Long-Term Effects of Continuous Subcutaneous Insulin Infusion on Glucose Control and Microvascular Complications in Patients With Type 1 Diabetes

Role of Systemic Factors in Improving the Prognosis of Diabetic Retinal Disease and Predicting Response to Diabetic Retinopathy Treatment

Topic

To review clinical evidence on systemic factors that might be relevant to update diabetic retinal disease (DRD) staging systems, including prediction of DRD onset, progression, and response to treatment.

Clinical relevance

Systemic factors may improve new staging systems for DRD to better assess risk of disease worsening and predict response to therapy.

Methods

The Systemic Health Working Group of the Mary Tyler Moore Vision Initiative reviewed systemic factors individually and in multivariate models for prediction of DRD onset or progression (i.e., prognosis) or response to treatments (prediction).

Results

There was consistent evidence for associations of longer diabetes duration, higher glycosylated hemoglobin (HbA1c), and male sex with DRD onset and progression. There is strong trial evidence for the effect of reducing HbA1c and reducing DRD progression. There is strong evidence that higher blood pressure (BP) is a risk factor for DRD incidence and for progression. Pregnancy has been consistently reported to be associated with worsening of DRD but recent studies reflecting modern care standards are lacking. In studies examining multivariate prognostic models of DRD onset, HbA1c and diabetes duration were consistently retained as significant predictors of DRD onset. There was evidence of associations of BP and sex with DRD onset. In multivariate prognostic models examining DRD progression, retinal measures were consistently found to be a significant predictor of DRD with little evidence of any useful marginal increment in prognostic information with the inclusion of systemic risk factor data apart from retinal image data in multivariate models. For predicting the impact of treatment, although there are small studies that quantify prognostic information based on imaging data alone or systemic factors alone, there are currently no large studies that quantify marginal prognostic information within a multivariate model, including both imaging and systemic factors.

Conclusion

With standard imaging techniques and ways of processing images rapidly evolving, an international network of centers is needed to routinely capture systemic health factors simultaneously to retinal images so that gains in prediction increment may be precisely quantified to determine the usefulness of various health factors in the prognosis of DRD and prediction of response to treatment.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Use of Diabetes Technologies and Retinopathy in Adults With Type 1 Diabetes

Importance

Diabetic retinopathy (DR) is a complication of diabetes that can lead to vision loss. Outcomes of continuous glucose monitoring (CGM) and insulin pump use in DR are not well understood.

Objective

To assess the use of CGM, insulin pump, or both, and DR and proliferative diabetic retinopathy (PDR) in adults with type 1 diabetes (T1D).

Design, Setting, and Participants

A retrospective cohort study of adults with T1D in a tertiary diabetes center and ophthalmology center was conducted from 2013 to 2021, with data analysis performed from June 2022 to April 2023.

Exposure

Use of diabetes technologies, including insulin pump, CGM, and both CGM and insulin pump.

Main Outcomes and Measures

The primary outcome was development of DR or PDR. A secondary outcome was the progression of DR for patients in the longitudinal cohort. Multivariable logistic regression models assessed for development of DR and PDR and association with CGM and insulin pump use.

Results

A total of 550 adults with T1D were included (median age, 40 [IQR, 28-54] years; 54.4% female; 24.5% Black or African American; and 68.4% White), with a median duration of diabetes of 20 (IQR, 10-30) years, and median hemoglobin A1c (HbA1c) of 7.8% (IQR, 7.0%-8.9%). Overall, 62.7% patients used CGM, 58.2% used an insulin pump, and 47.5% used both; 44% (244 of 550) of the participants had DR at any point during the study. On univariate analysis, CGM use was associated with lower odds of DR and PDR, and CGM with pump was associated with lower odds of PDR (all P < .05), compared with no CGM use. Multivariable logistic regression adjusting for age, sex, race and ethnicity, diabetes duration, microvascular and macrovascular complications, insurance type, and mean HbA1c, showed that CGM was associated with lower odds of DR (odds ratio [OR], 0.52; 95% CI, 0.32-0.84; P = .008) and PDR (OR, 0.42; 95% CI, 0.23-0.75; P = .004), compared with no CGM use. In the longitudinal analysis of participants without baseline PDR, 79 of 363 patients (21.8%) had progression of DR during the study.

