Background: Screening for persistent albuminuria among the high-risk population is important for early detection of CKD while studies regarding screening protocol and related cost-effectiveness analysis are limited. This study explored a feasible and cost-efficient screening strategy for detecting persistent albuminuria among the high-risk population.
Methods: A cohort study including 157 clinically stable outpatients with a risk factor of CKD and whose laboratory tests revealed an albumin-creatinine-ratio (ACR) between 30 and 300 mg/g of creatinine during the previous 12 months was conducted to assess the validity of alternative screening strategies. Each participant collected three first morning urine samples in three consecutive months. These samples were labeled as DAY-1, MONTH-2 and MONTH-3. In the first month, a random spot sample in the afternoon of the first day and another morning sample on the second day were collected and labeled as Random and DAY-2. Persistent albuminuria was defined by abnormal ACR (≥30 mg/g creatinine) for DAY-1, MONTH-2 and MONTH-3. Alternative strategies were DAY-1; Random; DAY-1 + Random; DAY-1 + DAY-2; and DAY-1 + Random + DAY-2. To evaluate the economic performance of those alternative strategies, a hybrid decision tree/Markov model was developed based on the cohort study to simulate both clinical and cost-effectiveness outcomes. Sensitivity analyses were conducted to investigate assumptions of the model and to examine the model's robustness.
Results: Altogether, 82 patients exhibited persistent albuminuria. All of the five strategies had sensitivity higher than 90%. Of these strategies, Random had the lowest specificity (46.7%), and DAY-1 + Random + DAY-2 had the highest specificity (81.3%). Estimated cost for each quality adjusted life year (QALYs) gained were ¥112,335.88 for DAY-1 + Random, ¥8134.69 for Random and ¥10,327.99 for DAY-1 + Random + DAY-2. When compared with DAY-1 strategy, the sensitivity and specificity of which were 100.0 and 69.3%, respectively. DAY-1 + Random + DAY-2 had the highest effectiveness and incremental effectiveness of 11.87 and 0.73 QALYs. At a willingness-to-pay threshold of ¥100,000 per QALY, DAY-1 + Random + DAY-2 had the highest acceptability of 91.0%. Sensitivity analyses demonstrated the robustness of the results.
Conclusions: In order to make a quick diagnosis of persistent albuminuria among high-risk population, the strategy of combining two first morning urine samples and one randomized spot urine sample in two consecutive days is accurate, saves time, and is cost-effective.
Keywords: Chronic kidney disease; Cost-effectiveness analysis; Persistent albuminuria; Screening strategy.