Projecting the Burden of Chronic Kidney Disease in a Developed Country and Its Implications on Public Health

Analysis of chronic kidney disease epidemiology in Kazakhstan using nationwide data for 2014-2020 and forecasting future trends of prevalence and mortality for 2030

According to the Global Burden of Disease (GBD) study, chronic kidney disease (CKD) was prevalent in 697.5 million individuals worldwide in 2017. By 2040, it is anticipated that CKD will rank as the fifth most common cause of death. This study aims to examine the epidemiology of CKD in Kazakhstan and to project future trends in CKD prevalence and mortality by 2030. The retrospective analysis was performed on a database acquired from the Unified National Electronic Health System for 703,122 patients with CKD between 2014 and 2020. During the observation period, 444,404 women and 258,718 men were registered with CKD, 459,900 (66%) were Kazakhs and 47% were older than 50. The incidence rate notably decreased: 6365 people per million population (PMP) in 2014 and 4040 people PMP in 2020. The prevalence changed from 10,346 to 38,287 people PMP, and the mortality rate increased dramatically from 279 PMP to 916 PMP. Kazakhstan's central regions, Turkestan and Kyzylorda were identified as the most burdensome ones. The ARIMA model projected 1,504,694 expected prevalent cases in 2030. The predicted mortality climbed from 17,068 cases in 2020 to 37,305 deaths in 2030. By 2030, the prevalence and mortality of CKD will significantly increase, according to the predicted model. A thorough action plan with effective risk factor management, enhanced screening among risk populations, and prompt treatment are required to lessen the burden of disease in Kazakhstan.

Validation of a Risk Prediction Equation for Incident Chronic Kidney Disease in a Hypertensive Non-Diabetes Cohort in Singapore Primary Care Patients

BACKGROUND

Accurate identification of individuals at risk of developing chronic kidney disease (CKD) may improve clinical care. Nelson et al. developed prediction equations to estimate the risk of incident eGFR of less than 60 mL/min/1.73 m2 in diabetic and non-diabetes patients using data from 34 multinational cohorts. We aim to validate the non-diabetes equation in our local multi-ethnic cohort and develop further prediction models.

METHODS

Demographics, clinical and laboratory data of hypertensive non-diabetes patients with baseline eGFR ≥60 mL/min/1.73 m2 on follow-up with primary care clinics between 2010 and 2015 were collected. Follow-up was 5 years from entry to study. We validated Nelson's equation and developed our own model which we subsequently validated. The developmental cohort included patients between 2010 and 2014 while the validation cohort included patients in 2015. Variables included age, sex, eGFR, history of cardiovascular disease, ever smoker, body mass index, albuminuria, cholesterol, and treatment. Primary outcome was incident eGFR <60/min/1.73 m2 within 5 years. Model performance was evaluated by C-statistics and calibration was assessed.

RESULTS

In the developmental cohort of 27,800 patients, 2823 (10.2%) developed the outcome during a mean follow-up of 4.4 years while 638 (12.8%) patients developed the outcome in the validation cohort of 4,994 patients. Applicability of Nelson's equation was limited by missing albuminuria, absence of black race, and exclusion of non-hypertensive patients in our cohort. Nonetheless, the modified Nelson's model demonstrated C-statistic of 0.85 (95% CI: 0.84-0.86). The C-statistic of our bespoke model was 0.85 (0.85-0.86) and 0.87 (0.85-0.88) for the developmental cohort and validation cohort, respectively. Calibration was suboptimal as the predicted risk exceeded the observed risk.

CONCLUSIONS

The modified Nelson's equation and our locally derived novel model demonstrated high discrimination. Both models may potentially be used in predicting risk of CKD in hypertensive patients who are managed in primary care, allowing for early interventions in high-risk population.

Effectiveness of mindfulness-based interventions delivered via technology versus therapist among patients on peritoneal dialysis at an outpatient clinic in Singapore

AIMS

This study aimed to (i) evaluate the effectiveness of mindfulness-based interventions in improving self-efficacy, reducing stress and anxiety among peritoneal dialysis patients, and (ii) compare the most effective method of mindfulness based interventions.

METHODS

This randomized three-arm controlled trial recruited first-time peritoneal dialysis patients from the peritoneal dialysis outpatient clinic in Singapore. Patients were randomly allocated to either video-assisted mindfulness training, therapist-assisted mindfulness training or treatment-as-usual. All groups received 4.5 days of structured peritoneal dialysis training at the peritoneal dialysis centre, while video-assisted mindfulness training and therapist-assisted mindfulness training groups were taught additional mindfulness-based techniques. The perceived stress scale, self-efficacy, and anxiety (State and Trait Anxiety Inventory) were measured at baseline, 4- and 12 weeks post-randomization, using reliable and valid instruments.