Conclusions and Relevance

In this cohort study of adults with T1D, CGM use was associated with lower odds of developing DR and PDR, even after adjusting for HbA1c. These findings suggest that CGM may be useful for diabetes management to mitigate risk for DR and PDR.

Continuous Glucose Monitor, Insulin Pump, and Automated Insulin Delivery Therapies for Type 1 Diabetes: An Update on Potential for Cardiovascular Benefits

PURPOSE OF REVIEW

The incidence of type 1 diabetes (T1D) is rising in all age groups. T1D is associated with chronic microvascular and macrovascular complications but improving glycemic trends can delay the onset and slow the progression of these complications. Utilization of technological devices for diabetes management, such as continuous glucose monitors (CGM) and insulin pumps, is increasing, and these devices are associated with improvements in glycemic trends. Thus, device use may be associated with long-term prevention of T1D complications, yet few studies have investigated the direct impacts of devices on chronic complications in T1D. This review will describe common diabetes devices and combination systems, as well as review relationships between device use and cardiovascular outcomes in T1D.

RECENT FINDINGS

Findings from existing cohort and national registry studies suggest that pump use may aid in improving cardiovascular risk factors such as hypertension and dyslipidemia. Furthermore, pump users have been shown to have lower arterial stiffness and better measures of myocardial function. In registry and case-control longitudinal data, pump use has been associated with fewer cardiovascular events and reduction of cardiovascular disease (CVD) and all-cause mortality. CVD is the leading cause of morbidity and mortality in T1D. Consistent use of diabetes devices may protect against the development and progression of macrovascular complications such as CVD through improvement in glycemic trends. Existing literature is limited, but findings suggest that pump use may reduce acute cardiovascular risk factors as well as chronic cardiovascular complications and overall mortality in T1D.

Long-term complications of type 1 diabetes: what do we know and what do we need to understand?

Long-term complications of type 1 diabetes (T1D) include microvascular complications and macrovascular disease. Despite the important advances in the treatment of T1D of the last decades, these complications still represent the leading cause of morbidity and mortality in patients with T1D. Extensive evidence indicates that structural and functional alterations of the kidney, retina, nerves and large arteries occur already in the first years after the onset of diabetes. We performed a comprehensive review of the available evidence on screening, diagnosis, prevention and treatment of vascular complications of T1D. In particular, we focused on three major challenges related to long-term complications of T1D: 1) finding of new biomarkers and diagnostic methods able to identify early signs of complications; 2) identifying specific risk factors for the development of these complications; 3) identifying and implementing new therapeutic strategies able to prevent the development and progression of vascular complications.

Continuous subcutaneous insulin infusion therapy is associated with reduced retinopathy progression compared with multiple daily injections of insulin

AIMS/HYPOTHESIS

We aimed to compare diabetic retinopathy outcomes in people with type 1 diabetes following introduction of continuous subcutaneous insulin infusion (CSII) therapy with outcomes in people receiving continuing therapy with multiple daily insulin injections (MDI).

METHODS

This is a retrospective cohort study using the Scottish Care Information - Diabetes database for retinal screening outcomes and HbA_1c changes in 204 adults commenced on CSII therapy between 2013 and 2016, and 211 adults eligible for CSII during the same period but who continued on MDI therapy. Diabetic retinopathy progression (time to minimum one-grade worsening in diabetic retinopathy from baseline grading) was plotted for CSII and MDI cohorts using Kaplan-Meier curves, and outcomes were compared using multivariate Cox regression analysis adjusting for age, sex, baseline HbA_1c, blood pressure, cholesterol, smoking status and socioeconomic quintile. Impact of baseline HbA_1c and change in HbA_1c on diabetic retinopathy progression was assessed within CSII and MDI cohorts.

