD) progression was investigated among 1748 older adults (>75 years). HRQoL was measured by the Euro-Quality of Life Visual Analog Scale (EQ-VAS) at baseline and at one and two years after recruitment. A full comprehensive geriatric assessment was performed, including sociodemographic and clinical characteristics, the Geriatric Depression Scale-Short Form (GDS-SF), Short Physical Performance Battery (SPPB), and estimated glomerular filtration rate (eGFR). The association between EQ-VAS decline and covariates was investigated by multivariable analyses. A total of 41% of the participants showed EQ-VAS decline, and 16.3% showed kidney function decline over the two-year follow-up period. Participants with EQ-VAS decline showed an increase in GDS-SF scores and a greater decline in SPPB scores. The logistic regression analyses showed no contribution of a decrease in kidney function on EQ-VAS decline in the early stages of CKD. However, older adults with a greater GDS-SF score were more likely to present EQ-VAS decline over time, whereas an increase in the SPPB scores was associated with less EQ-VAS decline. This finding should be considered in clinical practice and when HRQoL is used to evaluate health interventions among older adults.

Patient Management and Clinical Outcomes Associated with a Recorded Diagnosis of Stage 3 Chronic Kidney Disease: The REVEAL-CKD Study

INTRODUCTION

Guidelines for the treatment of chronic kidney disease (CKD) recommend early intervention and management to slow disease progression. However, associations between diagnosis and CKD progression are not fully understood.

METHODS

REVEAL-CKD (NCT04847531) is a retrospective observational study of patients with stage 3 CKD. Data were extracted from the US TriNetX database. Eligible patients had two consecutive estimated glomerular filtration rate (eGFR) measurements indicative of stage 3 CKD (≥ 30 and < 60 ml/min/1.73 m2) recorded 91-730 days apart from 2015 to 2020. Diagnosed patients were included if their first CKD diagnosis code was recorded at least 6 months after their second qualifying eGFR measurement. We assessed CKD management and monitoring practices for the 180 days before and after CKD diagnosis, annual eGFR decline in the 2 years before and after CKD diagnosis, and associations between diagnostic delay and post-diagnosis event rates.

RESULTS

The study included 26,851 patients. After diagnosis, we observed significant increases in the prescribing rate of guideline-recommended medications such as angiotensin-converting enzyme inhibitors (rate ratio [95% confidence interval]: 1.87 [1.82, 1.93]), angiotensin receptor blockers (1.91 [1.85, 1.97]) and mineralocorticoid receptor antagonists (2.23 [2.13, 2.34]). Annual eGFR decline was significantly reduced following a CKD diagnosis, from 3.20 ml/min/1.73 m2 before diagnosis to 0.74 ml/min/1.73 m2 after diagnosis. Delayed diagnosis (by 1-year increments) was associated with elevated risk of CKD progression to stage 4/5 (1.40 [1.31-1.49]), kidney failure (hazard ratio [95% confidence interval]: 1.63 [1.23-2.18]) and the composite of myocardial infarction, stroke and hospitalization for heart failure (1.08 [1.04-1.13]).

CONCLUSIONS

A recorded CKD diagnosis was associated with significant improvements in CKD management and monitoring practices and attenuated eGFR decline. Recorded diagnosis of stage 3 CKD is an important first step to reduce the risk of disease progression and minimize adverse clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04847531.

Nutritional status and the risk of malnutrition in older adults with chronic kidney disease - implications for low protein intake and nutritional care: A critical review endorsed by ERN-ERA and ESPEN

Increased life expectancy is posing unprecedented challenges to healthcare systems worldwide. These include a sharp increase in the prevalence of chronic kidney disease (CKD) and of impaired nutritional status with malnutrition-protein-energy wasting (PEW) that portends worse clinical outcomes, including reduced survival. In older adults with CKD, a nutritional dilemma occurs when indications from geriatric nutritional guidelines to maintain the protein intake above 1.0 g/kg/day to prevent malnutrition need to be adapted to the indications from nephrology guidelines, to reduce protein intake in order to prevent or slow CKD progression and improve metabolic abnormalities. To address these issues, the European Society for Clinical Nutrition and Metabolism (ESPEN) and the European Renal Nutrition group of the European Renal Association (ERN-ERA) have prepared this conjoint critical review paper, whose objective is to summarize key concepts related to prevention and treatment of both CKD progression and impaired nutritional status using dietary approaches, and to provide guidance on how to define optimal protein and energy intake in older adults with differing severity of CKD. Overall, the authors support careful assessment to identify the most urgent clinical challenge and the consequent treatment priority. The presence of malnutrition-protein-energy wasting (PEW) suggests the need to avoid or postpone protein restriction, particularly in the presence of stable kidney function and considering the patient's preferences and quality of life. CKD progression and advanced CKD stage support prioritization of protein restriction in the presence of a good nutritional status. Individual risk-benefit assessment and appropriate nutritional monitoring should guide the decision-making process. Higher awareness of the challenges of nutritional care in older adult patients with CKD is needed to improve care and outcomes. Research is advocated to support evidence-based recommendations, which we still lack for this increasingly large patient subgroup.

Identification of Serum Metabolites for Predicting Chronic Kidney Disease Progression according to Chronic Kidney Disease Cause

Early detection and proper management of chronic kidney disease (CKD) can delay progression to end-stage kidney disease. We applied metabolomics to discover novel biomarkers to predict the risk of deterioration in patients with different causes of CKD. We enrolled non-dialytic diabetic nephropathy (DMN, n = 124), hypertensive nephropathy (HTN, n = 118), and polycystic kidney disease (PKD, n = 124) patients from the KNOW-CKD cohort. Within each disease subgroup, subjects were categorized as progressors (P) or non-progressors (NP) based on the median eGFR slope. P and NP pairs were randomly selected after matching for age, sex, and baseline eGFR. Targeted metabolomics was performed to quantify 188 metabolites in the baseline serum samples. We selected ten progression-related biomarkers for DMN and nine biomarkers each for HTN and PKD. Clinical parameters showed good ability to predict DMN (AUC 0.734); however, this tendency was not evident for HTN (AUC 0.659) or PKD (AUC 0.560). Models constructed with selected metabolites and clinical parameters had better ability to predict CKD progression than clinical parameters only. When selected metabolites were used in combination with clinical indicators, random forest prediction models for CKD progression were constructed with AUCs of 0.826, 0.872, and 0.834 for DMN, HTN, and PKD, respectively. Select novel metabolites identified in this study can help identify high-risk CKD patients who may benefit from more aggressive medical treatment.

Predictors of rapid progression of estimated glomerular filtration rate among persons living with diabetes and/or hypertension in Ghana: Findings from a multicentre study

In Ghana, the prevalence of chronic kidney disease (CKD) is 28.5% in diabetic hypertensive patients, 26.3% in hypertensives, and 16.1% in those with diabetes only. Trajectories of estimated glomerular filtration rate (eGFR) among patients with hypertension and diabetes are important for monitoring and instituting prompt interventions to prevent the development of CKD, especially in the face of limited access to renal replacement therapy. In this prospective multi‐center study conducted at five hospitals in Ghana, we assessed predictors of rapid eGFR progression among adults with hypertension and/or diabetes. Serum creatinine at baseline and 18 months were taken and eGFR determined using the CKD‐EPI formula. eGFR trajectory was defined as fast when the decline of GFR was ≥ 5 ml/min/1.73 m² per year. A multivariable logistic regression model was fitted to identify predictors of the fast progression of eGFR. Total 13% of 1261 participants met the criteria for rapid decline in eGFR. The adjusted odds ratio, aOR (95%CI), of four factors adversely associated with fast progression of eGFR were: increasing age 1.20 (1.03–1.14), partial health insurance coverage for medications 1.48 (1.05–2.08), history of smoking 1.91 (1.11–3.27), angiotensin‐receptor blockade use 1.55 (1.06–2.25) while metformin use was protective .56 (.35–.90). Proportion with eGFR <60 ml/min increased from 14% at baseline to 19% at month 18. Effective health insurance policies to improve medication access and avoidance of smoking are interventions that may mitigate the rising burden of CKD in individuals with diabetes mellitus and/or hypertension.

Using CUSUM in real time to signal clinically relevant decreases in estimated glomerular filtration rate

Background

The electronic health record (EHR), utilized to apply statistical methodology, assists provider decision-making, including during the care of chronic kidney disease (CKD) patients. When estimated glomerular filtration (eGFR) decreases, the rate of that change adds meaning to a patient’s single eGFR and may represent severity of renal injury. Since the cumulative sum chart technique (CUSUM), often used in quality control and surveillance, continuously checks for change in a series of measurements, we selected this statistical tool to detect clinically relevant eGFR decreases and developed CUSUM_GFR.

Methods

In a retrospective analysis we applied an age adjusted CUSUM_GFR, to signal identification of eventual ESKD patients prior to diagnosis date. When the patient signaled by reaching a specified threshold value, days from CUSUM signal date to ESKD diagnosis date (earliness days) were measured, along with the corresponding eGFR measurement at the signal.

Results

Signaling occurred by CUSUM_GFR on average 791 days (se = 12 days) prior to ESKD diagnosis date with sensitivity = 0.897, specificity = 0.877, and accuracy = .878. Mean days prior to ESKD diagnosis were significantly greater in Black patients (905 days) and patients with hypertension (852 days), diabetes (940 days), cardiovascular disease (1027 days), and hypercholesterolemia (971 days). Sensitivity and specificity did not vary by sociodemographic and clinical risk factors.

