Why overestimate or underestimate chronic kidney disease when correct estimation is possible?

Prevalence of chronic kidney disease in France: methodological considerations and pitfalls with the use of Health claims databases

Background

Health policy-making require careful assessment of chronic kidney disease (CKD) epidemiology to develop efficient and cost-effective care strategies. The aim of the present study was to use the RENALGO-EXPERT algorithm to estimate the global prevalence of CKD in France.

Methods

An expert group developed the RENALGO-EXPERT algorithm based on healthcare consumption. This algorithm has been applied to the French National Health claims database (SNDS), where no biological test findings are available to estimate a national CKD prevalence for the years 2018-2021. The CONSTANCES cohort (+219 000 adults aged 18-69 with one CKD-EPI eGFR) was used to discuss the limit of using health claims data.

Results

Between 2018 and 2021, the estimated prevalence in the SNDS increased from 8.1% to 10.5%. The RENALGO-EXPERT algorithm identified 4.5% of the volunteers in the CONSTANCES as CKD. The RENALGO-EXPERT algorithm had a positive predictive value of 6.2% and negative predictive value of 99.1% to detect an eGFR<60 ml/min/1.73 m². Half of 252 false positive cases (ALGO+, eGFR > 90) had been diagnosed with kidney disease during hospitalization, and the other half based on healthcare consumption suggestive of a 'high-risk' profile; 95% of the 1661 false negatives (ALGO-, eGFR < 60) had an eGFR between 45 and 60 ml/min, half had medication and two-thirds had biological exams possibly linked to CKD. Half of them had a hospital stay during the period but none had a diagnosis of kidney disease.

Conclusions

Our result is in accordance with other estimations of CKD prevalence in the general population. Analysis of diverging cases (FP and FN) suggests using health claims data have inherent limitations. Such an algorithm can identify patients whose care pathway is close to the usual and specific CKD pathways. It does not identify patients who have not been diagnosed or whose care is inappropriate or at early stage with stable GFR.

Estimated pediatric glomerular filtration rate presentation improves the detection rate of kidney impairment in children

BACKGROUND

Accurate interpretation of everyday laboratory work is crucial for the early detection of impaired kidney function. Bedside estimation of glomerular filtration rate (eGFR) in children is based on serum creatinine standardized for body mass, most commonly using the revised Schwartz equation using height. This study evaluates how data presentation affects the correct assessment of children's kidney function.

METHODS

In this survey-based study, 121 physicians treating children routinely in a tertiary hospital answered 11 clinical questions requiring assessment of kidney function based on serum creatinine with general (adult) or pediatric normal serum creatinine ranges, or by presented eGFR. The demographic data of the participants were collected.

RESULTS

Presenting eGFR values rather than the customary presentation of serum creatinine and anthropometric parameters more than quadrupled the number of physicians who accurately estimated pediatric kidney function; 38.8% of physicians correctly assessed kidney function when presented with eGFR values but misinterpreted it when equivalent creatinine values were presented (p < 0.001). Seniority, specialty, and self-reported frequency of pediatric kidney function assessment did not affect the interpretation.

CONCLUSIONS

Presenting physicians with calculated eGFR can dramatically improve the ability of the medical team to assess kidney function correctly in children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prevalence and risk factors for chronic kidney disease in Indonesia: An analysis of the National Basic Health Survey 2018

Background

The prevalence of chronic kidney disease (CKD) in Indonesia is rising, but the exact extent of the burden of CKD in Indonesia is unknown. To design a screening program for individuals at high-risk, more knowledge is required regarding the prevalence and risk factors of CKD in Indonesia. The latter could have a big impact on the prevention and management of patients with CKD in Indonesia.

Methods

For this purpose, we analysed data from The National Basic Health Survey 2018 (Riset Kesehatan Dasar, Riskesdas 2018), a descriptive cross-sectional study in 34 provinces, 416 districts and 98 cities in Indonesia. We included subjects aged ≥18 years and analysed the prevalence of CKD. Using multiple logistic regression, we investigated the association between CKD and potential risk factors such as demographic factors (age, gender, occupational status, level of education), lifestyle and behaviours (consumption of salty food, consumption of fruit and vegetables, smoking, alcohol consumption, carbonated drink consumption, physical activity), comorbid conditions (hypertension, heart disease, diabetes mellitus, hepatitis, stroke, nutritional status) and others (clean water supply, pregnancy complication, access to health care).

