Diabetic kidney disease in primary care
Singapore medical journal
Approximately 25%-40% of all patients with diabetes mellitus develop DKD. (1) DKD is the leading cause of end-stage kidney disease (ESKD) in Singapore, with the number of patients initiated on dialysis due to DKD rising 74% from 2009 to 2018. (2) Singapore has the world's third highest incidence of treated ESKD due to DKD, at 221 per million population. (3) Many more patients with DKD die before they are initiated on dialysis, as DKD is strongly associated with additional cardiovascular
... diovascular mortality. WHY DO DIABETIC PATIENTS GET KIDNEY DISEASE? Diabetes mellitus causes kidney damage through complex, overlapping mechanisms. (4) Two key pathways are chronic hyperglycaemia and renin-angiotensin system (RAS) activation. Chronic hyperglycaemia leads to the accumulation of advanced glycation end-products, reactive oxygen species and inflammatory cytokines. This causes glomerular inflammation, structural changes, such as thickening of the glomerular basement membrane, and mesangial matrix expansion. Hyperglycaemia increases the amount of glucose filtered at the glomerulus. Correspondingly, sodium-glucose cotransporters (SGLT-1 and -2) are upregulated to reabsorb increased amounts of filtered glucose. This decreases sodium chloride delivery to the distal tubule, which is sensed by the macula densa and results in RAS activation. The combination of afferent arteriole vasodilation and efferent arteriole vasoconstriction increases intraglomerular pressures, causing physical stress to the glomeruli and triggering a profibrotic response. These processes eventually lead to glomerular sclerosis, albuminuria and kidney impairment. WHAT CAN I DO IN MY PRACTICE? As untreated DKD progresses inexorably towards ESKD, the goal of treatment is to prevent or delay the development of ESKD. The role of the family physician is, firstly, to make a timely diagnosis of DKD through screening of individuals with diabetes mellitus and secondly, to retard the progression of DKD through glycaemic control, blood pressure control, RAS blockade, SGLT-2 inhibition and avoidance of further kidney insults. Thirdly, the family physician has an important role in health promotion and in managing comorbidities, especially cardiovascular risk factors. Screening for diabetic kidney disease DKD is primarily diagnosed on screening. All diabetic patients should receive annual screening for DKD, beginning five years after the diagnosis of Type 1 diabetes mellitus and at the time of diagnosis of Type 2 diabetes mellitus (as the time of disease onset is unknown). DKD is identified in a diabetic patient by the presence of persistent albuminuria and/or reduced GFR, as well as the exclusion of other causes of kidney disease. Mdm Chee, a 55-year-old homemaker, visited your clinic for a routine follow-up for her chronic conditions. She shared that she is careful about what she cooks to keep her Type 2 diabetes mellitus, hypertension and hyperlipidaemia controlled. You were happy to note her compliance to medications (metformin 850 mg three times daily, glipizide 10 mg twice daily and amlodipine 10 mg every morning). Her blood pressure was 140/90 mmHg, and her home blood pressure diary revealed similar readings over the past few months. Laboratory results showed a glycated haemogloblin level of 8.0%, serum creatinine of 112 µmol/L (estimated glomerular filtration rate 48 mL/min/1.73 m 2 ) and urine albumin/creatinine ratio of 40 mg/mmol; four months ago, they were 7.8%, 106 µmol/L (51 mL/min/1.73 m 2 ) and 30 mg/mmol respectively. She would soon undergo panretinal photocoagulation on her right eye, but she was scared because the ophthalmologist had said that diabetes mellitus may lead to kidney failure. She asked if there was anything you could do to help her avoid needing dialysis.