Cohort profile: the Scottish Diabetes Research Network national diabetes cohort - a population-based cohort of people with diabetes in Scotland

Weight loss outcomes and associated factors after metabolic bariatric surgery: Analysis of routine clinical data in Scotland

BACKGROUND

Bariatric surgery is a cornerstone intervention for individuals with severe obesity, offering substantial and sustainable weight loss.

METHODS

This retrospective cohort study included 186 patients with obesity and Type2 diabetes who underwent sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) between 2009 and 2020 ​at University Hospital Ayr. Optimal clinical response weight loss was defined as excess weight loss (%EWL) ≥50 ​% or total weight loss (%TWL) ≥20 ​%.

RESULTS

At 2-years post-surgery, 43.6 ​% achieved ≥50 %EWL, and 44.1 ​% achieved ≥20%TWL, with 31.8 ​% maintaining this at 5-years. Depending on the definition used, between 11.2 ​% and 45.9 ​% of patients experienced recurrent weight gain. BMI had significant positive association with %TWL but negative with %EWL (p ​< ​0.05). RYGB had significantly higher %TWL compared to SG (p ​< ​0.05).

CONCLUSION

Most patients experienced weight loss which was maintained over time, however recurrent weight gain was noted. Pre-surgery BMI was significantly associated with weight changes.

Stopping Versus Continuing Metformin in Patients With Advanced CKD: A Nationwide Scottish Target Trial Emulation Study

RATIONALE & OBJECTIVE

Despite a lack of supporting evidence, current guidance recommends against the use of metformin in people with advanced kidney impairment. This observational study compared the outcomes of patients with type 2 diabetes who continued versus stopped metformin after developing stage 4 chronic kidney disease (CKD) (estimated glomerular filtration rate [eGFR]<30mL/min/1.73m2).

STUDY DESIGN

Nationwide observational cohort study.

SETTING & PARTICIPANTS

All adults with type 2 diabetes and incident stage 4 CKD in Scotland who were treated with metformin between January 2010 and April 2019.

EXPOSURE

Stopping versus continuing metformin within 6 months following incident stage 4 CKD.

OUTCOME

Primary outcome was all-cause mortality. Secondary outcomes included major adverse cardiovascular events (MACE).

ANALYTICAL APPROACH

Target trial emulation with clone-censor-weight design and marginal structural models fit for sensitivity analyses.

RESULTS

In a population of 371,742 Scottish residents with a diagnosis of type 2 diabetes before April 30, 2019, 4,278 were identified as prevalent metformin users with incident CKD stage 4. Within 6 months of developing CKD stage IV, 1,713 (40.1%) individuals discontinued metformin. Compared with continuing metformin, stopping metformin was associated with a lower 3-year survival (63.7% [95% CI, 60.9-66.6] vs 70.5% [95% CI, 68.0-73.0]; HR, 1.26 [95% CI, 1.10-1.44]), and the incidence of MACE was similar between both strategies (HR, 1.05 [95% CI, 0.88-1.26]). Marginal structural models confirmed the higher risk of all-cause mortality and similar risk of MACE in patients who stopped versus continued metformin (all-cause mortality: HR, 1.34 [95% CI, 1.08-1.67]; MACE: HR, 1.04 [95% CI, 0.81-1.33]).

LIMITATIONS

Residual confounding.

CONCLUSIONS

The continued use of metformin may be appropriate when eGFR falls below 30mL/min/1.73m2. Randomized controlled trials are needed to confirm these findings.

PLAIN-LANGUAGE SUMMARY

Current guidance recommends against the use of metformin in people with advanced kidney impairment despite a lack of evidence. It is therefore currently unclear how the decision to stop versus continue metformin in patients who reach stage 4 CKD impacts their risk of mortality and cardiovascular events. This study showed that stopping metformin after reaching stage 4 CKD was associated with reduced survival that did not appear to be mediated by an increase in adverse cardiovascular outcomes. These findings may support the continued use of metformin in patients with advanced kidney impairment, but further research is needed to confirm these observations.

Ethnic disparities in quality of diabetes care in Scotland: A national cohort study

AIMS

The aim of this study is to compare quality of diabetes care in people with type 2 diabetes by ethnicity, in Scotland.

