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Diabetic Nephropathy. Sunil Agrawal, MD. Disclosures. Amgen. Outline. INTRODUCTION EPIDEMOLOGY PATHOGENSIS AND MECHANISM PATHOLOGY DIAGNOSIS TREATMENT. Introduction. Why do we care? Most common disorder leading to kidney disease in adults
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Diabetic Nephropathy Sunil Agrawal, MD
Disclosures • Amgen
Outline • INTRODUCTION • EPIDEMOLOGY • PATHOGENSIS AND MECHANISM • PATHOLOGY • DIAGNOSIS • TREATMENT
Introduction Why do we care? Most common disorder leading to kidney disease in adults 44% of all new incidents of ESRD secondary to diabetes Annual cost to health care more than $9 billion
Introduction Prevalence of CKD (secondary to DM) by ethnic background: Severity 3 to 6 fold more in African Americans v. Caucasians Adjusted for Socioeconomics/HTN African Americans are 4.8 X greater to get DM Nephropathy Pima Indians have large Glomeruli than Caucasians
Epiemiology 0.5 % of US and Central Europe have Type I DM 25 to 35% will develop DM nephropathy in 20 years Type II DM 9 x more prevalent Risk in Type II: glycemic control, BP, and Genetic Factors
Diabetes and ESRD 5 year adjusted survival (2004): 31%! 5 year adjusted survival (1980s) 20%!
Pathogenesis and Mechanism • Clinical manifestations of diabetic nephropathy: • Albuminuria • Hematuria • Typically Bland • Rare finding • Progressive chronic kidney disease
Pathogenesis and Mechanism(Hyperfiltration) • Typical early change • Type I DM > Type II DM • Increase in GFR “supranormal” • Renal Hypertrophy > 12 cm • Amyloid/HIV/MM/PCKD • Hyperfiltration associated with: • FSGS • Obesity • OSA • Solitary Kidney
Pathogenesis and Mechanism(Hyperfiltration) • Unclear what the mechanism is for Hypertrophy: • Hyperglycemia • IGF-1 • TGF –b • Stimulates fibrosis • Increase growth of proximal tubular cells • Vascular endothelial growth factor (VEGF) • Released by podocyte • Ornithinedecarboxylase (OCD) • Increase secretion or prolonged ½ life • Stimulated by IGF-1? • Increase kidney growth • Protein Kinase C • AMP activated protein kinase
Pathogenesis and MechanismRole of Hyperglycemia: • Like directly causes injury to the kidney: • Mesangial expansion • Increased matrix production • Mesangial cell apoptosis • Microvascular/Macrovascular injury • Secondary to advanced glycation end products (AGEs) • AGE increase in renal insufficiency • Working on medications to inhibit effects • Cytokines • VEGF causes endothelial injury in DM • TGF-b
Pathogenesis and Mechanism • Genetics: • Family History of proteinuria/DM Nephropathy may be a clue • DD polymorphism has been associated with an increased risk for the development of diabetic nephropathy • Variation in the ACE gene? • Angiotensin-II type 2 receptor gene (AT2) on the X-chromosome
Pathogenesis and Mechanism • Genetic Linkage to Diabetes Nephropathy: • European-Americans: Chromosome 6p and 22q • American-Indians: Chromosome 7p • African Americans: Chromosomes 3p and 16q • Mexican Americans: Chromosome 22q
Pathogenesis and Mechanism “Sleeping Sickness” Interesting Overlap • Chromosome overlap of 22q with APOL1 • APOL1 may contribute to increase risk of DN • May be involved in: HTN/HIV/FSGS • Favored gene in African Americans: resistance to trypanosomiasis
Pathology • The common structural changes include seen in Diabetic Nephropathy: • Mesangial expansion • Glomerular basement membrane thickening • Glomerular sclerosis
Pathology Renal Pathology Society Calcification • Class I: Isolated glomerular basement membrane thickening. • Basement membranes are greater than 430 nm in males older than age 9 and 395 nm in females. • There is no evidence of mesangial expansion, increased mesangial matrix, or global glomerulosclerosis involving >50 percent of glomeruli. • Class II: Mild (class IIa) or severe (class IIb) mesangial expansion • considered severe if areas of expansion larger than the mean area of a capillary lumen are present in >25 percent of the total mesangium. • Class III: At least one Kimmelstiel-Wilson lesion (nodular intercapillaryglomerulosclerosis) is observed on biopsy and there is <50 percent global glomerulosclerosis. • Class IV: Advanced diabetic sclerosis. There is >50 percent global glomerulosclerosis that attributable to diabetic nephropathy.
