15th July 2024

Diagnosis and classification

As a common complication of diabetes, patients should be screened for renal disease at least once a year. A renal blood panel should be measured with an eGFR of <60ml/min/1.73m2 or a creatinine increase of >20% when compared with previous prompting further investigation. A measurement of proteinuria using a first pass spot urinary albumin:creatinine ratio (ACR) should be undertaken in all patients – a measurement of >3 mg/mmol on two or more occasions should be regarded as clinically important proteinuria.  As in those without diabetes, renal ultrasound may be indicated in cases of accelerated progression of disease and/or red flag features, e.g. persistent haematuria.

A five point staging system is used to classify the severity of diabetic nephropathy (see table below).

Patients are classically asymptomatic in the earlier stages of nephropathy.  Peripheral oedema, difficult to control hypertension and constitutional symptoms such as fatigue, itch and nausea becoming particularly prevalent from stage III to IV onwards.