Metabolic Effects of an SGLT2 Inhibitor (Dapagliflozin) During a Period of Acute Insulin Withdrawal and Development of Ketoacidosis in People With Type 1 Diabetes

Effect of dapagliflozin on blood and breath ketones during supervised insulin withdrawal in adults with type 1 diabetes: A randomized crossover trial

AIMS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors increase ketoacidosis risk, limiting their use in type 1 diabetes. To better understand the pathophysiology of SGLT2 inhibitor-mediated ketoacidosis, we measured blood glucose, capillary blood and plasma β-hydroxybutyrate (BOHB) and breath acetone (BrACE) during supervised insulin withdrawal in adults with type 1 diabetes with and without dapagliflozin treatment.

MATERIALS AND METHODS

Twenty adults with type 1 diabetes underwent supervised insulin withdrawal twice in a randomized crossover design: during usual care and after treatment with dapagliflozin (10 mg daily for 2 weeks plus the test day). After insulin withdrawal, capillary blood glucose, BOHB and BrACE measurements were obtained at least hourly until stopping rules were met (>8 h elapsed, symptoms of ketosis, glucose >400 mg/dL, BOHB >4 mmol/L or participant request).

RESULTS

The peak BOHB and BrACE values achieved during supervised insulin withdrawal were both greater with dapagliflozin than with usual care. Throughout the insulin withdrawal study, dapagliflozin treatment was associated with significantly greater BOHB and BrACE concentrations. The proportions of participants reaching BOHB >1.5 mmol/L and >2.5 mmol/L during supervised insulin withdrawal were greater in the dapagliflozin arm. Blood glucose reached a lower peak in the dapagliflozin arm.

CONCLUSIONS

In adults with type 1 diabetes undergoing supervised insulin withdrawal, dapagliflozin treatment compared to usual care was associated with greater blood and breath ketone concentrations in the absence of significant hyperglycaemia.

Breath Acetone Correlates With Capillary β-hydroxybutyrate in Type 1 Diabetes

BACKGROUND

Breath acetone (BrACE) is an end product of ketone metabolism that is measurable by noninvasive breath ketone analyzers. We assessed the correlation between capillary blood β-hydroxybutyrate (BOHB) and BrACE in people with type 1 diabetes during 14 days of outpatient care with and without dapagliflozin treatment and during supervised insulin withdrawal studies with and without dapagliflozin.

METHODS

In this randomized crossover study, participants completed two 14-day outpatient periods with or without dapagliflozin 10 mg daily. Each 14-day unsupervised outpatient period was followed by a 1-day supervised insulin withdrawal study. Paired BOHB and BrACE measurements were obtained 3 times daily during outpatient periods, then hourly during supervised insulin withdrawal. The correlation between BrACE and BOHB was assessed by Spearman's ρ.

RESULTS

Twenty people with type 1 diabetes completed the study. During outpatient periods, BrACE and BOHB were moderately correlated (n = 1425 paired readings; ρ = .41; 95% CI = 0.36 to 0.45; P < .0001). However, BrACE and BOHB were strongly correlated during insulin withdrawal (n = 246 paired values, ρ = .81; 95% CI = 0.77 to 0.85). In ROC analysis, BrACE > 5 ppm demonstrated optimal sensitivity (93%) and specificity (87%) for detecting capillary BOHB ≥ 1.5 mmol/L. No serious adverse events occurred.

CONCLUSIONS

In adults with type 1 diabetes, measurement of breath acetone provides a noninvasive estimate of blood BOHB concentration. The correlation between BrACE and BOHB was suboptimal during unsupervised outpatient care, but was strong during supervised insulin withdrawal.

TRIAL REGISTRATION

clinicaltrials.gov (NCT05541484).

