Participation rate and yield of two home-based screening methods to detect increased albuminuria in the general population in the Netherlands (THOMAS): a prospective, randomised, open-label implementation study

BACKGROUND

Chronic kidney disease (CKD) has a rising global prevalence and is expected to become the fifth leading cause of death by 2030. Increased albuminuria defines the early stages of CKD and is among the strongest risk factors for progressive CKD and cardiovascular disease. The value of population screening for albuminuria to detect CKD in an early phase has yet to be studied. We aimed to evaluate the effectiveness of two home-based albuminuria population screening methods.

METHODS

Towards Home-based Albuminuria Screening (THOMAS) was a prospective, randomised, open-label implementation study that invited Dutch adults aged 45-80 years for albuminuria screening. Individuals were randomly assigned (1:1) to screening by applying either a urine collection device (UCD) that was sent by post to a central laboratory for measurement of the albumin-to-creatinine ratio (ACR) by immunoturbidimetry or to screening via a smartphone application that measures the ACR with a dipstick method at home. Randomisation was done with a four-block method via a web-based system and was stratified by age, sex, and socioeconomic status. If two or more individuals per household were invited to participate, these individuals were randomly assigned to the same group. In case of confirmed increased albuminuria at home, participants were invited for an elaborate screening in a regional hospital (Amphia Hospital, Breda, Netherlands) for CKD and cardiovascular risk factors. When abnormalities were found, participants were referred to their general practitioner for treatment. The primary outcomes were the participation rate and yield of the home-based screening and elaborate screening. Participation rate was assessed in the intention-to-screen population (ie, all participants who were invited for the home-based screening or elaborate screening). Yield was assessed in the per-protocol population (ie, all individuals who participated in the home-based screening or elaborate screening). An exploratory analysis assessed the sensitivity and specificity of both home-based screening methods. To this end, an additional quantitative ACR test was performed among people participating in the elaborate screening, and a substudy was performed among participants with a first negative home-based screening test, who were invited for an additional test. The study is registered with ClinicalTrials.gov, NCT04295889.

FINDINGS

15 074 participants were enrolled between Nov 14, 2019, and March 19, 2021. 7552 (50·1%) were randomly assigned to home-based albuminuria screening by the UCD method and 7522 (49·9%) were assigned to albuminuria screening by the smartphone application method. The participation rate of the home-based screening was 4484 (59·4% [95% CI 58·3-60·5]) of the 7552 invited individuals for the UCD method and 3336 (44·3% [43·2-45·5]) of 7522 invited individuals for the smartphone application method (p<0·0001). Increased ACR was confirmed by home-based testing in 150 (3·3% [95% CI 2·9-3·9]) of 4484 individuals for the UCD method and 171 (5·1% [4·4-5·9]) of 3336 indivduals for the smartphone application method. 124 (82·7% [95% CI 75·8-87·9]) of 150 individuals assigned to the UCD method and 142 (83·0% [76·7-87·9]) of 171 participants assigned to the smartphone application method attended the elaborate screening. Sensitivity to detect increased ACR was 96·6% (95% CI 91·5-99·1) for the UCD method and 98·1% (89·9-99·9) for the smartphone application method, and specificity was 97·3% (94·7-98·8) for the UCD method and 67·9% (62·0-73·3) for the smartphone application method, indicating that the test characteristics of only the UCD method were sufficient for screening. Albuminuria, hypertension, hypercholesterolaemia, and decreased kidney function were newly diagnosed in 77 (62·1%), 44 (35·5%), 30 (24·2%), and 27 (21·8%) of 124 participants for the UCD method, respectively. Of the 124 participants assigned to the UCD method who completed elaborate screening, 111 (89·5%) were referred to their general practitioner for treatment because of newly diagnosed CKD or cardiovascular disease risk factors or known risk factors outside the target range.

INTERPRETATION

Home-based screening of the general population for increased ACR using a UCD had a high participation rate and correctly identified individuals with increased albuminuria and yet unknown or known but outside target range CKD and cardiovascular risk factors. By contrast, the smartphone application method had a lower at-home participation rate than the UCD method and the test specificity was too low to accurately assess individuals for risk factors during the elaborate screening. The UCD screening strategy could allow for an early start of treatment to prevent progressive kidney function loss and cardiovascular disease in patients with CKD.

