Acute effect of increasing glucocorticoid replacement dose on cardiovascular risk and insulin sensitivity in patients with adrenocorticotrophin deficiency

Conventional steroids vs. dual-release hydrocortisone on metabolic, cardiovascular, and bone outcomes in adrenal insufficiency: a 10-year study

OBJECTIVE

Adrenal insufficiency (AI) is characterized by increased mortality compared to general population, mainly due to cardiovascular disease. Conventional glucocorticoid (GC) replacement therapy has a role in determining the increased mortality risk. Primary outcome of the current study was to evaluate the impact of 10 years of conventional GCs and DR-HC on body weight changes in treatment-naive patients with AI. Secondary outcomes were changes from baseline to 5 and 10 years in anthropometric and metabolic profile, insulin sensitivity, cardiovascular, and bone parameters.

DESIGN AND METHODS

We prospectively randomized 42 patients to conventional GCs (cortisone acetate or hydrocortisone) and 44 to DR-HC (1:1). Anthropometric, metabolic, cardiovascular, and bone parameters were evaluated at baseline and after 5 and 10 years of follow-up. This trial is registered at ClinicalTrials.gov NCT06260462.

RESULTS

At 10 years of follow-up, patients with conventional GCs had significantly higher values of BMI (P = .031), waist circumference (P = .047), systolic blood pressure (P = .039), total and LDL cholesterol (P = .041 and P = .042), HbA1c (P = .040), HOMA-IR (P = .006), AUC2h of glucose (P < .001), thickness of the interventricular septum in diastole and of the posterior wall (both P < .001) and significantly lower values of oral disposition index (P = .001) and ISI-Matsuda (P < .001), lumbar spine T score (P = .036), and femoral neck Z score (P = .026), compared to patients treated with DR-HC.

CONCLUSIONS

In patients with treatment-naive AI, 10 years of conventional GC treatment is associated with a worsening of metabolic, insulin-sensitivity, cardiac, and bone outcomes, while DR-HC had no impact on them achieving a lower risk of developing comorbidities.

Atypical monocyte dynamics in healthy humans in response to fasting and refeeding are distinguished by fasting HDL and postprandial cortisol

Monocytes are innate immune cells that are continuously produced in bone marrow which enter and circulate the vasculature. In response to nutrient scarcity, monocytes migrate back to bone marrow, where, upon refeeding, they are rereleased back into the bloodstream to replenish the circulation. In humans, the variability in monocyte behavior in response to fasting and refeeding has not been characterized. To investigate monocyte dynamics in humans, we measured blood monocyte fluctuations in 354 clinically healthy individuals after a 12-h overnight fast and at 3 and 6 h after consuming a mixed macronutrient challenge meal. Using cluster analysis, we identified three distinct monocyte behaviors. Group 1 was characterized by relatively low fasting monocyte counts that markedly increased after consuming the test meal. Group 2 was characterized by relatively high fasting monocyte counts that decreased after meal consumption. Group 3, like Group 1, was characterized by lower fasting monocyte counts but increased to a lesser extent after consuming the meal. Although monocyte fluctuations observed in Groups 1 and 3 align with the current paradigm of monocyte dynamics in response to fasting and refeeding, the atypical dynamic observed in Group 2 does not. Although generally younger in age, Group 2 subjects had lower whole body carbohydrate oxidation rates, lower HDL-cholesterol levels, delayed postprandial declines in salivary cortisol, and reduced postprandial peripheral microvascular endothelial function. These unique characteristics were not explained by group differences in age, sex, or body mass index (BMI). Taken together, these results highlight distinct patterns of monocyte responsiveness to natural fluctuations in dietary fuel availability.NEW & NOTEWORTHY Our study composed of adult volunteers revealed that monocyte dynamics exhibit a high degree of individual variation in response to fasting and refeeding. Although circulating monocytes in most volunteers behaved in ways that align with previous reports, many exhibited atypical dynamics demonstrated by elevated fasting blood monocyte counts that sharply decreased after meal consumption. This group was also distinguished by lower HDL levels, reduced postprandial endothelial function, and a delayed postprandial decline in salivary cortisol.

Age-specific association between meal-skipping patterns and the risk of hyperglycemia in Korean adults: a national cross-sectional study using the KNHANES data

BACKGROUND

Glucose metabolism regulation is influenced by age and meal skipping, although research on their interplay with hyperglycemia remains limited. This study aims to explore the intricate relationship between meal-skipping patterns and hyperglycemia risk across distinct age groups in South Korean adults.

METHODS

Utilizing data from the Korea National Health and Nutrition Examination Surveys (KNHANES) conducted from 2013 to 2020, comprising 28,530 individuals aged 19 years and older, this study employed multivariable logistic regression models to examine the associations between meal-skipping patterns and the risk of hyperglycemia.

RESULTS

Meal-skipping patterns were categorized into three groups: no skipping (NS), skipping breakfast (SB), and skipping dinner (SD). Age groups were defined as "young" (aged 19-44), "middle-aged" (aged 45-64), and "elderly" adults (over 65 years old). Among "young" adults, SB was associated with a 1.33-fold higher risk of hyperglycemia (OR = 1.33, 95% CI = 1.14-1.54) compared to NS. Conversely, in "elderly" adults, SD was linked to a 0.49-fold reduced risk (95% CI = 0.29-0.82) when compared to NS. Additionally, we observed that the Korean Health Eating Index (KHEI) scores, representing the quality of diet on a scale of 0 to 100, were consistently lower in SB compared to NS across all age groups. Intriguingly, specifically among the "elderly" group, this score was higher in SD compared to NS (p < 0.001).

CONCLUSIONS

This study demonstrates age-specific variations in the association between meal-skipping patterns and the risk of hyperglycemia.

Cardiovascular Risk Markers in Adults With Adrenal Incidentaloma and Mild Autonomous Cortisol Secretion

CONTEXT

Many adrenal adenomas exhibit mild autonomous cortisol secretion (MACS). Although MACS is associated with increased cardiovascular mortality, the underlying mechanisms are not fully defined.

OBJECTIVE

To investigate mechanisms that may link MACS and cardiovascular mortality in adults with adrenal adenoma.

DESIGN

Cross-sectional study.

PATIENTS

Twenty adults with adrenal adenoma and MACS and 20 controls with nonfunctioning adrenal adenoma.

