Comparing advanced hybrid closed loop therapy and standard insulin therapy in pregnant women with type 1 diabetes (CRISTAL): a parallel-group, open-label, randomised controlled trial

BACKGROUND

Advanced hybrid closed loop (AHCL) therapy can improve glycaemic control in pregnant women with type 1 diabetes. However, data are needed on the efficacy and safety of AHCL systems as these systems, such as the MiniMed 780G, are not currently approved for use in pregnant women. We aimed to investigate whether the MiniMed 780G can improve glycaemic control with less hypoglycaemia in pregnant women with type 1 diabetes.

METHODS

CRISTAL was a double-arm, parallel-group, open-label, randomised controlled trial conducted in secondary and tertiary care specialist endocrinology centres at 12 hospitals (11 in Belgium and one in the Netherlands). Pregnant women aged 18-45 years with type 1 diabetes were randomly assigned (1:1) to AHCL therapy (MiniMed 780G) or standard insulin therapy (standard of care) at a median of 10·1 (IQR 8·6-11·6) weeks of gestation. Randomisation was done centrally with minimisation dependent on baseline HbA1c, insulin administration method, and centre. Participants and study teams were not masked to group allocation. The primary outcome was proportion of time spent in the pregnancy-specific target glucose range (3·5-7·8 mmol/L), measured by continuous glucose monitoring (CGM) at 14-17 weeks, 20-23 weeks, 26-29 weeks, and 33-36 weeks. Key secondary outcomes were overnight time in target range, and time below glucose range (<3·5 mmol/L) overall and overnight. Analyses were conducted on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov (NCT04520971).

FINDINGS

Between Jan 15, 2021 and Sept 30, 2022, 101 participants were screened, and 95 were randomly assigned to AHCL therapy (n=46) or standard insulin therapy (n=49). 43 patients assigned to AHCL therapy and 46 assigned to standard insulin therapy completed the study. At baseline, 91 (95·8%) participants used insulin pumps, and the mean HbA1c was 6·5% (SD 0·6). The mean proportion of time spent in the target range (averaged over four time periods) was 66·5% (SD 10·0) in the AHCL therapy group compared with 63·2% (12·4) in the standard insulin therapy group (adjusted mean difference 1·88 percentage points [95% CI -0·82 to 4·58], p=0·17). Overnight time in the target range was higher (adjusted mean difference 6·58 percentage points [95% CI 2·31 to 10·85], p=0·0026), and time below range overall (adjusted mean difference -1·34 percentage points [95% CI, -2·19 to -0·49], p=0·0020) and overnight (adjusted mean difference -1·86 percentage points [95% CI -2·90 to -0·81], p=0·0005) were lower with AHCL therapy than with standard insulin therapy. Participants assigned to AHCL therapy reported higher treatment satisfaction. No unanticipated safety events occurred with AHCL therapy.

INTERPRETATION

In pregnant women starting with tighter glycaemic control, AHCL therapy did not improve overall time in target range but improved overnight time in target range, reduced time below range, and improved treatment satisfaction. These data suggest that the MiniMed 780G can be safely used in pregnancy and provides some additional benefits compared with standard insulin therapy; however, it will be important to refine the algorithm to better align with pregnancy requirements.

FUNDING

Diabetes Liga Research Fund and Medtronic.

Glycaemic management around postprandial exercise in people with type 1 diabetes: Challenge accepted

CONTEXT

The precise glycaemic impact and clinical relevance of postprandial exercise in type 1 diabetes has not been clarified yet.

OBJECTIVE

Examine acute, subacute and late effects of postprandial exercise on blood glucose (BG).

DESIGN

RCT.

SETTING

Four lab visits, with 24h follow-up at home.

PARTICIPANTS

Adults with type 1 diabetes (n=8), age 44±13 years; BMI: 24±2.1 kg/m2.

INTERVENTION

30 min of rest (CONTROL), walking (WALK), moderate-intensity (MOD), or intermittent high-intensity (IHE) exercise performed 60min after a standardized meal.

MAIN OUTCOME MEASURES

BG change during exercise/control (acute), and secondary outcomes included the subacute (≤2h after) and late glycaemic effects (≤24h after).

