Impact of the estimation equation for GFR on population-based prevalence estimates of kidney dysfunction

Comparison of EKFC, Pakistani CKD-EPI and 2021 Race-Free CKD-EPI creatinine equations in South Asian CKD population: A study from Pakistani CKD community cohort

INTRODUCTION

South Asian individuals possess a high risk of chronic kidney disease. There is a need to study, evaluate, and compare the newly suggested glomerular filtration rate (eGFR) equations for accurate CKD diagnosis, staging, and drug dosing. This study aimed to (1) evaluate the European Kidney Function Consortium (EKFC), Pakistani CKD-EPI, and 2021 Race-Free CKD-EPI creatinine equation in the South Asian population with CKD and (2) to examine the expected implications on both CKD classification as well as End Stage Renal Disease (ESRD) prevalence across these equations in South Asian population.

METHODS

We carried out a cross-sectional investigation on 385 participants, a CKD cohort ≥ 18 years, at Allama Iqbal Medical College, Jinnah Hospital, Lahore. Serum creatinine was measured by Jaffe's method and rGFR was measured by inulin clearance.

RESULTS

Pakistani CKD-EPI has a lower median difference at -1.33 ml/min/1.73m2 elevated precision (IQR) at 2.33 (-2.36, -0.03) and higher P30 value at 89.35% than 2021 CKD-EPI and EKFC equations. The mean difference (ml/min/1.73m2), 95% agreement limits (ml/min/1.73m2) of CKD-EPI PK: -1.18, -6.14, 2021 CKD-EPI: -5.98, -13.24 and EKFC: -5.62, -13.01 (P <0.001). These equations highly correlated to rGFR (P <0.001). An upward re-classification in GFR categories was shown by 2021 CKD-EPI and EKFC compared to the Pakistani CKD-EPI equation. However, there was an exception regarding the G5 category, where an elevated count of 217 (56.36%) was shown for CKD-EPI PK. The prevalence of ESRD was seen in entire age groups and prevailed among females more than in males overall equations.

CONCLUSIONS

Pakistani CKD-EPI exhibited outstanding performance, while 2021 CKD-EPI and EKFC demonstrated poor performances and could not show an adequate advantage for both CKD classification and prevalence of ESRD compared to Pakistani CKD-EPI. Therefore, Pakistani CKD-EPI appears optimal for this region and warrants future validation in other South Asian countries. In contrast, suitable measures must be implemented in Pakistani laboratories.

Comparison of Pakistani CKD-EPI, new Asian-modified CKD-EPI and revised Lund-Malmö study equations in a South Asian CKD population: a study from a Pakistani CKD cohort

BACKGROUND

Newly proposed estimating glomerular filtration rate equations need to be studied, evaluated and compared for chronic kidney disease staging, diagnosis and medication dosing in South Asians. The objectives of the study were (1) to assess the performance of the CKD-EPIPK, CKD-EPIAsian-Modified, and LMRevised equations in the Pakistani chronic kidney disease population, and (2) to investigate prospective implications on chronic kidney disease classification and end-stage kidney disease prevalence.

METHODS

We conducted a cross-sectional analysis on a chronic kidney disease cohort of 385 participants 18 years of age or above.

RESULTS

CKD-EPIPK showed the lowest bias (- 1.33 ml/min/1.73 m2), highest precision [IQR, 2.33 (- 2.36, - 0.03)] and enhanced P30 accuracy (89.35%) compared to the CKD-EPIAsian-Modified and LMRevised equations. The mean difference (ml/min/1.73 m2), 95% limit of agreement (ml/min/1.73 m2) of the equations were; CKD-EPIAsian-Modified: - 5.98, - 13.03, LMRevised: - 4.06, - 8.13 and CKD-EPIPK: - 1.18, - 6.14 (P < 0.001). CKD-EPIAsian-Modified and LMRevised showed upward re-classification of the GFR categories compared to the CKD-EPIPK equation except in the G5 category where the highest count (217, 56.36%) was noted for the CKD-EPIPK equation. End-stage kidney disease prevailed in all age groups according to all equations, and the prevalence was high in females in all equations.

CONCLUSION

CKD-EPIPK showed the best performance, whereas both CKD-EPIAsian-Modified and LMRevised showed poor performance and did not offer a sufficient advantage in chronic kidney disease classification and end-stage kidney disease prevalence estimation over CKD-EPIPK. Hence, CKD-EPIPK seems ideal for South Asians, thus appropriate measures should be taken for its implementation, at least in Pakistani laboratories.

