Ongoing treatment with renin-angiotensin-aldosterone-blocking agents does not predict normoalbuminuric renal impairment in a general type 2 diabetes population.

Aim: To examine the prevalence and the clinical characteristics associated with normoalbuminuric renal impairment (RI) in a general type 2 diabetes (T2D) population.

Methods: We included 94 446 patients with T2D (56% men, age 68.3±11.6 years, BMI 29.6±5.3 kg/m², diabetes duration 8.5±7.1 years; means±SD) with renal function (serum creatinine) reported to the Swedish National Diabetes Register (NDR) in 2009. RI was defined as estimated glomerular filtration (eGFR)<60 ml/min/1.73 m² and albuminuria as a urinary albumin excretion rate (AER) >20 μg/min. We linked the NDR to the Swedish Prescribed Drug Register, and the Swedish Cause of Death and the Hospital Discharge Register to evaluate ongoing medication and clinical outcomes.

Results: 17% of the patients had RI, and 62% of these patients were normoalbuminuric. This group of patients had better metabolic control, lower BMI, lower systolic blood pressure and were more often women, non-smokers and more seldom had a history of cardiovascular disease as compared with patients with albuminuric RI. 28% of the patients with normoalbuminuric RI had no ongoing treatment with any RAAS-blocking agent. Retinopathy was most common in patients with RI and albuminuria (31%).

Conclusions: The majority of patients with type 2 diabetes and RI were normoalbuminuric despite the fact that 25% of these patients had no ongoing treatment with RAAS-blocking agents. Thus, RI in many patients with type 2 diabetes is likely to be caused by other factors than diabetic microvascular disease and ongoing RAAS-blockade.