What is the best screening test for DKD? Microalbuminuria is the best available test for screening of DKD, but it is imprecise. For this reason, additional research on the use of new biomarkers or better use of already available markers may lead to the important advances in this field. Markers may include:
Appropriately weighted risk algorithms should be derived using predictive variables:
Improved measures of glomerular filtration rate (GFR) should be developed and may include:
How should albuminuria be measured? Additional studies on urinary albumin measurements, including predictive values of gender-specific ACR cutoffs, urine collection methods, and processing of urine samples, are warranted.
What is the rate of progression of DKD in people with reduced GFR, but normal urinary albumin excretion? How does this compare with the rate in those with elevated urinary albumin excretion?
Does regression of albuminuria modify the long-term progression of DKD?
What is the effect of promising agents to prevent RCN in patients with various stages of CKD and both types of diabetes?
What is the best common definition of RCN?
Does intensive treatment of glycemia reduce progression of CKD, or prevent CKD stage 5 and CVD events, in people with diabetes and CKD (secondary prevention)? Do effects differ by albuminuria status (normoalbuminuria, microalbuminuria, macroalbuminuria) or level of GFR?
Do the TZDs have kidney or CVD benefits beyond glycemic control in people with diabetes and CKD?
Are risks of fluid retention with TZDs greater in people with CKD?
What is/are the best methods for assessing glycemic control in CKD?
What are the best methods for administering insulin in patients on dialysis?
What are the best ways of countering the hyperglycemic effects of glucocorticoids, cyclosporine, and tacrolimus in the transplant patient?
Are there kidney or CVD benefits beyond glycemic control of GLP-1 analogues (incretin mimetic or amylin analog) or DPP-4 inhibitors in people with DKD?
What are the risks in using GLP-1 analogues (incretin mimetic or amylin analog) or DPP-4 inhibitors in people with diabetes and CKD?
What are optimal doses of ACE inhibitors and ARBs for kidney disease protection in people with diabetes and hypertension?
What is the role of ARBs or other classes of antihypertensive agents, either alone or in combination with ACE inhibitors, on slowing kidney disease progression and preventing CVD in hypertensive people with DKD?
What is the optimal level of blood pressure to slow DKD progression? The question regarding the optimal level of blood pressure reduction for cardiovascular risk reduction may be answered in 2008 by the ACCORD trial. However, this may not answer the question about kidney protection.
Do ACE inhibitors or ARBs prevent progression of kidney disease in patients with diabetes and CKD, defined by low GFR without albuminuria?
What is the effect of lipid lowering with statins on CVD in patients with diabetes and CKD stages 1 to 4?
What is the impact of inflammation (ie, high C-reactive protein) on the response to lipid lowering with statins in diabetes and CKD stage 5? This question may be answered by subgroup analysis and biomarker determinations of the 4D participants.
What is the effect of statin treatment on progression of DKD? Do effects differ by albuminuria status (normoalbuminuria, microalbuminuria, macroalbuminuria) or level of GFR?
Randomized clinical trials in diabetes and CKD examining the role of nutrition on clinical outcomes are needed. Diet interventions are extremely challenging, but are required to identify new therapeutic options.
Studies examining specific nutrients on kidney disease would be beneficial. What is the effect of 0.8 g of protein/kg body weight per day on GFR and urinary albumin excretion with the diet defined as follows:
The above question modified for amino acid composition by altering the protein source:
What is the best strategy for nutrition interventions? Evaluate types and frequency of nutrition education sessions provided by a registered dietitian in conjunction with medical management.
What is the effect of nutritional intervention on progression of DKD using the diagnostic criteria defined in the NKF-KDOQI™ guidelines? Do effects differ by albuminuria status (normoalbuminuria, microalbuminuria, macroalbuminuria) or level of GFR?
What is the effect of RAS inhibition (ACE inhibitors and ARBs) on albuminuria and clinical outcomes in normotensive people with DKD?
What is the relationship between magnitude of albuminuria change and risks of CKD and CVD in people with DKD?
What is the optimal “target value” for urine albumin excretion in DKD during treatment with ACE inhibitors and ARBs?
Do different types of treatment that reduce albuminuria improve clinical outcomes in DKD?
Which facets of the intensive multifaceted intervention are associated with reduced risks of CKD and CVD?
Do people with diabetes and CKD already treated with RAS inhibitors benefit from intensive multifaceted intervention?
Does intensive multifaceted intervention provide CKD and CVD benefits at earlier or later stages of CKD in diabetes?
Can intensive multifaceted intervention for diabetes and CKD be accomplished in other clinical settings?
In overweight and obese people (BMI > 24.9 kg/m2) with diabetes and CKD, what is the effect of weight loss using a balanced calorie-restricted diet on glycemic control, GFR, urinary albumin excretion, and CVD risk factors?
What are the benefits and risks of using rimonabant for weight loss in people with diabetes and CKD?
What are the most effective means of translating clinical knowledge into public health interventions for DKD? While evaluation of direct clinical and public health efforts will be essential, development of systems models can be useful planning tools for predicting the most cost-effective way to use the limited resources that will be available in the countries most affected by DKD in the future.
What are the prenatal and early childhood factors that lead to later development of diabetes and CKD?
What are the causes of different risks of DKD progression and mortality after onset of kidney replacement therapy in various ethnic groups? American Indians on dialysis therapy have better survival compared with Caucasians in the United States, while Canadian First Nations members have similar survival as Canadian Caucasians. This difference in relative survival suggests that nongenetic factors may play a significant role in survival.
Are inexpensive combination antihypertensive agents safe and effective for DKD in populations of developing countries? Such an approach could have great clinical impact, particularly where limited resources are available for purchasing drugs. The effectiveness of low-cost interventions using less expensive generic drugs to control risk factors for DKD has been demonstrated in rural India.
Are programmatic efforts to improve the care of patients with CKD worldwide effective, such as the NKF Kidney Disease—Improving Global Outcomes and the International Society of Nephrology Commission for the Global Advancement of Nephrology? These programs should be regularly assessed.
What are effects of interventions that may decrease the risk of preeclampsia and preterm delivery in women with diabetes and CKD? This is an especially challenging population that should be included in clinical trials.
What factors influence maternal and fetal outcomes in women with type 2 diabetes and CKD?
To what extent do low-dose combinations of medicines for treatment of diabetes and CKD reduce adverse effects and improve adherence?
Do optimal interventions combine behavioral approaches with pharmacological therapies to improve management of risk factors for diabetes and CKD? Particular attention should be paid to identifying which behavioral strategies are most effective in producing the desired change.
What are effective strategies for maintaining long-term adherence to self-care requirements for management of diabetes and CKD?
The Work Group recognizes the importance of bringing new treatments into clinical research for DKD, especially for patients who have progressive kidney disease despite the current standard of care. Promising treatments, including novel agents and potential new uses of existing agents, are currently in phase 2/3 trials for DKD (listed below).