[High patient unawareness for chronic kidney disease even in later stages - but why is it more frequent in women than in men?]

INTRODUCTION

 Chronic kidney failure (CKD) is as common as diabetes or coronary heart disease in a population aged 40 years and older. Although CKD increases the risk of secondary diseases or premature death, patients with CKD are often unaware of their disease. In a recent analysis of German data, unawareness CKD was higher in women than in men.

METHODS

 Baseline data from 2010 of 3,305 CKD patients from German cohort studies and registries were analyzed. Stage 1-4 CKD was defined by eGFR (estimated glomerular filtration rate) and albumin-creatinine ratio according to the KDIGO-guideline. Patient knowledge of CKD was coded according to self-report. The proportion of patients without knowledge of CKD and the sex-specific proportion difference (each with 95 % confidence interval) were calculated according to CKD stages and additional comorbidities (diabetes, hypertension, anemia, and cardiovascular disease). In addition, the prevalence ratio (PR) for not knowing about CKD was estimated for women compared to men crude and adjusted for age and other risk factors.

RESULTS

 Women were less likely than men to know about their CKD in all subgroups studied by age, CKD stage, and comorbidities. The proportion difference for CKD awareness increased with higher CKD stage and was 21 percentage points (7.6; 34.6) at the expense of women in CKD stage 4. Among patients with CKD stage 3b and concomitant grade 2 hypertension, 61 % of women versus 45 % of men were unaware of their disease. The PR for CKD unawareness in women compared with men in the fully adjusted model increased from 1.08 (1.00; 1.16) in CKD stage 3a to 1.75 (1.14; 2.68) in CKD stage 4.

CONCLUSION

 Despite the presence risk factors that necessitate monitoring of renal function, less than half of patients know they have CKD stage 3b or 4. Women are less likely to be aware of their CKD in all subgroups. Possible causes are gender-related differences in primary health care (gender bias) or in patient-doctor communication.

External validation of six clinical models for prediction of chronic kidney disease in a German population

Background

Chronic kidney disease (CKD) is responsible for large personal health and societal burdens. Screening populations at higher risk for CKD is effective to initiate earlier treatment and decelerate disease progress. We externally validated clinical prediction models for unknown CKD that might be used in population screening.

Methods

We validated six risk models for prediction of CKD using only non-invasive parameters. Validation data came from 4,185 participants of the German Heinz-Nixdorf-Recall study (HNR), drawn in 2000 from a general population aged 45–75 years. We estimated discrimination and calibration using the full model information, and calculated the diagnostic properties applying the published scoring algorithms of the models using various thresholds for the sum of scores.

Results

The risk models used four to nine parameters. Age and hypertension were included in all models. Five out of six c-values ranged from 0.71 to 0.73, indicating fair discrimination. Positive predictive values ranged from 15 to 19%, negative predictive values were > 93% using score thresholds that resulted in values for sensitivity and specificity above 60%.

Conclusions

Most of the selected CKD prediction models show fair discrimination in a German general population. The estimated diagnostic properties indicate that the models are suitable for identifying persons at higher risk for unknown CKD without invasive procedures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02899-0.

High Unawareness of Chronic Kidney Disease in Germany

Chronic kidney disease (CKD) is associated with an increased risk for cardiovascular events, hospitalizations, end stage renal disease and mortality. Main risk factors for CKD are diabetes, hypertension, and older age. Although CKD prevalence is about 10%, awareness for CKD is generally low in patients and physicians, hindering early diagnosis and treatment. We analyzed baseline data of 3305 participants with CKD Stages 1-4 from German cohorts and registries collected in 2010. Prevalence of CKD unawareness and prevalence ratios (PR) (each with 95%-confidence intervals) were estimated in categories of age, sex, CKD stages, BMI, hypertension, diabetes and other relevant comorbidities. We used a log-binomial regression model to estimate the PR for CKD unawareness for females compared to males adjusting for CKD stage and CKD risk factors. CKD unawareness was high, reaching 71% (68-73%) in CKD 3a, 49% (45-54%) in CKD 3b and still 30% (24-36%) in CKD4. Prevalence of hypertension, diabetes or cardiovascular comorbidities was not associated with lower CKD unawareness. Independent of CKD stage and other risk factors unawareness was higher in female patients (PR = 1.06 (1.01; 1.10)). Even in patients with CKD related comorbidities, CKD unawareness was high. Female sex was strongly associated with CKD unawareness. Guideline oriented treatment of patients at higher risk for CKD could increase CKD awareness. Patient-physician communication about CKD might be amendable.