Breath Acetone Correlates with Capillary β-hydroxybutyrate in Type 1 Diabetes

Background

Breath acetone (BrACE) is an end product of ketone metabolism that is measurable by noninvasive breath ketone analyzers. We assessed the correlation between capillary blood β-hydroxybutyrate (BOHB) and BrACE in people with type 1 diabetes (T1D) during 14 days of outpatient care with and without dapagliflozin treatment and during supervised insulin withdrawal studies with and without dapagliflozin.

Methods

In this randomized crossover study, participants completed 14-day two outpatient periods with or without dapagliflozin 10 mg daily. Each 14-day unsupervised outpatient period was followed by a one-day supervised insulin withdrawal study. Paired BOHB and BrACE measurements were obtained three times daily during outpatient periods, then hourly during supervised insulin withdrawal. The correlation between BrACE and BOHB was assessed by Spearman's ρ.

Results

Twenty people with T1D completed the study. During outpatient periods, BrACE and BOHB were moderately correlated (n=1425 paired readings; ρ = 0.41; 95% CI: 0.36 to 0.45; P < 0.0001). However, BrACE and BOHB were strongly correlated during insulin withdrawal (n=246 paired values, ρ = 0.81; 95% CI: 0.77 to 0.85). In ROC analysis, BrACE > 5 ppm demonstrated optimal sensitivity (93%) and specificity (87%) for detecting capillary BOHB ≥ 1.5 mmol/L. No serious adverse events occurred.

Conclusions

In adults with T1D, measurement of breath acetone provides a noninvasive estimate of blood BOHB concentration. The correlation between BrACE and BOHB was suboptimal during unsupervised outpatient care, but was strong during supervised insulin withdrawal.Trial registration: clinicaltrials.gov (NCT05541484).

A perspective on treating type 1 diabetes mellitus before insulin is needed

Type 1 diabetes mellitus (T1DM) is a progressive autoimmune disease that starts long before a clinical diagnosis is made. The American Diabetes Association recognizes three stages: stage 1 (normoglycaemic and positive for autoantibodies to β-cell antigens); stage 2 (asymptomatic with dysglycaemia); and stage 3, which is defined by glucose levels consistent with the definition of diabetes mellitus. This Perspective focuses on the management of the proportion of individuals with early stage 3 T1DM who do not immediately require insulin; a stage we propose should be termed stage 3a. To date, this period of non-insulin-dependent T1DM has been largely unrecognized. Importantly, it represents a window of opportunity for intervention, as remaining at this stage might delay the need for insulin by months or years. Extending the insulin-free period and/or avoiding unnecessary insulin therapy are important goals, as there is no risk of hypoglycaemia during this period and the adherence burden on patients of glycaemic monitoring and daily adjustments for diet and exercise is substantially reduced. Recognizing the pressing need for guidance on adequate management of children and adults with stage 3a T1DM, we present our perspective on the subject, which needs to be tested in formal and adequately powered clinical trials.

Freeman JL, Dunn I, Dvergsten C, Madduri S, Giovannetti ER, Valcarce C, Buse JB, Pettus JH. Impact of the hepatoselective glucokinase activator TTP399 on ketoacidosis during insulin withdrawal in people with type 1 diabetes

AIMS

To determine the effect of TTP399, a hepatoselective glucokinase activator, on the risk of ketoacidosis during insulin withdrawal in individuals with type 1 diabetes (T1D).

MATERIALS AND METHODS

Twenty-three participants with T1D using insulin pump therapy were randomized to 800 mg TTP399 (n = 12) or placebo (n = 11) for 7 to 10 days. After the treatment period, an insulin withdrawal test (IWT) was performed, during which insulin pumps were removed to induce ketogenesis. The IWT was stopped after 10 hours or if blood glucose reached >399 mg/dL [22.1 mmol/L], if beta-hydroxybutyrate (BHB) was >3.0 mmol/L, or for patient discomfort. The primary endpoint was the proportion of participants who reached BHB concentrations of 1 mmol/L or greater.