Conclusions

CUSUM_GFR correctly identified 30.6% of CKD patients destined for ESKD when eGFR was > 60 ml/min/1.73 m² and signaled 12.3% of patients that did not go on to ESKD (though almost all went on to later-stage CKD). If utilized in an EHR, signaling patients could focus providers’ efforts to slow or prevent progression to later stage CKD and ESKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02910-8.

A Long-term Estimated Glomerular Filtration Rate Plot Analysis Permits the Accurate Assessment of a Decline in the Renal Function by Minimizing the Influence of Estimated Glomerular Filtration Rate Fluctuations

Objective Evaluating the rate of decline in the estimated glomerular filtration rate (eGFR) may help identify patients with occult chronic kidney disease (CKD). We herein report that eGFR fluctuation complicates the assessment of the rate of decline and propose a long-term eGFR plot analysis as a solution. Methods In 142 patients with persistent eGFR decline in a single hospital, we evaluated the factors influencing the rate of eGFR decline, calculated over the long term (≥3 years) and short term (<3 years) using eGFR plots, taking into account eGFR fluctuation between visits. Results The difference between the rate of eGFR decline calculated using short- and long-term plots increased as the time period considered in the short-term plots became shorter. A regression analysis revealed that eGFR fluctuation was the only factor that explained the difference and that the fluctuation exceeded the annual eGFR decline in all participants. Furthermore, the larger the eGFR fluctuation, the more difficult it became to detect eGFR decline using a short-term eGFR analysis. Obesity, a high eGFR at baseline, and faster eGFR decline were associated with larger eGFR fluctuations. To circumvent the issue of eGFR fluctuation in the assessment of the rate of eGFR decline, we developed a system that generates a long-term eGFR plot using all eGFR values for a participant, which enabled the detection of occult CKD, facilitating early therapeutic intervention. Conclusion The construction of long-term eGFR plots is useful for identifying patients with progressive eGFR decline, as it minimizes the effect of eGFR fluctuation.

The Effects of Oral Sodium Bicarbonate on Renal Function and Cardiovascular Risk in Patients with Chronic Kidney Disease: A Systematic Review and Meta-Analysis

OBJECTIVE

Oral sodium bicarbonate is often used to correct acid-base disturbance in patients with chronic kidney disease (CKD). However, there is little evidence on patient-level benign outcomes to support the practice.

METHODS

We conducted a systematic review and meta-analysis to examine the efficacy and safety of oral sodium bicarbonate in CKD patients. A total of 1853 patients with chronic metabolic acidosis or those with low-normal serum bicarbonate (22-24 mEq/L) were performed to compare the efficacy and safety of oral sodium bicarbonate in patients with CKD.

RESULTS

There was a significant increase in serum bicarbonate level (MD 2.37 mEq/L; 95% CI, 1.03 to 3.72) and slowed the decline in estimated glomerular filtration rate (eGFR) (MD -4.44 mL/min per 1.73 m2, 95% CI, -4.92 to -3.96) compared with the control groups. The sodium bicarbonate lowered T50-time, an indicator of vascular calcification (MD -20.74 min; 95% CI, -49.55 to 8.08); however, there was no significant difference between the two groups. In addition, oral sodium bicarbonate dramatically reduced systolic blood pressure (MD -2.97 mmHg; 95% CI, -5.04 to -0.90) and diastolic blood pressure (MD -1.26 mmHg; 95% CI, -2.33 to -0.19). There were no statistically significant body weight, urine pH and mean mid-arm muscle circumference.

CONCLUSION

Treatment of metabolic acidosis with sodium bicarbonate may slow the decline rate of kidney function and potentially significantly improve vascular endothelial function in patients with CKD.

PROSPERO REGISTRATION NUMBER

CRD42020207185.

Different kidney function trajectory patterns before dialysis in elderly patients: clinical implications and outcomes

Background. Identifying trajectories of kidney disease progression in chronic kidney disease (CKD) patients may help to deliver better care. We aimed to identify and characterize trajectories of renal function decline in CKD patients and to investigate their association with mortality after dialysis.

Methods. This retrospective cohort study included 378 CKD patients who initiated dialysis (aged 65 years and over) between 2009 and 2016. Were considered mixed models using linear quadratic and cubic models to define the trajectories, and we used probabilistic clustering procedures. Patient characteristics and care practices at and before dialysis were examined by multivariable multinomial logistic regression. The association of these trajectories with mortality after dialysis was examined using Cox models.

Results. Four distinct groups of eGFR trajectories decline before dialysis were identified: slower decline (18.3%), gradual decline (18.3%), early rapid decline (41.2%), and rapid decline (22.2%). Patients with rapid eGFR decline were more likely to have diabetes, more cognitive impairment, to have been hospitalized before dialysis, and were less likely to have received pre-dialysis care compared to the patients with a slower decline. They had a higher risk of death within the first and fourth year after dialysis initiation, and after being more than 4 years in dialysis.

Conclusions. There are different patterns of eGFR trajectories before dialysis initiation in the elderly, that may help to identify those who are more likely to experience an accelerated decline in kidney function, with impact on pre ESKD care and in the mortality risk after dialysis.

Burden of chronic kidney disease and rapid decline in renal function among adults attending a hospital-based diabetes center in Northern Europe

Introduction

This study aimed to determine the prevalence of diabetic kidney disease (DKD) and rapid renal function decline and to identify indices associated with this decline among adults attending a diabetes center in Northern Europe.

Research design and methods

This is a retrospective cohort study of 4606 patients who attended a diabetes center in Ireland between June 2012 and December 2016. Definition/staging of chronic kidney disease used the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 classification based on data from the most recently attended appointment. Relevant longitudinal trends and variabilities were derived from serial records prior to index visit. Rapid renal function decline was defined based on per cent and absolute rates of estimated glomerular filtration rate (eGFR) change. Multiple linear regression was used to explore the relationships between explanatory variables and per cent eGFR change.

Results

42.0% (total), 23.4% (type 1 diabetes), 47.9% (type 2 diabetes) and 32.6% (other diabetes) had DKD. Rapid decline based on per cent change was more frequent in type 2 than in type 1 diabetes (32.8% vs 14.0%, p<0.001). Indices independently associated with rapid eGFR decline included older age, greater number of antihypertensives, higher log-normalized urine albumin to creatinine ratio (LNuACR), serum alkaline phosphatase, thyroid stimulating hormone, variability in systolic blood pressure and variability in LNuACR, lower glycated hemoglobin, high-density lipoprotein cholesterol and diastolic blood pressure, and lack of ACE inhibitor/angiotensin receptor blocker prescription.

Conclusions

DKD (using the KDIGO 2012 classification) and rapid eGFR decline were highly prevalent among adults attending a hospital-based diabetes clinic in a predominantly Caucasian Northern European country. The burden was greater for adults with type 2 diabetes. Expected as well as potentially novel clinical predictors were identified.

Alterations in symptoms and health-related quality of life as kidney function deteriorates: A cross-sectional study

AIMS AND OBJECTIVES

To compare symptoms and health-related quality of life and to examine the relationship between these as kidney function deteriorates.

BACKGROUND

Chronic kidney disease is a global health problem, and while knowledge of symptom burden and health-related quality of life is understood in kidney failure (previously end-stage kidney disease), there is limited understanding about symptoms and health-related quality of life across the chronic kidney disease trajectory.

DESIGN

Cross-sectional design reported using the STROBE guidelines.

METHODS

Eight hundred eighty-six adults with varying levels of kidney function (chronic kidney disease grades 3b-5 including those receiving dialysis) completed the renal version of the Integrated Palliative care Outcome Scale and the Quality of Life Short Form-36 version 2. Socio-demographic and renal characteristics were also collected. Data were analysed using descriptive and inferential statistics.

RESULTS

Participants had a mean age of 57 years and were mostly male. Regardless of chronic kidney disease grade, pain, poor mobility, weakness, anxiety and depression were the most prevalent and severe symptoms reported. Health-related quality of life was significantly associated with physical and psychological symptom scores. As kidney function deteriorated, both physical and mental health-related quality of life decreased, and prevalence and severity of symptoms increased.

CONCLUSIONS

There is substantial symptom burden irrespective of chronic kidney disease grade, which overwhelmingly affects health-related quality of life. Early identification by nurses would enable proactive management plans to be implemented.

RELEVANCE TO CLINICAL PRACTICE

Nurses, whether in specialist renal services or in primary healthcare, are ideally placed to regularly assess symptoms and health-related quality of life in those with chronic kidney disease. Timely assessment could assist in the targeting of earlier interventions designed to reduce symptom burden and to increase health-related quality of life.

Adverse outcomes associated with rapid linear and non-linear patterns of chronic kidney disease progression

Background

Patients with rapidly declining renal function face the dual threat of end-stage renal disease (ESRD) and mortality prior to ESRD. What is less well characterised is whether the pattern of the renal trajectory, linear or non-linear, unmasks subgroups of rapidly progressing patients that face adverse outcomes in a differential manner.

Methods

An individual eGFR slope was applied to all outpatient estimated glomerular filtration rate (eGFR) values for each patient in the Salford Kidney Study from 2002 to 2018 who had at least 2 years follow-up, ≥4 eGFR values and baseline eGFR 15 to < 60 ml/min/1.73m². Rapid progression was defined as an annual eGFR slope of ≤ − 3 ml/min/1.73m²/yr and patients were categorised as linear or non-linear progressors based on the nature of their eGFR-time graphs. A Fine-Gray competing risk hazard model was used to determine factors associated with progression to ESRD and with mortality prior to ESRD. Cumulative incidence function curves highlighted differences in outcomes between linear and non-linear patients.