RESULTS

Thirty-nine patients were recruited (13 in each group). All the therapies showed a significant time trend in anxiety. Only therapist- and video-assisted mindfulness training showed a significant trend in perceived stress scale scores but not treatment-as-usual. All Intervention X Time interactions were not significant. Patients in therapist- and video-assisted mindfulness training groups had reduced perceived stress scale scores compared to treatment-as-usual at week 12.

CONCLUSION

This study demonstrated the potential of mindfulness-based interventions in reducing stress among first-time PD patients.

Health literacy and self-care among patients with chronic kidney disease in a primary care setting

INTRODUCTION

The study objective was to determine the levels of self-care and health literacy (HL) and their associations among patients with chronic kidney disease (CKD).

METHODS

This was a cross-sectional, questionnaire-based study conducted in a public primary care setting in Singapore. A total of 289 participants aged 21-80 years with hypertension were recruited. Self-care profiles were measured using the Hypertension Self-Care Profile (HTN-SCP; range 0-240, domain range 0-80). Health literacy was measured using the Short-Form Health Literacy Scale (HLS-SF12; range 0-50, limited literacy ≤33).

RESULTS

The mean self-care score was 182.7 (standard deviation [SD] 23.2). The median HL score was 34.7 (interquartile range [IQR] 31.9-40.3), and 31.1% of participants had limited HL. Self-care was not associated with age, CKD status, household income and education, but was associated with gender and HL score. In the final regression model, lower HL scores (adjusted β = 1.03, 95% confidence interval [CI] 0.7 to 1.36, P < 0.001) and male gender (adjusted β = -5.29, 95% CI -10.56 to -0.03, P = 0.049) were associated with lower self-care scores. The HL scores were associated with self-care domains of self-efficacy (HL: β = 0.30, 95% CI 0.17 to 0.42, P < 0.001), motivation (HL: β = 0.40, 95% CI 0.26 to 0.53, P < 0.001) and behaviour (HL: β = 0.38, 95% CI 0.26 to 0.50, P < 0.001).

CONCLUSION

Thirty-one percent of the participants had limited HL. Self-care was not associated with age, race, CKD status, household income or education. Male gender and limited HL were associated with lower self-care. Self-care was associated with self-efficacy, motivation and behaviour. Future research could focus on more targeted approaches to improve self-care and HL among patients with CKD.

Disparities in ethnicity and metabolic disease burden in referrals to nephrology

Introduction

The profile of patients referred from primary to tertiary nephrology care is unclear. Ethnic Malay patients have the highest incidence and prevalence of kidney failure in Singapore. We hypothesised that there is a Malay predominance among patients referred to nephrology due to a higher burden of metabolic disease in this ethnic group.

Methods

This is a retrospective observational cohort study. From 2014 to 2018, a coordinator and physician triaged patients referred from primary care, and determined co-management and assignment to nephrology clinics. Key disease parameters were collated on triage and analysed.

Results

A total of 6,017 patients were studied. The mean age of patients was 64 ± 16 years. They comprised 57% men; 67% were Chinese and 22% were Malay. The proportion of Malay patients is higher than the proportion of Malays in the general population (13.4%) and they were more likely than other ethnicities to have ≥3 comorbidities, including diabetes mellitus, hypertension, hyperlipidaemia, coronary artery disease and stroke (70% vs. 57%, P < 0.001). Malay and Indian patients had poorer control of diabetes mellitus compared to other ethnicities (glycated haemoglobin 7.8% vs. 7.4%, P < 0.001). Higher proportion of Malay patients compared to other ethnicities had worse kidney function with estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m2 on presentation (28% vs. 24%, P = 0.003). More ethnic Malay, Indian and younger patients missed appointments.

Conclusion

A disproportionately large number of Malay patients are referred for kidney disease. These patients have higher metabolic disease burden, tend to miss appointments and are referred at lower eGFR. Reasons underpinning these associations should be identified to facilitate efforts for targeting this at-risk population, ensuring kidney health for all.

[Key guidelines on the Spanish multi-society consensus on chronic kidney disease]

Chronic kidney disease (CKD) is a global health problem and affects approximately 15.1% of the general population in Spain (IBERICAN and ENRCA studies), although most of the literature agrees that there is an underdiagnosis that would further increase this prevalence. This article from the CKD monograph aims to summarize the main consensus guidelines for the management of CKD, highlighting the most important and novel aspects, as well as recently updated terminology and concepts. Sections addressing specific populations and prevention strategies are also included. As the family doctor (MAP) plays a fundamental role in the detection of CKD, recommendations on the multidisciplinary approach to CKD are collected.