METHODS

Reactive hyperemia index (RHI) was measured by peripheral artery tonometry and 24-hour ambulatory blood pressure monitoring (24h AMBP) was performed. Indices of insulin secretion and sensitivity were estimated by measuring glucose and insulin fasting and following a mixed meal.

MAIN OUTCOME MEASURE

The primary outcome was the difference in RHI between participants with MACS vs nonfunctioning adrenal adenoma.

RESULTS

The average cortisol after 1-mg dexamethasone and urinary free cortisol were higher in patients with MACS. There was no significant difference in fasting RHI (2.0 [interquartile range (IQR) 1.6-2.4] vs 2.0 [IQR 1.7-2.2, P = .72), but postprandial RHI was higher in patients with MACS (2.2 [1.8-2.7] vs 1.8 [1.5-2.2], P = .04). 24-hour ambulatory blood pressure monitoring and Matsuda index were not significantly different in the groups. Fasting glucose and glucose area under the curve after the mixed meal were higher and insulinogenic index was lower in participants with MACS.

CONCLUSION

Adults with adrenal adenoma and MACS do not have fasting endothelial dysfunction and postprandial endothelial function may be better. These patients have fasting and postprandial hyperglycemia with lower insulin secretion, which may underlie the association between MACS and increased cardiovascular mortality.

Cardio-metabolic pathophysiology in mild glucocorticoid excess: Potential implications for management of adrenal incidentaloma

Adrenal adenomas are incidentally identified in up to 5% of computer tomography scans performed for unrelated indications. A proportion of these adrenal incidentalomas are found to autonomously secrete cortisol based on definitions in current guidelines. Epidemiological studies suggest that chronic exposure to mild glucocorticoid excess from adrenal incidentalomas is associated with significantly increased cardiometabolic risk. However, current management guidelines adopt a conservative approach as no large prospective randomized studies have demonstrated that these patients benefit from surgery. This narrative review examines the epidemiological and mechanistic studies related to three common clinical settings of mild glucocorticoid excess to gain further insight into the potential benefits of treating patients with adrenal incidentaloma and possible autonomous cortisol secretion.

Non-invasive assessment of tissue sodium content in patients with primary adrenal insufficiency

OBJECTIVE

Replacement therapy in primary adrenal insufficiency (PAI) with corticosteroids modulates sodium homeostasis. Serum sodium is, however, prone to osmotic shifts induced by several additional factors besides corticosteroids and does not always reliably reflect treatment quality. Non-osmotic tissue storage can be visualized by sodium MRI (23Na-MRI) and might better reflect corticosteroid activity.

DESIGN

Longitudinal study of 8 patients with newly diagnosed PAI and cross-sectional study in 22 patients with chronic PAI is reported here. Comparison was made with matched healthy controls.

METHODS

Using a 23Na-MRI protocol on a 3T scanner, relative sodium signal intensities (rSSI) to signal intensities of the reference vial with 100 mmol/L of sodium were determined in the muscle and skin of the lower calf.

RESULTS

In newly diagnosed patients, tissue rSSI (median, range) were reduced and significantly increased after treatment initiation reaching levels similar to healthy controls (muscle: from 0.15 (0.08, 0.18) to 0.18 (0.14, 0.27), P = 0.02; skin: from 0.12 (0.09, 0.18) to 0.18 (0.14, 0.28), P < 0.01). Muscle rSSI was significantly higher in patients with chronic PAI compared to controls (0.19 (0.14, 0.27) vs 0.16 (0.12, 0.20), P < 0.01). In chronic PAI, skin rSSI significantly correlated with plasma renin concentration.

CONCLUSION

23Na-MRI provides an additional insight into sodium homeostasis, and thus the quality of replacement therapy in PAI, as tissue sodium significantly changes once therapy is initiated. The increased tissue sodium in patients with chronic PAI might be an indication of over-replacement.

Hypothalamic-pituitary-adrenal axis activity and vascular function in healthy adults

OBJECTIVE

The objective of this study is to assess the relationship between hypothalamic-pituitary-adrenal (HPA) axis activity, vascular function and insulin sensitivity in healthy adults.

DESIGN

Open observational study.

PATIENTS

Thirty healthy adults were studied at the Endocrine Research Unit, Repatriation General Hospital, Adelaide, SA, Australia.

MEASUREMENTS

HPA activity was assessed from the serum cortisol 30 min after 1 µg ACTH_1-24 (Novartis Pharmaceuticals). Subjects with a cortisol below (n = 15) and above (n = 15) the median were categorized as low and high responders, respectively. Reactive hyperaemia index (RHI) was measured fasting to estimate endothelial function. Matsuda index was calculated from glucose and insulin concentrations collected fasting and 30 minutely for 2 h after a mixed meal (10 kcal/kg, 45% carbohydrate, 15% protein, 40% fat). The primary endpoint was the difference in RHI between low and high responders.

RESULTS

There were no significant differences in age (61 ± 9 vs. 64 ± 7 years, p = .19), body mass index (BMI; 26 ± 3 vs. 24 ± 4 kg/m² , p = .25) and sex (p = .71) between low and high responders. High responders had a lower RHI (2.1 ± 0.2 vs. 2.6 ± 0.2, p = .04) than low responders and there was a negative association between RHI and peak cortisol post ACTH_1-24 (β = -.56, p < .01). There were no significant differences in Matsuda index (15.0 ± 2.4 vs. 22.7 ± 5.2, p = .19) between high and low responders.

CONCLUSION

In healthy adults, endothelial dysfunction is likely to contribute to the association between HPA hyperactivity and increased cardiovascular risk. As insulin sensitivity was not different in high and low responders, endothelial dysfunction is not primarily secondary to insulin resistance.

Prediction of diabetes mellitus induced by steroid overtreatment in adrenal insufficiency

To assess the differences between patients with normal glucose tolerance (NGT) and prediabetes/diabetes mellitus (DM) in secondary adrenal insufficiency (SAI). We cross-sectionally evaluated 102, out of a total of 140, patients with SAI, who were on hydrocortisone (HC) (n = 50) and cortisone acetate (n = 52) replacement therapy. Clinical, anthropometric, and metabolic parameters were compared in patients with NGT (n = 60) and DM (n = 42). Patients with prediabetes/DM have a more marked family history of DM (p = 0.002), BMI (p < 0.001), higher waist circumference (p < 0.001), total cholesterol (p = 0.012), LDL-cholesterol (p = 0.004), triglycerides (p = 0.031), fasting glucose (p = 0.002), fasting insulin (p = 0.035), glutamate pyruvate transaminase (p = 0.018), HOMA-IR (p = 0.039), area under curves of glucose (p = 0.001) and insulin (p = 0.002), HbA1c (p < 0.001), Visceral adiposity index (VAI) (p = 0.038) and lower ISI-Matsuda (p = 0.008) and oral disposition index (p < 0.001) than patients with NGT. Multivariate analysis showed that family history of DM and VAI are independent predictive factors for DM in patients with SAI. Family history of DM and VAI can be predictors of the development of DM in patients with SAI and need to be investigated during steroid replacement therapy. Interestingly, the type and the dose of replacement steroid do not impact on diabetes mellitus.