Results

There were 211 rapidly deteriorating patients with linear eGFR trajectories and 61 rapid non-linear patients in the study cohort. Factors associated with ESRD included younger age, male gender, lower baseline eGFR and higher serum phosphate, whilst older age, history of myocardial infarction and anaemia predicted mortality prior to ESRD. Over a median follow-up of 3.7 years, linear progressors reached ESRD sooner whilst those with non-linear progression faced significantly higher rates of mortality prior to ESRD.

Conclusions

Patients with rapid eGFR decline have high rates of adverse outcomes that are differentially expressed in those progressing linearly and non-linearly as a result of differing phenotypic profiles. Consequently, addressing individual risk factor profiles is important to deliver optimal personalised patient care.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02282-5.

Association of Glomerular Filtration Rate and Carotid Intima-Media Thickness in Non-Diabetic Chronic Kidney Disease Patients over a 4-Year Follow-Up

Patients with chronic kidney disease (CKD) have increased risk of cardiovascular events. However, the association of glomerular filtration rate (GFR) and carotid intima-media thickness (CIMT) in non-diabetic CKD patients is under-investigated. This prospective study was conducted at University Clinical Hospital Mostar over a 4-year period and enrolled a total of 100 patients with stage 2 and 4 CKD (50 patients per group). Stage 4 CKD group had significantly higher baseline CIMT values (1.13 ± 0.25 vs. 0.74 ± 0.03 mm, P < 0.001), and more atherosclerotic plaques at the study onset (13 (26%) vs. 0 (0%), P < 0.001) compared to stage 2 CKD. A statistically significant 4-year increase in GFR (coefficient of 2.51, 3.25, 2.71 and 1.50 for 1-year, 2-year, 3-year and 4-year follow-up, respectively, P < 0.05) with non-significant CIMT alterations has been observed in stage 2 CKD. Furthermore, linear mixed effects analysis revealed significant decrease in GFR (coefficient of −6.69, −5.12, −3.18 and −1.77 for 1-year, 2-year, 3-year and 4-year follow-up, respectively, P < 0.001) with increase in CIMT (coefficient of 0.20, 0.14, 0.07 and 0.03 for 1-year, 2-year, 3-year and 4-year follow-up, respectively, P < 0.001) in stage 4 CKD. GFR and CIMT showed significant negative correlation in both CKD groups during all follow-up phases (P < 0.001). Furthermore, multiple linear regression analysis revealed significant independent prediction of CIMT by baseline GFR (B = −0.85, P < 0.001), while there was no significant prediction of CIMT with other covariates. In conclusion, this study demonstrates significant association of GFR and CIMT in non-diabetic stage 2 and stage 4 CKD during the 4-year follow-up.

Impaired kidney function is associated with lower quality of life among community-dwelling older adults : The screening for CKD among older people across Europe (SCOPE) study

Background

Quality of life (QoL) refers to the physical, psychological, social and medical aspects of life that are influenced by health status and function. The purpose of this study was to measure the self-perceived health status among the elderly population across Europe in different stages of Chronic Kidney Disease (CKD).

Methods

Our series consisted of 2255 community-dwelling older adults enrolled in the Screening for Chronic Kidney Disease (CKD) among Older People across Europe (SCOPE) study. All patients underwent a comprehensive geriatric assessment (CGA), including included demographics, clinical and physical assessment, number of medications taken, family arrangement, Geriatric Depression Scale (GDS), Cumulative Illness Rating Scale, History of falls, Lower urinary tract symptoms, and Short Physical Performance Battery (SPPB). Estimated glomerular filtration rate (eGFR) was calculated by Berlin Initiative Study (BIS) equation. Quality of life was assessed by Euro Qol questionnaire (Euro-Qol 5D) and EQ-Visual Analogue Scale (EQ-VAS). The association between CKD (eGFR < 60, < 45 ml or < 30 ml/min/1.73m²) and low EQoL-VAS was investigated by multivariable logistic regression models.

Results

CKD was found to be significantly associated with low EQoL-VAS in crude analysis (OR = 1.47, 95%CI = 1.16–1.85 for eGFR< 60; OR = 1.38, 95%CI = 1.08–1.77 for eGFR< 45; OR = 1.57, 95%CI = 1.01–2.44). Such association was no longer significant only when adjusting for SPPB (OR = 1.20, 95%CI = 0.93–1.56 for eGFR< 60; OR = 0.87, 95%CI = 0.64–1.18 for eGFR< 45; OR = 0.84, 95%CI = 0.50–1.42), CIRS and polypharmacy (OR = 1.16, 95%CI = 0.90–1.50 for eGFR< 60; OR = 0.86, 95%CI = 0.64–1.16 for eGFR< 45; OR = 1.11, 95%CI = 0.69–1.80) or diabetes, hypertension and chronic obstructive pulmonary disease (OR = 1.28, 95%CI = 0.99–1.64 for eGFR< 60; OR = 1.16, 95%CI = 0.88–1.52 for eGFR< 45; OR = 1.47, 95%CI = 0.92–2.34). The association between CKD and low EQoL-VAS was confirmed in all remaining multivariable models.

Conclusions

CKD may significantly affect QoL in community-dwelling older adults. Physical performance, polypharmacy, diabetes, hypertension and COPD may affect such association, which suggests that the impact of CKD on QoL is likely multifactorial and partly mediated by co-occurrent conditions/risk factors.

Increasing tendency of urine protein is a risk factor for rapid eGFR decline in patients with CKD: A machine learning-based prediction model by using a big database

Artificial intelligence is increasingly being adopted in medical fields to predict various outcomes. In particular, chronic kidney disease (CKD) is problematic because it often progresses to end-stage kidney disease. However, the trajectories of kidney function depend on individual patients. In this study, we propose a machine learning-based model to predict the rapid decline in kidney function among CKD patients by using a big hospital database constructed from the information of 118,584 patients derived from the electronic medical records system. The database included the estimated glomerular filtration rate (eGFR) of each patient, recorded at least twice over a period of 90 days. The data of 19,894 patients (16.8%) were observed to satisfy the CKD criteria. We characterized the rapid decline of kidney function by a decline of 30% or more in the eGFR within a period of two years and classified the available patients into two groups—those exhibiting rapid eGFR decline and those exhibiting non-rapid eGFR decline. Following this, we constructed predictive models based on two machine learning algorithms. Longitudinal laboratory data including urine protein, blood pressure, and hemoglobin were used as covariates. We used longitudinal statistics with a baseline corresponding to 90-, 180-, and 360-day windows prior to the baseline point. The longitudinal statistics included the exponentially smoothed average (ESA), where the weight was defined to be 0.9*(t/b), where t denotes the number of days prior to the baseline point and b denotes the decay parameter. In this study, b was taken to be 7 (7-day ESA). We used logistic regression (LR) and random forest (RF) algorithms based on Python code with scikit-learn library (https://scikit-learn.org/) for model creation. The areas under the curve for LR and RF were 0.71 and 0.73, respectively. The 7-day ESA of urine protein ranked within the first two places in terms of importance according to both models. Further, other features related to urine protein were likely to rank higher than the rest. The LR and RF models revealed that the degree of urine protein, especially if it exhibited an increasing tendency, served as a prominent risk factor associated with rapid eGFR decline.

Predictive factors of rapid linear renal progression and mortality in patients with chronic kidney disease

BACKGROUND

Risk factors predictive of rapid linear chronic kidney disease (CKD) progression and its associations with end-stage renal disease (ESRD) and mortality requires further exploration, particularly as patients with linear estimated glomerular filtration rate (eGFR) trajectory represent a clear paradigm for understanding true CKD progression.

METHODS

A linear regression slope was applied to all outpatient eGFR values for patients in the Salford Kidney Study who had ≥2 years follow-up, ≥4 eGFR values and baseline CKD stages 3a-4. An eGFR slope (ΔeGFR) of ≤ - 4 ml/min/1.73m2/yr defined rapid progressors, whereas - 0.5 to + 0.5 ml/min/1.73m2/yr defined stable patients. Binary logistic regression was utilised to explore variables associated with rapid progression and Cox proportional hazards model to determine predictors for mortality prior to ESRD.

RESULTS

There were 157 rapid progressors (median ΔeGFR - 5.93 ml/min/1.73m2/yr) and 179 stable patients (median ΔeGFR - 0.03 ml/min/1.73m2/yr). Over 5 years, rapid progressors had an annual rate of mortality or ESRD of 47 per 100 patients compared with 6 per 100 stable patients. Factors associated with rapid progression included younger age, female gender, higher diastolic pressure, higher total cholesterol:high density lipoprotein ratio, lower albumin, lower haemoglobin and a urine protein:creatinine ratio of > 50 g/mol. The latter three factors were also predictive of mortality prior to ESRD, along with older age, smoking, peripheral vascular disease and heart failure.

CONCLUSIONS

There is a heterogenous interplay of risk factors associated with rapid linear CKD progression and mortality in patients with CKD. Furthermore, rapid progressors have high rates of adverse outcomes and require close specialist monitoring.