Chronic Kidney Disease and Periodontitis Interplay-A Narrative Review

Periodontitis (PO), a chronic microbially-induced inflammation of the supporting tissues of the tooth, is linked to various systemic diseases. We analyze its bidirectional relationship to chronic kidney disease (CKD), a major health-care problem with impressive excess mortality. Overwhelming associative relationship between CKD and PO are analyzed. Major pathophysiologic mechanisms that link CKD to PO are then presented: systemic inflammation, endothelial dysfunction, and imbalance of oxidative stress characteristic of CKD have a role in PO development and might influence escape mechanisms of oral microbiota. Subclinical local and systemic inflammation induced by PO might influence in turn CKD outcomes. Homeostatic changes induced by CKD such as mineral bone disorders, acidosis, uremic milieu, or poor salivary flow are also relevant for the occurrence of PO. There is insufficient evidence to recommend a standardized diagnostic and therapeutic approach regarding association of PO to CKD.

ARIMA model for predicting chronic kidney disease and estimating its economic burden in China

BACKGROUND

Chronic kidney disease (CKD) is an important global public health issue. In China, CKD affects a large number of patients and causes a huge economic burden. This study provided a new way to predict the number of patients with CKD and estimate its economic burden in China based on the autoregressive integrated moving average (ARIMA) model.

METHODS

Data of the number of patients with CKD in China from 2000 to 2019 were obtained from the Global Burden of Disease. The ARIMA model was used to fit and predict the number of patients with CKD. The direct and indirect economic burden of CKD were estimated by the bottom-up approach and the human capital approach respectively.

RESULTS

The results of coefficient of determination (0.99), mean absolute percentage error (0.26%), mean absolute error (343,193.8) and root mean squared error (628,230.3) showed that the ARIMA (1,1,1) model fitted well. Akaike information criterion (543.13) and Bayesian information criterion (546.69) indicated the ARIMA (1,1,1) model was reliable when analyzing our data. The result of relative error of prediction (0.23%) also suggested that the model predicted well. The number of patients with CKD in 2020 to 2025 was predicted to be about 153 million, 155 million, 157 million, 160 million, 163 million and 165 million respectively, accounting for more than 10% of the Chinese population. The total economic burden of CKD from 2019 to 2025 was estimated to be $179 billion, $182 billion, $185 billion, $188 billion, $191 billion, $194 billion and $198 billion respectively.

CONCLUSION

The number of patients with CKD and the economic burden of CKD will continue to rise in China. The number of patients with CKD in China would increase by 2.6 million (1.6%) per year on average from 2020 to 2025. Meanwhile, the total economic burden of CKD in China would increase by an average of $3.1 billion per year. The ARIMA model is applicable to predict the number of patients with CKD. This study provides a new perspective for more comprehensive understanding of the future risk of CKD.

A focus on CKD reporting and inappropriate prescribing among older patients discharged from geriatric and nephrology units throughout Italy: A nationwide multicenter retrospective cross-sectional study

Older hospitalized patients with chronic kidney disease (CKD) are part of the geriatric population with a substantial risk of potentially inappropriate medication (PIM) use. The high rates of multimorbidity and polypharmacy, along with the progressive decline of eGFR, contribute to increasing the risk of drug–drug and drug–disease interactions, overdosing, and adverse drug reactions (ADRs). In this multicenter cross-sectional study, we aimed to evaluate the prevalence of CKD under-reporting and PIMs among older patients discharged from acute geriatric and nephrology units throughout Italy. Renal function was determined by estimated glomerular filtration rate (eGFR) through the Berlin Initiative Study (BIS) equation; the prevalence of PIMs was calculated by revising drug prescriptions at discharge according to STOPP criteria, Beers criteria, and summaries of product characteristics (smPCs). A descriptive analysis was performed to compare the clinical and pharmacological characteristics of patients in the two distinct settings; univariate and multivariate logistic regression models were performed to explore factors associated with CKD under-reporting in the discharge report forms and PIM prevalence. Overall, the study population consisted of 2,057 patients, aged 83 (77–89) years, more commonly women, with a median of seven (5–10) drugs prescribed at discharge. CKD under-reporting was present in 50.8% of the study population, with higher rates in geriatric vs. nephrology units (71.1% vs. 10.2%, p < 0.001). 18.5% of the study population was discharged with at least one renally inappropriate medication; factors associated with at least one contraindicated drug at discharge were the number of drugs (PR 1.09, 95% CI 1.14–1.19); atrial fibrillation (PR 1.35, 95% CI 1.01–1.81); diabetes (PR 1.61, 95% CI 1.21–2.13); being hospitalized in nephrology units (PR 1.62, 95% CI 1.14–2.31), CKD stage 3b (PR 2.35, 95% CI 1.34–4.13), and stage 4–5 (PR 14.01, 95% CI 7.36–26.72). Conversely, CKD under-reporting was not associated with the outcome. In summary, CKD under-reporting and inappropriate medication use were common in older patients discharged from hospital; the relatively high number of PIMs in both nephrology and geriatric settings underlines the need to improve appropriate prescribing during hospital stay and to decrease the risk of ADRs and side effects in this highly vulnerable population.

