Causes of diabetic nephropathy you should look out for
July 1, 2019
Dr Mohan’s Diabetes Specialities Centre
Diabetes has become the most common cause of Chronic kidney disease in most countries, thanks to the increase in prevalence in diabetes and longevity of the patients.
Very often we come across patients in our practice asking ” Doctor, will taking these anti-diabetic medications cause kidney damage”??. The answer is “Strict NO“. Infact it is the delay in the diagnosis especially in case of type 2 diabetes mellitus or uncontrolled hypertension are some of the common causes for kidney damage and patient is generally asymptomatic during the initial stages.
Diabetic Nephropathy is characterized by persistent albuminuria (300mg/24hr) on at least two occasions separated by 3-6 months.
Moderately Increased albuminuria (formerly microalbuminuria): Urine albumin excretion of 30-300mg/24hr.
Risk factors for diabetic nephropathy:
Many epidemiological studies demonstrate that ethnicity, family history, gestational diabetes, elevated blood pressure, dyslipidaemia, obesity and insulin resistance are the major risk factors and causes of diabetic nephropathy
Other putative risk factors include elevated glycosylated haemoglobin level (HbA1c), elevated systolic blood pressure, proteinuria and smoking.
Family history of hypertension and cardiovascular events in the first degree relatives may act as a sentinel to warn of impending development of nephropathy .In both type 1 and type 2 diabetes mellitus males are more prone to develop nephropathy. Certain ethnic populations (blacks,mexican Americans,Pima Indians,south Asians) are at greater risk of developing nephropathy
Early in the course diabetic nephropathy is usually asymptomatic , later on patient may complain of foamy urine, limb swelling (especially if protein leakage is very high), fatigue
It maybe associated with other diabetic complications especially retinopathy (Concordance rate of 60-63% in t2dm & 85-90% in t1dm), hypertension, coronary artery disease, peripheral vascular disease.
For early detection of nephropathy, it is recommended all type 2 diabetics should have their urine screened at diagnosis and therefore yearly if it’s normal. Those who have moderately increased albuminuria (formerly microalbuminuria) should have their urine tested on two more occasions with overnight urine collections. In type 1 diabetes it’s usually recommended to check after five years after diagnosis. Those with elevated urine albumin should be screened every 3-6 months depending on patients condition and his co-morbidities.
Screening can be done by three methods:
a. Random (preferably early morning) urine sample: albumin to creatinine ratio
b. Twenty four hours urine protein collection
c. Timed urine collection
Care must be taken to avoid screening when there is any associated condition that may increase albumin excretion eg: fever, urinary tract infection, congestive heart failure, following vigorous exercise. Concomitant estimation of GFR (glomerular filtration rate) should also be done at screening and thereafter yearly.
Management: Prevention is better than Cure
1. Glycemic control: Various studies have shown early initiation of strict glycemic control (HbA1c <7%) has proven to reduce the risk of microalbuminuria or incipient nephropathy, indirectly slowing the progression to overt nephropathy and reduction in GFR.
2. Control of Hypertension/Blood pressure: Hypertension is common in patients with diabetes and presence of common risk factors. It is important that every visit blood pressure is recorded (multiple readings) and antihypertensive therapy (non pharmacolgic followed by drugs) must be started at a No of 130/85mmhg with a goal of 125/75,mmHg in proteinuric patients to reduce progression of diabetic nephropathy. In the absence of proteinuria (protein leakage) the BP goal is 130/80mmhg.
“It is important that patient doesn’t stop the blood pressure medications on his own without discussing with the doctor once his/her BP is under control”
Drugs belonging to Renin-Angiostensin-Aldosterone system (RAAS) blockade has several benefits in the management of patients with diabetic Nephropathy. Both ARBs &ACE inhibitors are helpful in preventing the progression of diabetic nephropathy.
Newer anti diabetic drugs SGLT2 inhibitors like canagliflozin has shown to reduce the progression of diabetic nephropathy
3.Dietary modification: Calorie restriction is necessary for most patients as part of the diabetic nephropathy treatment and weight loss does have some beneficial effects on proteinuria. Salt restrictions to less than or equal to 70meq/day enchances the antiproteinuric effects of ARBs. It also reduces the edema in patients with advanced nephropathy. Protein restriction is generally not advisable and has not shown much benefits in nephropathy. High cholesterol is a risk factor for progression and one of the major causes of diabetic nephropathy and chronic kidney disease, apart from dietary restriction some may need statins to control the cholesterol levels.
Diabetic nephropathy is the most common aetiology of adult checked today, therefore early detection, screening, timely referral to nephrologist & intervening appropriately is important so you can receive a timely diabetic nephropathy treatment in preventing progression of nephropathy and chronic kidney disease.
Dr Mohan’s Diabetes Specialities Centre