RESULTS

During the 7- to 10-day treatment period, mean fasting plasma glucose was significantly reduced ( -27.6 vs. -4.4 mg/dL [-1.5 vs. -0.2 mmol/L]; P = 0.03) and there were fewer adverse events, including hypoglycaemia, in the TTP399-treated arm. During the IWT, no differences were observed between TTP399 and placebo in mean serum BHB concentration, mean duration of IWT, or BHB at termination of IWT. However, serum bicarbonate was numerically higher and urine acetoacetate was quantitatively lower in the TTP399-treated participants. As a result of higher bicarbonate values, none of the TTP399-treated participants met the prespecified criteria for diabetic ketoacidosis (DKA), defined as BHB >3 mmol/L and serum bicarbonate <18 mEq/L, compared to 42% of placebo-treated participants.

CONCLUSIONS

When used as an adjunctive therapy to insulin, TTP399 improves glycaemia without increasing hypoglycaemia in individuals with T1D. During acute insulin withdrawal, TTP399 did not increase BHB concentrations and decreased the incidence of DKA.

The SGLT2 Inhibitor Dapagliflozin Increases the Oxidation of Ingested Fatty Acids to Ketones in Type 2 Diabetes

OBJECTIVE

To investigate the mechanism for increased ketogenesis following treatment with the SGLT2 inhibitor dapagliflozin in people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The design was a double-blind, placebo-controlled, crossover study with a 4-week washout period. Participants received dapagliflozin or placebo in random order for 4 weeks. After each treatment, they ingested 30 mL of olive oil containing [U-13C]palmitate to measure ketogenesis, with blood sampling for 480 min. Stable isotopes of glucose and glycerol were infused to measure glucose flux and lipolysis, respectively, at 450-480 min.

RESULTS

Glucose excretion rate was higher and peripheral glucose uptake lower with dapagliflozin than placebo. Plasma β-hydroxybutyrate (BOHB) concentrations and [13C2]BOHB concentrations were higher and glucose concentrations lower with dapagliflozin than placebo. Nonesterified fatty acids (NEFAs) were higher with dapagliflozin at 300 and 420 min, but lipolysis at 450-480 min was not different. Triacylglycerol at all time points and endogenous glucose production rate at 450-480 min were not different between treatments.

CONCLUSIONS

The increase in ketone enrichment from the ingested palmitic acid tracer suggests that meal-derived fatty acids contribute to the increase in ketones during treatment with dapagliflozin. The increase in BOHB concentration with dapagliflozin occurred with only minimal changes in plasma NEFA concentration and no change in lipolysis. This finding suggests a metabolic switch to increase ketogenesis within the liver.

Empagliflozin add-on therapy to closed-loop insulin delivery in type 1 diabetes: a 2 × 2 factorial randomized crossover trial

There is a need to optimize closed-loop automated insulin delivery in type 1 diabetes. We assessed the glycemic efficacy and safety of empagliflozin 25 mg d^-1 as add-on therapy to insulin delivery with a closed-loop system. We performed a 2 × 2 factorial randomized, placebo-controlled, crossover two-center trial in adults, assessing 4 weeks of closed-loop delivery versus sensor-augmented pump (SAP) therapy and empagliflozin versus placebo. The primary outcome was time spent in the glucose target range (3.9-10.0 mmol l^-1). Primary comparisons were empagliflozin versus placebo in each of closed-loop or SAP therapy; the remaining comparisons were conditional on its significance. Twenty-four of 27 randomized participants were included in the final analysis. Compared to placebo, empagliflozin improved time in target range with closed-loop therapy by 7.2% and in SAP therapy by 11.4%. Closed-loop therapy plus empagliflozin improved time in target range compared to SAP therapy plus empagliflozin by 6.1% but by 17.5% for the combination of closed-loop therapy and empagliflozin compared to SAP therapy plus placebo. While no diabetic ketoacidosis or severe hypoglycemia occurred during any intervention, uncomplicated ketosis events were more common on empagliflozin. Empagliflozin 25 mg d^-1 added to automated insulin delivery improves glycemic control but increases ketone concentration and ketosis compared to placebo.

