Subclinical Hypothyroidism Is Associated With Reduced All-Cause Mortality in Patients With Type 2 Diabetes

Subclinical hypothyroidism has been associated with a greater prevalence of cardiovascular disease (1) and is relatively common in patients with type 2 diabetes (2). If subclinical hypothyroidism contributed to an increase in cardiovascular risk, then, intuitively, its effect would be exaggerated in patients with type 2 diabetes. Patients were identified from a diabetes database at Hull Royal Infirmary from 1993–2005 for retrospective analysis. From the database, 6,540 consecutive patients enrolled through the end of 2000 were selected, and 472 patients with type 2 diabetes who had a raised thyrotropin-stimulating hormone (TSH) (on two occasions 6 months apart) and normal free T4 (fT4) were identified (subsequent case-note review reduced this number to 394 patients). They were compared with 472 consecutive age-matched …