Results

We included 389 093 subjects in this study out of 713 783 subjects that participated in Riskesdas 2018 survey. The prevalence of CKD was 0.5%. The survey included mostly younger adults age 18-59 years (83.1%) with a mean (SD) age of 44.3 (15.1) years. The majority of subjects were female (60.3%), unemployed (58.4%), and the proportion of obese subject was 25.4%. Hypertension was the major comorbid condition (40.8%), while the proportion of diabetes mellitus (DM), heart disease, stroke and hepatitis were quite low (3.3%, 2.6%, 1.7% and 0.5%; respectively). Despite the high proportion of hypertension, only 36.2% of subjects did receive a prescription for anti-hypertensive medication of which only 21.7% used this medication regularly. The multiple logistic regression analysis demonstrated that hepatitis was the strongest risk factor of CKD (odds ratio (OR) = 3.406; 95% confidence interval (CI) = 2.496-4.648), exceeding the risk of CKD in patients with physical inactivity (OR = 1.236; 95% CI = 1.128-1.354), low education status (OR = 1.307; 95% CI = 1.191-1.434), male (OR = 1.527; 95% CI = 1.398-1.668), stroke (OR = 1.916; 95% CI = 1.570-2.338), heart disease (OR = 2.941; 95% CI = 2.356-3.671), and DM (OR = 2.462; 95% CI = 1.979-3.063). We also observed that DM (OR = 4.280; 95% CI = 3.756-4.876) and male subjects (OR = 1.474; 95% CI = 1.352-1.606) were identified as independent risk factors for CKD in hepatitis-positive subjects.

Conclusions

This population-based survey confirmed the increasing burden of CKD in Indonesia and suggested that besides traditional metabolic risk factors, viral hepatitis has proven to be an independent risk factor for CKD in Indonesia. Furthermore, the risk of CKD is greater in male hepatitis patients with DM. The result of this study demonstrates the need for an aggressive screening program for patients with a high risk for the development of CKD. Apart from patients with traditional cardiometabolic risk factors, such a program should include patients with viral hepatitis.

Assessment of Pre-Donation Glomerular Filtration Rate: Going Back To Basics A Position Paper from the DESCARTES Working Group of the ERA-EDTA

The 2017 version of the KDIGO (Kidney Disease: Improving Global Outcomes) guidelines is the most recent international framework for the evaluation and care of living kidneys donors. Along with the call for an integrative approach evaluating the long-term end-stage kidney disease risk for the future potential donor, several recommendations are formulated regarding the predonation glomerular filtration rate (GFR) adequacy with no or little consideration for the donor candidate's age and for the importance of using reference methods of GFR measurements. Herein, we question the position of the KDIGO guidelines and discuss the rationale and modalities for a more basic, but not less demanding GFR evaluation susceptible to enable a more efficient selection of the potential kidney donor.

Chronic renal dysfunction in cirrhosis: A new frontier in hepatology

Chronic kidney disease (CKD) in patients with liver cirrhosis has become a new frontier in hepatology. In recent years, a sharp increase in the diagnosis of CKD has been observed among patients with cirrhosis. The rising prevalence of risk factors, such as diabetes, hypertension and nonalcoholic fatty liver disease, appears to have contributed significantly to the high prevalence of CKD. Moreover, the diagnosis of CKD in cirrhosis is now based on a reduction in the estimated glomerular filtration rate of < 60 mL/min over more than 3 mo. This definition has resulted in a better differentiation of CKD from acute kidney injury (AKI), leading to its greater recognition. It has also been noted that a significant proportion of AKI transforms into CKD in patients with decompensated cirrhosis. CKD in cirrhosis can be structural CKD due to kidney injury or functional CKD secondary to circulatory and neurohormonal imbalances. The available literature on combined cirrhosis-CKD is extremely limited, as most attempts to assess renal dysfunction in cirrhosis have so far concentrated on AKI. Due to problems related to glomerular filtration rate estimation in cirrhosis, the absence of reliable biomarkers of CKD and technical difficulties in performing renal biopsy in advanced cirrhosis, CKD in cirrhosis can present many challenges for clinicians. With combined hepatorenal dysfunctions, fluid mobilization becomes problematic, and there may be difficulties with drug tolerance, hemodialysis and decision-making regarding the need for liver vs simultaneous liver and kidney transplantation. This paper offers a thorough overview of the increasingly known CKD in patients with cirrhosis, with clinical consequences and difficulties occurring in the diagnosis and treatment of such patients.

Chronic kidney disease in adults aged 18 years and older in Chile: findings from the cross-sectional Chilean National Health Surveys 2009-2010 and 2016-2017

OBJECTIVES

This study estimates the prevalence of chronic kidney disease (CKD) among Chilean adults and examines its associations with sociodemographic characteristics, health behaviours and comorbidities.

DESIGN

Analysis of cross-sectional data from the two most recent large nationally representative Chilean Health Surveys (Encuesta Nacional de Salud, ENS) 2009-2010 and 2016-2017.

PARTICIPANTS

Adults aged 18+ years with serum creatine data (ENS 2009-2010: n=4583; ENS 2016-2017: n=5084).

