Onset and progression of kidney disease in type 2 diabetes among multi-ethnic Asian population.

Aim: To elucidate the natural history of chronic kidney disease(CKD), which is defined as estimated glomerular filtration rate(eGFR)<60ml/min/1.73m(2) and/or increase of urinary albumin-to-creatinine ratio (uACR)≥30mg/g), and to identify factors associated with its onset and progression.

Methods: Prospective cohort study on individuals with T2DM attending Diabetes Centre in a regional hospital in Singapore from 2002. There were 553 patients with no pre-existing CKD for "onset" analysis and 967 patients with pre-existing CKD for "progression" analysis. Multivariable logistic regression was performed to determine risk factors of the outcomes.

Results: The mean follow-up period was 5.8years (4.5-7.1) and 5.3years (3.9-6.9) for the onset and progression cohorts respectively. About 45% of individuals developed CKD and 41% had progression. Among subjects with CKD onset, albuminuria-only occurred in 75% of them. Majority of the patients remained in the same CKD risk-category during follow-up. Progression and regression occurred across all CKD-categories. Transitions to adjacent risk-category were much more likely than transitions bypassing adjacent state. Risk factors for CKD onset included baseline albuminuria, eGFR, HbA1c variability, body mass index, triglycerides and age (all P<0.05). The predictors for CKD progression or rapid-progression included HbA1c variability, baseline albuminuria, systolic blood pressure, LDL-cholesterol, eGFR, HbA1c and ethnicity (all P<0.05).

Conclusions: Albuminuria was the first manifestation of CKD in most T2DM patients. Transition across CKD-category occurred bi-directionally, but evolved largely in a stepwise fashion. The onset and progression of CKD were predicted by multiple risk factors, some of which were modifiable.