The term chronic kidney disease or CKD means lasting damage to the kidneys that can worsen over time. In CKD, the kidneys do not fail at once. Instead, it progresses slowly over years. If CKD is caught early, with suitable lifestyle changes & medications, the progress can be delayed.
Based upon Glomerular Filtration Rate (GFR), CKD is classified into 5 stages:Stage 1 with normal or high GFR (GFR > 90 mL/min)
Stage 2 Mild CKD (GFR = 60-89 mL/min)
Stage 3A Moderate CKD (GFR = 45-59 mL/min)
Stage 3B Moderate CKD (GFR = 30-44 mL/min)
Stage 4 Severe CKD (GFR = 15-29 mL/min)
Stage 5 End Stage CKD (GFR <15 mL/min)
Stage 5 is also called as end stage renal disease (ESRD) or Kidney Failure. A person with ESRD will require dialysis or kidney transplant to survive.
Globally, more than 80% of end-stage renal disease (ESRD) is caused by diabetes or hypertension, or both. The proportion of ESRD attributed to diabetes varies between 10% and 67%.[1] The prevalence of ESRD is also up to 10 times higher in people with diabetes than in those without diabetes.
In type 2 diabetes, hypertension often precedes CKD and contributes to the progression of nephropathy, whereas in type 1 diabetes, hypertension is more often a consequence of CKD.[2][3]
High blood sugar induces hyperfiltration and morphological changes in the kidneys that ultimately lead to an increased urinary albumin excretion (also called albuminuria) and loss of filtration surface[4] [5] hence the use of albuminuria and glomerular filtration as screening tests in this field.
The most effective strategy to treat CKD is to diagnose and manage it in its early stages. Screening for albuminuria, or glomerular filtration rate (GFR), is cost-effective in people with diabetes and hypertension[6].
Screening for albuminuria is recommended every year after diagnosis of type 2 diabetes, and the same after the first five years in people with type 1 diabetes.[7] Both diabetes and CKD are strongly associated with diseases of heart or blood vessels(also called Cardiovascular diseases or CVD) and, therefore, controlling blood glucose and blood pressure can reduce the risk of both CVD and CKD.
When CKD has advanced to stage 3, special considerations are needed regarding selection and dosage of glucose-lowering drugs and other medications. As for other drugs, the presence of an impaired renal function may significantly affect pharmacokinetics of the majority of glucose-lowering medicines, thus exposing diabetic CKD patients to a higher risk of side effects, mainly hypoglycaemia. Therefore, a reduction in dosing and/or frequency of administration of drugs is necessary to keep a satisfactory efficacy/safety profile.
Once the disease has advanced to stage 4 and 5, referral to a nephrologist is required for planning of renal replacement therapy (initially dialysis).
The achievement of a good glucose control is one of the cornerstones for preventing and delaying progression of complications in patients with both diabetes and chronic kidney disease (CKD).
(Dr Syed Iftikhar Ali is a doctor by profession. He completed his MBBS from King George Medical University, Lucknow and his MS in general surgery from Jhansi Medical College in 2013. He has more than 7 years of work experience in the field of medicine.)
[1] 2018 USRDS Annual Data Report: Epidemiology of Kidney Disease in the United States. Bethesda: National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, 2018. Available from: https://www.usrds.org/2018/view/Default.aspx, accessed 16 July 2019
[2] Coresh J, Astor BC, Greene T, Eknoyan G, Levey AS. Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third National Health and Nutrition Examination Survey. Am J Kidney Dis. 2003 Jan;41(1):1–12; DOI:doi:10.1053/ajkd.2003.50007
[3] Steinke JM. The natural progression of kidney injury in young type 1 diabetic patients. Curr Diab Rep. 2009 Dec;9(6):473–9
[4] Fakhruddin S, Alanazi W, Jackson KE. Diabetes-induced reactive oxygen species: mechanism of their generation and role in renal injury. J Diabetes Res. 2017;2017:8379327; DOI:10.1155/2017/8379327
[5] Pavkov ME, Collins AJ, Coresh J, Nelson RG. Kidney disease in diabetes. In: Diabetes in America, 3rd edition. Cowie CC, Casagrande SS, Menke A, Cissell MA, Eberhardt MS, Meigs JB, et al, editors. Bethesda: National Institutes of Health; 2018.
[6] Komenda P, Ferguson TW, Macdonald K, Rigatto C, Koolage C, Sood MM, et al. Cost-effectiveness of primary screening for CKD: a systematic review. Am J Kidney Dis. 2014 May;63(5):789–97; DOI:10.1053/j.ajkd.2013.12.012.
[7] . Kidney Disease Outcomes Quality Initiative. KDOQI Clinical practice guidelines and clinical practice recommendations for diabetes and chronic kidney disease. Am J Kidney Dis. 2007 Feb;49(2 Suppl 2):S12–-154; DOI:10.1053/j. ajkd.2006.12.005