METHODS

Using a linked national diabetes registry, we included 162,122 people newly diagnosed with type 2 diabetes between 2009 and 2018. We compared receipt of nine guideline indicated processes of care in the first-year post-diabetes diagnosis using logistic regression, comparing eight ethnicity groups to the White group. We compared annual receipt of HbA1c and eye screening during the entire follow-up using generalised linear mixed effects. All analyses adjusted for confounders.

RESULTS

Receipt of diabetes care was lower in other ethnic groups compared to White people in the first-year post-diagnosis. Differences were most pronounced for people in the: African, Caribbean or Black; Indian; and other ethnicity groups for almost all processes of care. For example, compared to White people, odds of HbA1c monitoring were: 44% lower in African, Caribbean or Black people (OR 0.56 [95% CI 0.48, 0.66]); 47% lower in Indian people (OR 0.53 [95% CI 0.47, 0.61]); and 50% lower in people in the other ethnicity group (OR 0.50 [95% CI 0.46, 0.58]). Odds of receipt of eye screening were 30%-40% lower in most ethnic groups compared to the White group. During median 5 year follow-up, differences in HbA1c monitoring and eye screening largely persisted, but attenuated slightly for the former.

CONCLUSIONS

There are marked ethnic disparities in routine diabetes care in Scotland in the short- and medium-term following diabetes diagnosis. Further investigation is needed to establish and effectively address the underlying reasons.

Impact of COVID-19 and Non-COVID-19 Hospitalized Pneumonia on Longer-Term Cardiovascular Mortality in People With Type 2 Diabetes: A Nationwide Prospective Cohort Study From Scotland

OBJECTIVE

In this study we examine whether hospitalized coronavirus disease 2019 (COVID-19) pneumonia increases long-term cardiovascular mortality more than other hospitalized pneumonias in people with type 2 diabetes and aim to quantify the relative cardiovascular disease (CVD) mortality risks associated with COVID-19 versus non-COVID-19 pneumonia.

RESEARCH DESIGN AND METHODS

With use of the SCI-Diabetes register, two cohorts were identified: individuals with type 2 diabetes in 2016 and at the 2020 pandemic onset. Hospital and death records were linked for determination of pneumonia exposure and CVD deaths. Poisson regression estimated rate ratios (RRs) for CVD death associated with both pneumonia types, with adjustment for confounders. Median follow-up durations were 1,461 days (2016 cohort) and 700 days (2020 cohort).

RESULTS

The adjusted RR for CVD death following non-COVID-19 pneumonia was 5.51 (95% CI 5.31-5.71) prepandemic and 7.3 (6.86-7.76) during the pandemic. For COVID-19 pneumonia, the RR was 9.13 (8.55-9.75). Beyond 30 days post pneumonia, the RRs converged, to 4.24 (3.90-4.60) for non-COVID-19 and 3.35 (3.00-3.74) for COVID-19 pneumonia, consistent even with exclusion of prior CVD cases.

CONCLUSIONS

Hospitalized pneumonia, irrespective of causal agent, marks an increased risk for CVD death immediately and over the long-term. COVID-19 pneumonia poses a higher CVD death risk than other pneumonias in the short-term, but this distinction diminishes over time. These insights underscore the need for including pneumonia in CVD risk assessments, with particular attention to the acute impact of COVID-19 pneumonia.

Cardiovascular risk management among individuals with type 2 diabetes and severe mental illness: a cohort study

AIMS/HYPOTHESIS

The aim of this study was to compare cardiovascular risk management among people with type 2 diabetes according to severe mental illness (SMI) status.

METHODS

We used linked electronic data to perform a retrospective cohort study of adults diagnosed with type 2 diabetes in Scotland between 2004 and 2020, ascertaining their history of SMI from hospital admission records. We compared total cholesterol, systolic BP and HbA1c target level achievement 1 year after diabetes diagnosis, and receipt of a statin prescription at diagnosis and 1 year thereafter, by SMI status using logistic regression, adjusting for sociodemographic factors and clinical history.

