Metabolic syndrome in patients receiving glucocorticoid replacement for primary adrenal insufficiency

Technical Summary: Metabolic Syndrome in Patients Receiving Glucocorticoid Replacement for Primary Adrenal Insufficiency

Problem Statement
Primary adrenal insufficiency (PAI) necessitates lifelong glucocorticoid (GC) replacement for patient survival. However, standard replacement regimens using immediate-release hydrocortisone (HC) fail to replicate the physiological circadian rhythm of endogenous cortisol secretion. This inherent inaccuracy often leads to either under-replacement, which is life-threatening, or recurrent exposure to supraphysiological cortisol concentrations. The latter is known to disrupt metabolic control, potentially inducing central obesity, glucose intolerance, dyslipidemia, and hypertension—collectively known as metabolic syndrome (MS). While registry data suggests PAI patients face elevated cardiovascular mortality, conflicting evidence exists regarding whether conventional steroid replacement directly increases the frequency of MS compared to the general population. Some studies report higher rates of impaired glucose tolerance and dyslipidemia, while others find no direct correlation with GC dosage. This study aimed to resolve these discrepancies by assessing the frequency of MS in a large cohort of PAI patients treated with conventional therapy.

Methodology
The study employed a cross-sectional clinical and biochemical analysis of 239 adult patients with confirmed PAI (170 females, 69 males) treated at a reference endocrine department in Poland.

• Inclusion/Exclusion: Participants were diagnosed with PAI based on clinical signs, low morning cortisol, elevated ACTH, and ACTH stimulation tests. Patients with secondary adrenal failure, adrenalectomy-induced PAI, or rare genetic causes (e.g., congenital adrenal hyperplasia) were excluded. Only euthyroid patients were enrolled to eliminate thyroid hormone influence on metabolism.
• Data Collection: Standard physical examinations included measurements of body mass index (BMI), waist circumference (WC), and blood pressure (BP). Biochemical analyses covered fasting plasma glucose, insulin, HbA1c, lipid profiles (total, HDL, LDL, triglycerides), electrolytes, and thyroid function.
• Treatment Regimens: All subjects received immediate-release hydrocortisone. Dosages were adjusted based on clinical features (wellbeing, appetite, weight, BP, electrolytes). Cumulative HC dose was calculated as (daily dose × years of treatment × 365).
• Diagnostic Criteria: MS was defined according to the 2009 Joint Interim Statement (IDF/AHA), requiring at least three of five features: abdominal obesity (WC ≥94 cm men, ≥80 cm women), elevated triglycerides (≥150 mg/dl), low HDL (≤40 mg/dl men, ≤50 mg/dl women), elevated BP (≥130/85 mmHg), or fasting hyperglycemia (≥100 mg/dl).
• Statistical Analysis: Continuous variables were analyzed using t-tests or Mann-Whitney tests depending on distribution. Categorical variables used Chi-square tests. A multivariate logistic regression model was developed to identify predictors of MS, controlling for age, gender, disease duration, PAI form, and HC dosage.

Key Results

• Demographics: The median patient age was 48 years, with a median disease duration of 7 years. Women were significantly older at diagnosis and at the time of the study compared to men, though disease duration was similar across sexes.
• Metabolic Syndrome Prevalence: MS was diagnosed in 62 patients (25.9%). There was a significant gender disparity: 31.8% of females vs. 11.6% of males (P=0.001).
• Menopausal Status: Among women, MS prevalence was significantly higher in postmenopausal women (43.1%) compared to premenopausal women (14.7%) (P<0.001).
• Component Analysis:
  • Abdominal obesity was the most frequent component (61.9% overall; 72.3% in females).
  • Elevated triglycerides affected 37.6% of patients.
  • Hypertension (or treated hypertension) was found in 15.5%.
  • Fasting hyperglycemia (including treated diabetes) occurred in 23.8%.
• Dosage Correlations:
  • Daily HC doses were comparable between patients with and without MS (P=0.338).
  • However, patients with MS had a significantly higher cumulative HC intake (P=0.009).
  • In the multivariate logistic regression model, age was the only significant predictor of MS (OR 1.074 per year; P<0.001). Disease duration, gender, PAI form, and body mass-adjusted daily HC dose were not statistically significant predictors.
• Comparison to General Population: The MS prevalence in PAI women (31.8%) was similar to the general Polish population (approx. 32.8% in WOBASZ II study), while the rate in PAI men (11.6%) was lower than the general population, though this may be influenced by the younger age of the male cohort.

Key Contributions and Claims
The paper contributes to the field by providing a detailed metabolic profile of a substantial cohort of PAI patients treated with conventional immediate-release hydrocortisone. The primary contribution is the finding that while metabolic disorders are common in this population, the frequency of full metabolic syndrome is not elevated compared to the general population, with the notable exception of postmenopausal women.

The authors claim that:

1. Tailored Conventional Therapy: When administered within recommended dosage ranges (median 22.5 mg/day), conventional HC replacement does not inherently increase the risk of developing metabolic syndrome.
2. Role of Age: Age is the dominant predictor of MS in PAI patients, likely reflecting the natural progression of metabolic risk and the loss of protective estrogen effects in postmenopausal women, rather than the cumulative steroid exposure itself.
3. Abdominal Obesity: There is a notable susceptibility to abdominal obesity in PAI patients (61.9%), which aligns with trends in the general Polish population but requires careful monitoring to distinguish between physiological weight restoration and GC overreplacement.

Significance
The study suggests that the elevated cardiovascular mortality observed in PAI patients may not be solely driven by an increased prevalence of metabolic syndrome caused by current replacement therapies. Instead, the risk appears more closely tied to patient age and menopausal status. The authors conclude that while tailored conventional HC therapy within current guidelines should not be blamed for a high frequency of MS, patients require careful, periodic monitoring of glucose, lipids, and blood pressure. The findings support the continued use of standard regimens while highlighting the need for vigilance, particularly in older and postmenopausal female patients, to mitigate metabolic complications through lifestyle changes and appropriate pharmacological intervention when necessary.