Beyond the Glycaemic Control of Dapagliflozin: Microangiopathy and Non-classical Complications

Risk of Diabetic Retinopathy in Patients With Type 2 Diabetes After SGLT-2 Inhibitors: A Nationwide Population Cohort Study

Diabetic retinopathy (DR) accounts for 80% of cases of vision loss in patients with type 2 diabetes mellitus (T2DM). Interventional treatments are only indicated in advanced DR and are ineffective in some patients. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) are used to attenuate T2DM-associated cardiovascular complications. We conducted the cohort study to investigate the effect of SGLT2is on DR development. Data (May 2016-December 2018) obtained from the Taiwan National Health Insurance Research Database were analyzed in this nationwide retrospective cohort study. After propensity score matching, a total of 31,764 patients receiving SGLT2is and another 31,764 patients receiving dipeptidyl peptidase 4 inhibitors (DPP4is) were included in this study. Multiple Cox proportional-hazards regression models were used to evaluate DR risk. Overall DR incidence among SGLT2i or DPP4i users was 10.9 or 15.6 per 10,000 patient-years, respectively. After covariate adjustment, DR (both early and late stage) risk was substantially lower in SGLT2i users (adjusted hazard ratio: 0.68, 95% confidence interval: 0.6-0.78) than in DPP4i users. DR risk appears to be considerably lower in SGLT2i users than in DPP4i users. Glycemic control measurement with HbA1C level was unavailable in this claim database.

Prevalence of self-reported visual impairment among people in Canada with and without diabetes: findings from population-based surveys from 1994 to 2014

BACKGROUND

Diabetes, a leading cause of visual impairment, is on the rise in Canada. We assessed trends in the prevalence of visual impairment among people in Canada with and without diabetes to inform the development of strategies and policies for the management of visual impairment.

METHODS

We analyzed self-reported data from respondents aged 45 years and older in 7 cycles of nationwide surveys (National Population Health Survey and Canadian Community Health Survey) from 1994/95 to 2013/14. The age- and sex-standardized prevalence of visual impairment was calculated. We assessed comparisons by levels of education and income, using sex-standardized prevalence owing to sparse data.

RESULTS

Among people in Canada with diabetes, the age- and sex-standardized prevalence of visual impairment was 7.37% (95% confidence interval [CI] 5.31%-9.43%) in 1994/95 and 1996/97 combined, decreasing to 3.03% (95% CI 2.48%-3.57%) in 2013/14, giving a standardized prevalence ratio of 0.41 (95% CI 0.30-0.56) comparing 2013/14 with 1994/95 and 1996/97 combined. Among people in Canada without diabetes, visual impairment prevalence decreased from 3.72% (95% CI 3.31%-4.14%) in 1994/95 and 1996/97 combined to 1.69% (95% CI 1.52%-1.87%) in 2013/14, with a standardized prevalence ratio of 0.45 (95% CI 0.40-0.52). Decreased sex-standardized prevalence of visual impairment was observed among people with high and low education levels and incomes among those with and without diabetes.

INTERPRETATION

Visual impairment prevalence was roughly 2 times higher among those with versus without diabetes in all survey years; from 1994 to 2014, visual impairment prevalence decreased among those with and without diabetes irrespective of education and income levels. These results suggest effective collective efforts by clinicians, researchers, the public and government.

Dapagliflozin Treatment Augments Bioactive Phosphatidylethanolamine Concentrations in Kidney Cortex Membrane Fractions of Hypertensive Diabetic db/db Mice and Alters the Density of Lipid Rafts in Mouse Proximal Tubule Cells

In addition to inhibiting renal glucose reabsorption and allowing for glucose excretion, the sodium/glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin may be efficacious in treating various comorbidities associated with type 2 diabetes mellitus (T2DM). The molecular mechanisms by which dapagliflozin exerts its beneficial effects are largely unknown. We hypothesized dapagliflozin treatment in the diabetic kidney alters plasma membrane lipid composition, suppresses extracellular vesicle (EV) release from kidney cells, and disrupts lipid rafts in proximal tubule cells. In order to test this hypothesis, we treated diabetic db/db mice with dapagliflozin (N = 8) or vehicle (N = 8) and performed mass spectrometry-based lipidomics to investigate changes in the concentrations of membrane lipids in the kidney cortex. In addition, we isolated urinary EVs (uEVs) from urine samples collected during the active phase and the inactive phase of the mice and then probed for changes in membrane proteins enriched in the EVs. Multiple triacylglycerols (TAGs) were enriched in the kidney cortex membrane fractions of vehicle-treated diabetic db/db mice, while the levels of multiple phosphatidylethanolamines were significantly higher in similar mice treated with dapagliflozin. EV concentration and size were lesser in the urine samples collected during the inactive phase of dapagliflozin-treated diabetic mice. In cultured mouse proximal tubule cells treated with dapagliflozin, the lipid raft protein caveolin-1 shifted from less dense fractions to more dense sucrose density gradient fractions. Taken together, these results suggest dapagliflozin may regulate lipid-mediated signal transduction in the diabetic kidney.