BMD and Microarchitecture in Endogenous Hypercortisolism
The population studied included 30 patients (24 women and 6 men) with endogenous active CS and 51 healthy controls. Age range was 13–69 years in CS and 19–65 years in control group. There were 22 (73·3%) patients with Cushing's disease (CD), six (20%) patients with cortisol-producing adrenal adenoma and two (6·6%) patients with ectopic ACTH syndrome. All male and most female CS patients and controls were eugonadal, as only six individuals were postmenopausal women (5 CS and 1 control), not receiving hormone replacement therapy. One patient with CS was receiving substitutive thyroid hormone therapy that maintained free T4 serum level within the normal range. There were no growth hormone-deficient patients in our series.
Glomerular filtration rate was at or above 60 mL/min/1·73 m according to MDRD calculation, and serum calcium corrected for albumin and intact PTH was normal in all participants. No control patient and fourteen patients with CS had type 2 diabetes mellitus (DM); two of them had HbA1c above 7·0% at the time of evaluation. The characteristics of the entire sample are summarized in Table 1.
At bone densitometry, none of the controls but 70% of the active CS had a lower than expected Z-score. In the five postmenopausal women and in two men 50 years and older with active CS, DXA scan showed a high prevalence of osteoporosis (28%) and osteopenia (42%). The prevalence of VF in CS patients was 30·4%. Two patients had grade 3 and the others had grade 1 VF. Considering all low-impact fractures (vertebral and nonvertebral), the prevalence was 46·7%. The nonvertebral fractures occurred at wrist (n = 2), ankle (n = 3), hip (n = 1), elbow (n = 1), ribs (n = 2), patella (n = 1) and proximal humerus (n = 1).
Age, gender and BMI were similar in both groups. aBMD and Z-score values in the LS, FN and TF were lower in the active CS group. The HR-pQCT showed that patients with CS had lower values of mean CtArea, total vBMD, cortical vBMD and CtTh, as shown in Table 2.
Age (P = 0·69), gender (P = 0·28) and BMI (P = 0·11) were similar between patients with eugonadal CS and eugonadal controls. The same densitometric and microarchitectural alterations found in the whole CS group persisted in the eugonadal CS subgroup.
Gender (P = 0·86), BMI (P = 0·56) and gonadal status (P = 0·09) were similar between active CS patients with and without type 2 DM. It was not possible to compare bone density measured by DXA nor the HR-pQCT parameters as patients with DM were older (P = 0·02). However, the BMD Z-score values and prevalence of low-trauma fractures were not significantly different between the groups.
Age (P = 0·28), gender (P = 0·14) and BMI (P = 0·20) were similar between active CS patients with and without low-impact fractures. The comparison of DXA and HR-pQCT parameters between these patients showed no significant difference.
Results
Patients' Characteristics
The population studied included 30 patients (24 women and 6 men) with endogenous active CS and 51 healthy controls. Age range was 13–69 years in CS and 19–65 years in control group. There were 22 (73·3%) patients with Cushing's disease (CD), six (20%) patients with cortisol-producing adrenal adenoma and two (6·6%) patients with ectopic ACTH syndrome. All male and most female CS patients and controls were eugonadal, as only six individuals were postmenopausal women (5 CS and 1 control), not receiving hormone replacement therapy. One patient with CS was receiving substitutive thyroid hormone therapy that maintained free T4 serum level within the normal range. There were no growth hormone-deficient patients in our series.
Glomerular filtration rate was at or above 60 mL/min/1·73 m according to MDRD calculation, and serum calcium corrected for albumin and intact PTH was normal in all participants. No control patient and fourteen patients with CS had type 2 diabetes mellitus (DM); two of them had HbA1c above 7·0% at the time of evaluation. The characteristics of the entire sample are summarized in Table 1.
At bone densitometry, none of the controls but 70% of the active CS had a lower than expected Z-score. In the five postmenopausal women and in two men 50 years and older with active CS, DXA scan showed a high prevalence of osteoporosis (28%) and osteopenia (42%). The prevalence of VF in CS patients was 30·4%. Two patients had grade 3 and the others had grade 1 VF. Considering all low-impact fractures (vertebral and nonvertebral), the prevalence was 46·7%. The nonvertebral fractures occurred at wrist (n = 2), ankle (n = 3), hip (n = 1), elbow (n = 1), ribs (n = 2), patella (n = 1) and proximal humerus (n = 1).
Comparison Between Patients With Active CS and Controls
Age, gender and BMI were similar in both groups. aBMD and Z-score values in the LS, FN and TF were lower in the active CS group. The HR-pQCT showed that patients with CS had lower values of mean CtArea, total vBMD, cortical vBMD and CtTh, as shown in Table 2.
Comparison Between Patients With Eugonadal Active CS and Eugonadal Controls
Age (P = 0·69), gender (P = 0·28) and BMI (P = 0·11) were similar between patients with eugonadal CS and eugonadal controls. The same densitometric and microarchitectural alterations found in the whole CS group persisted in the eugonadal CS subgroup.
Comparison Between Active CS Patients With and Without DM
Gender (P = 0·86), BMI (P = 0·56) and gonadal status (P = 0·09) were similar between active CS patients with and without type 2 DM. It was not possible to compare bone density measured by DXA nor the HR-pQCT parameters as patients with DM were older (P = 0·02). However, the BMD Z-score values and prevalence of low-trauma fractures were not significantly different between the groups.
Comparison Between Active CS Patients With and Without Fractures
Age (P = 0·28), gender (P = 0·14) and BMI (P = 0·20) were similar between active CS patients with and without low-impact fractures. The comparison of DXA and HR-pQCT parameters between these patients showed no significant difference.
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