RESULTS

CSII participants were significantly younger, were from less socially deprived areas, and had lower HbA_1c and higher diastolic BP at baseline. There was a larger reduction in HbA_1c at 1 year in those on CSII vs MDI (-6 mmol/mol [-0.6%] vs -2 mmol/mol [-0.2%], p < 0.01). Diabetic retinopathy progression occurred in a smaller proportion of adults following commencement of CSII vs continued MDI therapy over mean 2.3 year follow-up (26.5% vs 18.6%, p = 0.0097). High baseline HbA_1c (75 mmol/mol [9%]) was associated with diabetic retinopathy progression in the MDI group (p = 0.0049) but not the CSII group (p = 0.93). Change in HbA_1c at follow-up, irrespective of baseline glycaemic status, did not significantly affect diabetic retinopathy progression in either group.

CONCLUSIONS/INTERPRETATION

CSII was associated with reduced diabetic retinopathy progression compared with continued MDI therapy, and may be protective against diabetic retinopathy progression for those with high baseline HbA_1c. Progression of diabetic retinopathy over 3 years was not associated with a change in HbA_1c.

Metabolic control and hypoglycaemia in people with type 1 diabetes: insulin pump therapy vs. intensified insulin therapy in an unselected cohort in routine care

AIMS

The aim of this study was to compare individuals with type 1 diabetes with continuous subcutaneous insulin infusion (CSII) and intensified insulin therapy (ICT) in routine care regarding metabolic control and treatment satisfaction.

METHODS

Individuals with type 1 diabetes (CSII n = 74; ICT n = 163) were analysed regarding metabolic control, frequency of hypoglycaemia and treatment satisfaction (DTSQs range 0-36).

RESULTS

Individuals with CSII (duration of CSII: 14.1 ± 7.2 years) were younger (51.1 ± 15.8 vs. 56.2 ± 16.2 years, p = 0.023), had longer diabetes duration (28.7 ± 12.4 vs. 24.6 ± 14.3 years, p = 0.033), lower insulin dosage (0.6 ± 0.2 vs. 0.7 ± 0.4 IU/kg, p = 0.004), used more frequently short-acting analogue insulin (90.5% vs. 48.5%, p < 0.001) and flash/continuous glucose monitoring (50.0% vs. 31.9%, p = 0.009) than people with ICT. HbA1c was similar between CSII and ICT (7.1 ± 0.8%/54.4 ± 9.1 mmol/mol vs. 7.2 ± 1.0%/55.7 ± 10.9 mmol/mol, p = 0.353). Individuals with CSII had higher frequency of non-severe hypoglycaemia per week (in people with blood glucose monitoring: 1.9 ± 1.7 vs. 1.2 ± 1.6, p = 0.014; in people with flash/continuous glucose monitoring: 3.3 ± 2.2 vs. 2.1 ± 2.0, p = 0.006). Prevalence of polyneuropathy (18.9% vs. 38.0%, p = 0.004) and systolic blood pressure (138.0 ± 16.4 vs. 143.9 ± 17.1 mmHg, p = 0.014) was lower in CSII. Satisfaction with diabetes treatment (26.7 ± 7.3 vs. 26.0 ± 6.8, p = 0.600) did not differ between CSII and ICT.

CONCLUSIONS

CSII and ICT yielded comparable metabolic control and treatment satisfaction but CSII was associated with higher incidence of non-severe hypoglycaemia and lower insulin dosage.

Low uptake of continuous subcutaneous insulin infusion therapy in people with type 1 diabetes in Ireland: a retrospective cross-sectional study

BACKGROUND

The uptake of continuous subcutaneous insulin infusion (CSII) therapy in those with type 1 diabetes varies internationally and is mainly determined by the national healthcare reimbursement systems. The aim of this study is to estimate national and regional uptake of CSII therapy in children, adolescents and adults with type 1 diabetes in Ireland.

