HLA class II alleles specify phenotypes of ketosis-prone diabetes.

OBJECTIVE: Ketosis-prone diabetes (KPD) comprises four subgroups based on the presence or absence of beta-cell autoantibodies (A+ or A-) and beta-cell functional reserve (beta+ or beta-). Genetic factors could contribute to their distinctive phenotypes. Our aim was to specify the role of HLA class II alleles associated with susceptibility or resistance to autoimmune type 1 diabetes in determining KPD phenotypes. RESEARCH DESIGN AND METHODS: A total of 185 adults presenting with diabetic ketoacidosis were followed longitudinally for a mean of 5.5 years, with measurements of autoantibodies, beta-cell functional reserve, insulin sensitivity, and insulin requirement. Frequencies of susceptibility and resistance alleles at HLA DQA1, DQB1, and DRB1 loci were correlated with clinical and phenotypic features of KPD subgroups and compared with those of ethnic-specific population control subjects. RESULTS: Susceptibility alleles were more frequent (P < 0.0001) in the two A+ than the two A- KPD subgroups; in the latter, the frequency was no greater than in population control subjects (except for DQB1*0302). Susceptibility alleles differentiated the two clinically similar beta- subgroups (more frequent in A+beta- than A-beta- KPD; P < 0.01). Resistance alleles were more frequent in the two beta+ than the two beta- KPD subgroups (P < 0.01). The frequencies of certain susceptibility (e.g., DQB1*02) and resistance (DQB1*0602) alleles were higher in African-American A-beta+ KPD patients than in African-American control subjects. DQB1*0302 was more frequent in all KPD subgroups compared with control subjects. CONCLUSIONS: HLA class II alleles associated with susceptibility or resistance to autoimmune type 1 diabetes help specify the four subgroups of KPD. Inheritance of these alleles may influence long-term beta-cell functional reserve.

Accuracy and predictive value of classification schemes for ketosis-prone diabetes.

OBJECTIVE: Ketosis-prone diabetes (KPD) is an emerging, heterogeneous syndrome. A sound classification scheme for KPD is essential to guide clinical practice and pathophysiologic studies. Four schemes have been used and are based on immunologic criteria, immunologic criteria and insulin requirement, BMI, and immunologic criteria and beta-cell function (Abeta classification). The aim of the present study is to compare the four schemes for accuracy and predictive value in determining whether KPD patients have absent or preserved beta-cell function, which is a strong determinant of long-term insulin dependence and clinical phenotype. RESEARCH DESIGN AND METHODS: Consecutive patients (n = 294) presenting with diabetic ketoacidosis and followed for 12-60 months were classified according to all four schemes. They were evaluated longitudinally for beta-cell autoimmunity, clinical and biochemical features, beta-cell function, and insulin dependence. beta-Cell function was defined by peak plasma C-peptide response to glucagon >or=1.5 ng/ml. The accuracy of each scheme to predict absent or preserved beta-cell function after 12 months of follow-up was tested using multiple statistical analyses. RESULTS: The "Abeta" classification scheme was the most accurate overall, with a sensitivity and specificity of 99.4 and 95.9%, respectively, positive and negative likelihood ratios of 24.55 and 0.01, respectively, and an area under the receiver operator characteristic curve of 0.972. CONCLUSIONS: The Abeta scheme has the highest accuracy and predictive value in classifying KPD patients with regard to clinical outcomes and pathophysiologic subtypes.

Characteristics of ketosis-prone diabetes in a multiethnic indigent community.