Risk of progressive chronic kidney disease in individuals with early-onset type 2 diabetes: a prospective cohort study

BACKGROUND

The progression trajectory of renal filtration function has not been well characterized in patients with early-onset type 2 diabetes mellitus (T2DM) although albuminuria is often reported in this population. We aim to study the risk of progressive chronic kidney disease (CKD) in individuals with early-onset T2DM.

METHODS

In total, 1189 T2DM participants were followed for 3.9 (interquartile range 3.2-4.7) years. Progressive CKD was defined as estimated glomerular filtration rate (eGFR) decline of ≥5 mL/min/1.73 m2 per year. Early-onset T2DM was defined as age at T2DM diagnosis between 18 and 30 years.

RESULTS

Compared with later-onset counterparts (N = 1032), participants with early-onset T2DM (N = 157) were more obese and had poorer glycaemic control at baseline. In the follow-up, 24.2% and 15.6% experienced progressive CKD in early-onset and later-onset participants, respectively (P = 0.007). Logistic regression suggested that participants with early-onset T2DM had 2.63-fold [95% confidence interval (CI) 1.46-4.75] higher risk of progressive CKD after accounting for multiple traditional risk factors. Furthermore, the excess risk of progressive CKD associated with early-onset T2DM mainly occurred in participants with preserved renal function [eGFR ≥60 mL/min/1.73 m2, odds ratio (OR) 2.85, 95% CI 1.50-5.42] and was more pronounced in those with diabetes duration <10 years (OR 3.67, 95% CI 1.51-8.90).

CONCLUSIONS

Individuals with early-onset T2DM have a higher risk of progressive CKD. The excess risk mainly exhibits in early stage of CKD and cannot be solely attributed to traditional risk factors and a longer diabetes duration.

Discovery and Validation of a Biomarker Model (PRESERVE) Predictive of Renal Outcomes After Liver Transplantation

BACKGROUND AND AIMS

A high proportion of patients develop chronic kidney disease (CKD) after liver transplantation (LT). We aimed to develop clinical/protein models to predict future glomerular filtration rate (GFR) deterioration in this population.

APPROACH AND RESULTS

In independent multicenter discovery (CTOT14) and single-center validation (BUMC) cohorts, we analyzed kidney injury proteins in serum/plasma samples at month 3 after LT in recipients with preserved GFR who demonstrated subsequent GFR deterioration versus preservation by year 1 and year 5 in the BUMC cohort. In CTOT14, we also examined correlations between serial protein levels and GFR over the first year. A month 3 predictive model was constructed from clinical and protein level variables using the CTOT14 cohort (n = 60). Levels of β-2 microglobulin and CD40 antigen and presence of hepatitis C virus (HCV) infection predicted early (year 1) GFR deterioration (area under the curve [AUC], 0.814). We observed excellent validation of this model (AUC, 0.801) in the BUMC cohort (n = 50) who had both early and late (year 5) GFR deterioration. At an optimal threshold, the model had the following performance characteristics in CTOT14 and BUMC, respectively: accuracy (0.75, 0.8), sensitivity (0.71, 0.67), specificity (0.78, 0.88), positive predictive value (0.74, 0.75), and negative predictive value (0.76, 0.82). In the serial CTOT14 analysis, several proteins, including β-2 microglobulin and CD40, correlated with GFR changes over the first year.

CONCLUSIONS

We have validated a clinical/protein model (PRESERVE) that early after LT can predict future renal deterioration versus preservation with high accuracy. This model may help select recipients at higher risk for subsequent CKD for early, proactive renal sparing strategies.

A Study on Effect of Bicarbonate Supplementation on the Progression of Chronic Kidney Disease

Introduction:

Chronic kidney disease (CKD) is a major health problem in India. Prevalence of CKD will continue to rise, reflecting the growing elderly population and increasing number of patients with diabetes and hypertension.

Methods:

A total of 67 patients with CKD participated in the study. Patients were randomized into two groups. Group 1 received oral bicarbonate and Group 2 was the control group. Their baseline, 6 and 9 months estimated glomerular filtration rate (eGFR), bicarbonate, muscle mass and serum albumin were estimated. We analysed the effect of bicarbonate supplementation on the progression of CKD.

Results:

Bicarbonate supplementation decreased the metabolic acidosis in CKD patients. After bicarbonate supplementation, the serum bicarbonate level increased time-dependently from 16.62 to 18.02 and 19.77 mEq/L after 6 and 9 months, respectively. It also restored the eGFR to its baseline value. The eGFR values of Group 1 at baseline, after 6 months and 9 months were 22.39, 22.66, and 22.65 mL/min/1.73 m2, respectively. In contrast, the eGFR value in Group 2 reduced significantly. Patients who received bicarbonate supplementation displayed increased serum albumin levels compared with the controls. The albumin level was significantly increased from 4.05 to 4.24 and 4.34 g/dL, respectively, after 6 and 9 months (P = 0.0001). Also, bicarbonate supplementation showed significant improvement in muscle mass.

Conclusion:

Study confirms the role of bicarbonate in relieving the metabolic acidosis and thereby its possible role in the management of CKD progression.

Clustering Heatmap for Visualizing and Exploring Complex and High-dimensional Data Related to Chronic Kidney Disease

Background: Preventive medicine and primary health care are essential for patients with chronic kidney disease (CKD) because the symptoms of CKD may not appear until the renal function is severely compromised. Early identification of the risk factors of CKD is critical for preventing kidney damage and adverse outcomes. Early recognition of rapid progression to advanced CKD in certain high-risk populations is vital. Methods: This is a retrospective cohort study, the population screened and the site where the study has been performed. Multivariate statistical analysis was used to assess the prediction of CKD as many potential risk factors are involved. The clustering heatmap and random forest provides an interactive visualization for the classification of patients with different CKD stages. Results: uric acid, blood urea nitrogen, waist circumference, serum glutamic oxaloacetic transaminase, and hemoglobin A1c (HbA1c) were significantly associated with CKD. CKD was highly associated with obesity, hyperglycemia, and liver function. Hypertension and HbA1c were in the same cluster with a similar pattern, whereas high-density lipoprotein cholesterol had an opposite pattern, which was also verified using heatmap. Early staged CKD patients who are grouped into the same cluster as advanced staged CKD patients could be at high risk for rapid decline of kidney function and should be closely monitored. Conclusions: The clustering heatmap provided a new predictive model of health care management for patients at high risk of rapid CKD progression. This model could help physicians make an accurate diagnosis of this progressive and complex disease.

The Relationship Between Chronic Kidney Disease, Symptoms and Health-Related Quality of Life: A Systematic Review

BACKGROUND

People with chronic kidney disease (CKD) experience a wide range of symptoms due to reduced kidney function. As the disease progresses these symptoms become more burdensome and often negatively affect a person's health-related quality of life (HRQoL).

OBJECTIVE

To examine the evidence of symptoms and HRQoL in CKD stages 1-5 and the relationships between these.

METHODS

Studies published in English from January 2008 to July 2018 using six databases (PubMed, MEDLINE, CINAHL, PsycINFO, Cochrane Library and JBI Library) were searched.

RESULTS

Thirteen studies were included in this review although only three had interventional designs. By considering symptom experience and HRQoL together, four studies found that HRQoL decreased when symptoms increased. Feeling washed out, fatigue and drowsiness were found to be the most common symptoms reported. Only two studies reported follow-up measurements although six studied how symptoms change over time. None of the studies examined the change of symptoms over time across the different CKD stages. The majority of studies showed a decline in physical HRQoL and improvement in mental HRQoL over time. Nutritional and exercise interventions showed some improvements in symptom experience and HRQoL.

CONCLUSIONS

Only four studies were found that reported the relationship between symptoms and HRQoL of those with CKD. Of these, in view of symptom experience and HRQoL together, HRQoL decreased when symptoms increased. However, more research is warranted to establish a clear understanding of the relationship between symptoms and HRQoL in CKD to enable the design of appropriate interventions.

Arterial Stiffness Modulates the Association of Resting Heart Rate With Rapid Renal Function Decline in Individuals With Type 2 Diabetes Mellitus

Objective:

Resting heart rate (RHR) has been associated with cardiovascular risk, but data on renal outcomes are still scarce. We aimed to study the association of RHR with rapid renal function decline (RRFD) and to explore whether the association of RHR with RRFD is modulated by arterial stiffness in individuals with type 2 diabetes mellitus.

Approach and Results:

One thousand one hundred forty-two Asian people with type 2 diabetes mellitus were followed for 3.9±0.9 years in a regional hospital and a primary care facility. RRFD was defined as eGFR decline of 5 mL/min per 1.73 m2 or greater per year. Arterial stiffness was assessed by carotid-femoral pulse wave velocity. One hundred sixty-eight participants (15%) were classified as having RRFD. Participants with elevated RHR were younger, had higher levels of HbA1c, albuminuria, C-reactive protein, and pulse wave velocity. Compared with the lowest quartile, participants in quartile 4 had a higher risk for RRFD after adjustment for known risk factors (adjusted odds ratio 1.91 [1.11–3.28]). RHR improved discrimination and net reclassification for prediction of RRFD above traditional risk factors. Remarkably, arterial stiffness modulated the association of RHR with RRFD ( P for interaction =0.03). RHR was significantly associated with risk of RRFD only in those with increased arterial stiffness (pulse wave velocity above age-reference value 7.7 m/s).

Conclusions:

RHR independently predicts RRFD, and the association is modulated by arterial stiffness. An elevated heart rate may be one factor in the spectrum of cardiovascular risk factors associated with renal functional impairment, especially in those with type 2 diabetes mellitus and an increased arterial stiffness.