METHODS

A retrospective cross-sectional study was conducted utilizing the national pharmacy claims database in 2016. Individuals using CSII were identified by dispensing of infusion sets. The uptake of CSII was calculated as the percentage of people with type 1 diabetes claiming CSII sets in 2016, both in children and adolescent (age < 18 years) and adult populations (≥ 18 years). Descriptive statistics including percentages with 95% confidence intervals (CIs) are presented, stratified by age-groups and geographical regions, and chi-square tests used for comparisons.

RESULTS

Of 20,081 people with type 1 diabetes, 2111 (10.5, 95% CI: 10.1-10.9%) were using CSII in 2016. Uptake was five-fold higher in children and adolescents at 34.7% (95% CI: 32.9-36.5%) than in adults at 6.8% (95% CI: 6.4-7.2%). Significant geographical heterogeneity in CSII uptake was found, from 12.6 to 53.7% in children and adolescents (p < 0.001), and 2 to 9.6% in adults (p < 0.001).

CONCLUSIONS

Uptake of CSII in people with type 1 diabetes is low in Ireland, particularly in those ≥18 years. Identification of barriers to uptake, particularly in this group, is required.

Effect of Streptozotocin-Inducted Diabetes on the Pathophysiology of Enteric Neurons in the Small Intestine Based on the Porcine Diabetes Model

Hyperglycemia is one of the main causes of diabetes complications. Gastrointestinal (GI) disturbances are one of the most frequent complications during diabetes. The porcine digestive tract possesses physiological and pathological similarities to the human digestive tract. This also applies to the innervation of the gastrointestinal tract. In this study, the influence of experimentally-inducted hyperglycemia was examined on the expression of vesicular acetylcholine transporter (VAChT), cocaine- and amphetamine-regulated transcript (CART), galanin (GAL), vasoactive intestinal polypeptide (VIP), and calcitonin gene-related peptide (CGRP) in the enteric nervous system (ENS) neurons in the small intestine of the pig. During the current study, an increased number of neurons containing CART, VIP, GAL, and CGRP under streptozotocin injection were observed. The augmentation of expression included all enteric plexuses present in the small intestine. The same results were obtained in the case of VAChT; namely, chronic hyperglycemia led to an increase in the number of neurons utilizing VAChT in all investigated plexuses. The obtained results suggested that the function of neuropeptides studied in this experiment depended on their localization in the ENS structures, as well as part of the GI tract. Diabetes led to alterations in the neurochemical phenotype of small intestine enteric neurons.

Glyco-metabolic control, inflammation markers, and cardiovascular outcomes in type 1 and type 2 diabetic patients on insulin pump or multiple daily injection (italico study)

BACKGROUND

To evaluate if the positive effects recorded on glycaemic control with continuous subcutaneous insulin infusion (CSII) were maintained on the long-term compared with multiple daily injection (MDI). The secondary objective was to evaluate if there is a reduction of type and number of cardiovascular events (CV).

METHODS

This retrospective, observational study evaluated glycaemic control and the number of CV in 104 patients with type 1 or 2 diabetes previously treated with MDI and initiating CSII therapy with tubed insulin pumps compared with 109 patients previously treated with MDI continuing MDI.

RESULTS

After 8 years, the glycaemic control including glycated haemoglobin (HbA_1c ), fasting plasma glucose (FPG), and prandial plasma glucose (PPG) improved with both CSII and MDI compared with baseline; however, HbA_1c , FPG, and PPG recorded with CSII were lower than data recorded with MDI. During the 8 years, there were fewer CV events with CSII, compared with MDI, and in particular, there were fewer cases of atrial fibrillation, premature ventricular contractions, acute coronary infarction, angina pectoris, heart failure, and peripheral vascular ischemia. We did not record any reduction of ischemic stroke events.

CONCLUSION

Our preliminary data suggest that CSII treatment seems to reduce the rates of CV compared with MDI therapy. Moreover, CSII also improved glycaemic control, without increasing the number of hypoglycaemia. However, given the observational design of this trial, our data should be validated in a randomized clinical trial; if they will be confirmed, CSII could be chosen for fully informed and motivated patients at higher risk of developing CV.

