GAD65Abs Are Not Associated With Beta-Cell Dysfunction in Patients With T2D in the GRADE Study

Context

Autoantibodies directed against the 65-kilodalton isoform of glutamic acid decarboxylase (GAD65Abs) are markers of autoimmune type 1 diabetes (T1D) but are also present in patients with Latent Autoimmune Diabetes of Adults and autoimmune neuromuscular diseases, and also in healthy individuals. Phenotypic differences between these conditions are reflected in epitope-specific GAD65Abs and anti-idiotypic antibodies (anti-Id) against GAD65Abs. We previously reported that 7.8% of T2D patients in the GRADE study have GAD65Abs but found that GAD65Ab positivity was not correlated with beta-cell function, glycated hemoglobin (HbA1c), or fasting glucose levels.

Context

In this study, we aimed to better characterize islet autoantibodies in this T2D cohort. This is an ancillary study to NCT01794143.

Methods

We stringently defined GAD65Ab positivity with a competition assay, analyzed GAD65Ab-specific epitopes, and measured GAD65Ab-specific anti-Id in serum.

Results

Competition assays confirmed that 5.9% of the patients were GAD65Ab positive, but beta-cell function was not associated with GAD65Ab positivity, GAD65Ab epitope specificity or GAD65Ab-specific anti-Id. GAD65-related autoantibody responses in GRADE T2D patients resemble profiles in healthy individuals (low GAD65Ab titers, presence of a single autoantibody, lack of a distinct epitope pattern, and presence of anti-Id to diabetes-associated GAD65Ab). In this T2D cohort, GAD65Ab positivity is likely unrelated to the pathogenesis of beta-cell dysfunction.

Conclusion

Evidence for islet autoimmunity in the pathophysiology of T2D beta-cell dysfunction is growing, but T1D-associated autoantibodies may not accurately reflect the nature of their autoimmune process.

Symptomatic Deep Vein Thrombosis Associated With Peripherally Inserted Central Catheters of Different Diameters: A Systematic Review and Meta-Analysis

We assessed the relationship between peripherally inserted central catheter (PICC) diameters and symptomatic deep vein thrombosis (DVT) rates. We conducted a systematic search for articles published between 2010 and 2021 reporting DVT incidence by catheter diameter in patients who had a PICC, followed by meta-analyses for DVT risk in each diameter group. Pooled DVT rates were incorporated into an economic model. Of 1627 abstracts screened, 47 studies were included. The primary meta-analysis of 40 studies demonstrated the incidence of DVT was 0.89%, 3.26%, 5.46%, and 10.66% for 3, 4, 5, and 6 French (Fr) PICCs (P  =  .01 between 4 and 5 Fr). Rates of DVT were not significantly different between oncology and nononcology patients (P  =  .065 for 4 Fr and P  =  .99 for 5 Fr). The DVT rate was 5.08% for ICU patients and 4.58% for non-ICU patients (P  =  .65). The economic model demonstrated an annual, incremental cost savings of US$114 053 for every 5% absolute reduction in 6 Fr PICCs use. Using the smallest PICC that meets the patients' clinical needs may help to mitigate risks and confer savings.