PRIMARY AND SECONDARY OUTCOME MEASURES

Reduced kidney function (CKD stages 3a-5) based on the estimated glomerular filtration rate (eGFR <60 mL/min/1.73 m2) was the primary outcome measure. Using the urine albumin-to-creatinine ratio (ACR ≥30 mg/g), increased albuminuria was ascertained among adults aged 40+ years with diabetes and/or hypertension. Both outcomes were analysed using logistic regression with results summarised using OR. CKD prevalence (stages 1-5) among adults aged 40+ years was estimated including participants with an eGFR of >60 mL/min/1.73 m2 but with increased albuminuria (stages 1-2).

RESULTS

Overall, 3.2% (95% CI: 2.4% to 3.8%) of adults aged 18+ in ENS 2016-2017 had reduced kidney function. After full adjustment, participants with hypertension (OR: 2.37; 95% CI: 1.19 to 4.74) and those with diabetes (OR: 1.66; 95% CI: 1.03 to 2.66) had significantly higher odds of reduced kidney function. In ENS 2016-2017, 15.5% (13.5% to 17.8%) of adults aged 40+ years with diabetes and/or hypertension had increased albuminuria. Being obese versus normal-weight (OR: 1.66; 95% CI: 1.08 to 2.54) and having both diabetes and hypertension versus having diabetes alone (OR: 2.30; 95% CI: 1.34 to 3.95) were significantly associated with higher odds of increased albuminuria in fully-adjusted analyses. At least 15.4% of adults aged 40+ years in ENS 2016-2017 had CKD (stages 1-5), including the 9.6% of adults at CKD stages 1-2.

CONCLUSIONS

Prevention strategies and Chilean guidelines should consider the high percentage of adults aged 40 years and older at CKD stages 1-2.

Experience of a tertiary-level urology center in the clinical urological events of rare and very rare incidence. III. Psychourological events: 2. Phobia of renal failure due to loin pain

Background

End-stage renal disease and loin pain are prevalent nephrourological topics with unfavorable reputations among populations. We aimed to present our center’s experience with the cases of phobia of renal failure in relation to loin pain.

Methods

It is a retrospective study of phobia of renal failure among the patients who presented with loin pain to our center between July 1991 and June 2017. Description of perception of renal failure risk was guided by the modified Common Sense Model of Illness Representation.

Results

Of more than 64, 000 patients who presented with loin pain, only 78 patients (0.12%) had phobia of renal failure. Mean age ± SD (Range) was 41.12 ± 9.58 (23–60) years. Sixty-four patients (82.1%) expressed directly fear of renal failure. Physical examination and investigations revealed no risks of renal failure in all patients. High percentages of phobia of renal failure were associated with the female gender (73.1%), the presence of a relative patient with renal failure (83.3%), and low socioeconomic levels: education (89.7%), residential (75.6%), and economic status (88.5%) levels. The modified Common Sense Model of Illness Representation revealed predominant emotional representations and unreal cognitive domains with altered perception of renal failure risk.

Conclusions

Phobia of renal failure is very rare. It is a consequence of the altered perception of risk of renal failure due to unconscious attribution of loin pain to renal failure. Female gender, the presence of a relative with renal failure, and low socioeconomic levels could be suggested as risk factors for phobia of renal failure.

Experience of a tertiary-level urology center in the clinical urological events of rare and very rare incidence. III. Psychourological events: 2. Phobia of renal failure due to loin pain

Background

End-stage renal disease and loin pain are prevalent nephrourological topics with unfavorable reputations among populations. We aimed to present our center’s experience with the cases of phobia of renal failure in relation to loin pain.

Methods

It is a retrospective study of phobia of renal failure among the patients who presented with loin pain to our center between July 1991 and June 2017. Description of perception of renal failure risk was guided by the modified Common Sense Model of Illness Representation.

Results

Of more than 64, 000 patients who presented with loin pain, only 78 patients (0.12%) had phobia of renal failure. Mean age ± SD (Range) was 41.12 ± 9.58 (23–60) years. Sixty-four patients (82.1%) expressed directly fear of renal failure. Physical examination and investigations revealed no risks of renal failure in all patients. High percentages of phobia of renal failure were associated with the female gender (73.1%), the presence of a relative patient with renal failure (83.3%), and low socioeconomic levels: education (89.7%), residential (75.6%), and economic status (88.5%) levels. The modified Common Sense Model of Illness Representation revealed predominant emotional representations and unreal cognitive domains with altered perception of renal failure risk.

Conclusions

Phobia of renal failure is very rare. It is a consequence of the altered perception of risk of renal failure due to unconscious attribution of loin pain to renal failure. Female gender, the presence of a relative with renal failure, and low socioeconomic levels could be suggested as risk factors for phobia of renal failure.