FUNDING

Dutch Kidney Foundation, Top Sector Life Sciences & Health of the Dutch Ministry of Economic Affairs.

Protocol for a randomized study assessing the feasibility of home-based albuminuria screening among the general population: The THOMAS study

BACKGROUND

Chronic kidney disease (CKD) is a rising public health problem that may progress to kidney failure, requiring kidney replacement therapy. It is also associated with an increased incidence of cardiovascular disease (CVD). Because of its asymptomatic nature, CKD is often detected in a late stage. Population screening for albuminuria could allow early detection of people with CKD who may benefit from preventive treatment. In case such screening is performed in a general practitioner (GP) setting, this will result in relatively high costs. Home-based screening might be an effective and cost-effective alternative.

AIM

The THOMAS study (Towards HOMe-based Albuminuria Screening) is designed to prospectively investigate two methods for home-based population screening for increased albuminuria to detect yet undiagnosed CKD and risk factors for progression and CVD.

METHODS

This investigator initiated, randomized population-based study will include 15.000 individuals aged 45-80 years, who will be randomly assigned to be invited for a home-based screening test for albuminuria with a more conventional urine collection device or an innovative smartphone application. If the test result is positive upon confirmation (i.e., elevated albuminuria), participants are invited to a central screening facility for an elaborate screening for CKD and CVD risk factors. Participants are referred to their GP for appropriate treatment, if abnormalities are found. Primary endpoints are the participation rate, yield, and cost-effectiveness of the home-based screening and elaborate screening.

CONCLUSIONS

The THOMAS study will evaluate the effectiveness and cost-effectiveness of home-based albuminuria screening in the general population for the early detection of CKD and CVD risk factors. It will provide insight into the willingness to participate in population screening for CKD and into the compliance of the general population to a corresponding screening protocol and compliance to participate. Thus, it may help to develop an attractive novel screening strategy for the early detection of CKD.

TRIAL REGISTRATION

ClinicalTrials.gov, registration number NCT04295889, registered 05 March 2020. https://www.google.com/search?client=firefox-b-d&q=NCT04295889.

COVID-19-related mortality in kidney transplant and dialysis patients: results of the ERACODA collaboration

BACKGROUND

Patients on kidney replacement therapy comprise a vulnerable population and may be at increased risk of death from coronavirus disease 2019 (COVID-19). Currently, only limited data are available on outcomes in this patient population.

METHODS

We set up the ERACODA (European Renal Association COVID-19 Database) database, which is specifically designed to prospectively collect detailed data on kidney transplant and dialysis patients with COVID-19. For this analysis, patients were included who presented between 1 February and 1 May 2020 and had complete information available on the primary outcome parameter, 28-day mortality.

RESULTS

Of the 1073 patients enrolled, 305 (28%) were kidney transplant and 768 (72%) dialysis patients with a mean age of 60 ± 13 and 67 ± 14 years, respectively. The 28-day probability of death was 21.3% [95% confidence interval (95% CI) 14.3-30.2%] in kidney transplant and 25.0% (95% CI 20.2-30.0%) in dialysis patients. Mortality was primarily associated with advanced age in kidney transplant patients, and with age and frailty in dialysis patients. After adjusting for sex, age and frailty, in-hospital mortality did not significantly differ between transplant and dialysis patients [hazard ratio (HR) 0.81, 95% CI 0.59-1.10, P = 0.18]. In the subset of dialysis patients who were a candidate for transplantation (n = 148), 8 patients died within 28 days, as compared with 7 deaths in 23 patients who underwent a kidney transplantation <1 year before presentation (HR adjusted for sex, age and frailty 0.20, 95% CI 0.07-0.56, P < 0.01).

CONCLUSIONS

The 28-day case-fatality rate is high in patients on kidney replacement therapy with COVID-19 and is primarily driven by the risk factors age and frailty. Furthermore, in the first year after kidney transplantation, patients may be at increased risk of COVID-19-related mortality as compared with dialysis patients on the waiting list for transplantation. This information is important in guiding clinical decision-making, and for informing the public and healthcare authorities on the COVID-19-related mortality risk in kidney transplant and dialysis patients.

