Insulin sensitivity and pancreatic β-cell function in patients with primary aldosteronism

BACKGROUND

Primary aldosteronism (PA) is associated with an increased risk for dysglycemia. However, the effects of hyperaldosteronism on insulin sensitivity and β-cell function are unclear.

METHODS

Using a cross-sectional study design, we assessed insulin sensitivity and pancreatic β-cell function from an oral glucose tolerance test (OGTT) in patients from two cohorts: subjects with PA (n = 21) and essential hypertension control (EHC) subjects (n = 22). Age, sex, BMI, and mean arterial pressure adjusted measures of insulin sensitivity and β-cell function were compared between the groups.

RESULTS

PA individuals were less insulin sensitive compared to EHC subjects (Quantitative insulin sensitivity check index [QUICKI]: 0.340 ± 0.006 vs. 0.374 ± 0.013, p < 0.001; Matsuda index: 4.14 ± 0.49 vs. 7.87 ± 1.42, p < 0.001; S_I: 11.45 ± 4.85 vs. 21.23 ± 6.11 dL/kg/min per μU/mL, p = 0.02). The hepatic insulin resistance index (HIRI) was higher in PA subjects (PA: 5.61 ± 1.01 vs. EHC: 4.13 ± 0.61, p = 0.002). The insulinogenic index (IGI), an index of β-cell function was higher in the PA cohort (PA: 1.49 ± 0.27 vs. 1.11 ± 0.21 μU/mL/mg/dL, p = 0.03). However, the oral disposition index (DI) was similar between the groups (PA: 4.77 ± 0.73 vs. EHC: 5.46 ± 0.85, p = 0.42), which likely accounts for the similar glucose tolerance between the two cohorts, despite lower sensitivity.

CONCLUSIONS

In summary, insulin sensitivity is significantly lower in PA with an appropriately compensated β-cell function. These results suggest that excess aldosterone and/or other steroids in the context of PA may negatively affect insulin action without adversely impacting β-cell function.

OR31-6 Insulin Sensitivity and Pancreatic Beta-Cell Function in Patients with Primary Aldosteronism

Insulin sensitivity and pancreatic beta-cell function are primary determinants of glucose tolerance. Primary aldosteronism (PA) is associated with increased risk for glucose intolerance. However, its effects on insulin sensitivity and β-cell function have shown mixed results. In this study, we compared indices of insulin sensitivity and pancreatic β-cell function derived from an oral glucose tolerance test (OGTT) in patients from two cohorts: subjects with PA (n=25) and essential hypertension control (EHC) subjects. The EHC controls (n=25) were similar in age and BMI range, gender composition (female, n=14), and number of subjects with type 2 diabetes (n=3). Group comparisons were performed after adjusting for age, sex, and BMI; data is presented as unadjusted mean ± SD. As expected, the PA group show lower potassium concentrations compared to the EHC group, as well as elevated aldosterone and reduced renin levels. Mean arterial pressure was not significantly different between the groups (PA:100.6 ± 11.7, EHC: 96.7 ± 15.5 mm Hg, p=0.22). The area under the curve (AUC) for insulin during an OGTT, but not glucose, was higher in the PA group (insulin AUC: 14831 ± 9545 vs. 8582 ± 4948, μU/mL∙min, p<0.05). Whole-body and hepatic insulin sensitivity were determined using surrogate indices and oral minimal model (SI_MM) analysis. PA individuals were found to be less insulin sensitive compared to EHC subjects (Quantitative insulin sensitivity check index (QUICKI): 0.337 ± 0.035 vs. 0.367 ± 0.062, p<0.001; Matsuda Index: 3.98 ± 2.33 vs. 7.24 ± 6.50, p<0.001; and SI_MM: 1.01x10^-3 ± 2.01x10^-3 vs. 1.87x10^-3 ± 2.71x10^-3, min^-1 per μU/mL, p=0.08). The hepatic insulin resistance index (HIRI) was significantly higher in PA individuals (HIRI: 5.62 ± 4.52 vs. 4.02 ± 2.78, mg/dL∙ μU/mL ∙ 10⁶, p<0.001), suggesting decreased hepatic insulin sensitivity. Insulinogenic index (IGI), a measure of β -cell function is calculated as change in insulin concentrations divided by change in glucose from 0 to 30 min (ΔI_0-30/ΔG_0-30). IGI was slightly higher in the PA cohort (169 ± 150 vs. 124 ± 122, pmol/mmol, p=0.06). Oral disposition index (DI), a marker of integrated islet β-cell function, is the product of insulin secretion and sensitivity derived from OGTT. DI was similar between the groups (561 ± 434 vs. 605 ± 517, p=0.80). This accounts for the similar glucose tolerance between the groups. In summary, insulin sensitivity is significantly lower in PA and is accompanied by a compensatory increase in β-cell function. These results suggest that excess aldosterone and/or other steroids in the context of PA may negatively affect insulin action without adversely impacting beta-cell function.

The impact of personal problems on accessing prenatal care in low-income urban African American women

OBJECTIVE

The purpose of this study was to investigate the nature and contribution of personal factors related to the use of prenatal care in a sample of high-risk women residing in an urban environment where care was accessible and free.

STUDY DESIGN

The sample consisted of 297 African American women with low socioeconomic status and a high school education or less who were newly delivered of neonates. The level of prenatal care was classified according to the Kessner 3 Parameter Index (adequate, intermediate, inadequate). Women who received no prenatal care made up a fourth group. Subjects responded to the "Ten-Item Checklist" of Richwald. Rhodes, and Kersey and an in-person interview that queried their reasons for obtaining different levels of prenatal care.

RESULTS

Both personal and structural reasons were described by women for not obtaining care earlier in pregnancy or at all. The mean number of personal and structural problems reported per subject was inversely correlated to the level of prenatal care obtained. However, personal problems were the single most important reason cited by these women. Personal problems that were statistically significant different among the groups were drug use and desire for an abortion. The structural barriers that exhibited statistically significant differences among the groups were trouble scheduling an appointment, access totransportation, dislike of health care professionals and institutions, access to child care, and not knowing where to go.

CONCLUSION

Both personal and structural problems were cited as reasons for not obtaining adequate prenatal care. Structural barriers to prenatal care have been identified and extensively studied. These barriers to care continue to persist, despite innovations in program delivery and access. This study demonstrates that the significance of personal problems has not been adequately considered as a major factor associated with insufficient prenatal care.