Daily Glucocorticoid Replacement Dose in Adrenal Insufficiency, a Mini Review

The Endocrine Society Guidelines and recent reviews of adrenal insufficiency (AI) recommend a daily glucocorticoid replacement dose of 15 to 25 mg with a midpoint of 20 mg of hydrocortisone (HC) (alternatively 3 to 5 mg prednisolone) in divided doses in otherwise healthy individuals with AI. In contrast, a daily glucocorticoid replacement dose of 4.3 to 26 mg/d HC with a midpoint of 15 mg/d is predicted from current measurements of daily cortisol production rates and oral HC bioavailability. The higher HC doses recommended in the current guidelines may result in glucocorticoid overtreatment of some AI patients and associated long-term adverse outcomes. A titration method for determination of the individual patient's daily glucocorticoid replacement dose and the impact of lower doses are reviewed. Future related research questions are identified.

Metabolic comorbidities of adrenal insufficiency: Focus on steroid replacement therapy and chronopharmacology

Adrenal insufficiency (AI) is characterized by higher mortality and morbidity compared with the general population. Conventional replacement steroid therapy, currently recommended for the treatment of AI, is associated with increased frequency of metabolic comorbidities due to daily overexposure. By contrast, dual-release hydrocortisone is associated with a decreased risk of metabolic comorbidities, providing an adequate release of hydrocortisone and mimicking the physiological profile of cortisol. These favorable effects are due to a reduced daily steroid exposure that does not affect the expression of the clock genes which are involved in metabolic pathways and are regulated by the normal physiological circadian rhythm of endogenous cortisol. This narrative review focuses on the possible metabolic comorbidities of AI due to steroid replacement therapy, which evaluates the effects of conventional and novel drugs with attention to chronopharmacology.

Heart Rate Variability in Postoperative Patients with Nonfunctioning Pituitary Adenoma

BACKGROUND

Decreased heart rate variability (HRV) has been reported to be associated with cardiac autonomic dysfunction. Hypopituitarism in nonfunctioning pituitary adenoma (NFPA) is often linked to increased cardiovascular mortality. We therefore hypothesized that postoperative NFPA patients with hormone deficiency have an elevated risk of HRV alterations indicating cardiac autonomic dysfunction.

METHODS

A total of 22 patients with NFPA were enrolled in the study. Between 3 and 6 months after surgery, a combined pituitary function test (CPFT) was performed, and HRV was measured. The period of sleep before the CPFT was deemed the most stable period, and the hypoglycemic period that occurred during the CPFT was defined as the most unstable period. Changes in HRV parameters in stable and unstable periods were observed and compared depending on the status of hormone deficiencies.

RESULTS

In patients with adrenocorticotropic hormone (ACTH) deficiency with other pituitary hormone deficiencies, the low frequency to high frequency ratio, which represents overall autonomic function and is increased in the disease state, was higher (P=0.005). Additionally, the standard deviation of the normal-to-normal interval, which decreases in the autonomic dysfunction state, was lower (P=0.030) during the hypoglycemic period. In panhypopituitarism, the low frequency to high frequency ratio during the hypoglycemic period was increased (P=0.007).

CONCLUSION

HRV analysis during CPFT enables estimation of cardiac autonomic dysfunction in patients with NFPA who develop ACTH deficiency with other pituitary hormone deficiencies or panhypopituitarism after surgery. These patients may require a preemptive assessment of cardiovascular risk.

Micro- and macrovascular function in patients suffering from primary adrenal insufficiency: a cross-sectional case-control study

BACKGROUND

Despite adequate glucocorticoid (GC) and mineralocorticoid (MC) replacement therapy, patients suffering from primary adrenal insufficiency (AI) have an increased mortality, mainly due to cardiovascular diseases. Only little knowledge exists on the contribution of MC substitution to the cardiovascular risk. Therefore, this study investigates the impact of plasma renin concentration on parameters of micro- and macrovascular function.

METHODS

26 patients with primary AI [female = 18, age: 51 (28; 78) years; BMI: 24 (18; 40) kg/m²; disease duration: 18 (5; 36) years] were included in this cross-sectional analysis. Intima media thickness (IMT) and pulse wave velocity (PWV) were investigated to assess macrovascular remodeling and arterial stiffness. Microvascular function was estimated by post-occlusive reactive hyperemia using laser Doppler fluxmetry. Baseline perfusion, biological zero, peak perfusion, time to peak and recovery time were recorded. Patients were grouped according to their median plasma renin concentration of previous visits (Renin_high vs Renin_low) and were compared to a group of healthy women [age: 44 (43; 46) years; BMI: 24.2 (21.8; 27.5)].

RESULTS

PWV was significantly higher in AI patients compared to controls [9.9 (5; 18.5) vs 7.3 (6.8; 7.7) m/s; p < .01], whereas no differences in microvascular function could be found. In Renin_low time to peak perfusion was significantly longer [6.0 (3; 15) vs 3.5 (1.5; 11) s; p < .05], whereas no differences in IMT and PWV were observed between Renin_high and Renin_low. No impact of GC dose was observed.

CONCLUSIONS

Microvascular function is not impaired in patients with primary AI under adequate replacement therapy, although higher renin concentrations are associated with subclinical improvements. No relation between RAAS activity and macrovascular function is observed, while arterial stiffness might be increased in primary AI.

Hydrocortisone decreases lethality and inflammatory cytokine and nitric oxide production in rats challenged with B. anthracis cell wall peptidoglycan

Background

Lethal B. anthracis infection produces high proinflammatory peptidoglycan (PGN) burdens in hosts. We investigated whether the lethality and inflammation anthrax PGN can produce are related.

