Hypothyroidism and the risk of lower extremity arterial disease.
BACKGROUND
Although an independent association between hypothyroidism and coronary artery disease has been demonstrated, few studies have examined the association between hypothyroidism and peripheral arterial disease. In the current study, we test the hypothesis that there is an independent association between hypothyroidism and lower extremity arterial disease.


METHODS
We retrospectively compared the prevalence of hypothyroidism in patients who had infra-inguinal arterial bypass surgery over a 6-year period with that of a control group of surgical patients who had pure cardiac valve surgery during the same time period. Both unadjusted and adjusted odds ratios were calculated to estimate the association between hypothyroidism and lower extremity arterial disease.


RESULTS
A total of 614 cases and 529 control subjects had surgery during the study period. When comparing all subjects, there was no association between hypothyroidism and lower extremity arterial disease (unadjusted odds ratio 0.88; 95% confidence intervals [CI]: 0.61-1.28). However, gender was found to be a significant effect modifier (P < 0.001), and gender-stratified analyses were subsequently performed. In men, there was a positive independent association between hypothyroidism and lower extremity arterial disease (adjusted odds ratio 2.65; 95% CI: 1.19-5.89), whereas in women there was a negative independent association (adjusted odds ratio 0.22; 95% CI: 0.11-0.46).


CONCLUSIONS
Gender is a significant effect modifier for the association between hypothyroidism and lower extremity arterial disease. The association is positive in men and negative in women. Future prospective studies that evaluate hypothyroidism as a risk factor for peripheral arterial disease should consider gender stratification in order to corroborate this finding.
Department of Anesthesiology, Mount Sinai School of Medicine, New York, NY, USA. michael.mazzeffi@mssm.edu
Michael A
MA
Mazzeffi
Hung-Mo
HM
Lin
Brigid C
BC
Flynn
Thomas L
TL
O'Connell
David E
DE
DeLaet
D000368:Aged; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D005260:Female; D005263:Femoral Artery / Q000601:surgery; D006801:Humans; D007037:Hypothyroidism / Q000150:complications*; D007866:Leg / Q000098:blood supply; D008297:Male; D016017:Odds Ratio; D058729:Peripheral Arterial Disease / Q000209:etiology* / Q000601:surgery; D011150:Popliteal Artery / Q000601:surgery; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D016909:Tibial Arteries / Q000601:surgery