A Self-management Approach for Dietary Sodium Restriction in Patients With CKD: A Randomized Controlled Trial

RATIONALE & OBJECTIVE

Patients with chronic kidney disease (CKD) are particularly sensitive to dietary sodium. We evaluated a self-management approach for dietary sodium restriction in patients with CKD.

STUDY DESIGN

Randomized controlled trial.

SETTING & PARTICIPANTS

Nephrology outpatient clinics in 4 Dutch hospitals. 99 adults with CKD stages 1 to 4 or a functioning (estimated glomerular filtration rate≥25mL/min/1.73m²) kidney transplant, hypertension, and sodium intake>130mmol/d.

INTERVENTION

Routine care was compared with routine care plus a web-based self-management intervention including individual e-coaching and group meetings implemented over a 3-month intervention period, followed by e-coaching over a 6-month maintenance period.

OUTCOMES

Primary outcomes were sodium excretion after the 3-month intervention and after the 6-month maintenance period. Secondary outcomes were blood pressure, proteinuria, costs, quality of life, self-management skills, and barriers and facilitators for implementation.

RESULTS

Baseline estimated glomerular filtration rate was 55.0±22.0mL/min/1.73m². During the intervention period, sodium excretion decreased in the intervention group from 188±8 (SE) to 148±8mmol/d (P<0.001), but did not change significantly in the control group. At 3 months, mean sodium excretion was 24.8 (95% CI, 0.1-49.6) mmol/d lower in the intervention group (P=0.049). At 3 months, systolic blood pressure (SBP) decreased in the intervention group from 140±3 to 132±3mm Hg (P<0.001), but was unchanged in the control group. Mean difference in SBP across groups was-4.7 (95% CI, -10.7 to 1.3) mm Hg (P=0.1). During the maintenance phase, sodium excretion increased in the intervention group, but remained lower than at baseline at 160±8mmol/d (P=0.01), while it decreased in the control group from 174±9 at the end of the intervention period to 154±9mmol/d (P=0.001). Consequently, no difference in sodium excretion between groups was observed after the maintenance phase. There was no difference in SBP between groups after the maintenance phase.

LIMITATIONS

Limited power, postrandomization loss to follow-up, Hawthorne effect, lack of dietary data, short-term follow-up.

CONCLUSIONS

A coaching intervention reduced sodium intake at 3 months. Efficacy during the maintenance phase was diminished, possibly due to inadvertent adoption of the intervention by the control group.

FUNDING

Grant funding from the Netherlands Organization for Health Research and Development and the Dutch Kidney Foundation.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT02132013.

Glomerular filtration rate is associated with free triiodothyronine in euthyroid subjects: Comparison between various equations to estimate renal function and creatinine clearance

BACKGROUND

Effects of variations in thyroid function within the euthyroid range on renal function are unclear. Cystatin C-based equations to estimate glomerular filtration rate (GFR) are currently advocated for mortality and renal risk prediction. However, the applicability of cystatin C-based equations is discouraged in patients with overt thyroid dysfunction, since serum cystatin C and creatinine levels are oppositely affected by thyroid dysfunction. Here, we compared relationships of thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) with various measures of kidney function in euthyroid subjects.

METHODS

Relationships of eGFR, based on creatinine (eGFRcrea), cystatin C (eGFRcysC), creatinine+cystatin C combined (eGFRcrea-cysC) and creatinine clearance (CrCl) with TSH, FT4 and FT3 were determined in 2180 euthyroid subjects (TSH, FT4 and FT3 all within the reference range; anti-thyroid peroxidase autoantibodies negative) who did not use thyroid hormones, anti-thyroid drugs, amiodarone or lithium carbonate.

RESULTS

In multivariable models including TSH, FT3 and FT4 together, eGFRcrea, eGFRcysC and eGFRcrea-cysC and CrCl were all positively related to FT3 (P≤0.001), translating into a 2.61 to 2.83mL/min/1.73m² increase in eGFR measures and a 3.92mL/min increase in CrCl per 1pmol/L increment in FT3. These relationships with FT3 remained taking account of relevant covariates.

CONCLUSIONS

In euthyroid subjects renal function is associated with thyroid function status, especially by serum FT3, irrespective of the eGFR equation applied. In the euthyroid state, cystatin C-based eGFR equations are appropriate to assess the relationship of renal function with variation in thyroid function status.