OBJECTIVE: To compare demographic and clinical characteristics among 3 ethnic groups of indigent patients exhibiting diabetic ketoacidosis (DKA), in Houston, Texas. METHODS: Over a span of 3.5 years, 321 patients were interviewed at the time of admission for DKA. Demographic, clinical, and biochemical data and measures of pancreatic beta-cell function were obtained at baseline and during follow up. Pearson's chi-square test, or one-way ANOVA, were used, as appropriate, to evaluate group differences. RESULTS: Of the 321 subjects, 44% were African-American, 40% were Hispanic, and 16% were Caucasian. A significantly higher proportion of Hispanics had preserved beta-cell function, compared to African Americans and Caucasians (51% vs 32% and 32%, respectively; P = .002). This difference, present at the time of the admission, was maintained through follow up. In a multivariate analysis, Hispanic ethnicity (OR 3.61; 95% CI 1.48-9.29) was a significant predictor of preserved beta-cell function. In addition, Hispanics were less likely to develop DKA as a result of treatment non-compliance, and more likely to have DKA precipitated by an acute illness. CONCLUSIONS: Our findings indicated that ethnicity is associated with significant differences in the pathophysiologic and clinical characteristics of indigent, ketosis-prone patients. Hispanic ethnicity was found to be associated with greater beta-cell functional reserve, and less dependence on chronic insulin therapy.

Ketosis-prone diabetes: dissection of a heterogeneous syndrome using an immunogenetic and beta-cell functional classification, prospective analysis, and clinical outcomes.

Ketosis-prone diabetes is heterogeneous. Its causes could include novel beta-cell functional defects. To characterize such defects, 103 patients with diabetic ketoacidosis were evaluated for beta-cell autoimmunity and human leukocyte antigen (HLA) class II alleles, with longitudinal measurements of beta-cell function and biochemical and clinical parameters. They were classified into four A beta groups, based on the presence of glutamic acid decarboxylase (GAD)65, GAD67, or IA-2 autoantibodies (A+ or A-) and beta-cell functional reserve (beta+ or beta-). The group distribution was: 18 A+beta-, 23 A-beta-, 11 A+beta+, and 51 A-beta+. Collectively, the two beta- groups differed from the two beta+ groups in earlier onset and longer duration of diabetes, lower body mass index, less glycemic improvement, and persistent insulin requirement. HLA class II genotyping showed that the A-beta- group differed from the A+beta- group in having lower frequencies of two alleles strongly associated with autoimmune type 1 diabetes susceptibility: DQA*03 and DQB1*02. Similarly, the A-beta+ group differed from the A+beta+ group in having a lower frequency of DQB1*02. Ketosis-prone diabetes comprises at least four etiologically distinct syndromes separable by autoantibody status, HLA genotype, and beta-cell functional reserve. Novel, nonautoimmune causes of beta-cell dysfunction are likely to underlie the A-beta+ and A-beta- syndromes.

Improved outcomes in indigent patients with ketosis-prone diabetes: effect of a dedicated diabetes treatment unit.

OBJECTIVE: To investigate whether a specialized intervention program could improve diabetes-related health outcomes in indigent patients with type 1 diabetes who were prone to occurrence of diabetic ketoacidosis (DKA). METHODS: Patients with type 1 diabetes mellitus admitted because of DKA during a 24-month period were invited to receive outpatient care in a diabetes treatment unit (DTU). We compared DKA-related readmission rates, change in hemoglobin A1c (HbA1c) values, and diabetes-related medical costs in patients who participated in the DTU program (+DTU) and in those who did not (-DTU). RESULTS: During the study period, 115 patients underwent assessment. Of this overall group, 57 patients (49.6%) consented to participate in the DTU program, and 58 (50.4%) did not. After the follow-up period (median duration, 657 days), the following significant improvements were observed in the +DTU group (in comparison with the -DTU group): lower frequency of readmission for DKA (16% versus 43%; P = 0.001), lower number of readmissions for DKA per patient (0.22 +/- 0.6 versus 1.17 +/- 2.2 [mean +/- standard deviation]; P = 0.003), lower HbA1c level (10.4 +/- 2.3% versus 13.5 +/- 2.3%; P<0.0001), and lower cost of diabetes-related medical care (3,427.20 US dollars +/- 6,275.60 versus 10,119.10 US dollars +/- 19,688.10; P = 0.01). Multivariate analysis revealed that participation in the DTU program was the only factor associated with a significantly decreased risk of DKA-related readmission. CONCLUSION: Low-cost intervention by a dedicated outpatient DTU resulted in significant decreases in DKA-associated readmissions, in HbA1c values, and in costs of diabetes care in a multiethnic, indigent, ketosis-prone patient population.