Temporal validation of the CT-PIRP prognostic model for mortality and renal replacement therapy initiation in chronic kidney disease patients

Background

A classification tree model (CT-PIRP) was developed in 2013 to predict the annual renal function decline of patients with chronic kidney disease (CKD) participating in the PIRP (Progetto Insufficienza Renale Progressiva) project, which involves thirteen Nephrology Hospital Units in Emilia-Romagna (Italy). This model identified seven subgroups with specific combinations of baseline characteristics that were associated with a differential estimated glomerular filtration rate (eGFR) annual decline, but the model’s ability to predict mortality and renal replacement therapy (RRT) has not been established yet.

Methods

Survival analysis was used to determine whether CT-PIRP subgroups identified in the derivation cohort (n = 2265) had different mortality and RRT risks. Temporal validation was performed in a matched cohort (n = 2051) of subsequently enrolled PIRP patients, in which discrimination and calibration were assessed using Kaplan-Meier survival curves, Cox regression and Fine & Gray competing risk modeling.

Results

In both cohorts mortality risk was higher for subgroups 3 (proteinuric, low eGFR, high serum phosphate) and lower for subgroups 1 (proteinuric, high eGFR), 4 (non-proteinuric, younger, non-diabetic) and 5 (non-proteinuric, younger, diabetic). Risk of RRT was higher for subgroups 3 and 2 (proteinuric, low eGFR, low serum phosphate), while subgroups 1, 6 (non-proteinuric, old females) and 7 (non-proteinuric, old males) showed lower risk. Calibration was excellent for mortality in all subgroups while for RRT it was overall good except in subgroups 4 and 5.

Conclusions

The CT-PIRP model is a temporally validated prediction tool for mortality and RRT, based on variables routinely collected, that could assist decision-making regarding the treatment of incident CKD patients. External validation in other CKD populations is needed to determine its generalizability.

Predictores de progresión de enfermedad renal en el paciente anciano

El riñón del anciano experimenta cambios estructurales y funcionales, que lo convierte en más vulnerable para la enfermedad renal. La mayoría de ancianos con enfermedad renal crónica fallece antes de desarrollar progresión renal. Sin embargo, el principal grupo de pacientes incidentes de nefropatía terminal es el de personas mayores de 65 años, representando la diabetes mellitus y las causas vasculares sus principales etiologías. En esta revisión se analizan elementos renales (filtrado glomerular, proteinuria/albuminuria, potasio, fracaso renal agudo y diuréticos) y factores geriátricos (estado funcional, cognitivo y fragilidad) como predictores de progresión de enfermedad renal. La identificación de estos factores contribuirá a establecer estrategias de prevención renal y al pronóstico de la enfermedad en la toma decisiones.

Role of Ultrasound in the Diagnosis of Chronic Kidney Disease and its Correlation with Serum Creatinine Level

Objective: We aimed to study the role of ultrasound in the diagnosis of chronic kidney disease (CKD) and its correlation with serum creatinine level.

Materials and methods: This was a retrospective cross sectional study conducted in the ultrasound department of Dr. Ziauddin Hospital Clifton campus, Karachi from April 6, 2017 to October 6, 2017 for a period of six months. A total of 200 patients with CKD and glomerular filtration rate (GFR) determined to be < 60 ml/min were included in this study. Blood tests were gathered from the chosen patients, serum creatinine estimation was done for those patients and they underwent ultrasonography on the same day to assess echogenicity, parenchymal thickness, cortical thickness, and longitudinal length. This information was noted in the pro forma.

Results: The average age of the patients was 54.62±13.3 years. Mean serum creatinine was significant among echogenicity grades [p=0.0005]. Mean parenchymal thickness was also significant among echogenicity grades (p=0.0005). Mean longitudinal length was also significant among echogenicity grades (p=0.0005). Mean corticomedullary distinction was also significant among echogenicity grades (p=0.0005). A statistically significant highly positive correlation was observed between serum creatinine and cortical echogenicity grading (r=0.915 P = 0.0005).

Conclusion: The best sonographic parameter that correlates with serum creatinine is renal cortical echogenicity and its grading in comparison to longitudinal length, parenchymal thickness, and cortical thickness in patients of CKD. Since renal cortical echogenicity has the advantage of being irreversible in comparison to serum creatinine levels, it can be used as a parameter of renal function.

Asian Americans & chronic kidney disease in a nationally representative cohort

Background

There is a paucity of specific data on early stages of chronic kidney disease (CKD) among Asian Americans (AAs). The objective of this study was to examine the independent association of Asian race/ethnicity and socio-demographic and co-morbidity factors with markers of early kidney damage, ascertained by ACR levels, as well as kidney dysfunction, ascertained by eGFR levels in a large cross-sectional sample of AAs enrolled in the National Health and Nutrition Examination Survey (NHANES).

Methods

Secondary data analyses of the NHANES 2011–2014 data of a nationally representative sample of 5907 participants 18 years and older, US citizens, and of Asian and White race. NHANES data included race (Asian vs. White), as well as other socio-demographic information and comorbidities. Urine albumin-to-creatinine ratio (ACR) categories and estimated glomerular filtration rate (eGFR) were used as indicators for CKD. Descriptive analyses using frequencies, means (standard deviations), and chi-square tests was first conducted, then multivariable logistic regression serial adjustment models were used to examine the associations between race/ethnicity, other socio-demographic factors (age, sex, education), and co-morbidities (obesity, diabetes, hypertension) with elevated ACR levels (A2 & A3 – CKD Stages 3 and 4–5, respectively) as well as reduced eGFR (G3a-G5 and G3b –G5 - CKD Stage 3–5).

Results

AAs were more likely than White participants to have ACR levels > 300 mg/g (A3) (adjusted OR (aOR) (95% CI) 2.77 (1.55, 4.97), p = 0.001). In contrast, adjusted analyses demonstrated that AAs were less likely to have eGFR levels < 60 ml/min/1.73 m2 (G3a-G5) (aOR (95% CI) 0.50 (0.35, 0.72), p < .001).

Conclusions

This is one of the first large U.S. population-based studies of AAs that has shown a comparatively higher risk of elevated ACR > 300 mg/g levels (A3) but lower risk of having eGFR levels < 60 ml/min/1.732 m2 (G3a-G5). The findings support the need to address the gaps in knowledge regarding disparities in risk of early stage CKD among AAs.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1145-5) contains supplementary material, which is available to authorized users.

Risk factors for decline in renal function among young adults with type 1 diabetes

AIMS

To investigate risk factors for declining renal function among subjects with type-1-diabetes.

METHODS

Observational study based on data from the diabetes registry DPV. 4424 type-1-diabetes subjects aged ≥18 years, age at onset <18 years were identified. Modification of Diet in Renal Disease (MDRD) equation was used to estimate glomerular filtration rate (eGFR). Annual rate of renal decline was estimated for each patient using hierarchic linear regression models. Additional regression models were fitted to adjust for covariates.

RESULTS

Median age was 26 [Q1; Q3: 21; 39] years. Annual decline of renal function was -1.22 (95% CI: -1.50; -0.94) ml/min/1.73 m². At baseline, higher eGFR was related to more rapid decline compared to impaired or reduced eGFR (GFR ≥ 90: -2.06 (-2.35; -1.76), 60 ≤ GFR < 90: 0.45 (0.08; 0.81), GFR < 60: 0.52 (-0.24; 1.29) ml/min/1.73 m², p < 0.01). During follow-up, the highest decline was associated with reduced renal function, whereas the lowest decline was related to normal kidney function (p < 0.01). Poor metabolic control (p = 0.04), hypertension (p < 0.01) and albuminuria (p = 0.03) were associated with more rapid loss of kidney function. No difference was observed among insulin regimen.

CONCLUSION

Among this large type-1-diabetes cohort, more rapid loss of kidney function was related to higher baseline eGFR, log-term worse metabolic control and diabetic comorbidities.

Effect of Coaching to Increase Water Intake on Kidney Function Decline in Adults With Chronic Kidney Disease: The CKD WIT Randomized Clinical Trial

IMPORTANCE

In observational studies, increased water intake is associated with better kidney function.

OBJECTIVE

To determine the effect of coaching to increase water intake on kidney function in adults with chronic kidney disease.

DESIGN, SETTING, AND PARTICIPANTS

The CKD WIT (Chronic Kidney Disease Water Intake Trial) randomized clinical trial was conducted in 9 centers in Ontario, Canada, from 2013 until 2017 (last day of follow-up, May 25, 2017). Patients had stage 3 chronic kidney disease (estimated glomerular filtration rate [eGFR] 30-60 mL/min/1.73 m2 and microalbuminuria or macroalbuminuria) and a 24-hour urine volume of less than 3.0 L.

INTERVENTIONS

Patients in the hydration group (n = 316) were coached to drink more water, and those in the control group (n = 315) were coached to maintain usual intake.

MAIN OUTCOMES AND MEASURES

The primary outcome was change in kidney function (eGFR from baseline to 12 months). Secondary outcomes included 1-year change in plasma copeptin concentration, creatinine clearance, 24-hour urine albumin, and patient-reported overall quality of health (0 [worst possible] to 10 [best possible]).