RESULTS

We included 291,644 individuals with type 2 diabetes, of whom 1.0% had schizophrenia, 0.5% had bipolar disorder and 3.3% had major depression. People with SMI were less likely to achieve cholesterol targets, although this difference did not reach statistical significance for all disorders. However, people with SMI were more likely to achieve systolic BP targets compared to those without SMI, with effect estimates being largest for schizophrenia (men: adjusted OR 1.72; 95% CI 1.49, 1.98; women: OR 1.64; 95% CI 1.38, 1.96). HbA1c target achievement differed by SMI disorder and sex. Among people without previous CVD, statin prescribing was similar or better in those with vs those without SMI at diabetes diagnosis and 1 year later. In people with prior CVD, SMI was associated with lower odds of statin prescribing at diabetes diagnosis (schizophrenia: OR 0.54; 95% CI 0.43, 0.68, bipolar disorder: OR 0.75; 95% CI 0.56, 1.01, major depression: OR 0.92; 95% CI 0.83, 1.01), with this difference generally persisting 1 year later.

CONCLUSIONS/INTERPRETATION

We found disparities in cholesterol target achievement and statin prescribing by SMI status. This reinforces the importance of clinical review of statin prescribing for secondary prevention of CVD, particularly among people with SMI.

Prediction of retinopathy progression using deep learning on retinal images within the Scottish screening programme

BACKGROUND/AIMS

National guidelines of many countries set screening intervals for diabetic retinopathy (DR) based on grading of the last screening retinal images. We explore the potential of deep learning (DL) on images to predict progression to referable DR beyond DR grading, and the potential impact on assigned screening intervals, within the Scottish screening programme.

METHODS

We consider 21 346 and 247 233 people with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), respectively, each contributing on average 4.8 and 4.4 screening intervals of which 1339 and 4675 intervals concluded with a referable screening episode. Information extracted from fundus images using DL was used to predict referable status at the end of interval and its predictive value in comparison to screening-assigned DR grade was assessed.

RESULTS

The DL predictor increased the area under the receiver operating characteristic curve in comparison to a predictor using current DR grades from 0.809 to 0.87 for T1DM and from 0.825 to 0.87 for T2DM. Expected sojourn time-the time from becoming referable to being rescreened-was found to be 3.4 (T1DM) and 2.7 (T2DM) weeks less for a DL-derived policy compared with the current recall policy.

CONCLUSIONS

We showed that, compared with using the current retinopathy grade, DL of fundus images significantly improves the prediction of incident referable retinopathy before the next screening episode. This can impact screening recall interval policy positively, for example, by reducing the expected time with referable disease for a fixed workload-which we show as an exemplar. Additionally, it could be used to optimise workload for a fixed sojourn time.

Ongoing burden and recent trends in severe hospitalised hypoglycaemia events in people with type 1 and type 2 diabetes in Scotland: A nationwide cohort study 2016-2022

AIMS

We examined severe hospitalised hypoglycaemia (SHH) rates in people with type 1 and type 2 diabetes in Scotland during 2016-2022, stratifying by sociodemographics.

METHODS

Using the Scottish National diabetes register (SCI-Diabetes), we identified people with type 1 and type 2 diabetes alive anytime during 2016-2022. SHH events were determined through linkage to hospital admission and death registry data. We calculated annual SHH rates overall and by age, sex, and socioeconomic status. Summary estimates of time and stratum effects were obtained by fitting adjusted generalised additive models using R package mgcv.

RESULTS

Rates for those under 20 with type 1 diabetes reached their minimum at the 2020-2021 transition, 30% below the study period average. A gradual decline over time also occurred among 20-49-year-olds with type 1 diabetes. Overall, females had 15% higher rates than males with type 2 diabetes (rate ratio 1.15, 95% CI 1.08-1.22). People in the most versus least deprived quintile experienced 2.58 times higher rates (95% CI 2.27-2.93) in type 1 diabetes and 2.33 times higher (95% CI 2.08-2.62) in type 2 diabetes.

CONCLUSIONS

Despite advances in care, SHH remains a significant problem in diabetes. Future efforts must address the large socioeconomic disparities in SHH risks.