Real-Life Management and Effectiveness of Insulin Pump with or Without Continuous Glucose Monitoring in Adults with Type 1 Diabetes

INTRODUCTION

To describe and compare the routine use of continuous subcutaneous insulin infusion (CSII) in type 1 diabetes (T1D) patients with and without continuous glucose monitoring (CGM) in routine clinical practice and its relationship with glycemic outcomes.

METHODS

Retrospective observational case-control study collecting routine use of CSII and CGM in T1D patients between January 2016 and December 2016. Patients with T1D using sensor augmented pump (SAP) were matched by sex and disease duration in a 1:3 ratio with those treated only with CSII. Patients used a Paradigm Veo or 640G Medtronic-Minimed^® insulin pump with or without a glucose sensor (Enlite, Medtronic-Minimed^®) for at least 12 months.

RESULTS

A total of 160 subjects with T1D were included, 40 using SAP and 120 on CSII (age 47 ± 12 years, 88 women, diabetes duration 29 ± 9.0 years, 10 ± 4.7 years on CSII, HbA_1C 7.6 ± 0.8%). Those in SAP therapy used the sensor 63% of time, performed less self-monitored blood glucose (SMBG)/day (3.3 ± 1.9 vs. 4.5 ± 2.0; p < 0.01), more bolus/day (6.2 ± 3.6 vs. 4.8 ± 1.6; p < 0.05), more basal insulin segment/day (6.5 ± 2.1 vs. 5.9 ± 1.5; p < 0.05), and more suspension time of the pump (97 ± 93 vs. 9.6 ± 20 min/day; p < 0.0001). Regarding metabolic control, SAP therapy patients had lower HbA_1c (7.4 ± 0.7 vs. 7.7 ± 0.9%; p = 0.068), lower average SMBG value (151 ± 32 vs. 163 ± 30 mg/dL; p < 0.05), a lower percentage of SMBG values greater than 180 mg/dL (30 ± 19 vs. 37 ± 16%; p < 0.05) with no differences in SMBG values less than 70 mg/dL (12 ± 8.0 vs. 9.8 ± 9.8%; p = 0.33) compared with patients on CSII. There were no differences in bolus wizard targets or in insulin/carbohydrate ratios per day.

CONCLUSION

In a real-world setting, SAP therapy is associated with more self-adjustments of insulin therapy when compared to CSII alone. This could result in an improvement in glucose control.

Persistent heterogeneity in diabetes technology reimbursement for children with type 1 diabetes: The SWEET perspective

BACKGROUND

Frequent use of modern diabetes technologies increases the chance for optimal type 1 diabetes (T1D) control. Limited reimbursement influences the access of patients with T1D to these modalities and could worsen their prognosis. We aimed to describe the situation of reimbursement for insulins, glucometers, insulin pumps (CSII) and continuous glucose monitoring (CGM) for children with T1D in European countries participating in the SWEET Project and to compare data from EU countries with data from our previous study in 2009.

METHODS

The study was conducted between March 2017 and August 2017. First, we approached diabetes technology companies with a survey to map the reimbursement of insulins and diabetic devices. The data collected from these companies were then validated by members of the SWEET consortium.

RESULTS

We collected data from 29 European countries, whereas all types of insulins are mostly fully covered, heterogeneity was observed regarding the reimbursement of strips for glucometers (from 90 strips/month to no limit). CSII is readily available in 20 of 29 countries. Seven countries reported significant quota issues or obstacles for CSII prescription, and two countries had no CSII reimbursement. CGM is at least partially reimbursed in 17 of 29 countries. The comparison with the 2009 study showed an increasing availability of CSII and CGM across the EU.

CONCLUSIONS

Although innovative diabetes technology is available, a large proportion of children with T1D still do not benefit from it due to its limited reimbursement.