The factorial microvascular analysis of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) blood-pressure trial (Ismail-Beigi et al., 2012) found that simultaneous intensive systolic blood-pressure (below 120 mm Hg) and glycemic (HbA1c below 6.0%) control conferred no additive microvascular benefit in older patients with established type 2 diabetes, that neither intervention prevented renal failure, and that 45% of participants who developed renal failure had no antecedent albuminuria. Later literature resolved parts of what the authors left open: long-term ACCORDION (post-trial) follow-up confirmed a durable macroalbuminuria benefit of intensive glycemia (hazard ratio 0.68) but no renal-failure benefit, with a creatinine-doubling harm signal under intensive blood-pressure control; ADVANCE-ON (post-trial follow-up of ADVANCE), the Veterans Affairs Diabetes Trial follow-up, and 24-year UKPDS monitoring show that the renal and microvascular benefits of intensive control persist for a decade or more and are largest at earlier stages of disease or when treatment begins at diagnosis; and SGLT2-inhibitor and finerenone outcome trials resolved the medication-class question by demonstrating kidney protection independent of blood-pressure or glucose lowering. The open core is mechanistic and predictive: which pathways and risk factors, beyond hypertension and hyperglycemia, account for renal failure that arises without antecedent albuminuria in type 2 diabetes, and whether any biomarker or imaging measure predicts this progression more reliably than albuminuria. The source's suggestion that treatment initiated late in the disease may have missed irreversible pathology remains one candidate explanation that later trials informed but never tested head-on.

Background

Type 2 diabetes mellitus (T2DM) damages the small vessels of the kidney, retina, and peripheral nerves (the microvascular complications). Glycated hemoglobin (HbA1c) traces average blood glucose over roughly three months, and systolic blood pressure (SBP) is the blood-pressure component most tightly linked to vascular injury. Large randomized trials tested whether intensively lowering these risk factors prevents complications. The UK Prospective Diabetes Study (UKPDS), in newly diagnosed patients, showed that intensive glucose control reduces microvascular events and that tight blood-pressure control reduces them while the pressure difference is maintained; the Veterans Affairs Diabetes Trial (VADT) and the ADVANCE factorial trial, in longer-standing disease, showed smaller and less consistent microvascular effects. In ACCORD, 10,251 patients with established T2DM at high cardiovascular risk were randomized to intensive versus standard glycemic control (HbA1c below 6.0% versus 7.0–7.9%), and a subgroup of 4,733 with hypertension was further randomized to intensive versus standard SBP targets (below 120 versus below 140 mm Hg). The source is the prespecified microvascular analysis of that blood-pressure subpopulation over a mean 4.7 years: intensive blood-pressure control improved only 1 of 10 microvascular outcomes (incident microalbuminuria, hazard ratio 0.84), intensive glycemic control reduced incident macroalbuminuria, the two interventions did not interact, no outcome was improved by their combination, and neither prevented renal failure (dialysis, transplantation, or a rise in serum creatinine to at least 292 µmol/L). The authors attributed the missed renal-failure benefit to few events, possibly inadequate duration or intensity of exposure, and treatment initiated late in the disease when pathology may be irreversible, and called for further analysis of medication-class effects.

Albuminuria — urinary albumin excretion above normal (microalbuminuria) or frankly elevated (macroalbuminuria) — is the traditional surrogate marker for diabetic kidney disease and the entry criterion for most renal trials. But the source analysis, like UKPDS before it, found albuminuria an unreliable herald of renal failure: 33 of 74 (45%) participants who developed renal failure had never shown micro- or macroalbuminuria. This defines the clinically important phenotype of nonalbuminuric diabetic kidney disease, first quantified in the third US National Health and Nutrition Examination Survey (NHANES III; Kramer et al. 2003): impaired kidney function in people with diabetes who lack both albuminuria and retinopathy (a stricter criterion than the absence of micro- or macroalbuminuria alone), implying injury pathways — tubular, vascular, aging-related, or repeated episodic acute kidney injury — that bypass the classic albumin-leaking glomerular route.

Two later concepts organize the follow-up literature. The glycemic legacy effect (metabolic memory) is the persistence of risk reduction after between-group HbA1c differences vanish, demonstrated in UKPDS post-trial monitoring and extended to 24 years, in contrast to blood-pressure benefits, which fade once pressure differences are lost. The class-effect era is the demonstration, beginning around 2019, that sodium–glucose cotransporter-2 (SGLT2) inhibitors — drugs originally developed to lower glucose — and the nonsteroidal mineralocorticoid-receptor antagonist finerenone reduce kidney failure through mechanisms beyond blood-pressure or glucose lowering, reshaping diabetic-kidney-disease therapy. Some evidence implicates circulating inflammatory markers — the tumor-necrosis-factor receptors 1 and 2 (TNFR1/TNFR2, inflammatory receptors shed into blood) and broader inflammatory-protein signatures — as candidate predictors of renal failure independent of albuminuria. Against this backdrop, the unresolved questions are why renal failure still arrives without albuminuria despite risk-factor control and whether it can be predicted better than by albuminuria.

