Hypothyroidism (primary)

INTRODUCTION: Hypothyroidism is six times more common in women, affecting up to 40 in 10,000 each year (compared with 6/10,000 men). METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for clinical (overt) hypothyroidism? What are the effects of treatments for subclinical hypothyroidism? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). RESULTS: We found nine studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. CONCLUSIONS: In this systematic review, we present information relating to the effectiveness and safety of the following interventions: levothyroxine, and levothyroxine plus liothyronine. QUESTIONS What are the effects of treatments for clinical (overt) hypothyroidism?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 What are the effects of treatments for subclinical hypothyroidism?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 INTERVENTIONS TREATING OVERT HYPOTHYROIDISM Likely to be beneficial Levothyroxine (L-thyroxine)* . . . . . . . . . . . . . . . . . . . 3 Unlikely to be beneficial Levothyroxine (L-thyroxine) plus liothyronine compared with levothyroxine alone** . . . . . . . . . . . . . . . . . . . . . 4 SUBCLINICAL HYPOTHYROIDISM Unknown effectiveness Levothyroxine (L-thyroxine) . . . . . . . . . . . . . . . . . . . . 8 Footnote *No RCT evidence, but there is clinical consensus that levothyroxine is beneficial in clinical (overt) hypothyroidism. A placebo-controlled trial would be considered unethical. **We don't know whether a subgroup of people with thyroid hormone pathway polymorphisms improve with combination treatment levothryoxine plus liothyronine compared with levothyroxine alone.