Strategically Playing with Fire: SGLT Inhibitors as Possible Adjunct to Closed-Loop Insulin Therapy

As closed-loop insulin therapies emerge into clinical practice and evolve in medical research for type 1 diabetes (T1D) treatment, the limitations in these therapies become more evident. These gaps include unachieved target levels of glycated hemoglobin in some patients, postprandial hyperglycemia, the ongoing need for carbohydrate counting, and the lack of non-glycemic benefits (such as prevention of metabolic syndrome and complications). Multiple adjunct therapies have been examined to improve closed-loop systems, yet none have become a staple. Sodium-glucose-linked cotransporter inhibitors (SGLTi's) have been extensively researched in T1D, with average reductions in placebo-adjusted HbA1c by 0.39%, and total daily dose by approximately 10%. Unfortunately, many trials revealed an increased risk of diabetic ketoacidosis, as high as 5 times the relative risk compared to placebo. This narrative review discusses the proven benefits and risks of SGLTi in patients with T1D with routine therapy, what has been studied thus far in closed-loop therapy in combination with SGLTi, the potential benefits of SGLTi use to closed-loop systems, and what is required going forward to improve the benefit to risk ratio in these insulin systems.

Euglycemic Ketoacidosis as a Complication of SGLT2 Inhibitor Therapy

Sodium-glucose cotransporter-2 (SGLT2) inhibitors are drugs designed to lower plasma glucose concentration by inhibiting Na+-glucose-coupled transport in the proximal tubule. Clinical trials demonstrate these drugs have favorable effects on cardiovascular outcomes to include slowing the progression of CKD. Although most patients tolerate these drugs, a potential complication is development of ketoacidosis, often with a normal or only a minimally elevated plasma glucose concentration. Inhibition of sodium-glucose cotransporter-2 in the proximal tubule alters kidney ATP turnover so that filtered ketoacids are preferentially excreted as Na+ or K+ salts, leading to indirect loss of bicarbonate from the body and systemic acidosis under conditions of increased ketogenesis. Risk factors include reductions in insulin dose, increased insulin demand, metabolic stress, low carbohydrate intake, women, and latent autoimmune diabetes of adulthood. The lack of hyperglycemia and nonspecific symptoms of ketoacidosis can lead to delays in diagnosis. Treatment strategies and various precautions are discussed that can decrease the likelihood of this complication.

Association of British Clinical Diabetologists (ABCD) and Diabetes UK joint position statement and recommendations on the use of sodium-glucose cotransporter inhibitors with insulin for treatment of type 1 diabetes (Updated October 2020)

Dapagliflozin (SGLT-2 inhibitor) and sotagliflozin (SGLT1/2 inhibitor) are two of the drugs of SGLT inhibitor class which have been recommended by the National Institute for Health and Care Excellence (NICE) in people with type 1 diabetes with BMI ≥27 kg/m² . Dapagliflozin is licensed in the UK for use in the NHS while sotagliflozin may be available in future. These and possibly other SGLT inhibitors may be increasingly used in people with type 1 diabetes as new licences are obtained. These drugs have the potential to improve glycaemic control in people with type 1 diabetes with the added benefit of weight loss, better control of blood pressure and more time in optimal glucose range. However, SGLT inhibitors are associated with a higher incidence of diabetic ketoacidosis without significant hyperglycaemia. The present ABCD/Diabetes UK joint updated position statement is to guide people with type 1 diabetes and clinicians using these drugs help mitigate this risk and other potential complications. Particularly, caution needs to be exercised in people who are at risk of diabetic ketoacidosis due to low calorie diets, illnesses, injuries, starvation, excessive exercise, excessive alcohol consumption and reduced insulin administration among other precipitating factors for diabetic ketoacidosis.