Diabetic nephropathy is an important cause of morbidity and death amongst diabetics.
- 30% **of patients with type 1 diabetes go on to develop chronic renal failure
- 25% ***of patients with type 2 diabetes develop CRF though this level may be 50% in certain ethnic groups
The incidence of diabetic nephropathy increases with age. It almost never occurs in childhood.
Different forms of nephropathy:
- pyelonephritis - which may show papillary necrosis
- glomerulonephritis:
- Kimmelstiel-Wilson - eosinophilic nodules in the glomerular tuft
- proliferative
- atherosclerosis and hypertensive changes
Features:
- microscopic albuminuria is a sensitive early predictor of subsequent overt renal disease
- proteinuria is usually the earliest clinical sign of nephropathy.
- hypertension is not a feature of early nephropathy. Hypertension is a feature associated with a more rapid progression of diabetic nephropathy.
- nodular sclerosis (Kimmelstiel-Wilson), although the most specific form of diabetic nephropathy, only accounts for less than 20% of renal involvement
Insulin requirements are often reduced in diabetic nephropathy because the kidneys clear insulin from the blood of normal individuals.
Diabetic nephropathy is frequently associated with diabetic retinopathy and neuropathy.
There is increasing evidence that the risks of end-stage renal disease (need for dialysis) (ESRD) in type 1 and type 2 diabetes is lower than previously estimated:
- ** a cohort study in type 1 diabetics was followed up for maximally 37 years, with a median of 16.7 years (1)
- cumulative incidence of ESRD was 2.2% at 20 years and 7.8% at 30 years after diagnosis
- risk of developing ESRD was lowest in patients whose diagnosis occurred at younger than 5 years
- risk of ESRD was lower for patients diagnosed as having type 1 diabetes in later years of the study
- *** a cohort study in type 2 diabetics has provided evidence that the individual risk of ESRD and chronic renal failure is low (2)
- in this cohort, only 10 of 1,408 patients followed for 10 years developed ESRD, giving an incidence rate of 1.0 per 1,000 person-years, whereas cumulative risks for chronic renal failure adjusted for competing mortality were 6.1 and 9.3% after 20 and 30 years from diagnosis of diabetes, respectively.
The Kidney Disease: Improving Global Outcomes (KDIGO) Diabetes Management in CKD Guideline states:
- recommends the initiation of sodium-glucose cotransporter 2 (SGLT2) inhibitor therapy mong all patients with T2D (type 2 diabetes) and CKD (based on albuminuria or low eGFR without albuminuria) with an eGFR of at least 20 mL/min/1.73 m2
- suggest the use of an nonsteroidal mineralocorticoid antagonist (ns-MRA) with proven kidney or cardiovascular benefit is recommended for patients with T2D, eGFR of at least 25 mL/min/1.73 m2, normal serum potassium concentration, and albuminuria (albumin-creatinine ratio >=30mg/g) despite receiving the maximum tolerated dose of a RAS (renin angiotensin system) inhibitor
- GLP-1 RA (glucagon-like peptide-1 receptor agonists) may be preferentially used in patients with obesity, T2D, and CKD to promote intentional weight loss
Reference:
- Finn P et al. Incidence of end-stage renal disease in patients with type 1 diabetes.JAMA 2005;294:1782-7.
- Bruno G et al. Low incidence of end-stage renal disease and chronic renal failure in type 2 diabetes: a 10-year prospective study. Diabetes Care. 2003 Aug;26(8):2353-8.
- Sankar D. Navaneethan, Sophia Zoungas, M. Luiza Caramori, et al. Diabetes Management in Chronic Kidney Disease: Synopsis of the KDIGO 2022 Clinical Practice Guideline Update. Ann Intern Med. [Epub 10 January 2023]. doi:10.7326/M22-2904