Diabetic Nephropathy • How do we make the diagnosis? • Gold Standard: Kidney Biopsy • History • Retinopathy • Neuropathy • Family • Screening for proteinuria • Microablumin First Morning Void • Best sensitivity and specificity • 5 years after diagnosis
Diabetic Nephropathy • Exclusion Criteria • Rapid rise in creatinine or decrease of GFR • Rapid increase in proteinuria • Active urinary sediment • Refractory HTN
Glycemic Control in DM Nephropathy • Goal Therapy A1C 7% • Diabetes Control and Complication Trial (DCCT) • 1441 participants • Showed tight glycemic control <8% (A1C) • Prevented development of albuminuria/proteinuria • Reduced relative risk of loss of renal function
Glycemic Control in DM Nephropathy • Early glycemic control in Type I DM: • Reduction of retinopathy • Reduction of Neuropathy • Reduction of Cardiovascular endpoints • Early glycemic control in Type II DM: • Reduced microaluminuria • No clear reduction of macroalbuminuria • No clear reduction of worsening of renal function (once decline has occurred) • Studies: The Kumamoto Study/VA Cooperative Study
Glycemic Control in DM Nephropathy • Important new concepts about A1C in type II: • A1C 6.5% did show 21% reduction in renal outcomes than A1C of 7.3% • Between the groups of Type II DM: NO MAJOR REDUCTION IN CARDIOVASCULAR EVENTS • Intensive glycemic control in type I DM did show some cardiovascular benefit
Glycemic Control in DM Nephropathy • How good is A1C in ESRD/CKD patients? • Reduced RBC lifespan • Get transfusions • Hemolysis • Fructosamine (glycated albumin) • May be better for ESRD/CKD • Mixed results
Glycemic Control in DM Nephropathy • General recommendations of choice of therapy in DM: • 1/3 of the degradation of Insulin is conducted by the kidney! • First Generation sulfonyureas should be avoid in CKD Stage III – ESRD • Second Generation: Glipizde is recommended • Cleared by the Liver • Thiazolidinediones/pioglitazone/rosiglitazone • Watch for fluid retention via ENAC • Increase bone fractures
Glycemic Control in DM Nephropathy • Metformin • FDA recommendation: • Contraindicated in creatinine >1.5 in men, >1.4 women • Contraindicated in GFR < 60 ml/min • Decreased clearance and life threatening Lactic Acidosis • Sitagliptin/saxagliptin/linagliptin • Dipeptidylpeptidase inhibitor • May effect the kidney directly • SGLT2 inhibitors • Block Na-Glucose Transporter of the proximal tubule • Under review by the FDA • Will lower glucose level/reduce weight/lower insulin requirements
Blood Pressure Control in CKD/DM • Target >130/80 (JNC-7/NKF/ADA) • Strong correlation with reduction in progression with good SBP in DM/CKD • Question: “The lower the blood pressure the better?” • Common question form patients! • What is the answer? LETS SEE WHAT THE TRIALS SAY!
Blood Pressure Control in CKD/DM • Action to Control Cardiovascular Risk in Diabetes (ACCCORD) • 4733 participants Type II DM • Two arms randomly assigned: • Intensive arm (SBP <120) • Standard arm (SBP < 140) • Follow-up after about 5 years • NOT a significant reduction in primary outcomes • Nonfatal MI/CVA/death from CV causes • Slight increase in annual rates of death and adverse events in intensive arms
Blood Pressure Control in CKD/DM • Irbesartan in Diabetic Nephropathy Trial (IDNT) • 1715 participants with CKD/DM • Randomly assigned to irbesartan/amlodipine/placebo • Showed reduction in decline of renal function with every 10 mm Hg reduction in SBP • Increase in all-cause mortality in patients with SBP <120
Blood Pressure Control in CKD/DM • What does this mean? • Patients with CKD and DM: • Good control of SBP important! • Goal: reasonable to treat <130/80 • If they have CKD SBP 120 to 130 • If the don’t have CKD SBP 120 to140
Blood Pressure Control in CKD/DM • What to use for blood pressure control? • The Standard is: the use of medications that block RAS (Renin-Angiotensin-System) • Ace inhibitors (First Line therapy) • Angiotensin Receptor Blockers • Projecting with the use of these mediations: • Reducing incidence of ESRD • Reducing cost per patient by $24,000
Quick review about how Acei/ARBs work. They effect the efferent arteriole. Vasodilitation leading to decrease in hydraulic pressure thus reduction in GFR.
Blood Pressure Control in CKD/DM • More Trials: • ACEi Efficacy • DETAIL • RENAAL • ONTARGET • AVOID • ALTITUDE DON’T WORRY WE WILL GO FAST!
Blood Pressure Control in CKD/DM • DETAIL • Randomized participants to enalapril and telmisartan • Participants had proteinuria (macro/micro) and CKD Stage I • Followed for 5 years • Both groups showed similar reductions : • GFR/Change in Serum creatinine • Blood pressure • Urinary albumin excretion • ESRD • Cardiovascular events • Mortality.
Blood Pressure Control in CKD/DM • ACE Inhibitors vs. ARBs • Very few studies available • Similar rates of protection • ACE inhibitors first line • ARBs usually for intolerance of Acei ACE Inhibitor ARB
Blood Pressure Control in CKD/DM • RENAAL • 1513 participants with type 2 diabetes and nephropathy • Randomly assigned to: • Losartan or Placebo • In addition to conventional therapy (Not Acei) • Results: • Losartan reduced the incidence of a doubling of the creatinine by 25 % • Reduced ESRD by 28 %
Blood Pressure Control in CKD/DM • Other Conclusions form RENAAL: • Every 10 mmHg increase in the baseline systolic • Enhanced risk of ESRD or death of 6.7 % • Reduction of albuminuria within the first 6 months • decreased subsequent cardiovascular risk • Baseline retinopathy was associated with: • Poor renal outcome • Increased proteinuria • Decreased GFR • Development of ESRD • Higher risk of death