Renal dysfunction in systemic sclerosis beyond scleroderma renal crisis

Research regarding renal involvement in SSc has almost exclusively focused on scleroderma renal crisis (SRC). There are relatively limited data regarding renal impairment in SSc beyond SRC. We performed an electronic search using the key words systemic sclerosis or scleroderma combined with each of the following: renal dysfunction, kidney, glomerular filtration rate (GFR), proteinuria and hematuria. We searched for reports relevant to renal dysfunction in SSc beyond SRC. In 796 SSc patients recruited in five studies. 251 (31.5%) had GFR < 90 ml/min whereas 155(19.5%) patients had GFR < 60 ml/min. Most data indicate that the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula should be considered as the most suitable tool for assessing renal function in SSc pts, since it provides similar results to measured GFR. These data indicate that renal dysfunction in SSc in not uncommon and therefore patients with SSc should have their renal function assessed by GFR estimation on a regular basis.

Implementation of a renal pharmacist consultant service - Information sharing in paper versus digital form

WHAT IS KNOWN AND OBJECTIVE

Renal impairment (RI) and renal drug-related problems (rDRP) often remain unrecognized in the community setting. A "renal pharmacist consultant service" (RPCS) at hospital admission can support patient safety by detecting rDRP. However, the efficient information sharing from pharmacists to physicians is still discussed. The aim of the study was to test the implementation of a RPCS and its effectiveness on prescription changes and to evaluate two ways of written information sharing with physicians.

METHODS

Urological patients with eGFR_non-indexed of 15-59 ml/min and ≥1 drug were reviewed for manifest and potential rDRP at admission by a pharmacist. Written recommendations for dose or drug adaptation were forwarded to physicians comparing two routes: July-September 2017 paper form in handwritten chart; November 2017-January 2018 digital PDF document in the electronic patient information system and e-mail alert. Prescription changes regarding manifest rDRP were evaluated and compared with a previous retrospective study without RPCS.

RESULTS AND DISCUSSION

The RPCS detected rDRP in 63 of 234 (26.9%) patients and prepared written recommendations (median 1 rDRP (1-5) per patient) concerning 110 of 538 (20.5%) drugs at admission. For manifest rDRP, acceptance rates of recommendations were 62.5% (paper) vs 42.9% (digital) (P = 0.16). Compared with the retrospective study without RPCS (prescription changes in 21/76 rDRP; 27.6%), correct prescribing concerning manifest rDRP significantly increased by 27.1%.

WHAT IS NEW AND CONCLUSION

A RPCS identifies patients at risk for rDRP and significantly increases appropriate prescribing by physicians. In our hospital (no electronic order entry, electronic chart or ward pharmacists), consultations in paper form seem to be superior to a digital PDF document.

Costs of patients with chronic kidney disease in Germany

BACKGROUND

This study aimed to determine the costs and distribution of healthcare spending of patients with chronic kidney disease (CKD) at stages 3 and 4 and on dialysis both at the individual and population level in Germany.

METHODS

The study took the perspective of the German statutory health insurance (SHI) system and analyzed claims data on 3,687,015 insurees from the year 2014. To extrapolate costs to the whole SHI population, a literature search on the prevalence of CKD was conducted.

RESULTS

Average costs per person per year in an age- and gender-matched control group of the normal population were €2,876 (95% confidence interval [CI], €2,798 to €2,955) and ≥2.8-fold higher in CKD patients (€8,030 [95% CI, €7,848 to €8,212] at CKD stage 3, €9,760 [95% CI, €9,266 to €10,255] at CKD stage 4, and €44,374 [95% CI, €43,608 to €45,139] on dialysis). At CKD stages 3 and 4 the major cost driver was hospitalizations, contributing to more than 50% of total expenditures. Among dialysis patients, hospitalizations and dialysis-treatment costs contributed to 23% and 53% of total healthcare spending, respectively. At CKD stages 3 and 4, patients with the highest 20% of healthcare spending showed a considerable increase in per-patient costs over the reference population, while the bottom 80% of patients generated only moderately higher per-patient costs (p < 0.001). Comparing total CKD costs to total SHI expenditures yields that 10.2% of SHI expenditures was driven by patients at CKD stages 3 and 4 and 1.6% by dialysis patients.

CONCLUSIONS

Healthcare spending of patients with CKD at stages 3 and 4 and on dialysis is concentrated among a small number of high-need patients. As hospitalizations and dialysis treatment are key drivers of total expenditures, strategies that lead to a reduction in hospitalizations, delay in dialysis onset, or increase in the availability of kidney donors should become important considerations by policymakers.