RESULTS

Exercise reduced postprandial glucose (PPG) excursion compared to CONTROL, with a consistent BG decline in all patients for all modalities (mean declines -45±24, -71±39, and -35±21 mg/dL, during WALK, MOD and IHE, respectively (p<0.001). For this decline, clinical superiority was demonstrated separately for each exercise modality vs. CONTROL. Non-inferiority of WALK vs. MOD was not demonstrated, non-inferiority of WALK vs. IHE was demonstrated, and equivalence of IHE vs. MOD was not demonstrated. Hypoglycaemia did not occur during exercise. BG increased in the hour after exercise (more than after CONTROL, p<0.001). More than half of participants showed hyperglycaemia after exercise necessitating insulin correction. There were more nocturnal hypoglycaemic events after exercise vs. CONTROL (p<0.05).

CONCLUSIONS

Postprandial exercise of all modalities is effective, safe and feasible if necessary precautions are taken (i.e., prandial insulin reductions), as exercise lowered maximal PPG excursion and caused a consistent and clinically relevant BG decline during exercise while there was no hypoglycaemia during or shortly after exercise. However, there seem two remaining challenges, being subacute post-exercise hyperglycaemia and nocturnal hypoglycaemia.

Effects of postprandial exercise on blood glucose levels in adults with type 1 diabetes: a review

People with type 1 diabetes experience challenges in managing blood glucose around exercise. Previous studies have examined glycaemic responses to different exercise modalities but paid little attention to participants' prandial state, although this is an important consideration and will enhance our understanding of the effects of exercise in order to improve blood glucose management around activity. This review summarises available data on the glycaemic effects of postprandial exercise (i.e. exercise within 2 h after a meal) in people with type 1 diabetes. Using a search strategy on electronic databases, literature was screened until November 2022 to identify clinical trials evaluating acute (during exercise), subacute (≤2 h after exercise) and late (>2 h to ≤24 h after exercise) effects of postprandial exercise in adults with type 1 diabetes. Studies were systematically organised and assessed by exercise modality: (1) walking exercise (WALK); (2) continuous exercise of moderate intensity (CONT MOD); (3) continuous exercise of high intensity (CONT HIGH); and (4) interval training (intermittent high-intensity exercise [IHE] or high-intensity interval training [HIIT]). Primary outcomes were blood glucose change and hypoglycaemia occurrence during and after exercise. All study details and results per outcome were listed in an evidence table. Twenty eligible articles were included: two included WALK sessions, eight included CONT MOD, seven included CONT HIGH, three included IHE and two included HIIT. All exercise modalities caused consistent acute glycaemic declines, with the largest effect size for CONT HIGH and the smallest for HIIT, depending on the duration and intensity of the exercise bout. Pre-exercise mealtime insulin reductions created higher starting blood glucose levels, thereby protecting against hypoglycaemia, in spite of similar declines in blood glucose during activity between the different insulin reduction strategies. Nocturnal hypoglycaemia occurred after higher intensity postprandial exercise, a risk that could be diminished by a post-exercise snack with concomitant bolus insulin reduction. Research on the optimal timing of postprandial exercise is inconclusive. In summary, individuals with type 1 diabetes exercising postprandially should substantially reduce insulin with the pre-exercise meal to avoid exercise-induced hypoglycaemia, with the magnitude of the reduction depending on the exercise duration and intensity. Importantly, pre-exercise blood glucose and timing of exercise should be considered to avoid hyperglycaemia around exercise. To protect against late-onset hypoglycaemia, a post-exercise meal with insulin adjustments might be advisable, especially for exercise in the evening or with a high-intensity component.

Time-varying parameters of glycemic control and glycation in relation to arterial stiffness in patients with type 1 diabetes

BACKGROUND

A substantial proportion of type 1 diabetes (T1D) patients free from known cardiovascular disease (CVD) show premature arterial stiffening, with age, blood pressure, and HbA1c-as gold standard of glycemic control-as main predictors. However, the relationship of arterial stiffness with other time-varying parameters of glycemic control and glycation has been far less explored. This study investigated the relationship of arterial stiffness with several short- and long-term parameters of glycemic control and glycation in patients with T1D, such as advanced glycation end-products (AGEs) and continuous glucose monitoring (CGM)-derived parameters.

METHODS

Cross-sectional study at a tertiary care centre including 54 patients with T1D free from known CVD. Arterial stiffness was assessed with carotid-femoral pulse wave velocity (cf-PWV). Current level and 10-year history of HbA1c were evaluated, and skin AGEs, urinary AGEs, and serum soluble AGE-receptor (sRAGE) concentrations. CGM for 7 days was used to determine time in range, time in hyper- and hypoglycemia, and glycemic variability.