Structural design and mechanical performance of composite vascular grafts

This study reviews the state of the art in structural design and the corresponding mechanical behaviours of composite vascular grafts. We critically analyse surface and matrix designs composed of layered, embedded, and hybrid structures along the radial and longitudinal directions; materials and manufacturing techniques, such as tissue engineering and the use of textiles or their combinations; and the corresponding mechanical behaviours of composite vascular grafts in terms of their physical–mechanical properties, especially their stress–strain relationships and elastic recovery. The role of computational studies is discussed with respect to optimizing the geometrics designs and the corresponding mechanical behaviours to satisfy specialized applications, such as those for the aorta and its subparts. Natural and synthetic endothelial materials yield improvements in the mechanical and biological compliance of composite graft surfaces with host arteries. Moreover, the diameter, wall thickness, stiffness, compliance, tensile strength, elasticity, and burst strength of the graft matrix are determined depending on the application and the patient. For composite vascular grafts, hybrid architectures are recommended featuring multiple layers, dimensions, and materials to achieve the desired optimal flexibility and function for complying with user-specific requirements. Rapidly emerging artificial intelligence and big data techniques for diagnostics and the three-dimensional (3D) manufacturing of vascular grafts will likely yield highly compliant, subject-specific, long-lasting, and economical vascular grafts in the near-future.

Graphic abstract

Prediction models used in the progression of chronic kidney disease: A scoping review

Objective

To provide a review of prediction models that have been used to measure clinical or pathological progression of chronic kidney disease (CKD).

Design

Scoping review.

Data sources

Medline, EMBASE, CINAHL and Scopus from the year 2011 to 17th February 2022.

Study selection

All English written studies that are published in peer-reviewed journals in any country, that developed at least a statistical or computational model that predicted the risk of CKD progression.

Data extraction

Eligible studies for full text review were assessed on the methods that were used to predict the progression of CKD. The type of information extracted included: the author(s), title of article, year of publication, study dates, study location, number of participants, study design, predicted outcomes, type of prediction model, prediction variables used, validation assessment, limitations and implications.

Results

From 516 studies, 33 were included for full-text review. A qualitative analysis of the articles was compared following the extracted information. The study populations across the studies were heterogenous and data acquired by the studies were sourced from different levels and locations of healthcare systems. 31 studies implemented supervised models, and 2 studies included unsupervised models. Regardless of the model used, the predicted outcome included measurement of risk of progression towards end-stage kidney disease (ESKD) of related definitions, over given time intervals. However, there is a lack of reporting consistency on details of the development of their prediction models.

Conclusions

Researchers are working towards producing an effective model to provide key insights into the progression of CKD. This review found that cox regression modelling was predominantly used among the small number of studies in the review. This made it difficult to perform a comparison between ML algorithms, more so when different validation methods were used in different cohort types. There needs to be increased investment in a more consistent and reproducible approach for future studies looking to develop risk prediction models for CKD progression.

Validation of the kidney failure risk equation in predicting the risk of progression to kidney failure in a multi-ethnic Singapore chronic kidney disease cohort

INTRODUCTION

The Kidney Failure Risk Equation (KFRE) was developed to predict the risk of progression to end-stage kidney disease (ESKD). Although the KFRE has been validated in multinational cohorts, the Southeast Asian population was under-represented. This study aimed to validate the KFRE in a multi-ethnic Singapore chronic kidney disease (CKD) cohort.

METHODS

Stage 3-5 CKD patients referred to the renal medicine department at Singapore General Hospital in 2009 were included. The primary outcome (time to ESKD) was traced until 30 June 2017. The eight- and four-variable KFRE (non-North America) models using age, gender, estimated glomerular filtration rate, urine albumin-creatinine ratio, serum albumin, phosphate, bicarbonate and calcium were validated in our cohort. Cox regression, likelihood ratio (Χ2), adequacy index, Harrell's C-index and calibration curves were calculated to assess the predictive performance, discrimination and calibration of these models on the cohort.

RESULTS

A total of 1,128 patients were included. During the study period, 252 (22.3%) patients reached ESKD at a median time to ESKD of 84.8 (range 0.1-104.7) months. Both the eight- and four-variable KFRE models showed excellent predictive performance and discrimination (eight-variable: C-index 0.872, 95% confidence interval [CI] 0.850-0.894, adequacy index 97.3%; four-variable: C-index 0.874, 95% CI 0.852-0.896, adequacy index 97.9%). There was no incremental improvement in the prediction ability of the eight-variable model over the four-variable model in this cohort.