Methods

At 6 h before and the start of 24 h anthrax PGN infusions, rats (n = 198) were treated with diluent (controls) or one of three IV-doses of either hydrocortisone (125, 12.5 or 1.25 mg/kg) or TNF-soluble receptor (TNFsr; 2000, 1000 or 333 μg/kg), non-selective and selective anti-inflammatory agents, respectively.

Results

Compared to controls, hydrocortisone 125 and 12.5 mg/kg each decreased 7-day lethality (p ≤ 0.004). Hydrocortisone 125 mg/kg decreased IL-1β, IL-6, TNFα, MCP, MIP-1α, MIP-2, RANTES and nitric oxide (NO) blood levels at 4 and 24 h after starting PGN (except MCP at 24 h). Each decrease was significant at 4 h (except MIP-1α that was significant at 24 h) (p ≤ 0.05). Similarly, hydrocortisone 12.5 mg/kg decreased each measure at 4, 24 and 48 h (except TNFα at 24 h and MIP-1α at 24 and 48 h and NO at 48 h). Decreases were significant for IL-6 and NO at 4 h and RANTES at 48 h (p ≤ 0.05). Hydrocortisone 1.25 mg/kg had non-significant effects. Each TNFsr dose decreased lethality but non-significantly. However, when doses were analyzed together, TNFsr decreased lethality in a potential trend (p = 0.16) and IL-6 and NO significantly at 4 h (p = 0.05).

Conclusions

Peptidoglycan-stimulated host inflammation may contribute to B. anthracis lethality.

Dual-release hydrocortisone vs conventional glucocorticoids in adrenal insufficiency

BACKGROUND

Dual-release hydrocortisone (DR-HC) improves metabolism in patients with adrenal insufficiency. The aims of this study were to compare the cardiovascular and metabolic effects of conventional glucocorticoids (GCs) vs. DR-HC and of high vs. low doses of GCs, after 48 months of observation.

METHODS

We selected 27 patients on hydrocortisone (mean dose 17.5 ± 4.2 mg/day) and 20 patients on cortisone acetate (mean dose 37.5 ± 12.1 mg/day) who maintained this treatment (group A) and 53 patients switched to DR-HC (mean dose 22 ± 4.8 mg/day) (group B). At baseline and after 48 months, clinical and metabolic parameters and Framingham Risk Score (FRS) were obtained.

RESULTS

After 48 months, patients in group A had a significant increase from baseline in BMI (P < 0.001), waist circumference (P = 0.001), systolic blood pressure (P = 0.001), LDL cholesterol (P = 0.018), HbA1c (P = 0.020) and FRS (P = 0.002). By contrast, patients in group B had a significant decrease in BMI (P = 0.002), waist circumference (P = 0.015), diastolic blood pressure (P = 0.031), total (P = 0.006) and LDL cholesterol (P = 0.005), HbA1c (P < 0.001) and FRS (P = 0.015) compared to baseline. No significant differences between high and low doses of both conventional GCs and DR-HC were observed.

CONCLUSIONS

DR-HC is associated with an improvement of metabolic parameters and cardiovascular risk compared to conventional GCs, which are associated with a worsening of these parameters, regardless of the dose used.

Novel insights into glucocorticoid replacement therapy for pediatric and adult adrenal insufficiency

Adrenal insufficiency is defined as impaired adrenocortical hormone synthesis. According to its source, the deficit is classified as primary (adrenal steroidogenesis impairment), secondary (pituitary adrenocorticotropic hormone deficit) or tertiary (hypothalamic corticotropin-releasing hormone deficit). The management of adrenal insufficiency resides primarily in physiological replacement of glucocorticoid secretion. Standard glucocorticoid therapy is shrouded in several controversies. Along the difficulties arising from the inability to accurately replicate the pulsatile circadian cortisol rhythm, come the uncertainties of dose adjustment and treatment monitoring (absence of reliable biomarkers). Furthermore, side effects of inadequate replacement significantly hinder the quality of life of patients. Therefore, transition to circadian hydrocortisone therapy gains prominence. Recent therapeutic advancements consist of oral hydrocortisone modified-release compounds (immediate, delayed and sustained absorption formulations) or continuous subcutaneous hydrocortisone infusion. In addition to illustrating the current knowledge on conventional glucocorticoid regimens, this review outlines the latest research outcomes. We also describe the management of pediatric patients and suggest a novel strategy for glucocorticoid replacement therapy in adults.

Insulin Sensitivity Is Not Decreased in Adult Patients With Hypopituitarism Without Growth Hormone Replacement

Decreased insulin sensitivity in patients with hypopituitarism without GH replacement (pHP-WGHR) remains conflicting in literature. It is known that these patients present a decrease in free fat mass and an increase in fat mass. Typically, these kinds of alterations in body composition are associated with a decrease in insulin sensitivity; however, there is no consensus if this association is found in pHP-WGHR. Thus, we investigated pHP-WGHR regarding insulin sensitivity by euglycemic hyperinsulinemic clamp, the gold standard method, and body composition. In a cross-sectional study, we evaluated 15 pHP-WGHR followed up in a Service of Neuroendocrinology and 15 individuals with normal pituitary function as a control group with similar age, gender and body mass index. Insulin sensitivity was evaluated by euglycemic hyperinsulinemic clamp and homeostatic model assessment insulin resistance (HOMA-IR). Kappa coefficient evaluated the agreement between these two methods. Percentage of fat mass, percentage of free fat mass, fat mass weight and free fat mass weight were assessed by electrical bioimpedance. The pHP-WGHR presented similar insulin sensitivity to control group by euglycemic hyperinsulinemic clamp, both by the M-value, (p = 0.0913) and by the area under the glucose infusion rate curve, (p = 0.0628). These patients showed lower levels of fasting glycemia (p = 0.0128), insulin (p = 0.0007), HOMA-IR (p = 0.009). HOMA-IR shows poor concordance with euglycemic hyperinsulinemic clamp (Kappa = 0.16) in pHP-WGHR, while in the control group the agreement was good (Kappa = 0.53). The pHP-WGHR presented higher values of percentage of fat mass (p = 0.0381) and lower values of percentage of free fat mass (p = 0.0464) and free fat mass weight (0.0421) than the control group. This study demonstrated that the insulin sensitivity evaluated by euglycemic hyperinsulinemic clamp in pHP-WGHR was similar to individuals with normal pituitary function, despite the pHP-WGHR presenting higher fat mass percentage. HOMA-IR was not a good method for assessing insulin sensitivity in pHP-WGHR.