Too much nephrology? The CKD epidemic is real and concerning. A CON view

The prevalence of chronic kidney disease (CKD) clearly depends on its definition, and the definition used most often is the one proposed by the Kidney Disease: Improving Global Outcomes guidelines in 2012: 'CKD is defined as abnormalities of kidney structure or function, present for >3 months, with implications for health.' Abnormality of kidney function is a glomerular filtration rate (GFR) <60 mL/min/1.73 m2, and the most frequently used marker of kidney damage is the presence of albuminuria [albumin excretion rate >30 mg/24 h or albumin/creatinine ratio (ACR) >30 mg/g (or 3 mg/mmol)]. However, two major aspects of this definition could explain why CKD prevalence is, in our view, overstated in most epidemiological studies. First, the fixed threshold at 60 mL/min/1.73 m2 is questionable because normal GFR decreases with age. This and the profound consequence it has on CKD epidemiology will be illustrated. The second aspect of the definition is the criterion of chronicity, which is ignored by the vast majority of epidemiological studies. In other words, confirming CKD (low GFR and/or high ACR) is mandatory. Indeed, a large proportion of subjects with a low first GFR level has a normal GFR level when tested a second time. The prevalence of CKD may hence, in fact, be considerably lower although still neither negligible nor irrelevant.

CKD: A Call for an Age-Adapted Definition

Current criteria for the diagnosis of CKD in adults include persistent signs of kidney damage, such as increased urine albumin-to-creatinine ratio or a GFR below the threshold of 60 ml/min per 1.73 m2 This threshold has important caveats because it does not separate kidney disease from kidney aging, and therefore does not hold for all ages. In an extensive review of the literature, we found that GFR declines with healthy aging without any overt signs of compensation (such as elevated single-nephron GFR) or kidney damage. Older living kidney donors, who are carefully selected based on good health, have a lower predonation GFR compared with younger donors. Furthermore, the results from the large meta-analyses conducted by the CKD Prognosis Consortium and from numerous other studies indicate that the GFR threshold above which the risk of mortality is increased is not consistent across all ages. Among younger persons, mortality is increased at GFR <75 ml/min per 1.73 m2, whereas in elderly people it is increased at levels <45 ml/min per 1.73 m2 Therefore, we suggest that amending the CKD definition to include age-specific thresholds for GFR. The implications of an updated definition are far reaching. Having fewer healthy elderly individuals diagnosed with CKD could help reduce inappropriate care and its associated adverse effects. Global prevalence estimates for CKD would be substantially reduced. Also, using an age-specific threshold for younger persons might lead to earlier identification of CKD onset for such individuals, at a point when progressive kidney damage may still be preventable.

Epithelial Cell Cycle Behaviour in the Injured Kidney

Acute kidney injury (AKI), commonly caused by ischemia-reperfusion injury, has far-reaching health consequences. Despite the significant regenerative capacity of proximal tubular epithelium cells (PTCs), repair frequently fails, leading to the development of chronic kidney disease (CKD). In the last decade, it has been repeatedly demonstrated that dysregulation of the cell cycle can cause injured kidneys to progress to CKD. More precisely, severe AKI causes PTCs to arrest in the G1/S or G2/M phase of the cell cycle, leading to maladaptive repair and a fibrotic outcome. The mechanisms causing these arrests are far from known. The arrest might, at least partially, be attributed to DNA damage since activation of the DNA-damage response pathway leads to cell cycle arrest. Alternatively, cytokine signalling via nuclear factor kappa beta (NF-κβ) and p38-mitogen-activated protein kinase (p38-MAPK) pathways, and reactive oxygen species (ROS) can play a role independent of DNA damage. In addition, only a handful of cell cycle regulators (e.g., p53, p21) have been thoroughly studied during renal repair. Still, why and how PTCs decide to arrest their cell cycle and how this arrest can efficiently be overcome remain open and challenging questions. In this review we will discuss the evidence for cell cycle involvement during AKI and development of CKD together with putative therapeutic approaches.

Chronic kidney disease

Chronic kidney disease (CKD) is defined by persistent urine abnormalities, structural abnormalities or impaired excretory renal function suggestive of a loss of functional nephrons. The majority of patients with CKD are at risk of accelerated cardiovascular disease and death. For those who progress to end-stage renal disease, the limited accessibility to renal replacement therapy is a problem in many parts of the world. Risk factors for the development and progression of CKD include low nephron number at birth, nephron loss due to increasing age and acute or chronic kidney injuries caused by toxic exposures or diseases (for example, obesity and type 2 diabetes mellitus). The management of patients with CKD is focused on early detection or prevention, treatment of the underlying cause (if possible) to curb progression and attention to secondary processes that contribute to ongoing nephron loss. Blood pressure control, inhibition of the renin-angiotensin system and disease-specific interventions are the cornerstones of therapy. CKD complications such as anaemia, metabolic acidosis and secondary hyperparathyroidism affect cardiovascular health and quality of life, and require diagnosis and treatment.