Tyrosine phosphatase-like protein (IA-2) and glutamic acid decarboxylase (GAD65) autoantibodies: a study of Chinese patients with diabetes mellitus

Persistent Anxiety Is Associated with Higher Glycemia Post-Transition to Adult Services in Asian Young Adults with Diabetes

BACKGROUND

There is little longitudinal information on psychological burden and metabolic outcomes in young adults with diabetes (YAD) in Asia. We aimed to evaluate the association between psychological status and glycemia at baseline and 2 years following transition in a cohort of YAD in Singapore.

METHODS

Subjects with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), aged 17 to 25 years, were recruited from the YAD clinic in Singapore General Hospital. The Hospital Anxiety and Depression and Problem Areas for Diabetes scales were administered at transition (baseline) and at 18 to 24 months. Glycosylated hemoglobin (HbA1c) assessed during routine visits was tracked longitudinally.

RESULTS

A total of 98 T1DM (74.8%) and 33 T2DM (25.2%) subjects were recruited between January 2011 and November 2017. At baseline, mean HbA1c was 8.6%±1.7%. Only 26.0% achieved HbA1c of ≤7.5% and 16.8% achieved HbA1c of <7%. At baseline, prevalence of anxiety was 29.8%. At 24 months, 14.1% had persistent anxiety. Those with persistent anxiety had the highest mean HbA1c, particularly at 6 months (persistently anxious vs. persistently non-anxious: 9.9%±1.2% vs. 8.2%±1.9%, P=0.009). At baseline, 9.2% of subjects had depression. This group also had poorer glycemia at baseline (HbA1c of depressed vs non-depressed: 9.6%±2.1% vs. 8.5%±1.6%, P=0.04), which persisted up to 24 months.

CONCLUSION

The majority of YAD in Singapore have suboptimal glycemia. Psychological distress is a critical harbinger of poorer metabolic outcomes.

Incremental cost-effectiveness of algorithm-driven genetic testing versus no testing for Maturity Onset Diabetes of the Young (MODY) in Singapore

BACKGROUND

Offering genetic testing for Maturity Onset Diabetes of the Young (MODY) to all young patients with type 2 diabetes has been shown to be not cost-effective. This study tests whether a novel algorithm-driven genetic testing strategy for MODY is incrementally cost-effective relative to the setting of no testing.

METHODS

A decision tree was constructed to estimate the costs and effectiveness of the algorithm-driven MODY testing strategy and a strategy of no genetic testing over a 30-year time horizon from a payer's perspective. The algorithm uses glutamic acid decarboxylase (GAD) antibody testing (negative antibodies), age of onset of diabetes (<45 years) and body mass index (<25 kg/m² if diagnosed >30 years) to stratify the population of patients with diabetes into three subgroups, and testing for MODY only among the subgroup most likely to have the mutation. Singapore-specific costs and prevalence of MODY obtained from local studies and utility values sourced from the literature are used to populate the model.

RESULTS

The algorithm-driven MODY testing strategy has an incremental cost-effectiveness ratio of US$93 663 per quality-adjusted life year relative to the no testing strategy. If the price of genetic testing falls from US$1050 to US$530 (a 50% decrease), it will become cost-effective.

CONCLUSION

Our proposed algorithm-driven testing strategy for MODY is not yet cost-effective based on established benchmarks. However, as genetic testing prices continue to fall, this strategy is likely to become cost-effective in the near future.

Glycemic control in youth with type 2 diabetes declines as early as two years after diagnosis

OBJECTIVES

To determine the course of glycemic decline in a pediatric cohort with type 2 diabetes mellitus (T2DM) by defining longitudinal changes in hemoglobin A1c (HbA1c) and insulin requirement. We also followed markers of insulin reserve (fasting C-peptide and IGFBP-1) over time.

STUDY DESIGN

Participants included two groups: (1) T2DM Nonacidotic (NA) (n = 46); and (2) T2DM diabetic ketoacidosis (n = 13). HbA1c, insulin dose, and fasting C-peptide and IGFBP-1 were obtained at baseline and every 6 months for 4 years.

RESULTS

At baseline, Mann Whitney tests demonstrated that the diabetic ketoacidosis group had higher HbA1c (P = .002), required more insulin (P = .036), and had lower C-peptide (P = .003) than the NA group. Baseline insulin dose (Spearman r = -0.424, P = .009) and baseline IGFBP-1 (Spearman r = -0.349, P = .046) correlated negatively with C-peptide. Over time, HbA1c, insulin dose, and C-peptide changed significantly in a complex manner, with group differences. HbA1c reached a nadir at 6 to 12 months and began to rise after 1.5 years. Insulin requirements reached a nadir at 1 year and began to rise after 2 years.

CONCLUSIONS

Unlike adults, children with T2DM require increasing insulin doses over a 4-year period, and diabetic ketoacidosis at diagnosis predicts greater β-cell decline over time.