CONCLUSION

The KFRE was validated in a multi-ethnic Singapore CKD cohort. This risk score may help to identify patients requiring early renal care.

[Features of structural and microvascular changes of the choroid in angioretinopathy of various etiologies]

PURPOSE

To study structural and microvascular changes in the choroid in patients with chronic kidney disease (CKD), diabetic retinopathy (DR) and arterial hypertension (AH), and their relationship with the level of renal function, carbohydrate metabolism and blood pressure.

MATERIAL AND METHODS

The study involved 172 patients (325 eyes): 56 patients with CKD (109 eyes); 66 patients with DR (121 eyes); 50 patients with AH (95 eyes). All patients underwent comprehensive ophthalmological examination including visometry, biomicroscopy, ophthalmoscopy, optical coherence tomography (OCT) and OCT angiography.

RESULTS

In patients with DR and CKD, a decrease in the thickness of the ganglion cell complex and the inner plexiform layer (GCL+IPL) was noted: in proliferative DR (PDR) - 62.45±4.25 µm, in stage 4-5 CKD - 75.23±6.43 µm; a decrease in choroidal thickness (CT) of minimal values in stage 4-5 CKD (179.9±37.72 µm) and PDR (211.0±40.7 µm). The decrease in choroidal vascularity index (CVI) depended on the stage of CKD and PDR (in PDR - 63.47±1.37, in stage 4-5 CKD - 65.93±2.01). Maximum decrease in perfusion density and vascular density was found in patients with DR (37.22±9.00% and 15.11±3.39 mm, respectively). An increase in the area, perimeter of the foveolar avascular zone (FAZ), and a decrease in the circularity index were noted in all groups, with most pronounced changes in PDR and stage 4-5 CKD. Patients with CKD were found to have strong correlations of CT and CVI with creatinine, urea, proteinuria and glomerular filtration rate (GFR). Patients with diabetes mellitus and PDR were revealed to have strong relations of CT, CVI, GCL+IPL, the area and perimeter of FAZ with creatinine levels and the duration of diabetes mellitus.

CONCLUSION

Choroidal thickness and choroidal vascularity index are important diagnostic markers of disorders of chorioretinal microcirculation that allow stratifying individual assessment of risk factors for progression of both chronic kidney disease and diabetic retinopathy.

Nephrologist referrals of elderly CKD patients in Singapore: A cross-sectional study

Background

Chronic kidney disease (CKD) is common in the elderly population. By 2035, approximately one-quarter of Singapore residents are expected to have CKD. Many of these patients are not referred to nephrologists.

Aim

We aimed to compare the characteristics of elderly (≥ 65 years old) patients with stage 3B CKD and above in the referral and non-referral groups.

Design and settings

A cross-sectional study in the primary care organisation National University Polyclinics (NUP), Singapore.

Method

Retrospective data were extracted from the electronic health records of CKD patients (≥ 65 years old) with stage 3B CKD and above.

Results

From 1 January to 31 December 2018, a total of 1,536 patients aged 65 years or older were diagnosed with stage 3B CKD or above (non-referral group =1,179 vs. referral group =357). The mean patient age in the non-referral group (78.3 years) was older than that in the referral group (75.9 years) (P<0.001). Indian elderly patients were referred more compared to their Chinese counterparts (P=0.008). The non-referral group was prescribed significantly less fibrate, statins, insulin, sulfonylureas, dipeptidyl peptidase-4 inhibitors, and antiplatelet than the referral group (P<0.05), but only the difference in fibrates remained significant on subsequent multivariate analysis.

Conclusions

This study demonstrates that there is a considerable number of elderly CKD patients exclusively managed in the primary care setting (n = 1,179) and that referrals primarily depend on demographic factors, namely age and ethnicity, rather than medical determinants of CKD severity or case complexity.

Clinical factors and mortality rates for non-traumatic upper extremity amputations

Non-traumatic upper extremity amputations are an increasing concern with the rising prevalence of diabetes mellitus. To ascertain the risk factors and mortality rates for these amputations, the demographic information, amputation history, comorbidities and clinical outcomes of 140 patients who underwent non-traumatic upper extremity amputations between 1 January 2004 and 31 October 2017 were studied. Correlations were assessed using Cochran-Armitage chi-squared tests, odds ratios and multivariate binomial logistic regression as appropriate. Diabetes mellitus, coronary artery disease, end-stage renal failure, peripheral arterial disease and prior lower extremity amputation were significant risk factors for multiple upper extremity amputations. One-year, 2-year and 5-year mortality rates were 12%, 15% and 38%, respectively, following first upper extremity amputation. The risk factors for upper extremity amputations correspond with those for lower extremity amputations, comprising mainly diabetes mellitus and its related comorbidities. The mortality rates for non-traumatic upper extremity amputations highlight their significant burden on patients.Level of evidence: III.