Problem Statement

The source leaves open a mechanistic and predictive question: identify, with the evidence bearing on each, the mechanisms, risk factors, and pathological pathways — other than hypertension and hyperglycemia acting through albuminuric glomerular injury — that account for the substantial fraction of patients with type 2 diabetes who progress to renal failure (in the source's definition, dialysis, transplantation, or a rise in serum creatinine to at least 292 µmol/L) without ever developing micro- or macroalbuminuria, regardless of retinopathy; and establish whether any biomarker or imaging measure predicts progression to renal failure in these patients more reliably than albuminuria-based monitoring, where 'more reliably' means better discrimination or risk reclassification than albuminuria-based monitoring. Medication-class effects and longer follow-up of the late-stage population are outside the scope of this question. The source's fourth candidate explanation for its null renal-failure result — that treatment was initiated late in the disease when pathological changes were irreversible — is likewise outside its scope: later trials informed but did not test it head-on, and the source itself tempered that explanation by noting that rates of renal failure were not affected by intensive glycemic control in newly diagnosed UKPDS participants.

References

  1. Ismail-Beigi F, Craven TE, O'Connor PJ, Karl D, Calles-Escandon J, Hramiak I, Genuth S, Cushman WC, Gerstein HC, Probstfield JL, Katz L, Schubart U. Combined intensive blood pressure and glycemic control does not produce an additive benefit on microvascular outcomes in type 2 diabetic patients. Kidney International 2012;81(6):586-594. doi:10.1038/ki.2011.415. https://doi.org/10.1038/ki.2011.415
  2. UK Prospective Diabetes Study (UKPDS) Group. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). The Lancet 1998;352:837-853. doi:10.1016/S0140-6736(98)07019-6. https://doi.org/10.1016/S0140-6736(98)07019-6
  3. UK Prospective Diabetes Study (UKPDS) Group. Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes (UKPDS 38). BMJ 1998;317(7160):703-713. doi:10.1136/bmj.317.7160.703. https://doi.org/10.1136/bmj.317.7160.703
  4. Kramer HJ, Nguyen QD, Curhan G, Hsu CY. Renal insufficiency in the absence of albuminuria and retinopathy among adults with type 2 diabetes mellitus. JAMA 2003;289(24):3273-3277. doi:10.1001/jama.289.24.3273. https://doi.org/10.1001/jama.289.24.3273
  5. Gæde P, Vedel P, Larsen N, Jensen GV, Parving HH, Pedersen O. Multifactorial intervention and cardiovascular disease in patients with type 2 diabetes. New England Journal of Medicine 2003;348(5):383-393. doi:10.1056/NEJMoa021778. https://doi.org/10.1056/NEJMoa021778
  6. Zoungas S, de Galan BE, Ninomiya T, et al. Combined effects of routine blood pressure lowering and intensive glucose control on macrovascular and microvascular outcomes in patients with type 2 diabetes: new results from the ADVANCE trial. Diabetes Care 2009;32(11):2068-2074. doi:10.2337/dc09-0959. https://doi.org/10.2337/dc09-0959
  7. Holman RR, Paul SK, Bethel MA, Matthews DR, Neil HAW. 10-year follow-up of intensive glucose control in type 2 diabetes. New England Journal of Medicine 2008;359(15):1577-1589. doi:10.1056/NEJMoa0806470. https://doi.org/10.1056/NEJMoa0806470
  8. Holman RR, Paul SK, Bethel MA, Neil HAW, Matthews DR. Long-term follow-up after tight control of blood pressure in type 2 diabetes. New England Journal of Medicine 2008;359(15):1565-1576. doi:10.1056/NEJMoa0806359. https://doi.org/10.1056/NEJMoa0806359
  9. Margolis KL, O'Connor PJ, Morgan TM, et al. Outcomes of combined cardiovascular risk factor management strategies in type 2 diabetes: the ACCORD randomized trial. Diabetes Care 2014;37(6):1721-1728. doi:10.2337/dc13-2334. https://doi.org/10.2337/dc13-2334