RESULTS

Of 631 randomized patients (mean age, 65.0 years; men, 63.4%; mean eGFR, 43 mL/min/1.73 m2; median urine albumin, 123 mg/d), 12 died (hydration group [n = 5]; control group [n = 7]). Among 590 survivors with 1-year follow-up measurements (95% of 619), the mean change in 24-hour urine volume was 0.6 L per day higher in the hydration group (95% CI, 0.5 to 0.7; P < .001). The mean change in eGFR was -2.2 mL/min/1.73 m2 in the hydration group and -1.9 mL/min/1.73 m2 in the control group (adjusted between-group difference, -0.3 mL/min/1.73 m2 [95% CI, -1.8 to 1.2; P = .74]). The mean between-group differences (hydration vs control) in secondary outcomes were as follows: plasma copeptin, -2.2 pmol/L (95% CI, -3.9 to -0.5; P = .01); creatinine clearance, 3.6 mL/min/1.73 m2 (95% CI, 0.8 to 6.4; P = .01); urine albumin, 7 mg per day (95% CI, -4 to 51; P = .11); and quality of health, 0.2 points (95% CI, -0.3 to 0.3; P = .22).

CONCLUSIONS AND RELEVANCE

Among adults with chronic kidney disease, coaching to increase water intake compared with coaching to maintain the same water intake did not significantly slow the decline in kidney function after 1 year. However, the study may have been underpowered to detect a clinically important difference.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01766687.

Kidney Biomarkers and Decline in eGFR in Patients with Type 2 Diabetes

BACKGROUND AND OBJECTIVES

Biomarkers may improve identification of individuals at risk of eGFR decline who may benefit from intervention or dialysis planning. However, available biomarkers remain incompletely validated for risk stratification and prediction modeling.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined serum cystatin C, urinary kidney injury molecule-1 (uKIM-1), and urinary neutrophil gelatinase-associated lipocalin (UNGAL) in 5367 individuals with type 2 diabetes mellitus and recent acute coronary syndromes enrolled in the Examination of Cardiovascular Outcomes with Alogliptin versus Standard of Care (EXAMINE) trial. Baseline concentrations and 6-month changes in biomarkers were also evaluated. Cox proportional regression was used to assess associations with a 50% decrease in eGFR, stage 5 CKD (eGFR<15 ml/min per 1.73 m2), or dialysis.

RESULTS

eGFR decline occurred in 98 patients (1.8%) over a median of 1.5 years. All biomarkers individually were associated with higher risk of eGFR decline (P<0.001). However, when adjusting for baseline eGFR, proteinuria, and clinical factors, only baseline cystatin C (adjusted hazard ratio per 1 SD change, 1.66; 95% confidence interval, 1.41 to 1.96; P<0.001) and 6-month change in urinary neutrophil gelatinase-associated lipocalin (adjusted hazard ratio per 1 SD change, 1.07; 95% confidence interval, 1.02 to 1.12; P=0.004) independently associated with CKD progression. A base model for predicting kidney function decline with nine standard risk factors had strong discriminative ability (C-statistic 0.93). The addition of baseline cystatin C improved discrimination (C-statistic 0.94), but it failed to reclassify risk categories of individuals with and without eGFR decline.

CONCLUSIONS

The addition of cystatin C or biomarkers of tubular injury did not meaningfully improve the prediction of eGFR decline beyond common clinical factors and routine laboratory data in a large cohort of patients with type 2 diabetes and recent acute coronary syndrome.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_01_16_CJASNPodcast_18_3_G.mp3.

Fast GFR decline and progression to CKD among primary care patients with preserved GFR

BACKGROUND

Fast glomerular filtration rate (GFR) decline is associated with adverse outcomes, but the associated risk factors among patients without chronic kidney disease (CKD) are not well defined.

METHODS

From a primary care registry of 37,796, we identified 2219 (6%) adults with at least three estimated (e)GFR values and a baseline eGFR between 60 and 119 ml/min/1.73 m² during an observation period of 8 years. We defined fast GFR decline as > 5 ml/min/1.73 m² per year. The outcome measure was incident CKD (eGFR < 60 ml/min/1.73 m²). Clinical and demographic characteristics were compared using Chi-square and independent-samples t tests.

RESULTS

Older age, African-American race, unmarried status, hypertension and type 2 diabetes were more common in both fast decliners and those who developed incident CKD (p < 0.0001 to < 0.05). Lower neighborhood socioeconomic status, current smoking and baseline eGFR 90-119 ml/min/1.73 m² were associated with fast decline (p < 0.01), while baseline eGFR 60-74 ml/min/1.73 m² with incident CKD (p < 0.05). In multivariate regression models, among fast decliners with mildly reduced baseline eGFR (60-89 ml/min/1.73 m²), older age was significantly associated with incident CKD [odds ratio (OR) 1.04; 95% CI 1.01-1.08], and among those with normal baseline eGFR (≥ 90-119 ml/min/1.73 m²), type 2 diabetes was significantly associated with incident CKD (OR 3.83; 95% CI 1.35-10.89).

CONCLUSIONS

Among primary care patients without CKD, GFR is checked infrequently. We have identified patients at high risk of progressive CKD, in whom we suggest a closer monitoring of renal function.

Awareness, self-management behaviors, health literacy and kidney function relationships in specialty practice

AIM

To determine the relationship between chronic kidney disease (CKD) awareness (CKD-A), self-management behaviors (CKD-SMB) knowledge, performance of CKD-SMBs, health literacy (HL) and kidney function.

METHODS

Participants were eligible patients attending an outpatient nephrology clinic. Participants were administered: Newest Vital Sign to measure HL, CKD self-management knowledge tool (CKD-SMKT) to assess knowledge, past performance of CKD-SMB, CKD-A. Estimated GFR (eGFR) was determined using the MDRD-4 equation. Duration of clinic participation and CKD cause were extracted from medical charts.

RESULTS

One-hundred-fifty patients participated in the study. eGFRs ranged from 17-152 mL/min per 1.73 m². Majority (83%) of respondents had stage 3 or 4 CKD, low HL (63%), and were CKD aware (88%). Approximately 40% (10/25) of patients in stages 1 and 2 and 6.4% (8/125) in stages 3 and 4 were unaware of their CKD. CKD-A differed with stage (P < 0.001) but not by HL level, duration of clinic participation, or CKD cause. Majority of respondents (≥ 90%) correctly answered one or more CKD-SMKT items. Knowledge of one behavior, “controlling blood pressure” differed significantly by CKD-A. CKD-A was associated with past performance of two CKD-SMBs, “controlling blood pressure” (P = 0.02), and “keeping healthy body weight” (P = 0.01). Adjusted multivariate analyses between CKD-A and: (1) HL; and (2) CKD-SMB knowledge were non-significant. However, there was a significant relationship between CKD-A and kidney function after controlling for demographics, HL, and CKD-SMB (P < 0.05).

CONCLUSION

CKD-A is not associated with HL, or better CKD-SMBs. CKD-A is significantly associated with kidney function and substantially lower eGFR, suggesting the need for focused patient education in CKD stages 1.

Analytic Considerations for Repeated Measures of eGFR in Cohort Studies of CKD

Repeated measures of various biomarkers provide opportunities for us to enhance understanding of many important clinical aspects of CKD, including patterns of disease progression, rates of kidney function decline under different risk factors, and the degree of heterogeneity in disease manifestations across patients. However, because of unique features, such as correlations across visits and time dependency, these data must be appropriately handled using longitudinal data analysis methods. We provide a general overview of the characteristics of data collected in cohort studies and compare appropriate statistical methods for the analysis of longitudinal exposures and outcomes. We use examples from the Chronic Renal Insufficiency Cohort Study to illustrate these methods. More specifically, we model longitudinal kidney outcomes over annual clinical visits and assess the association with both baseline and longitudinal risk factors.

Rate of renal function decline, race and referral to nephrology in a large cohort of primary care patients

INTRODUCTION

Late nephrology referral is associated with adverse outcomes especially among minorities. Research on the association of the rate of chronic kidney disease (CKD) progression with nephrology referral in white versus black patients is lacking.

OBJECTIVES

Compute the odds of nephrology referral in primary care and their associations with race and the rate of CKD progression.

METHODS

Electronic health record data were obtained from 2170 patients in primary care clinics in the Saint Louis metropolitan area with at least two estimated glomerular filtration rate (eGFR) values over a 7-year observation period. Fast CKD progression was defined as a decline in eGFR of ≥5 ml/min/1.73 m2/year. Logistic regression models were computed to measure the associations between eGFR progression, race and nephrology referral before and after adjusting for potential confounding factors.

RESULTS

Nephrology referrals were significantly more prevalent among those with fast compared to slow progression (5.6 versus 2.0%, P < 0.0001), however, a majority of fast progressors were not referred. Fast CKD progression and black race were associated with increased odds of nephrology referral (OR = 2.74; 95% CI: 1.60-4.72 and OR = 2.42; 95% CI: 1.28-4.56, respectively). The interaction of race and eGFR progression in nephrology referral was found to be non-significant.

CONCLUSION

Nephrology referrals are more common in fast CKD progression, but referrals are underutilized. Nephrology referral is more common among blacks but its' association with rate of decline does not differ by race. Further studies are required to investigate the benefit of early referral of patients at risk of fast CKD progression.