Effects of calcitriol on peripheral endothelial progenitor cells and renal renovation in rats with chronic renal failure

BACKGROUND

The role of calcitriol (1,25-dihydroxyvitamin D₃ or 1,25-(OH)₂D₃) in physiological processes, such as anti-fibrosis, anti-inflammation, and immunoregulation is known; however, its role in the remodeling of the glomerular capillary endothelium in rats with chronic renal failure (CRF) remains unclear.

METHODS

Here, we analyzed the role/number of endothelial progenitor cells (EPCs), renal function, and pathological alterations in rats with CRF, and compared the results before and after supplementation with calcitriol in vivo.

RESULTS

Amongst the three experimental groups (sham group, CRF group, and calcitriol-treated group (0.03 μg/kg/d), we observed substantially elevated cell adhesion and vasculogenesis in vivo in the calcitriol-treated group. Additionally, lower levels of serum creatinine (Scr) and blood urea nitrogen (BUN) was recorded in the calcitriol-treated group than the CRF group (p > 0.05). Calcitriol treatment also resulted in an improvement in renal pathological injury.

CONCLUSIONS

Thus, calcitriol could ameliorate the damage of glomerular arterial structural and renal tubules vascular network integrity, maybe through regulating the number and function of EPCs in the peripheral blood of CRF rats. Treatment with it may improve outcomes in patients with renal insufficiency or combined cardiac insufficiency. Calcitriol could ameliorate CRF-induced renal pathological injury and renal dysfunction by remodeling of the glomerular capillary endothelium, thus, improving the function of glomerular endothelial cells.

Projection of the health and economic impacts of Chronic kidney disease in the Chilean population

BACKGROUND

Chronic Kidney Disease (CKD) is a leading public health problem, with substantial burden and economic implications for healthcare systems, mainly due to renal replacement treatment (RRT) for end-stage kidney disease (ESKD). The aim of this study is to develop a multistate predictive model to estimate the future burden of CKD in Chile, given the high and rising RRT rates, population ageing, and prevalence of comorbidities contributing to CKD.

METHODS

A dynamic stock and flow model was developed to simulate CKD progression in the Chilean population aged 40 years and older, up to the year 2041, adopting the perspective of the Chilean public healthcare system. The model included six states replicating progression of CKD, which was assumed in 1-year cycles and was categorised as slow, medium or fast progression, based on the underlying conditions. We simulated two different treatment scenarios. Only direct costs of treatment were included, and a 3% per year discount rate was applied after the first year. We calibrated the model based on international evidence; the exploration of uncertainty (95% credibility intervals) was undertaken with probabilistic sensitivity analysis.

RESULTS

By the year 2041, there is an expected increase in cases of CKD stages 3a to ESKD, ceteris paribus, from 442,265 (95% UI 441,808-442,722) in 2021 to 735,513 (734,455-736,570) individuals. Direct costs of CKD stages 3a to ESKD would rise from 322.4M GBP (321.7-323.1) in 2021 to 1,038.6M GBP (1,035.5-1,041.8) in 2041. A reduction in the progression rates of the disease by the inclusion of SGLT2 inhibitors and pre-dialysis treatment would decrease the number of individuals worsening to stages 5 and ESKD, thus reducing the total costs of CKD by 214.6M GBP in 2041 to 824.0M GBP (822.7-825.3).

CONCLUSIONS

This model can be a useful tool for healthcare planning, with development of preventive or treatment plans to reduce and delay the progression of the disease and thus the anticipated increase in the healthcare costs of CKD.

Low Health Literacy is Associated with the Onset of CKD during the Life Course

BACKGROUND

Health literacy, the ability to deal with information related to one's health, is a predictor of health outcomes in CKD. However, research has not explored whether low health literacy predicts the onset of CKD.

METHODS

We used data from participants of Lifelines, a prospective population-based cohort study of individuals living in The Netherlands, to assess the share of individuals with low health literacy by eGFR category, whether low health literacy is associated with CKD onset in the general population and in the subgroup of older adults, and whether established CKD risk factors mediate this association.

RESULTS

In the total sample of 93,885 adults (mean follow-up 3.9 years), low health literacy was more likely among individuals in worse eGFR categories, increasing from 26.4% in eGFR category 1 to 50.0% in category 5 (P=0.02). Low health literacy, compared with adequate health literacy, was associated with the onset of CKD in the total sample (3.0% versus 2.1%) and in the subgroup of older adults (13.4% versus 11.3%), with odds ratios (ORs) of 1.44 (95% confidence interval (95% CI), 1.31 to 1.59) and 1.21 (95% CI, 1.04 to 1.41), respectively. After adjustment for sex, age, education, and income, health literacy was associated with CKD onset only in older adults (OR, 1.25; 95% CI, 1.04 to 1.50). This association was mediated by hypertension and high body mass index (BMI) in the crude model, but only by BMI after adjustment (with BMI explaining 18.8% of the association).

