Influência da função tireoidiana nos níveis séricos de CPK Influence of thyroid function in CPK serum levels

Objective: To determine serum CPK variation based on TSH e free T4 (FT4), and to assess serum CPK in pathological states of the thyroid (hyperthyroidism and hypothyroidism), in relation to the euthyroidism. Materials and methods: We evaluated retrospectively 6,230 laboratory results of TSH and CPK from 2007 to 2011. From these, 3,369 had free T4 results. We evaluated the corre- lation between CPK and TSH and the pathological states of the thyroid. Results: The correlation between TSH and CPK was positive (r = 0.065), while that between CPK and FT4 was negative (r = -0.091, p < 0.05). From the total of results analyzed, 586 (9.4%) were measures of hyperthyroi- dism, with a median (range) of CPK of 98 U/L (27 to 1,113), and 556 (8.9%) were of hypothyroidism, with CPK of 114 U/L (25-4,182). Conclusion: A positive correlation was found between serum CPK and TSH, and a negative correlation between CPK and FT4. CPK was lower in the group with hyperthyroidism, and greater in that with hypothyroidism. Arq Bras Endocrinol Metab. 2012;56(3):190-4