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.