Beta-cell autoantibodies and their function in Taiwanese children with type 1 diabetes mellitus

BACKGROUND/PURPOSE

To understand the importance of autoimmunity in the development of type 1 diabetes in Taiwanese children, we evaluated the presence of beta-cell autoantibodies and their correlation with residual beta-cell function.

METHODS

From 1989 to 2006, 157 Taiwanese children with newly diagnosed type 1 diabetes were enrolled in this study. We determined the presence of beta-cell autoantibodies, such as glutamic acid decarboxylase autoantibodies (GADAs), insulinoma antigen 2 autoantibodies (IA-2As), and insulin autoantibodies (IAAs). A 6-minute glucagon test was also performed at diagnosis.

RESULTS

At diagnosis, 73% of children tested positive for GADAs, 76% for IA-2As and 21% for IAAs. Ninety-two percent of them had at least one of the beta-cell autoantibodies detected. Positivity for IAAs was more frequent in patients younger than 5 years than in those older than 5 years (45% vs. 13%). Using multiple regression analysis, the presence of GADAs or IAAs, or age of onset of these patients was an independent factor for residual beta-cell function. Younger patients and those with GADAs had less residual beta-cell function at disease onset, whereas those with IAAs had more insulin reserve.

CONCLUSION

Autoimmunity plays an important role in the pathogenesis of type 1 diabetes in Taiwanese children, and the presence of IAAs tends to be more common in younger children.

Fasting c-peptide and insulin-like growth factor-binding protein-1 levels help to distinguish childhood type 1 and type 2 diabetes at diagnosis

BACKGROUND

Children with new onset diabetes (n = 175) were evaluated over 12-months. Patients were presumptively diagnosed with type 2 diabetes mellitus (T2DM) (n = 26) based on obesity, a relative with T2DM, the ability to wean from insulin, and absence of glutamic acid decarboxylase-65 (GAD-65) antibodies. We hypothesized that markers of insulinization at diagnosis, including fasting C-peptide and insulin-like growth factor-binding protein (IGFBP)-1, in addition to initial CO(2) levels and urine ketones, would help in distinguishing type 1 diabetes mellitus (T1DM) from T2DM.

RESULTS

Children with T1DM (84 male, 65 female) had a mean age of 8.7 +/- 4.3 yr and a racial background of 78% white, 19% black, and 3% other. In contrast, children with T2DM (13 female, 13 male) had a mean age of 14.2 +/- 3.1 yr with a racial background of 58% black, 27% white, and 15% other. Fasting C-peptide level was 0.38 +/- 0.37 ng/mL in T1DM vs. 2.66 +/- 2.14 ng/mL in T2DM; a C-peptide of 0.85 ng/mL had 83% sensitivity in distinguishing T1DM from T2DM. Fasting IGFBP-1 level was 38.1 +/- 39.1 ng/mL (T1DM) vs. 3.6 +/- 4.5 ng/mL (T2DM); a value of 3.6 ng/dL could distinguish the two types of diabetes with 93% sensitivity. Urinary ketones were found in 79% of children with T1DM compared with 56% of those with T2DM, and the magnitude was associated with type of diabetes. Initial CO(2) level for T1DM was 17.9 +/- 6.9 mmol/L vs. 22.7 +/- 5.7 mmol/L for T2DM; a value of 21.5 mmol/L could distinguish the two types of diabetes with 83% sensitivity.

CONCLUSIONS

In addition to obesity, family history of T2DM, and absence of GAD-65 antibodies, children with new-onset T2DM may be distinguished from those with T1DM by a combination of biochemical parameters (C-peptide, IGFBP-1, CO(2), and urine ketones).

Islet autoimmunity and genetic mutations in Chinese subjects initially thought to have Type 1B diabetes

AIMS

To explore the contribution of islet autoimmunity and genetic mutations in Chinese patients initially thought to have Type 1B diabetes.

METHODS

A group of 33 Chinese patients with newly diagnosed Type 1B diabetes, were identified by the absence of autoantibodies to glutamic acid decarboxylase (GAD), IA-2, insulin, thyroid globulin or thyroid peroxidase, or high-risk HLA-DQ haplotypes. The cohort was further characterized by measurement of autoantibodies to carboxypeptidase H (CPH) and SOX13 using radioligand assays, and testing for genetic mutations associated with MODY3/MODY6 and mitochondrial diabetes. Mutations of HNF-1alpha (MODY3) and neuroD1/beta2 (MODY6) genes were screened using the single-strand conformation polymorphism (SSCP) technique and sequencing. Mitochondrial DNA mutations were analysed with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Within the cohort, we found one patient with a novel mutation, R321H (CGC-->CAC) in exon 5 of the HNF-1alpha gene, one with ND1 mt3316 G-->A mutation in mitochondrial DNA, five with Ala45Thr polymorphisms in the neuroD1/beta2 gene, and two patients with autoantibodies to SOX13.

CONCLUSIONS

Some of the Chinese patients originally thought to have Type 1B diabetes do have other evidence of islet autoimmunity and genetic mutations involved in the underlying aetiology. This suggests that more rigorous screening for these conditions is needed before classifying subjects as having Type 1B diabetes.