Takeaway
- In patients with hypothyroidism, high concentrations of thyroid-stimulating hormone (TSH) are associated with increased risk of cardiovascular disease (CVD) and fractures, while both high and low TSH concentrations are linked to increased mortality risk.
Why this matters
- This study indicates that long-term health outcomes are not adversely affected by hypothyroidism as long as TSH levels are within the recommended normal range.
Key results
- High TSH (>10 mIU/L) was associated with increased risk of ischaemic heart disease (HR, 1.18; P=.03), heart failure (HR, 1.42; P<.001), and fragility fractures (HR, 1.15; P=.03) compared with normal TSH (2-2.5 mIU/L).
- Low TSH was associated with reduced risk of heart failure (HR, 0.79; P=.04 for <0.1 mIU/L; HR, 0.76; P=.006 for 0.1-0.4 mIU/L).
- Mortality risk was increased in patients with low TSH (HR, 1.18; P<.001 for <0.1 mIU/L) and in patients with high TSH (HR, 1.29; P<.001 for 4-10 mIU/L; HR, 2.21; P<.001 for >10 mIU/L).
Study design
- 162,369 patients with hypothyroidism (863,072 total TSH measurements) were analysed for TSH levels and associations with CVD, fractures, and mortality.
- Funding: None.
Limitations
- Retrospective study.
References
References
