Comparison of injection dose force, accuracy and precision among three growth hormone injection devices.

Successful growth hormone (GH) therapy requires sustained treatment adherence, usually over long periods of time. However, adherence rates are often poor and this can lead to suboptimal clinical outcomes. Developments in GH injection devices aim to help improve adherence by making daily injections easier. Injection force is an important practical aspect for patients receiving daily GH injections, particularly for patients with small hands or reduced hand strength due to muscle weakness. Norditropin FlexPro (Novo Nordisk A/S, Bagsværd, Denmark) is an easy-to-use GH injection pen device, shown here to have reduced injection force, similar dose accuracy and greater dose precision compared with Norditropin NordiFlex (Novo Nordisk A/S) and Genotropin GoQuick (Pfizer Inc., NY, USA). Easier injections may enable patients to self-administer GH more readily and therefore potentially may help improve adherence and clinical outcome.