CONCLUSIONS

Low health literacy is a risk factor for CKD onset among older adults, which suggests that CKD prevention might benefit from strategies to address low health literacy.

Primary Care Networks and Starfield's 4Cs: A Case for Enhanced Chronic Disease Management

The primary care network (PCN) was implemented as a healthcare delivery model which organises private general practitioners (GPs) into groups and furnished with a certain level of resources for chronic disease management. A secondary qualitative analysis was conducted with data from an earlier study exploring facilitators and barriers GPs enrolled in PCN's face in chronic disease management. The objective of this study is to map features of PCN to Starfield's "4Cs" framework. The "4Cs" of primary care-comprehensiveness, first contact access, coordination and continuity-offer high-quality design options for chronic disease management. Interview transcripts of GPs (n = 30) from the original study were purposefully selected. Provision of ancillary services, manpower, a chronic disease registry and extended operating hours of GP practices demonstrated PCN's empowering features that fulfil the "4Cs". On the contrary, operational challenges such as the lack of an integrated electronic medical record and disproportionate GP payment structures limit PCNs from maximising the "4Cs". However, the enabling features mentioned above outweighs the shortfalls in all important aspects of delivering optimal chronic disease care. Therefore, even though PCN is in its early stage of development, it has shown to be well poised to steer GPs towards enhanced chronic disease management.

Assessment of acute kidney injury risk using a machine-learning guided generalized structural equation model: a cohort study

Background

Acute kidney injury is common in the surgical intensive care unit (ICU). It is associated with poor patient outcomes and high healthcare resource usage. This study’s primary objective is to help identify which ICU patients are at high risk for acute kidney injury. Its secondary objective is to examine the effect of acute kidney injury on a patient’s prognosis during and after the ICU admission.

Methods

A retrospective cohort of patients admitted to a Singaporean surgical ICU between 2015 to 2017 was collated. Patients undergoing chronic dialysis were excluded. The outcomes were occurrence of ICU acute kidney injury, hospital mortality and one-year mortality. Predictors were identified using decision tree algorithms. Confirmatory analysis was performed using a generalized structural equation model.

Results

A total of 201/940 (21.4%) patients suffered acute kidney injury in the ICU. Low ICU haemoglobin levels, low ICU bicarbonate levels, ICU sepsis, low pre-ICU estimated glomerular filtration rate (eGFR) and congestive heart failure was associated with the occurrence of ICU acute kidney injury. Acute kidney injury, together with old age (> 70 years), and low pre-ICU eGFR, was associated with hospital mortality, and one-year mortality. ICU haemoglobin level was discretized into 3 risk categories for acute kidney injury: high risk (haemoglobin ≤9.7 g/dL), moderate risk (haemoglobin between 9.8–12 g/dL), and low risk (haemoglobin > 12 g/dL).

Conclusion

The occurrence of acute kidney injury is common in the surgical ICU. It is associated with a higher risk for hospital and one-year mortality. These results, in particular the identified haemoglobin thresholds, are relevant for stratifying a patient’s acute kidney injury risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02238-9.

Recombinant Erythropoietin Provides Protection against Renal Fibrosis in Adenine-Induced Chronic Kidney Disease

Chronic kidney disease (CKD) causes anemia by renal damage. In CKD, the kidney is submitted to hypoxia, persistent inflammation, leading to fibrosis and permanent loss of renal function. Human recombinant erythropoietin (rEPO) has been widely used to treat CKD-associated anemia and is known to possess organ-protective properties that are independent from its well-established hematopoietic effects. Nonhematopoietic effects of EPO are mediated by an alternative receptor that is proposed to consist of a heterocomplex between the erythropoietin receptor (EPOR) and the beta common receptor (βcR). The present study explored the effects of rEPO to prevent renal fibrosis in adenine-induced chronic kidney disease (Ad-CKD) and their association with the expression of the heterodimer EPOR/βcR. Male Wistar rats were randomized to control group (CTL), adenine-fed rats (Ad-CKD), and Ad-CKD with treatment of rEPO (1050 IU/kg, once weekly for 4 weeks). Ad-CKD rats exhibited anemia, uremia, decreased renal function, increased infiltration of inflammatory cells, tubular atrophy, and fibrosis. rEPO treatment not only corrected anemia but reduced uremia and partially improved renal function as well. In addition, we observed that rEPO diminishes tubular injury, prevents fibrosis deposition, and induces the EPOR/βcR heteroreceptor. The findings may explain the extrahematopoietic effects of rEPO in CKD and provide new strategies for the treatment of renal fibrosis in CKD.

