Bariatric surgery in individuals with type 2 diabetes is not associated with short or long-term risk of diabetic retinopathy progression: results from a nationwide cohort study

AIMS

Bariatric surgery is used to induce weight loss and glycemic stability in type 2 diabetes (T2D). It has been a concern that this may lead to early worsening of diabetic retinopathy (DR) due to a rapid decline in HbA1c. In this study, we evaluated the risk of short and long-term DR development and need for ocular intervention in an entire nation of individuals with T2D undergoing bariatric surgery.

METHODS

The study comprised a national, register-based cohort of individuals with T2D screened for DR. Cases were matched by age, sex and DR level at the date of surgery (index date) with non-bariatric controls. We extracted information on DR levels, in- and outpatient treatments, pharmaceutical prescriptions and laboratory values. We evaluated worsening of DR (incident and progressive DR) at follow-up (6 and 36 months).

RESULTS

Amongst 238,967 individuals with T2D, who attended diabetic eye screening, we identified 553 that underwent bariatric surgery (0.2%) and 2677 non-bariatric controls. Median age was 49 years, and 63% were female. Cases had more comorbidities, lower HbA1c as well as more frequent use of glucose-lowering and antihypertensive medication than controls at index date. In a fully adjusted logistic regression model, the risk of DR worsening for cases was not significantly different compared to controls, neither short-term (OR 0.41 [CI 95% 0.13; 1.33], p = 0.14) nor long-term (OR 0.64 [CI 95% 0.33; 1.24], p = 0.18).

CONCLUSIONS

In this nationwide study, bariatric surgery did not associate with increased risk of short- or long-term DR worsening.

Longitudinal bidirectional associations between diabetic retinopathy and diagnosed depression: Results from a Danish nationwide registry-based cohort study

OBJECTIVE

Diabetic retinopathy (DR) is a feared complication and a leading course of visual impairment, but the connection between DR and depression including the direction has never been studied in a nationwide cohort. We aimed to assess, whether the associations between DR and diagnosed depression are bidirectional.

METHODS

We performed a national register-based cohort study of individuals with type 2 diabetes, who attended diabetic eye screening between January 2013 and June 2022. Level of DR was extracted from the Danish Registry of Diabetic Retinopathy. The severity of DR was assessed according to the International Clinical Diabetic Retinopathy severity scale. Diagnosed depression was ascertained by physician diagnostic codes of unipolar depression (F32), recurrent depression (F33) or dysthymia (F34.1) from the Danish National Patient Register. We estimated presence of diagnosed depression according to DR level at index date and risk of diagnosed depression during follow-up using multivariable logistic and Cox regression, respectively. Secondly, we assessed whether diagnosed depression at index date could predict incident DR.

RESULTS

We included 240,893 individuals with type 2 diabetes with baseline rates of diagnosed depression ranging from 5.2 to 6.0 % for DR level 1-4. At index date, individuals with type 2 diabetes and DR were less likely to have a history of diagnosed depression (multivariable adjusted OR, 0.77 [95 % CI 0.73-0.82]). In 226,523 individuals with type 2 diabetes followed for 1,159,755 person-years, 1.7 % developed at least one episode of diagnosed depression. In a model adjusted for age and sex, individuals with DR at index date had an increased risk of incident diagnosed depression compared to those without DR (HR 1.25 [95 % CI 1.16-1.36]). Adjusting for marital status, use of glucose-, lipid- and blood pressure lowering medication, HbA1c, diabetic neuropathy and Charlson comorbidity index waived the above risk (multivariable adjusted HR 1.02 [95 % CI 0.93-1.12]). Furthermore a previous history of diagnosed depression was not associated with increased risk of incident DR (multivariable adjusted HR 0.89 [95 % CI 0.77-1.03]).

CONCLUSION

In this nationwide cohort study, individuals with DR at first screening were 23 % less likely to have a history of depression, but our data did not support a bidirectional association between DR and depression. Selection bias may have occurred as diagnosed depression is a known barrier for attending DR-screening.

Inverse Cross-sectional and Longitudinal Relationships between Diabetic Retinopathy and Obstructive Sleep Apnea in Type 2 Diabetes

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Results

Conclusions

Estimation of Tumor Volumes by 11C-MeAIB and 18F-FDG PET in an Orthotopic Glioblastoma Rat Model

Brain tumor volume assessment is a major challenge. Molecular imaging using PET may be a promising option because it reflects the biologically active cells. We compared the agreement between PET- and histology-derived tumor volumes in an orthotopic glioblastoma rat model with a noninfiltrating (U87MG) and an infiltrating (T87) tumor phenotype using 2 different radiotracers, 2 different image reconstruction algorithms, parametric imaging, and 2 different image segmentation techniques.

METHODS

Rats with U87MG- and T87-derived glioblastomas were continuously scanned with PET for 1 h starting immediately after the injection of 11C-methylaminoisobutyric acid (11C-MeAIB). One hour later, 18F-FDG was injected, followed by a 3-h dynamic PET scan. Images were reconstructed using 2-dimensional ordered-subsets expectation maximization and 3-dimensional maximum a posteriori probability (MAP3D) algorithms. In addition, a parametric image, encompassing the entire tumor kinetics in a single image, was calculated on the basis of the 11C-MeAIB images. All reconstructed images were segmented by fixed thresholding of maximum voxel intensity (VImax) and mean background intensity. The agreement between PET- and histology-derived tumor volumes and intra- and interobserver agreement of the PET-derived volumes were evaluated using Bland-Altman plots.

RESULTS

By PET, the mean U87MG tumor volume was 35.0 mm3 using 18F-FDG and 34.1 mm3 with 11C-MeAIB, compared with 33.7 mm3 by histology. Corresponding T87 tumor volumes were 122.1 mm3 using 18F-FDG, 118.3 mm3 with 11C-MeAIB, and 125.4 mm3 by histology. None of these volumes were significantly different. The best agreement between PET- and histology-derived U87MG tumor volumes was achieved with 11C-MeAIB, MAP3D reconstruction, and fixed thresholding of VImax. The intra- and interobserver agreement was high using this method. For T87 tumors, the best agreement between PET- and histology-derived volumes was obtained using 18F-FDG, MAP3D reconstruction, and fixed thresholding of mean background intensity. The agreement using 11C-MeAIB, parametric imaging, and fixed thresholding of VImax was slightly inferior, but the intra- and interobserver agreement was clearly superior.

CONCLUSION

Estimation of tumor volume by PET of noninfiltrating brain tumors was accurate and reproducible. In contrast, tumor volume estimation by PET of infiltrating brain tumors was difficult and hard to reproduce. On the basis of our results, PET evaluation of highly infiltrating brain tumors should be further developed.