Comorbidities of hypothyroidism

Hypothyroidism is a relatively common condition that may affect as many as 10% of the population worldwide when its overt and subclinical presentations are considered. Important clinical comorbidities are highly prevalent in people with hypothyroidism and diminish quality of life and functional status in a manner that is proportional to the number of comorbidities present and their severity. This article reviews the common comorbidities of hypothyroidism, as reported in the literature. The comorbidities of hypothyroidism include clinical conditions commonly associated with hypothyroidism, such as dyslipidaemia, hypertension, fatigue or (possibly) cardiovascular disease, and can appear whether or not intervention with LT4 is applied appropriately to ensure biochemical euthyroidism. Other comorbidities may share some pathogenetic background with hypothyroidism, including depression or anxiety, or autoimmune conditions. Hypothyroidism may arise as a comorbidity of some other conditions, e.g. following the application of targeted cancer therapies or some disease-modfying treatments for multiple sclerosis. Other common treatments, including metformin, glucocorticoids or proton pump inhibitors, among others, may alter levels of thyrotropin, thus impacting on the monitoring of thyroid dysfunction and the diagnosis of thyroid dysfunction. Ensuring good control of hypothyroidism is a necessary first step in managing any patient with hypothyroidism. Then, physicians should be aware of the possibility of other comorbid conditions that must be addressed to achieve an optimal patient outcome.