Diabetic kidney disease (DKD) is one of the microvascular complications of diabetes mellitus (DM) with the highest mortality rate, with a progressive increase of albuminuria and a progressive decrease of glomerular filtration rate as the main clinical features.1 In China, DKD occurs in approximately 20% to 40% of patients with diabetes, which is the leading cause of end-stage renal disease.2 The occurrence of microalbuminuria is the early manifestation of DKD and persistent microalbuminuria has also been shown to be associated with the risk of coronary heart disease and death.3 Early DKD can be treated with drugs, such as angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs), sodium-glucose cotransporter 2 inhibitor (SGLT2i), glucagon-like peptide-1 receptor antagonist (GLP1-RA), and finerenone, which have been shown to reduce the risk or delay the progression of diabetic nephropathy.3 Hence, early detection of albuminuria and taking intervention measures accordingly are necessary to delay the development of DKD and other adverse health outcomes in clinical practice. It is recommended that albuminuria, which is usually tested by urine creatinine-to-albumin ratio (UACR), should be assessed annually for all persons with type 2 diabetes mellitus (T2DM), starting at diagnosis of diabetes.3 However, screening for albuminuria is underutilized, particularly at diagnosis of diabetes. In the United States, albuminuria is assessed in less than half of patients with T2DM in a given year.4 Data from United Kingdom Prospective Diabetes Study that mainly enrolled White Caucasians newly diagnosed with T2DM in 1977 showed that 7.3% of patients had microalbuminuria at diagnosis of diabetes and progressed to macroalbuminuria at a rate of 2.8% per year.5 It is estimated that 60.5% of patients with T2DM developed albuminuria and the prevalence of microalbuminuria in Asians with T2DM is significantly higher than in Caucasians.2,6,7 However, there is limited information on the prevalence of albuminuria among patients newly diagnosed with T2DM in Asia and its impact on the progression of the renal function.

Due to the slow rate of renal function decline, most studies on risk factors for the progression of renal function have been carried out in participants with advanced chronic kidney disease. It is challenging to assess the progression of renal function in patients in the early stage of diabetes with a baseline estimated glomerular filtration rate (eGFR) of 90 mL/min/1.73 m2 or more. In recent years, a surrogate marker to detect the worsening of renal function, eGFR slope, has been used to reliably predict an intervention’s effect on the progression of chronic kidney disease (CKD) at an earlier stage.8, 9, 10 Therefore, it is possible to study the risk factors for renal function progression in patients newly diagnosed with T2DM.

The objectives of this study were to determine the following: 1) the incidence of albuminuria among patients newly diagnosed with T2DM in the primary care setting in China and 2) the impact of the incidence of albuminuria on the progression of DKD estimated by the eGFR slope.