Skin Cutibacterium acnes Mediates Fermentation to Suppress the Calcium Phosphate-Induced Itching: A Butyric Acid Derivative with Potential for Uremic Pruritus

Pruritus and inflammation associated with accumulation of calcium phosphate (CaP) under the skin are common problems among dialysis patients with chronic kidney disease (CKD). The role of skin commensal microbiota in the CaP-induced uremic pruritus remains uncharacterized. Skin Cutibacterium acnes (C. acnes) can solubilize CaP by the production of short-chain fatty acids (SCFAs), such as butyric acid, through glucose fermentation. Like butyric acid, the N-[2-(2-Butyrylamino-ethoxy)-ethyl]-butyramide (BA-NH-NH-BA), a butyric acid derivative, remarkably induced acetylation of histone H3 lysine 9 (AcH3K9) in keratinocytes. Topical application of fermenting C. acnes, butyric acid or BA-NH-NH-BA onto mouse skin effectively ameliorated CaP-induced skin itching, interleukin (IL)-6 up-regulation in keratinocytes, and extracellular signal-regulated kinase (ERK) 1/2 activation in dorsal root ganglia (DRG). Activation of ERK 1/2 by CaP was markedly reduced in IL-6 knockout mice. Genus Cutibacterium was detected in relatively low abundance in itchy skin of patients with CKD. Our results identify a role for the skin fermenting C. acnes in ameliorating CaP-induced activation of IL-6/p-ERK signaling and resulting skin inflammation. Furthermore, we provide evidence for the potential therapeutic efficacy of BA-NH-NH-BA as a postbiotic for the treatment of uremic pruritus.

A model of functional thyroid disease status over the lifetime

Mathematical models of the natural history of disease can predict incidence rates based on prevalence data and support simulations of populations where thyroid function affects other aspects of physiology. We developed a Markov chain model of functional thyroid disease status over the lifetime. Subjects were in one of seven thyroid disease states at any given point in their lives [normal, subclinical hypothyroidism, overt hypothyroidism, treated thyroid disease (ever), subclinical hyperthyroidism, overt hyperthyroidism, and reverted to normal thyroid status]. We used a Bayesian approach to fitting model parameters. A priori probabilities of changing from each disease state to another per unit time were based on published data and summarized using meta-analysis, when possible. The probabilities of changing state were fitted to observed prevalence data based on the National Health and Nutrition Examination Survey 2007–2012. The fitted model provided a satisfactory fit to the observed prevalence data for each disease state, by sex and decade of age. For example, for males 50–59 years old, the observed prevalence of ever having treated thyroid disease was 4.4% and the predicted value was 4.6%. Comparing the incidence rates of treated disease predicted from our model with published values revealed that 82% were within a 4-fold difference. The differences seemed to be systematic and were consistent with expectation based on national iodine intakes. The model provided new and comprehensive estimates of functional thyroid disease incidence rates for the U.S. Because the model provides a reasonable fit to national prevalence data and predicts thyroid disease status over the lifetime, it is suitable for simulating populations, thereby making possible quantitative bias analyses of selected epidemiologic data reporting an association of thyroid disease with serum concentrations of environmental contaminants.

Early retinal microvascular abnormalities in patients with chronic kidney disease

Objective

To evaluate early retinal microvascular abnormalities in patients with chronic kidney disease (CKD) via optical coherence tomography angiography.

Methods

A cross‐sectional study. Two hundred patients with CKD stage ≧3 were enrolled in the CKD group, and 50 age‐matched healthy subjects were enrolled in the control group. Main outcome measures were the differences in parafoveal vessel densities in the superficial vascular plexus (SVP) and deep vascular plexus (DVP) between the CKD and control groups.

Results

The mean ages were 62.7 ± 10.1 in the CKD group and 61.9 ± 9.7 (P = 0.622) in the control group. The CKD group had reduced parafoveal vessel densities in SVP (46.7 ± 4.3 vs 49.7 ± 2.9, P < 0.001) and DVP (50.1 ± 4.1 vs 52. 6 ± 2.9, P < 0.001) when compared to those of the control group. In multiple linear regression models, age, diabetes, estimated glomerular filtration rate, and use of anti‐hypertensive drugs were factors associated with vessel density in SVP, whereas age, diabetes, and smoking were factors associated with vessel density in DVP.

Conclusion

Patients with CKD had reduced vessel densities in parafoveal SVP and DVP, as compared to that of control subjects. Microvasculature in the different retinal layers may be affected by different systemic factors.