Treatment decisions for older adults with advanced chronic kidney disease

Dialysis initiation rates among older adults, aged 75 years or greater, are increasing at a faster rate than for younger age groups. Older adults with advanced CKD (eGFR < 30 ml/min/1.73 m2) typically lose renal function slowly, often suffer from significant comorbidity and thus may die from associated comorbidities before they require dialysis.A patient's pattern of renal function loss over time in relation to their underlying comorbidities can serve as a guide to the probability of a future dialysis requirement. Most who start dialysis, initiate treatment "early", at an estimated glomerulofiltration rate (eGFR) >10 ml/min/1.73 m2 and many initiate dialysis in hospital, often in association with an episode of acute renal failure. In the US older adults start dialysis at a mean e GFR of 12.6 ml/min/1.73 m2 and 20.6% die within six months of dialysis initiation. In both the acute in hospital and outpatient settings, many older adults appear to be initiating dialysis for non-specific, non-life threatening symptoms and clinical contexts. Observational data suggests that dialysis does not provide a survival benefit for older adults with poor mobility and high levels of comorbidity. To optimize the care of this population, early and repeat shared decision making conversations by health care providers, patients, and their families should consider the risks, burdens, and benefits of dialysis versus conservative management, as well as the patient specific symptoms and clinical situations that could justify dialysis initiation. The potential advantages and disadvantages of dialysis therapy should be considered in conjunction with each patient's unique goals and priorities.In conclusion, when considering the morbidity and quality of life impact associated with dialysis, many older adults may prefer to delay dialysis until there is a definitive indication or may opt for conservative management without dialysis. This approach can incorporate all CKD treatments other than dialysis, provide psychosocial and spiritual support and active symptom management and may also incorporate a palliative care approach with less medical monitoring of lab parameters and more focus on the use of drug therapies directed to relief of a patient's symptoms.

Absence of Decline of Kidney Function in Human Immunodeficiency Virus-Infected Patients Under Routine Clinical Management

BACKGROUND

Since the introduction of antiretroviral therapy (ART), human immunodeficiency virus (HIV)-infected patients have a drastically improved prognosis but at the same time they are also more affected by non-HIV related complications, such as chronic kidney disease. The objective of our study was to investigate the effect of proteinuria and tenofovir (TDF)-containing ART regimens on the temporal evolution of estimated glomerular filtration rate (eGFR).

METHODS

Between April 2008 and October 2012, we enrolled 395 patients with a complete renal evaluation among patients from the ANRS C03 Aquitaine cohort, a prospective hospital-based cohort of HIV-1-infected patients under routine clinical management in southwestern France. eGFR was estimated at each patient follow-up visit. A linear mixed model was used to analyze eGFR dynamics, accounting for change in TDF by modeling eGFR trajectory according to treatment periods.

RESULTS

At inclusion, 56.7% of patients were treated with TDF-containing ART regimens; prevalence of glomerular and tubular proteinuria was 7.9 and 10.8% respectively. A 1-year increase of cumulative exposure to TDF was significantly associated with a mean eGFR decrease of 1.27 mL/min/1.73 m2 (95% CI [-2.14 to -0.41]). Only a urine protein to creatinine ratio >100 mg/mmol and/or a urine albumin to creatinine ratio >70 mg/mmol were associated with eGFR trajectory (mean slope 6.18 mL/min/1.73 m2 per year; 95% CI [2.71 to 9.65]), whereas TDF use was not associated with such eGFR temporal evolution.

CONCLUSION

Decline in kidney function is limited under routine clinical management with monitoring of renal function and interventions including decision to continue or discontinue TDF.

Longitudinal change in estimated GFR among CKD patients: A 10-year follow-up study of an integrated kidney disease care program in Taiwan

BACKGROUND

This study examined the progression of chronic kidney disease (CKD) by using average annual decline in estimated GFR (eGFR) and its risk factors in a 10-year follow-up CKD cohort.

METHODS

A prospective, observational cohort study, 4600 individuals fulfilled the definition of CKD, with or without proteinuria, were followed for 10 years. The eGFR was estimated by the MDRD equation. Linear regression was used to estimate participants' annual decline rate in eGFR. We defined subjects with annual eGFR decline rate <1 ml/min/1.73 m2 as non-progression and the decline rate over 3 ml/min/1.73 m2 as rapid progression.

RESULTS

During the follow-up period, 2870 (62.4%) individuals had annual eGFR decline rate greater than 1 ml/min/1.73 m2. The eGFR decline rate was slower in individuals with CKD diagnosed over the age of 60 years than those with onset at a younger age. Comparing to subjects with decline rate <1 ml/min/1.73 m2/year, the odds ratio (OR) of developing rapid CKD progression for diabetes, proteinuria and late onset of CKD was 1.72 (95% CI: 1.48-2.00), 1.89(1.63-2.20) and 0.68 (0.56-0.81), respectively. When the model was adjusted for the latest CKD stage, comparing to those with CKD stage 1, patients with stage 4 and stage 5 have significantly higher risks for rapid progression (OR, 5.17 (2.60-10.25), 19.83 (10.05-39.10), respectively). However, such risk was not observed among patients with the latest CKD stage 2 and 3. The risk for incident ESRD was 17% higher for each 1 ml/min/1.73 m2 increasing in annual decline rate.

CONCLUSIONS

Not everyone with CKD develops ESRD after a 10-year follow-up. Absolute annual eGFR decline rate can help clinicians to better predict the progression of CKD. Individuals with renal function decline rate over 3 ml/min/1.73 m2/year require intensive CKD care.

Older Patients' Perspectives on Managing Complexity in CKD Self-Management

BACKGROUND AND OBJECTIVES

Patients with CKD are asked to perform self-management tasks including dietary changes, adhering to medications, avoiding nephrotoxic drugs, and self-monitoring hypertension and diabetes. Given the effect of aging on functional capacity, self-management may be especially challenging for older patients. However, little is known about the specific challenges older adults face maintaining CKD self-management regimens.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted an exploratory qualitative study designed to understand the relationship among factors facilitating or impeding CKD self-management in older adults. Six focus groups (n=30) were held in August and September of 2014 with veterans≥70 years old with moderate-to-severe CKD receiving nephrology care at the Atlanta Veterans Affairs Medical Center. Grounded theory with a constant comparative method was used to collect, code, and analyze data.

RESULTS

Participants had a mean age (range) of 75.1 (70.1-90.7) years, 60% were black, and 96.7% were men. The central organizing concept that emerged from these data were managing complexity. Participants typically did not have just one chronic condition, CKD, but a number of commonly co-occurring conditions. Recommendations for CKD self-management therefore occurred within a complex regimen of recommendations for managing other diseases. Participants identified overtly discordant treatment recommendations across chronic conditions (e.g., arthritis and CKD). Prioritization emerged as one effective strategy for managing complexity (e.g., focusing on BP control). Some patients arrived at the conclusion that they could group concordant recommendations to simplify their regimens (e.g., protein restriction for both gout and CKD).

CONCLUSIONS

Among older veterans with moderate-to-severe CKD, multimorbidity presents a major challenge for CKD self-management. Because virtually all older adults with CKD have multimorbidity, an integrated treatment approach that supports self-management across commonly occurring conditions may be necessary to meet the needs of these patients.

Low renal replacement therapy incidence among slowly progressing elderly chronic kidney disease patients referred to nephrology care: an observational study

Background

Elderly patients with advanced chronic kidney disease (CKD) have a high risk of death before reaching end-stage kidney disease. In order to allocate resources, such as advanced care nephrology where it is most needed, it is essential to know which patients have the highest absolute risk of advancing to renal replacement therapy (RRT).

Methods

We included all nephrology-referred CKD stage 3b-5 patients in Sweden 2005–2011 included in the Swedish renal registry (SRR-CKD) who had at least two serum creatinine measurements one year apart (+/− 6 months). We followed these patients to either initiation of RRT, death, or September 30, 2013. Decline in estimated glomerular filtration rate (eGFR) (%) was estimated during the one-year baseline period. The patients in the highest tertile of progression (>18.7% decline in eGFR) during the initial year of follow-up were classified as “fast progressors”. We estimated the cumulative incidence of RRT and death before RRT by age, eGFR and progression status using competing risk models.

Results

There were 2119 RRT initiations (24.2%) and 2060 deaths (23.5%) before RRT started. The median progression rate estimated during the initial year was −8.8% (Interquartile range [IQR] - 24.5–6.5%). A fast initial progression rate was associated with a higher risk of RRT initiation (Sub Hazard Ratio [SHR] 2.24 (95% confidence interval [CI] 2.00–2.51) and also a higher risk of death before RRT initiation (SHR 1.27 (95% CI 1.13–1.43). The five year probability of RRT was highest in younger patients (<65 years) with fast initial progression rate (51% in CKD stage 4 and 76% in stage 5), low overall in patients >75 years with a slow progression rate (7, 13, and 25% for CKD stages 3b, 4 and 5 respectively), and slightly higher in elderly patients with a fast initial progression rate (28% in CKD stage 4 and 47% in CKD stage 5) or with diabetic kidney disease.

Conclusions

The 5-year probability of RRT was low among referred slowly progressing CKD patients >75 years of age because of the competing risk of death.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0473-1) contains supplementary material, which is available to authorized users.

Management of diabetes patients during the year prior to initiation of dialysis in France

AIM

This study looked at the management of diabetes patients during the year prior to the initiation of dialysis.

METHODS

For this observational study, data were extracted from the National Health Insurance database for general-scheme beneficiaries (77% of the French population). Diabetes patients were identified by at least three reimbursements for antidiabetic drugs in 2012, while the initiation of dialysis was identified by specific refunds in 2013.