MANAGEMENT OF ENDOCRINE DISEASE: Critical review of the evidence underlying management of glucocorticoid-induced hyperglycaemia

Glucocorticoids are frequently prescribed to patients with a wide range of inflammatory and autoimmune diseases. The semi-synthetic glucocorticoid prednisolone is most commonly prescribed and in two main patterns. Prednisolone is prescribed short term at medium-high doses to treat an acute inflammatory illness or long term at lower doses to attenuate chronic inflammatory disease progression. In hospitalized patients with acute prednisolone-induced hyperglycaemia, there is a distinct circadian pattern of glucose elevation, which occurs predominantly in the afternoon and evening. As a morning dose of isophane insulin has a pharmacokinetic pattern that matches this pattern of glucose elevation, treatment comprising a basal dose of morning isophane insulin in combination with short-acting insulin boluses is generally recommended. However, evidence is lacking that isophane-based basal bolus insulin is more efficacious than other insulin regimens. In outpatients, low-dose prednisolone causes a small increase in post glucose-load glucose concentration but no change in overall glycaemic control as measured by glycosylated haemoglobin. If treatment is indicated, metformin has been shown to be effective and may attenuate other adverse effects of long-term prednisolone therapy. Further studies are necessary in order to identify factors underlying the variability in response to insulin therapy and clinical benefits of treatment in hospitalized patients with prednisolone-induced hyperglycaemia. In outpatients prescribed low-dose prednisolone, the cardiovascular risk associated with postprandial hyperglycaemia and efficacy of hypoglycaemic therapies should be evaluated in future randomized clinical trials.

Improved insulin sensitivity and secretion in prediabetic patients with adrenal insufficiency on dual-release hydrocortisone treatment: a 36-month retrospective analysis

OBJECTIVE

Dual-release hydrocortisone (DR-HC) provides physiological cortisol exposure, leading to an improvement of anthropometric and metabolic parameters. The aim of the study was to evaluate the effects of DR-HC on insulin secretion and sensitivity and cardiometabolic risk, indirectly expressed by the visceral adiposity index (VAI).

DESIGN AND PATIENTS

Retrospective analysis of 49 patients, 13 with primary and 36 with secondary adrenal insufficiency (AI), respectively, on conventional glucocorticoid treatment at baseline and switched to DR-HC for 36 months. Overall, 24 patients had AI-pre-diabetes (impaired fasting glucose, impaired glucose tolerance and the combination), and 25 had AI-normal glucose tolerance (NGT).

MEASUREMENTS

Clinical and metabolic parameters, including VAI, insulin secretion and sensitivity indexes (fasting insulinaemia, AUC_{2 h insulinaemia} , oral disposition index [Dio] and ISI-Matsuda), were evaluated.

RESULTS

In patients with AI-NGT and AI-prediabetes, a significant decrease in BMI (P = .017 and P < .001), waist circumference (P = .008 and P < .001), HbA1c (P = .034 and P = .001) and a significant increase in HDL-C (P = .036 and P = .043) was, respectively, observed. In addition, in prediabetic patients, only we found a significant decrease in insulinaemia (P = .014), AUC_{2 h insulinaemia} (P = .038) and VAI (P = .001), in concomitance with a significant increase in DIo (P = .041) and ISI-Matsuda (P = .038).

CONCLUSIONS

Long-term DR-HC therapy is associated with an improvement in insulin secretion and sensitivity in patients with prediabetes. However, all patients appear to benefit from the treatment in terms of improvement of metabolic and anthropometric parameters. Larger studies are required to confirm our preliminary data.

Glycometabolic Alterations in Secondary Adrenal Insufficiency: Does Replacement Therapy Play a Role?

Secondary adrenal insufficiency (SAI) is a potentially life-threatening endocrine disorder due to an impairment of corticotropin (ACTH) secretion from any process affecting the hypothalamus or pituitary gland. ACTH deficit can be isolated or associated with other pituitary failures (hypopituitarism). An increased mortality due to cardiovascular, metabolic, and infectious diseases has been described in both primary and secondary adrenal insufficiency. However, few studies have provided compelling evidences on the underlying mechanism in SAI, because of the heterogeneity of the condition. Recently, some studies suggested that inappropriate glucocorticoid (GCs) replacement therapy, as for dose and/or timing of administration, may play a role. Hypertension, insulin resistance, weight gain, visceral obesity, increased body mass index, metabolic syndrome, impaired glucose tolerance, diabetes mellitus, dyslipidemia have all been associated with GC excess. These conditions are particularly significant when SAI coexists with other pituitary alterations, such as growth hormone deficiency, hypogonadism, and residual tumor. Novel regimen schemes and GC preparations have been introduced to improve compliance and better mimick endogenous cortisol rhythm. The controlled trials on the improved replacement therapies, albeit in the short-term, show some beneficial effects on cardiovascular risk, glucose metabolism, and quality of life. This review examines the current evidence from the available clinical trials investigating the association between different glucocorticoid replacement therapies (type, dose, frequency, and timing of treatment) and glycometabolic alterations in SAI.

Relative hyperglycemia is associated with complications following an acute myocardial infarction: a post-hoc analysis of HI-5 data

Background

Hyperglycemia is associated with increased morbidity and mortality in patients with an acute myocardial infarction (AMI). We evaluated whether complications after AMI are associated with absolute or relative glycemia.

Methods

A total of 192 patients with AMI were randomized to intensive or conventional insulin therapy. Absolute glycemia was defined as mean blood glucose level (BGL) during the first 24 h following randomization. Relative glycemia was defined by the stress hyperglycaemia ratio (SHR), calculated as mean BGL divided by average glucose concentration over the prior 3 months estimated from glycosylated haemoglobin. The primary endpoint was a “complicated AMI”, defined as an AMI complicated by death, congestive cardiac failure, arrhythmia, cardiac arrest, reinfarction, cardiogenic shock, inotrope use or emergency revascularization.

Results

There was not a significant association between mean BGL and complicated AMI (odds ratio (OR) 1.05 per mmol/L glucose increment, 95% confidence intervals (CI) 0.93–1.19). In contrast, SHR was positively associated with a complicated myocardial infarction (OR 1.22 per 0.1 SHR increment, 95% CI 1.06–1.42), and individual complications of death (OR 1.55, 95% CI 1.14–2.11), congestive cardiac failure (OR 1.27, 95% CI 1.05–1.54), arrhythmia (OR 1.31, 95% CI 1.12–1.54) and cardiogenic shock (OR 1.42, 95% CI 1.03–1.97). The relationship between SHR and a complicated AMI was independent of diabetic status, intensive insulin therapy, sex and hypoglycemia.