Secretome Derived from Mesenchymal Stem/Stromal Cells: A Promising Strategy for Diabetes and its Complications

Diabetes is a complex metabolic disease with a high global prevalence. The health and quality of life of patients with diabetes are threatened by many complications, including diabetic foot ulcers, diabetic kidney diseases, diabetic retinopathy, and diabetic peripheral neuropathy. The application of mesenchymal stem/stromal cells (MSCs) in cell therapies has been recognized as a potential treatment for diabetes and its complications. MSCs were originally thought to exert biological effects exclusively by differentiating and replacing specific impaired cells. However, the paracrine function of factors secreted by MSCs may exert additional protective effects. MSCs secrete multiple compounds, including proteins, such as growth factors, chemokines, and other cytokines; nucleic acids, such as miRNAs; and lipids, extracellular vesicles (EVs), and exosomes (Exos). Collectively, these secreted compounds are called the MSC secretome, and usage of these chemicals in cell-free therapies may provide stronger effects with greater safety and convenience. Recent studies have demonstrated positive effects of the MSC secretome, including improved insulin sensitivity, reduced inflammation, decreased endoplasmic reticulum stress, enhanced M2 polarization of macrophages, and increased angiogenesis and autophagy; however, the mechanisms leading to these effects are not fully understood. This review summarizes the current research regarding the secretome derived from MSCs, including efforts to quantify effectiveness and uncover potential molecular mechanisms in the treatment of diabetes and related disorders. In addition, limitations and challenges are also discussed so as to facilitate applications of the MSC secretome as a cell-free therapy for diabetes and its complications.

Associations between glucagon prescribing, hospital admissions for hypoglycaemia and continuous glucose monitoring metrics in adults with type 1 diabetes

AIMS

To assess features associated with glucagon prescribing and hospital admissions with hypoglycaemia in type one diabetes.

METHODS

Observational study of 4462 adults. Outcome measures were features associated with glucagon prescriptions and predictors of hospital admissions with hypoglycaemia and high levels of glucagon prescribing.

RESULTS

74 % did not collect any glucagon prescriptions and 2.7 % collected >6 over 3.5 years. Hospital admission with hypoglycaemia (P = 0.032), impaired awareness (P = 0.049) and female sex (P < 0.001) were associated with glucagon collection. More frequent prescribing of glucagon was associated with diabetes duration (P < 0.001) and socioeconomic deprivation (P < 0.001). Higher average glucose (P = 0.047), higher time above 13.9 mM (P = 0.008) and higher SD (P = 0.002) were associated with glucagon prescribing. Diabetes duration (P < 0.001) and HbA1c (P < 0.001) were higher in people with hospitalised hypoglycaemia. Higher time above 13.9 mM (P = 0.004) and SD glucose (P < 0.001) were most clearly associated with hospitalised hypoglycaemia.

CONCLUSIONS

A minority of people with type 1 diabetes have access to glucagon suggesting more could be done to better target this treatment. Individuals with risk factors and those with frequent glucagon prescriptions should be identified for interventions known to reduce hypoglycaemia.

Type 1 diabetes incidence in Scotland between 2006 and 2019

AIMS

To describe type 1 diabetes incidence in Scotland between 2006 and 2019.

METHODS

Repeated annual cross-sectional studies of type 1 diabetes incidence were conducted. Incident cases were identified from the Scottish Care Information-Diabetes Collaboration (SCI-DC), a population-based register of people with diagnosed diabetes derived from primary and secondary care data. Mid-year population estimates for Scotland were used as the denominator to calculate annual incidence with stratification by age and sex. Joinpoint regression was used to investigate whether incidence changed during the study period. Age and sex-specific type 1 diabetes incidence over the whole time period was estimated by quintile of the Scottish Index of Multiple Deprivation (SIMD), an area-based measure, in which Q1 and Q5 denote the most and least deprived fifths of the population, respectively, with quasi-Poisson regression used to compare incidence for Q5 compared to Q1.

RESULTS

The median (IQR) age of the study population of 14,564 individuals with incident type 1 diabetes was 24.1 (12.3-42.4) years, 56% were men, 23% were in Q1 and 16% were in Q5. Incidence of T1DM was higher in men than women overall (at around 22 and 17 per 100,000, respectively) and in under 15 year olds (approximately 40 per 100,000 in both sexes) than other age groups and was similar across the study period in all strata. There was an inverse association between socio-economic status and type 1 diabetes incidence for 15-29, 30-49 and 50+ year olds [incidence rate ratio (IRR) for Q5 compared to Q1; IRR (95% CI) 0.52 (0.47-0.58), 0.68 (0.61-0.76) and 0.53(0.46-0.61), respectively] but not for under 15 year olds [1.02 (0.92-1.12)].

CONCLUSION

Incidence of type 1 diabetes varies by age, sex and socio-economic status and has remained approximately stable from 2006 to 2019 in Scotland.