RESULTS

Of the 6412 patients initiating dialysis, 37% (n=2378) had diabetes (men: 61%, median age: 71 years, haemodialysis: 92%). Six months prior to dialysis, 68% had filled at least one prescription for insulin, 38% for other antidiabetics (25% glinides, 8% sulphonylureas, 8% metformin, 6% DPP-4 inhibitors), 69% for three or more classes of antihypertensive drugs and 55% for erythropoiesis-stimulating agents. Within 12 months to 1 month of dialysis, 81% were hospitalized, 28% with a main diagnosis of kidney disease. No nephrologist referral or hospitalization was identified at 6-0 months before dialysis in 6% of patients or in 24% at 12-7 months. One in five patients with diabetes consulted a private endocrinologist within 6 months of dialysis. An arteriovenous fistula was created 1 month before haemodialysis in 43% of patients.

CONCLUSION

The quality of preparation for dialysis was variable despite frequent hospitalizations. These data illustrate the need to mobilize patients with diabetes, and for healthcare professionals to more effectively anticipate and coordinate dialysis.

Association between periodontal condition and kidney dysfunction in Japanese adults: A cross-sectional study

Recent studies have demonstrated that chronic kidney disease (CKD) may be associated with the progression of periodontal disease. Diabetes mellitus (DM) is a major risk factor for CKD. The objective of this study was to clarify the relationship between periodontal condition and kidney dysfunction in patients who had kidney failure with or without DM. One hundred sixty-four patients with kidney dysfunction were enrolled (male: N = 105; female: N = 59), and the relationship between periodontal condition and kidney dysfunction was analyzed in a cross-sectional study. The subjects were divided into three groups: (a) patients with DM, (b) dialysis patients with nephropathy due to various kidney diseases, and (c) dialysis patient with nephropathy due to DM (diabetic nephropathy). Then, the effect of DM on the periodontal condition was analyzed. The patients were also stratified by CKD stage (into G1-G5) using the estimated glomerular filtration rate (eGFR), and the G5 group was divided in patients with or without DM. Correlations between eGFR and parameters of periodontal condition were calculated in patients from G1 to G4. The number of missing teeth was significantly higher in dialysis patients with diabetic nephropathy than in patients with DM, whereas alveolar bone loss did not show a significant difference among the three groups. In addition, the G5 patients with DM had a significantly higher number of missing teeth than the other CKD groups, whereas alveolar bone loss did not show a significant difference. In G5 patients with DM, Community Periodontal Index and Oral Hygiene Index scores were significantly higher than in G1-4 patients with DM. There was a significant negative correlation between eGFR and the number of missing teeth. Patients with diabetic nephropathy have a higher rate of periodontal problems such as missing teeth in Japanese adults.

Racial differences in renal replacement therapy initiation among children with a nonglomerular cause of chronic kidney disease

PURPOSE

African American (AA) adults with chronic kidney disease (CKD) have a faster progression to end-stage renal disease and are less likely to receive a kidney transplant. It is unclear whether AA children experience renal replacement therapy (RRT) for end-stage renal disease sooner than non-AA children after accounting for socioeconomic status (SES).

METHODS

Among children with nonglomerular CKD in the Chronic Kidney Disease in Children study, we investigated time to RRT (i.e., first dialysis or transplant) after CKD onset using parametric survival models and accounted for SES differences by inverse probability weights.

RESULTS

Of 110 AA and 493 non-AA children (median age = 10 years), AA children had shorter time to first RRT: median time was 3.2 years earlier than non-AA children (95% CI: -6.1, -0.3). When accounting for SES, this difference was diminished and nonsignificant (-1.6 years; 95% CI: -4.6, +1.5), and its directionality was consistent with faster glomerular filtration rate decline among AA children (-6.2% vs. -4.4% per year, P = .098). When RRT was deconstructed into dialysis or transplant, the time to dialysis was 37.5% shorter for AA children and 53.7% longer for transplant. These inferences were confirmed by the frequency and timing of transplant after initiating dialysis.

CONCLUSIONS

Racial differences in time to RRT were almost fully accounted for by SES, and the remaining difference was congruent with a faster glomerular filtration rate decline among AA children. Access to transplant occurred later, yet times to dialysis were shorter among AA children even when accounting for SES which may be due to a lack of organ availability.

Patterns of Kidney Function Decline Associated with APOL1 Genotypes: Results from AASK

BACKGROUND AND OBJECTIVES

Trajectories of eGFR in patients with CKD are highly variable. Only a subset of patients with CKD experiences a steady decline in eGFR. The objective of our study was to investigate whether eGFR trajectory patterns differ by APOL1 risk status.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our study was a longitudinal observational study of 622 participants in the African American Study of Kidney Disease and Hypertension with APOL1 genotyping and sufficient follow-up for estimating GFR trajectories. The predictor was APOL1 high-risk status (having two copies of the G1 or G2 risk alleles) versus low-risk status (zero or one copy of the risk alleles), and the outcome was four eGFR trajectory patterns on the basis of the joint probabilities of linearity and progression: steady decline, unsteady decline, steady stable, and unsteady stable.

RESULTS

Over a median follow-up of 9 years, 24.0% of participants experienced steady eGFR decline, 25.9% had an unsteady decline, 25.6% were steady and stable, and 24.6% were unsteady but stable. Those experiencing steady decline had lower eGFR and higher urine protein-to-creatinine ratio at baseline than participants with the other eGFR trajectory patterns. The APOL1 high-risk group was associated with a greater odds for the steady decline pattern than the APOL1 low-risk group (unadjusted odds ratio, 2.45; 95% confidence interval, 1.62 to 3.69). This association remained significant after adjusting for demographic factors, baseline eGFR, urine protein-to-creatinine ratio, treatment assignment, and follow-up time (adjusted odds ratio, 1.59; 95% confidence interval, 1.00 to 2.52).

CONCLUSIONS

Among patients with CKD attributed to hypertension, those with the APOL1 high-risk genotype were more likely to experience a steady decline trajectory in eGFR than those without the APOL1 high-risk genotype. These findings suggest a persistent underlying pathophysiologic process in those patients with the APOL1 high-risk genotype.

Estimated GFR Trajectories of People Entering CKD Stage 4 and Subsequent Kidney Disease Outcomes and Mortality

BACKGROUND

Estimated glomerular filtration rate (eGFR) trajectories of people entering chronic kidney disease (CKD) stage 4 and their associations with subsequent kidney disease outcomes or death are not known.

STUDY DESIGN

Longitudinal observational cohort study.

SETTING & PARTICIPANTS

26,246 patients in the Veterans Affairs Healthcare System who entered CKD stage 4 in fiscal year 2008 followed up until October 2013.

FACTORS

5-year eGFR trajectories, demographic and health characteristics.

OUTCOMES

Composite kidney disease outcome of kidney failure, dialysis therapy or transplantation, and death.

RESULTS

Latent class group modeling and functional characterization suggest the presence of 3 distinct trajectory classes: class 1 (72%), consistent slow decline with absolute eGFR change of -2.45 (IQR, -3.89 to -1.16) mL/min/1.73m(2) per year; class 2 (18%), consistent fast decline and eGFR change of -8.60 (IQR, -11.29 to -6.66) mL/min/1.73m(2) per year; and class 3 (10%), early nondecline and late fast decline with eGFR change of -0.4mL/min/1.73m(2) per year in years 1 to 3 and -7.98 and -21.36mL/min/1.73m(2) per year in years 4 and 5, respectively. During 4.34 years of follow-up, 9,809 (37%) patients had the composite kidney disease outcome and 14,550 (55%) patients died. Compared to the referent group (trajectory class 1), HRs for 1-year risk for composite kidney disease outcome for trajectory classes 2 and 3 were 1.13 (95% CI, 1.05-1.22) and 0.67 (95% CI, 0.59-0.75), whereas HRs for 1-year risk for death for classes 2 and 3 were 1.17 (95% CI, 1.10-1.28) and 1.29 (95% CI, 1.18-1.42), respectively. The 1-year risk for composite kidney disease outcome was 32% and was 42% more likely than the risk for death in trajectory classes 1 and 2, respectively, whereas the risk for death was 67% more likely than the risk for composite kidney disease outcome in trajectory class 3.

LIMITATIONS

Inclusion criteria and mostly male participants limit generalizability of study results.

CONCLUSIONS

We characterized 3 different eGFR trajectory classes of people entering CKD stage 4. Our results suggest that the pattern of eGFR trajectory informs the risk for kidney disease outcomes and death.

Renal function trajectory over time and adverse clinical outcomes

The growing burden of chronic kidney disease (CKD), with its associated morbidity and mortality, is recognized as a major public health problem globally and causing substantial load on health care systems. The current framework for the definition and staging of CKD, based on eGFR levels or presence of kidney damage, is useful for clinical classification of patients, but identifies a huge number of people as having CKD which is too many to target for intervention. The ability to identify a subset of patients, at high risk for adverse outcomes, would be useful to inform clinical management. The current staging system applies static definitions of kidney function that fail to capture the dynamic nature of the kidney disease over time. Now-a-days, it is possible to capture multiple measurements of different laboratory test results for an individual including eGFR values. A new possibility for identifying individuals at higher risk of adverse outcomes is being explored through assessment and consideration of the rate of change in kidney function over time, and this approach will be feasible in the current context of digitalization of health record keeping system. On the basis of the existing evidence, this paper summarizes important findings that support the concept of dynamic changes in kidney function over time, and discusses how the magnitude of these changes affect the future adverse outcomes of kidney disease, particularly the End Stage Renal Disease (ESRD), CVD and mortality.