Conclusions

Relative, but not absolute, glycemia during insulin treatment is independently associated with complications after an AMI. Future studies should investigate whether basing therapeutic glycaemic targets on relative glycemia improves patient outcomes.

Increased Cardiovascular Risk in Patients with Adrenal Insufficiency: A Short Review

Cardiovascular disease (CVD) is the most common cause of death in the world. Recent studies have shown an association between adrenal insufficiency (AI) and increased cardiovascular risk (CVR). Patients with AI receive glucocorticoid (GC) replacement therapy which can lead to varying levels of blood cortisol. It was shown that these imbalances in blood cortisol may lead to a higher prevalence of coronary heart disease, major adverse coronary events, and increased mortality. GC substitution is essential in the treatment of AI without which the disease has been shown to be fatal. The most frequently used GC formula for replacement therapy is hydrocortisone (HC). There is no uniform opinion on hydrocortisone replacement therapy. Alternative GC such as prednisolone is also in use. Overreplacement of GC may lead to adverse effects including obesity, high blood pressure, and hyperglycaemia. Outcome may vary between primary and secondary AI mainly due to differences in the renin-angiotensin-aldosterone system (RAAS). Furthermore, decreased blood levels of cortisol may lead to a compensatory secretion of inflammatory mediators such as Interleukin-1 (IL-1), Interleukin-6 (IL-6), and/or tumor-necrosis factor (TNF). Physicians and patients should be properly educated about the increased risk of CVD in patients with AI.

Opposing effects of rheumatoid arthritis and low dose prednisolone on arginine metabolomics

BACKGROUND AND AIMS

The effects of low dose prednisolone on circulating markers of endothelial function, the arginine metabolites asymmetric dimethyl arginine (ADMA), mono methyl arginine (MMA), and homoarginine, are uncertain. We assessed whether patients with rheumatoid arthritis have perturbations in arginine metabolite concentrations that are reversed by low dose prednisolone.

METHODS

Eighteen rheumatoid arthritis patients who had not taken prednisolone for >6 months (non-glucocorticoid (GC) users), 18 rheumatoid arthritis patients taking continuous oral prednisolone (6.5 ± 1.8 mg/day) for >6 months (GC users) and 20 healthy controls were studied. Fasting plasma concentrations of ADMA, MMA, and homoarginine were measured by ultra-performance liquid-chromatography. Baseline data from non-GC users were compared with healthy controls to assess the effect of rheumatoid arthritis. The change in arginine metabolites in non-GC users after 7 days of prednisolone (6 mg/day) was used to assess the acute effects of prednisolone. Baseline data from non-GC users were compared with GC users to assess the chronic effects of prednisolone.

RESULTS

Non-GC users had higher ADMA (0.59 ± 0.03 vs. 0.47 ± 0.01 μM, p = 0.004) and MMA concentrations (0.10 ± 0.01 vs. 0.05 ± 0.00 μM, p < 0.001) than controls. The only change with acute prednisolone was a reduction in homoarginine (1.23 ± 0.06 vs. 1.08 ± 0.06 μM, p = 0.04) versus baseline. GC users had lower concentrations of ADMA (0.51 ± 0.02 vs. 0.59 ± 0.03 μM, p = 0.03) than non-GC users.

CONCLUSIONS

Rheumatoid arthritis patients have higher concentrations of ADMA and MMA, inhibitors of endothelial function. Chronic, but not acute, prednisolone therapy is associated with a lower ADMA concentration, suggesting a salutary effect of long-term glucocorticoid treatment on endothelial function.

FKBP5 methylation as a possible marker for cortisol state and transient cortisol exposure in healthy human subjects

Current glucocorticoid replacement regimens, in adrenal insufficiency, fail to mimic the physiological cortisol secretion, thereby fostering serious side effects.

AIM

To experimentally evaluate the impact of CpG methylation within the FKBP5 gene as a possible short- and long-term marker for cortisol exposure in humans.

MATERIALS & METHODS

An ACTH-stimulation test was carried out and methylation status of the FKBP5 gene in leukocytes was determined.

RESULTS

A negative correlation between basal levels of methylation and serum cortisol was observed. Individual changes in FKBP5 methylation after 24 h correlated with cortisol responses.

CONCLUSION

Considering previous studies conducted with murine leucocytes, FKBP5 methylation may be suitable as a long-term biomarker, rather than acute glucocorticoid exposure, also in humans.

Low dose prednisolone and insulin sensitivity differentially affect arterial stiffness and endothelial function: An open interventional and cross-sectional study

BACKGROUND AND AIMS

Glucocorticoids could impair vascular function directly, or indirectly by reducing insulin sensitivity. The aim of this study was to determine the direct and indirect effects of acute and chronic low dose prednisolone on arterial stiffness and endothelial function.

METHODS

Twelve subjects with inflammatory arthritis, who had not taken oral glucocorticoids for ≥6 months, and 12 subjects with inflammatory arthritis, taking chronic (>6 months) low dose (6.3 ± 2.2 mg/day) prednisolone, were studied. Patients not on glucocorticoids underwent measurement of arterial stiffness (pulse wave velocity (PWV)) and endothelial function (reactive hyperaemia index (RHI)) before and after 7-10 days of prednisolone (6 mg/day), to assess the acute effects of prednisolone. Baseline data from patients not on glucocorticoids were compared with patients on long-term prednisolone to assess the chronic effects of prednisolone. Hepatic insulin sensitivity was estimated from percentage suppression of endogenous glucose production and peripheral insulin sensitivity as glucose infusion rate (M/I) during a hyperinsulinaemic-euglycaemic clamp.

RESULTS

There were no significant changes in PWV with acute (9.2 ± 0.8 vs. 8.9 ± 0.8 m/sec, p = 0.33) or chronic (8.9 ± 0.8 vs. 9.0 ± 0.7 m/sec, p = 0.69) prednisolone. In multiple regression analysis, PWV was negatively associated with M/I during hyperinsulinemic-euglycemic clamp (p = 0.02), but not with suppression of endogenous glucose production (p = 0.15) or glucocorticoid use (p = 0.70). Chronic (2.4 ± 0.2 vs. 1.9 ± 0.1, p = 0.02), but not acute (1.8 ± 0.2 vs. 1.9 ± 0.1, p = 0.24), prednisolone resulted in a higher RHI.