  10. Zoungas S, Chalmers J, Neal B, et al. Follow-up of blood-pressure lowering and glucose control in type 2 diabetes. New England Journal of Medicine 2014;371(15):1392-1406. doi:10.1056/NEJMoa1407963. https://doi.org/10.1056/NEJMoa1407963
  11. Pavkov ME, Nelson RG, Knowler WC, Cheng Y, Krolewski AS, Niewczas MA. Elevation of circulating TNF receptors 1 and 2 increases the risk of end-stage renal disease in American Indians with type 2 diabetes. Kidney International 2015;87(4):812-819. doi:10.1038/ki.2014.330. https://doi.org/10.1038/ki.2014.330
  12. Wong MG, Perkovic V, Chalmers J, et al. Long-term benefits of intensive glucose control for preventing end-stage kidney disease: ADVANCE-ON. Diabetes Care 2016;39(5):694-700. doi:10.2337/dc15-2322. https://doi.org/10.2337/dc15-2322
  13. Beddhu S, Greene T, Boucher R, et al. Intensive systolic blood pressure control and incident chronic kidney disease in people with and without diabetes mellitus: secondary analyses of two randomised controlled trials. The Lancet Diabetes & Endocrinology 2018;6(7):555-563. doi:10.1016/S2213-8587(18)30099-8. https://doi.org/10.1016/S2213-8587(18)30099-8
  14. Mottl AK, Buse JB, Ismail-Beigi F, et al. Long-term effects of intensive glycemic and blood pressure control and fenofibrate use on kidney outcomes. Clinical Journal of the American Society of Nephrology 2018;13(11):1693-1702. doi:10.2215/CJN.06200518. https://doi.org/10.2215/CJN.06200518
  15. Agrawal L, Azad N, Bahn GD, Ge L, Reaven PD, Hayward RA, Reda DJ, Emanuele NV; VADT Study Group. Long-term follow-up of intensive glycaemic control on renal outcomes in the Veterans Affairs Diabetes Trial (VADT). Diabetologia 2018;61(2):295-299. doi:10.1007/s00125-017-4473-2. https://doi.org/10.1007/s00125-017-4473-2
  16. Perkovic V, Jardine MJ, Neal B, et al. Canagliflozin and renal outcomes in type 2 diabetes and nephropathy. New England Journal of Medicine 2019;380(24):2295-2306. doi:10.1056/NEJMoa1811744. https://doi.org/10.1056/NEJMoa1811744
  17. Niewczas MA, Pavkov ME, Skupien J, et al. A signature of circulating inflammatory proteins and development of end-stage renal disease in diabetes. Nature Medicine 2019;25(5):805-813. doi:10.1038/s41591-019-0415-5. https://doi.org/10.1038/s41591-019-0415-5
  18. Heerspink HJL, Stefánsson BV, Correa-Rotter R, et al. Dapagliflozin in patients with chronic kidney disease. New England Journal of Medicine 2020;383(15):1436-1446. doi:10.1056/NEJMoa2024816. https://doi.org/10.1056/NEJMoa2024816
  19. Bakris GL, Agarwal R, Anker SD, et al. Effect of finerenone on chronic kidney disease outcomes in type 2 diabetes. New England Journal of Medicine 2020;383(23):2219-2229. doi:10.1056/NEJMoa2025845. https://doi.org/10.1056/NEJMoa2025845
  20. D'Marco L, Guerra-Torres X, Viejo I, Lopez-Romero L, Yugueros A, Bermúdez V. Non-albuminuric diabetic kidney disease phenotype: beyond albuminuria. touchREVIEWS in Endocrinology 2022;18(2):102-105. doi:10.17925/EE.2022.18.2.102. https://doi.org/10.17925/EE.2022.18.2.102
  21. Lee K, He JC. AKI-to-CKD transition is a potential mechanism for non-albuminuric diabetic kidney disease. Faculty Reviews 2022;11:21. doi:10.12703/r/11-21. https://doi.org/10.12703/r/11-21
  22. EMPA-KIDNEY Collaborative Group. Empagliflozin in patients with chronic kidney disease. New England Journal of Medicine 2023;388(2):117-127. doi:10.1056/NEJMoa2204233. https://doi.org/10.1056/NEJMoa2204233
  23. Adler AI, Coleman RL, Leal J, Whiteley WN, Clarke P, Holman RR. Post-trial monitoring of a randomised controlled trial of intensive glycaemic control in type 2 diabetes extended from 10 years to 24 years (UKPDS 91). The Lancet 2024;404(10448):145-155. doi:10.1016/S0140-6736(24)00537-3. https://doi.org/10.1016/S0140-6736(24)00537-3
  24. Kim DW, Song SH; Korean Diabetic Kidney Disease Study Group. Sodium-glucose cotransporter 2 inhibitors in diabetic kidney disease. Kidney Research and Clinical Practice 2026 (online ahead of print). doi:10.23876/j.krcp.26.139. https://doi.org/10.23876/j.krcp.26.139