Progressive Changes in Kidney Size in Chronic Kidney Disease: Comparison between Diabetes and Non-diabetes

Abstract

BACKGROUND: With the progression of chronic kidney disease (CKD), the kidney size gradually decreases. Although kidney size is commonly measured, the nature of progressive change, however, has rarely been investigated. Little information is available regarding factors relevant to the kidney size of CKD patients. METHODS: We conducted a cross-sectional study to investigate the kidney size of CKD patients. Mean kidney length of bilateral kidneys determined by sonography was used to represent kidney size. Clinical features and biochemical data, including serum creatinine, estimated glomerular filtration rate (eGFR), haemoglobin and proteinuria (calculated as urine protein-creatinine ratio, UPCR) of 660 type 2 diabetes and 334 non-diabetic patients were reviewed and recorded. We compared the progressive changes in kidney length for the biochemical data of various CKD stages and also analyzed the difference between diabetic and non-diabetic patients. RESULTS: With the progression of CKD, proteinuria increased and haemoglobin decreased in both the diabetes and non-diabetes groups. The kidney size gradually diminished as eGFR decreased in both groups (P ＜ 0.0001). With the same CKD stage, UPCR was greater in the diabetes than non-diabetes group in stages 3, 4 and 5. Across all stages of CKD, non-diabetic patients had smaller kidney size than that of diabetic patients (all P ＜ 0.05). The magnitude of decrease was more pronounced in moderate and advanced non-diabetic CKD patients. Logistic regression analysis revealed age, male gender and body mass index (BMI) were significantly associated with kidney size in CKD patients. Moreover, diabetes was a significant determinant of kidney size and macroproteinuria (UPCR greater than 500 mg/g) was associated with larger kidney size in moderate and severe CKD. CONCLUSION: During CKD progression, the kidney size manifested a decremental change in association with increased proteinuria. There was a discrepancy in the decrease in kidney size between diabetic and non-diabetic CKD patients. Age, gender and BMI independently predicted kidney size. Both diabetes and overt proteinuria were associated with increased kidney size in CKD patients.