CONCLUSIONS

Arterial stiffness is not affected by low dose prednisolone per se, but is negatively associated with peripheral insulin sensitivity. Patients with rheumatoid arthritis taking long-term prednisolone had better endothelial function.

Hormonal Replacement in Hypopituitarism in Adults: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To formulate clinical practice guidelines for hormonal replacement in hypopituitarism in adults.

PARTICIPANTS

The participants include an Endocrine Society-appointed Task Force of six experts, a methodologist, and a medical writer. The American Association for Clinical Chemistry, the Pituitary Society, and the European Society of Endocrinology co-sponsored this guideline.

EVIDENCE

The Task Force developed this evidence-based guideline using the Grading of Recommendations, Assessment, Development, and Evaluation system to describe the strength of recommendations and the quality of evidence. The Task Force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of the Endocrine Society, the American Association for Clinical Chemistry, the Pituitary Society, and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines.

CONCLUSIONS

Using an evidence-based approach, this guideline addresses important clinical issues regarding the evaluation and management of hypopituitarism in adults, including appropriate biochemical assessments, specific therapeutic decisions to decrease the risk of co-morbidities due to hormonal over-replacement or under-replacement, and managing hypopituitarism during pregnancy, pituitary surgery, and other types of surgeries.

ACTH and gonadotropin deficiencies predict mortality in patients treated for nonfunctioning pituitary adenoma: long-term follow-up of 519 patients in two large European centres

CONTEXT AND OBJECTIVE

Nonfunctioning pituitary adenomas (NFPAs) are the most common subtype of pituitary tumour. Hypopituitarism is observed in NFPAs due to tumour- or treatment-related factors and may increase mortality risk. Here, we analysed the associations of hypopituitarism, hormone replacement and mortality in a large NFPA cohort derived from two large European centres.

DESIGN, SETTING AND PARTICIPANTS

Case note review of all patients treated for NFPA in University Hospitals Birmingham and Beaumont Hospital Dublin between 1999 and 2014 was performed.

MAIN OUTCOME MEASURES

Clinical presentation, treatment strategies, pituitary function and vitality status were recorded in each patient. A multivariate Cox regression model was used to examine the association between hypopituitarism, hormone replacement and premature mortality.

RESULTS

A total of 519 patients were included in the analysis. Median duration of follow-up was 7·0 years (0·5-43). A total of 81 deaths were recorded (15·6%). On multivariate analysis, adrenocorticotropic hormone (ACTH) and gonadotropin (Gn) deficiencies were associated with an increased relative risk of death (OR 2·26, 95% CI 1·15-4·47, P = 0·01 and OR 2·56, 95% CI 1·10-5·96, P = 0·01, respectively). Increased hydrocortisone (HC) (P-trend = 0·02) and lower levothyroxine (LT4) doses (P-trend = 0·03) were associated with increased risk of death. Mortality increased with the degree of pituitary failure observed (P-trend = 0·04).

CONCLUSION

ACTH and gonadotropin-deficient patients have higher mortality rates compared to those with intact hormonal axes. Excessive HC and suboptimal LT4 replacement may also increase risk of death. Complex associations between hormone deficiency and replacement underpin the increased mortality risk in NFPA patients.

Effects of Hydrocortisone on the Regulation of Blood Pressure: Results From a Randomized Controlled Trial

CONTEXT

Cardiovascular risk is increased in patients with secondary adrenal insufficiency, which may be ascribed to an unfavorable metabolic profile consequent to a relatively high hydrocortisone replacement dose.

OBJECTIVE

We determined the effects of a higher versus a lower glucocorticoid replacement dose on blood pressure (BP), the renin-angiotensin-aldosterone system, 11β-hydroxysteroid dehydrogenase enzyme activity and circulating (nor)metanephrines.

DESIGN, SETTING, AND PATIENTS

Forty-seven patients with secondary adrenal insufficiency from the University Medical Center Groningen participated in this randomized double-blind crossover study.

INTERVENTIONS

Patients randomly received 0.2-0.3 mg hydrocortisone/kg body weight followed by 0.4-0.6 mg hydrocortisone/kg body weight, or vice versa, each during 10 weeks.

MAIN OUTCOME MEASURE(S)

BP and regulating hormones were measured.

RESULTS

The higher hydrocortisone dose resulted in an increase in systolic BP of 5 (12) mm Hg (P = .011), diastolic BP of 2 (9) mm Hg (P = .050), and a median [interquartile range] drop in plasma potassium of -0.1 [-0.3; 0.1] nmol/liter (P = .048). The higher hydrocortisone dose led to decreases in serum aldosterone of -28 [-101; 9] pmol/liter (P = .020) and plasma renin of -1.3 [-4.5; 1.2 ] pg/mL (P = .051), and increased the ratio of plasma and urinary cortisol to cortisone (including their metabolites) (P < .001 for all). Furthermore, on the higher dose, plasma and urinary normetanephrine decreased by -0.101 [-0.242; 0.029] nmol/liter (P < .001) and -1.48 [-4.06; 0.29] μmol/mol creatinine (P < .001) respectively.

CONCLUSIONS

A higher dose of hydrocortisone increased systolic and diastolic BP and was accompanied by changes in the renin-angiotensin-aldosterone system, 11β-hydroxysteroid dehydrogenase enzyme activity, and circulating normetanephrine. This demonstrates that hydrocortisone dose even within the physiological range affects several pathways involved in BP regulation.

