DEXA Scanning Recommendations for Patients with Hashimoto's Thyroiditis
Patients with Hashimoto's thyroiditis should undergo DEXA scanning if they have additional risk factors for osteoporosis, particularly if they are receiving long-term glucocorticoid therapy, as thyroid disorders are considered endocrine conditions that can adversely affect bone mineral density. 1
Indications for DEXA in Hashimoto's Patients
Primary Indications:
- Patients with Hashimoto's thyroiditis who are receiving (or expected to receive) glucocorticoid therapy for >3 months 1
- Patients with Hashimoto's who have an endocrine disorder known to adversely affect BMD (including hyperthyroidism, which may occur during periods of hashitoxicosis) 1
- Postmenopausal women with Hashimoto's aged 65 years and older (standard recommendation for all women in this age group) 1
- Postmenopausal women with Hashimoto's younger than 65 years who have additional risk factors for fracture 1
Additional Risk Factors That Should Prompt DEXA Testing:
- History of fragility fracture 1
- Body weight less than 127 lb (58 kg) 1
- Parental history of hip fracture 1
- Prolonged immobilization 1
- Malabsorption or malnutrition (which may occur with autoimmune comorbidities) 1
- Chronic inflammatory disease (Hashimoto's itself is inflammatory) 2
Timing of DEXA Scans
- Initial scan: At diagnosis of Hashimoto's if other risk factors are present, particularly if starting glucocorticoid therapy 1
- Follow-up scans: Every 1-2 years for patients on glucocorticoid therapy 1
- Standard follow-up: Every 2 years for monitoring BMD changes in untreated patients with risk factors 1
Special Considerations for Hashimoto's Patients
- Z-scores (not T-scores) should be reported for premenopausal women and men under 50 with Hashimoto's, as they represent gender- and age-matched controls for evaluation of secondary osteoporosis 1
- Z-scores of -2.0 or less are considered to be below the expected age range 1
- For patients with Hashimoto's on glucocorticoid therapy, treatment should be considered at higher BMD levels (T-score <-1.5) than in postmenopausal osteoporosis 2
Recommended DEXA Scanning Sites
- DXA lumbar spine and hip(s) is the primary recommended modality (rated 9/9 for appropriateness) 1
- DXA distal forearm should be included if there are concerns about accuracy of spine measurements due to degenerative changes 1, 3
- For patients with advanced degenerative changes of the spine, QCT lumbar spine and hip may be more appropriate 1
Preventive Measures While Awaiting DEXA Results
- Counsel patients on recommended daily dietary allowances for calcium and vitamin D 1:
- Ages 19-50: 1,000 mg calcium, 600 IU vitamin D
- Ages 51-70: 1,200 mg calcium, 600 IU vitamin D
- Ages 71+: 1,200 mg calcium, 800 IU vitamin D
- Recommend lifestyle modifications including weight-bearing exercise, smoking cessation, and reducing alcohol intake 1
Treatment Thresholds Based on DEXA Results
- Treatment is recommended for T-score of -2.5 or less 1
- For T-scores between -1.0 and -2.5, FRAX can assist in making treatment decisions 1
- For patients on glucocorticoids, treatment should be considered at T-scores of <-1.5 2
- Treatment should also be considered in patients who have had a low-trauma fracture, even if DEXA does not indicate osteoporosis 1
Remember that Hashimoto's thyroiditis is considered a risk factor for bone loss as an endocrine disorder, and patients with this condition should be monitored appropriately for osteoporosis, especially when additional risk factors are present 1.