Critical appraisal of 13C breath tests for microsomal liver function: aminopyrine revisited

As liver diseases are a major health problem and especially the incidence of metabolic liver diseases like non-alcoholic fatty liver disease (NAFLD) is rising, the demand for non-invasive tests is growing to replace liver biopsy. Non-invasive tests such as carbon-labelled breath tests can provide a valuable contribution to the evaluation of metabolic liver function. This review aims to critically appraise the value of the (13) C-labelled microsomal breath tests for the evaluation of metabolic liver function, and to discuss the role of cytochrome P450 enzymes in the metabolism of the different probe drugs, especially of aminopyrine. Although a number of different probe drugs have been used in breath tests, the perfect drug to assess the functional metabolic capacity of the liver has not been found. Data suggest that both the (13) C(2) -aminopyrine and the (13) C-methacetin breath test can play a role in assessing the capacity of the microsomal liver function and may be useful in the follow-up of patients with chronic liver diseases. Furthermore, CYP2C19 seems to be an important enzyme in the N-demethylation of aminopyrine, and polymorphisms in this gene may influence breath test values, which should be kept in mind when performing the (13) C(2) -aminopyrine breath test in clinical practice.

Large intestine permeability is increased in patients with compensated liver cirrhosis

Intestinal barrier dysfunction, facilitating translocation of bacteria and bacterial products, plays an important role in the pathophysiology of liver cirrhosis and its complications. Increased intestinal permeability has been found in patients with liver cirrhosis, but data on small and large intestine permeability and tight junctions (TJs) in patients with compensated cirrhosis are scarce. We aimed to investigate both small and large intestine permeability in patients with stable compensated cirrhosis compared with healthy controls and evaluated the expression of TJ proteins in mucosal biopsies at duodenal and sigmoid level. Intestinal permeability was assessed in 26 patients with compensated cirrhosis and 27 matched controls using a multisugar test. Duodenal and sigmoid biopsies were available from a subgroup for analyses of gene transcription and expression of key TJ proteins by qRT-PCR and ELISA, respectively. Median 0-5-h urinary sucrose excretion and lactulose/rhamnose ratio were comparable between patients with compensated cirrhosis and controls, whereas 5-24-h urinary sucralose/erythritol ratio was increased in these patients. Downregulation of gene transcription was found for claudin-3 in duodenal biopsies and claudin-4 in sigmoid biopsies, and at the protein level occludin expression was significantly increased in both duodenal and sigmoid biopsies. This study shows that gastroduodenal and small intestine permeability are not altered, whereas large intestine permeability is increased in patients with stable compensated cirrhosis. Only limited alterations were found regarding the expression of TJ proteins in both the small and large intestine.

T- and B-areas in immune reactions. Volume changes in T and B cell compartments of the rat spleen following intravenous administration of a thymus-dependent (SRBC) and a thymus-independent (paratyphoid vaccin-endotoxin) antigen. A histometric study

In the white pulp of rat spleens cell numbers were studied in the different compartments following intravenous administration of comparable doses of paratyphoid vaccine (PTV, thymus-independent) and sheep red blood cells (SRBC, thymus-dependent). In the periarteriolar lymphatic sheaths (PALS) both cell concentration and volume were measured. For the follicles and the marginal zone only volume was recorded in the first 5 days following antigen administration. Additionally, histologic observations were made. In the thymus-dependent area PTV caused oedema 12-24 hours after administration. Following SRBC administration an increase in lymphocyte numbers occurred until the second day, probably representing an influx of T cells from the recirculating pool. Both antigens gave rise to a plasmacellular reaction in the peripheral PALS (2nd-4th day). In the bone marrow-dependent areas a massive shift of medium-sized lymphocytes from the marginal zone to the follicles took place in the first 24 hours following PTV administration. These cells subsequently transformed into blasts. After SRBC (6 and 12 hours) only a few marginal zone lymphocytes seemed to migrate into the follicles. It is aruged that the endotoxin present in PTV is responsible for the fact that, following administration of the antigen, all marginal zone (B) cells responded. Endotoxin stimulation might provide a model for the fate of marginal zone cells stimulated by other agents, such as antigen (stimulating antigen binding B cells) or antigen-antibody complexes (stimulating Fc-receptor B cells).