Relationship between Vitamin D Status and Autonomic Nervous System Activity

Vitamin D deficiency is associated with increased arterial stiffness. However, the mechanisms underlying this association have not been clarified. The aim was to investigate whether changes in autonomic nervous system activity could underlie an association between 25 hydroxy vitamin D and arterial stiffness. A total of 49 subjects (age = 60 ± 8 years, body mass index = 26.7 ± 4.6 kg/m², 25 hydroxy vitamin D = 69 ± 22 nmol/L) underwent measurements of pulse wave velocity (PWV) and augmentation index (AIx), spontaneous baroreflex sensitivity, plasma metanephrines and 25 hydroxy vitamin D. Subjects with 25 hydroxy vitamin D ≤ 50 nmol/L were restudied after 200,000 International Units 25 hydroxy vitamin D. Plasma metanephrine was positively associated with AIx (p = 0.02) independent of age, sex, smoking and cholesterol and negatively associated with 25 hydroxy vitamin D (p = 0.002) independent of age, sex and season. In contrast, there was no association between baroreflex sensitivity and 25 hydroxy vitamin D (p = 0.54). Treatment with vitamin D increased 25 hydroxy vitamin D from 43 ± 5 to 96 ± 24 nmol/L (p < 0.0001) but there was no significant change in plasma metanephrine (115 ± 25 vs. 99 ± 39 pmol/L, p = 0.12). We conclude that as plasma metanephrine was negatively associated with 25 hydroxy vitamin D and positively with AIx, it could mediate an association between these two variables. This hypothesis should be tested in larger interventional studies.

Low-dose hydrocortisone replacement is associated with improved arterial stiffness index and blood pressure dynamics in severely adrenocorticotrophin-deficient hypopituitary male patients

OBJECTIVE

Increased cardiovascular and cerebrovascular morbidity and mortality in hypopituitary subjects may be linked to inappropriate glucocorticoid exposure; however, the pathophysiology remains unclear. We aimed to examine the effect of three commonly prescribed hydrocortisone (HC) regimens on vascular risk factors.

DESIGN

An open crossover study randomising ten hypopituitary men with severe adrenocorticotrophic hormone deficiency to three HC dose regimens: dose A (20mg mane and 10mg tarde), dose B (10mg mane and 10mg tarde) and dose C (10mg mane and 5mg tarde).

METHODS

Following 6 weeks on each regimen, participants underwent 24-h serum cortisol sampling, 24-h ambulatory blood pressure (BP) measurements, calculation of the Ambulatory Arterial Stiffness Index (AASI), oral glucose tolerance testing and fasting serum osteoprotegerin (OPG) sampling.

RESULTS

There were no differences in 24-h BP between dose regimens and controls; however, low-dose HC replacement (dose C) was associated with the lowest AASI, indicating a less stiff arterial tree (P<0.05) compared with the other dose regimens. Loss of the physiologic nocturnal BP dip was more common in higher HC replacement regimens, although only significant for dose B compared with dose C (P=0.03). Twenty per cent of patients had abnormal glucose tolerance, but this was unrelated to dose regimen. OPG correlated strongly with 24-h BP in those on dose A only (r=0.65, P=0.04).

CONCLUSION

Currently prescribed HC replacement doses do not result in significant differences in absolute BP levels or improvements in insulin sensitivity. However, lower HC doses may result in lower arterial stiffness and a more physiological nocturnal BP dip. Long-term studies are required to confirm these findings and evaluate their impact on vascular morbidity in this patient group.

Effect of acute and chronic glucocorticoid therapy on insulin sensitivity and postprandial vascular function

OBJECTIVE

Postprandial hyperglycaemia is associated with increased arterial stiffness and cardiovascular events. Low-dose prednisolone causes insulin resistance that typically manifests as postprandial hyperglycaemia. We investigated whether prednisolone causes postprandial vascular dysfunction in a cohort of patients with rheumatoid arthritis.

DESIGN

An open interventional and cross-sectional study was undertaken.

PATIENTS AND MEASUREMENTS

Eighteen subjects with rheumatoid arthritis who had not taken oral glucocorticoids for ≥6 months were studied before and after prednisolone 6 mg/day for 7 days to determine the acute effects of prednisolone. Pre-prednisolone data were compared to 18 subjects with rheumatoid arthritis taking long-term (>6 months) prednisolone (6·5 ± 1·8 mg/day) to assess the chronic effects of prednisolone. Augmentation index (by applanation tonometry) and reactive hyperaemia index (by peripheral artery tonometry) were measured before and after a mixed-meal (10 kcal/kg, 45% carbohydrate, 15% protein, 40% fat). Insulin sensitivity was estimated by the Matsuda index and sympathetic nervous system activity from urinary noradrenaline excretion.

RESULTS

Matsuda index was lower after acute (2·0 ± 1·0 vs 3·6 ± 1·1, P = 0·01) and chronic (1·9 ± 1·0 vs 3·6 ± 1·1, P = 0·04) prednisolone. Postprandial augmentation index was lower after acute prednisolone (2551 ± 197 vs 2690 ± 272%*min, P ≤ 0·001), but not chronic prednisolone. There were no significant differences in reactive hyperaemia index with acute or chronic prednisolone. Noradrenaline excretion was lower after acute (54 ± 8 vs 93 ± 23 nmol/6 h, P = 0·02), but not chronic, prednisolone.

CONCLUSIONS

Prednisolone-induced insulin resistance is not associated with postprandial vascular dysfunction in patients with rheumatoid arthritis. Reduced sympathetic activity may contribute to the reduction in postprandial arterial stiffness with acute prednisolone.

Cardio-metabolic consequences of glucocorticoid replacement: relevance of ultradian signalling

Chronic exposure to elevated glucocorticoid levels is associated with obesity, insulin resistance, impaired glucose tolerance, hypertension and dyslipidaemia, manifest classically in Cushing's syndrome and with high-dose glucocorticoid therapy. However, cardiovascular events are also reportedly higher in patients with primary and secondary hypoadrenalism receiving 'replacement' glucocorticoid doses. This has been attributed to an inability to mimic accurately the diurnal rhythm of cortisol with current oral replacement therapy and subsequent glucocorticoid excess. Although development of delayed release oral preparations has sought to overcome this problem, there has been little attention on the ultradian rhythm of glucocorticoids and its relevance for replacement therapy and associated cardio-metabolic comorbidity. Endogenous glucocorticoids are released in a pulsatile manner, and this ultradian rhythm is important in maintaining homeostatic control through glucocorticoid-receptor (GR)-dependent transcription regulation that rapidly responds to circulating hormone levels. Constant glucocorticoid exposure can result in continuous transcription, aberrant mRNA accumulation and abnormal protein levels. GR regulation of transcription programmes is highly cell and tissue specific, binding to distinct genomic loci in different cellular contexts. GR also interacts with a large cohort of DNA-binding factors with cell-specific interactions. The relevance of kinetic patterns of GR-dependent gene expression in vivo is not yet fully elucidated. However, given that GR gene variants are associated with cardiovascular disease, it is possible that ultradian delivery of glucocorticoid replacement may become important, at least in selected patients.