Renal Function and Metabolic Risk: Reduced eGFR Does Not Independently Increase DKA Risk in Type 1 Diabetes

Highlights of the DCCT/EDIC Analysis

The relationship between renal health and acute metabolic complications has long been a subject of clinical concern. Key findings from this longitudinal study include:

1. In a cohort of 1,441 participants followed over 35 years, reduced eGFR (between 30 and 90 mL/min/1.73 m2) was not associated with a statistically significant increase in the risk of diabetic ketoacidosis (DKA) compared to those with normal renal function.

2. The incidence rate of DKA events remained consistent across varying stages of mild-to-moderate chronic kidney disease (CKD), with an adjusted rate of approximately 0.65 events per 100 person-years.

3. These findings suggest that the baseline risk of DKA in type 1 diabetes (T1D) is driven more by glycemic control and insulin management than by moderate declines in kidney function itself.

4. This research provides a crucial baseline for the medical community, particularly when evaluating the safety of sodium-glucose cotransporter inhibitors (SGLTi) which are known to improve renal outcomes but carry an inherent risk of euglycemic DKA.

Background: The Intersection of Renal Function and Metabolic Crises

Chronic kidney disease is a frequent and debilitating complication of type 1 diabetes. For decades, clinicians have managed the delicate balance between intensive glycemic control to prevent microvascular damage and the avoidance of acute crises such as hypoglycemia and diabetic ketoacidosis. As renal function declines, the metabolic environment of the patient shifts. Changes in insulin clearance, glucose reabsorption thresholds, and acid-base buffering capacity in the kidneys theoretically could predispose patients to ketosis.

The emergence of sodium-glucose cotransporter inhibitors (SGLTi) has complicated this clinical landscape. While SGLTis have shown transformative benefits in slowing the progression of CKD in type 2 diabetes, their adoption in type 1 diabetes has been hampered by a well-documented increase in DKA risk. A significant question remained: does the presence of CKD itself lower the threshold for DKA, or is the risk purely a pharmacological side effect of the SGLTi class? Understanding the independent contribution of a reduced eGFR to DKA risk is essential for personalizing T1D therapy.

Study Design and Methodology

Patient Population and Data Source

The researchers utilized data from the Diabetes Control and Complications Trial (DCCT) and its long-term follow-up, the Epidemiology of Diabetes Interventions and Complications (EDIC) study. This dataset is unique in its depth and duration, providing 35 years of meticulously recorded metabolic and renal metrics. The study included 1,441 participants who were originally randomized to either intensive or conventional insulin therapy.

Statistical Approaches

To capture the dynamic nature of renal function over time, the investigators employed time-varying eGFR models. This allowed the analysis to account for participants moving through different stages of CKD over the three-decade period. The primary endpoint was the hazard of the first DKA event. The team utilized Poisson regression and extended Cox proportional hazards models to adjust for potential confounders, including HbA1c levels, age, sex, and treatment group (intensive vs. conventional therapy).

Key Findings: Does Reduced eGFR Increase DKA Risk?

The analysis identified 488 DKA events occurring in 297 participants over the follow-up period. When the data was stratified by eGFR levels, the results were striking in their lack of association between renal decline and DKA incidence.

Incidence Rates and Hazard Ratios

Participants with an eGFR between 30 and 90 mL/min/1.73 m2 showed no statistical difference in DKA rates when compared with the reference group (eGFR 90-120 mL/min/1.73 m2). The unadjusted and adjusted models converged on a similar conclusion: a reduced eGFR in the moderate range does not inherently make a patient more susceptible to DKA. The incidence rate was stable at roughly 0.65 events per 100 person-years.

Stability Across eGFR Strata

One might expect a gradient of risk as kidney function worsens, but the study found that even as patients approached the lower end of the eGFR spectrum (nearing 30 mL/min/1.73 m2), the hazard ratio did not significantly climb. This suggests that the physiological changes associated with moderate CKD—such as decreased glucose filtration and altered renal gluconeogenesis—do not significantly disrupt the systemic ketone balance enough to trigger DKA in the absence of other provocations (like insulin omission or severe illness).

Expert Commentary: Reassessing Risk for SGLTi Initiation

This study, published in Diabetes Care, offers a vital piece of the puzzle for endocrinologists and nephrologists. The finding that CKD does not independently increase DKA risk is a “green light” of sorts for further investigation into renal-protective therapies. If the baseline risk of DKA is not elevated by kidney disease, then the incremental risk added by SGLT inhibitors can be more accurately quantified and managed.

Mechanistically, the kidney plays a dual role in DKA. It is both a site of ketone reabsorption and a primary organ for acid excretion. In advanced CKD (Stage 4 or 5), the inability to excrete hydrogen ions can worsen the acidosis seen in DKA. However, this study focused on the 30-90 eGFR range, suggesting that in these earlier-to-middle stages, the body’s compensatory mechanisms remain robust. Clinicians should continue to focus on the primary drivers of DKA: insulin deficiency, infection, and patient education on “sick day” rules, rather than viewing a moderate decline in eGFR as a specific DKA warning sign.

Limitations and Future Directions

While the DCCT/EDIC data is robust, it is important to note that the study population primarily consisted of individuals who were relatively healthy at enrollment. Furthermore, the number of participants with an eGFR below 30 mL/min/1.73 m2 was limited, meaning these results cannot be generalized to patients with end-stage renal disease (ESRD). Future research should specifically target the DKA risk profiles of T1D patients with Stage 4 and 5 CKD to determine if a threshold exists where renal failure becomes a primary driver of metabolic instability.

Conclusion

The 35-year longitudinal analysis by Bakhsh et al. clarifies a significant point of clinical uncertainty. In type 1 diabetes, a reduced eGFR between 30 and 90 mL/min/1.73 m2 is not an independent predictor of diabetic ketoacidosis. For health policy experts and clinicians, this reinforces the importance of focusing on glycemic management and insulin adherence as the primary preventatives for DKA. Most importantly, it supports the continued exploration of SGLT inhibitors as a kidney-protective strategy for those with T1D and CKD, as the underlying renal disease does not appear to heighten the baseline risk for this life-threatening complication.

References

1. Bakhsh A, Saleemi A, Budhram D, et al. Chronic Kidney Disease and Risk of Diabetic Ketoacidosis in Type 1 Diabetes. Diabetes Care. 2026;49(3):478-482. PMID: 41591367.

2. Nathan DM, DCCT/EDIC Research Group. The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study at 30 years: overview. Diabetes Care. 2014;37(1):9-16.

3. Taylor SI, Blau JE, Rother KI. SGLT2 Inhibitors May Predispose to Ketoacidosis. J Clin Endocrinol Metab. 2015;100(8):2849-2852.