Randomised controlled trial of a hypothyroid educational booklet to improve thyroxine adherence.

BACKGROUND Non-adherence with medication prescribed for chronic disease is ubiquitous and undermines the benefits of effective therapy. AIM To evaluate the influence of an educational booklet on thyroxine adherence and health in patients with primary hypothyroidism. DESIGN OF STUDY Unblinded randomised clinical trial of individual patients (by stratified permutated blocks) to receive an 'educational booklet' or 'usual care'. SETTING Three general practices in the north-west of England serving 497 adults with primary hypothyroidism (prevalence 1.5%). METHOD A total of 332 adults who had been prescribed thyroxine for hypothyroidism were allocated to either a group that was posted a hypothyroid booklet addressing lay health beliefs or to a group that received usual care. Outcomes were mean within-subject change over 3 months in thyroid stimulating hormone (TSH), the SF-36 domains of vitality and general health, and a hypothyroid symptoms index. All results were concealed until the end of the trial. RESULTS A total of 332 randomised patients were analysed by 'intention to treat' (TSH available for 330 patients). Groups were comparable at baseline, although 'undetectable TSH' was higher in the intervention than the control group (20% versus 13%). Mean change in TSH was -0.11 mIU/L (intervention) and -0.12 mIU/L (control). An absolute difference of 0.01 mIU/L (95% confidence interval [CI] -0.93 to 0.94 mIU/L). Analysis adjusted (ANCOVA) for baseline TSH produced a difference of -0.12 mIU/L (95% CI = -1.97 to 1.95). Changes in SF-36 and hypothyroid index were minimal. Trial participants were younger than non-participants and more likely to have a previous TSH in the normal range. CONCLUSION Brief intervention with an educational booklet has no influence on thyroxine adherence or health in patients with primary hypothyroidism. These findings do not support the routine distribution of health educational materials to improve medication adherence.