RESULTS

Cf-PWV was associated with current HbA1c (r_s = + 0.28), mean 10-years HbA1c (r_s = + 0.36), skin AGEs (r_s = + 0.40) and the skin AGEs-to-sRAGE ratio (r_s = + 0.40), but not with urinary AGE or serum sRAGE concentrations; and not with any of the CGM-parameters. Multiple linear regression for cf-PWV showed that the model with the best fit included age, T1D duration, 24-h mean arterial pressure and mean 10-years HbA1c (adjusted R² = 0.645, p < 0.001).

CONCLUSIONS

Longer-term glycemic exposure as reflected by current and mean 10-years HbA1c is a key predictor of arterial stiffness in patients with T1D, while no relationship was found with any of the short-term CGM parameters. Our findings stress the importance of early and sustained good glycemic control to prevent premature CVD in patients with T1D and suggest that HbA1c should continue to be used in the risk assessment for diabetic complications. The role of skin glycation, as a biomarker for vascular aging, in the risk assessment for CVD is an interesting avenue for further research.

Central hypothyroidism: are patients undertreated?

Introduction

Thyroid hormone replacement in central hypothyroidism (CHT) is more difficult than in primary hypothyroidism (PHT), putting patients at risk for inappropriate substitution. In this study, we compared the dosage of thyroid hormone replacement in patients with CHT with that of patients with PHT. In addition, we explored and compared quality of life (QoL) between both groups, based on two questionnaires, the SF-36 health score and the thyroid-specific ThyPRO score.

Methods

This is a monocentric, cross-sectional study, performed at the Ghent University Hospital (Belgium). We included 82 patients in total, 41 patients with CHT and 41 patients with PHT. At the time of inclusion, all patients had to have a stable dose of levothyroxine over the past 6 months and patients with PHT needed to be euthyroid (defined as having a thyroid-stimulating hormone level within the reference range, 0.2-4.5 mU/L). All data were retrieved from medical files, and questionnaires on QoL were self-administered.

Results

The CHT and PHT groups were comparable regarding age and BMI. There was no significant difference between both groups regarding total daily dose of levothyroxine (100 (93.75-125.00) vs 107.14 (75.00-133.93) μg in CHT and PHT, respectively; P = 0.87) or daily dose of levothyroxine per kg body weight (1.34 (1.16-1.55) vs 1.55 (1.16-1.82) μg/kg, respectively; P = 0.13). Serum levels of fT4 (P = 0.20) and fT3 (P = 0.10) also did not differ between the two groups and both were in the normal (mid)range for the two groups. Regarding QoL, patients with CHT scored worse in terms of depressive and emotional symptoms, impaired daily and social life.

Conclusion

We could demonstrate a difference in QoL between patients with CHT and PHT. Although patients with CHT had a somewhat lower levothyroxine substitution dose than patients with PHT, this difference was also not significant and probably does not explain the difference in QoL.

Ipilimumab, not just another anti-cancer therapy: hypophysitis as side effect illustrated by four case-reports

Ipilimumab is a monoclonal antibody that blocks cytotoxic T-lymphocyte antigen4 (CTLA-4), an inhibitory molecule typically expressed on T cells. Blockade of CTLA-4 induces an overall activation of T cells, including an immune-mediated anti-tumour response. Unfortunately, this broad T cell stimulation also causes immune-related adverse events (irAEs), such as dermatitis, colitis, hepatitis and hypophysitis. Ipilimumab is currently available in Belgium as a second line of treatment for patients with advanced melanoma, and is used at a dose of 3 mg/kg of body weight, although higher doses were previously used (up to 10 mg/kg). We performed a retrospective analysis to identify melanoma patients treated with ipilimumab at the Ghent University Hospital between 2010 and 2013. Data on symptoms, stage and timing of ipilimumab, response and adverse events were collected with a special attention to endocrine disturbances, going from a limited involvement of one endocrine axis to development of a hypophysitis. We identified a total of 39 patients with stage III (No. = 7) or stage IV (No. = 32) melanoma, who received a dose of 3 (No. = 31) or 10 (No. = 8) mg/kg. Six patients developed a severe form of irAEs, including one case of colitis (2 %), one case of sarcoidosis (2 %) and 4 cases (10 %) of hypophysitis. Hypophysitis developed between the second and fourth cycle of ipilimumab administration and was independent of the dose used. We describe four cases of involvement of the pituitary gland during treatment with ipilimumab. When managed with vigilant monitoring and high-dose corticosteroids, the acute symptoms resolve, but lifelong hormone substitution therapy can be necessary. Involvement of the pituitary axes is a severe side effect of treatment with ipilimumab with an urgent need for the correct medical intervention.