Comparison of intuitiveness, ease of use and preference among three prefilled, disposable growth hormone injection...

Growth hormone (GH) therapy is an effective treatment for growth failure in children. Adherence rates are often low, resulting in poor linear growth. Intuitive and easy-to-use injection devices may improve adherence.

To determine injection time, ease of use, intuitiveness and subjects' preference for Norditropin FlexPro (FP) pen (Novo Nordisk A/S, Denmark) versus Genotropin GoQuick (GQ; Pfizer Inc., USA) and Norditropin NordiFlex (NF; Novo Nordisk) pens.

Subjects aged ≥ 10 to < 18 years, with GH deficiency, Turner syndrome or short stature following small-for-gestational-age birth were randomized to intuitiveness (no instruction) or instruction groups. Time taken to perform an injection, dose accuracy and errors were recorded. Intuitiveness, ease-of-learning and overall preference were assessed using questionnaires.

Sixty-four subjects, randomized to intuitiveness (n = 32; mean [SD] age, 13.1 [2.1] years) and instruction (n = 32; 13.4 [2.0] years) groups, required less time to perform the injection with FP than with GQ (mean [SD], intuitiveness 39.8 s [17.0] vs. 65.6 s [42.9], p < 0.01; instruction 40.7 s [19.7] vs. 48.1 s [25.8], p < 0.05), and a similar amount of time with NF. NF and FP were more accurate than GQ (intuitiveness group only). Fewer errors were recorded with NF followed by FP and GQ. FP and NF were considered easier to learn than GQ in both groups. In the intuitiveness group, the majority of subjects (31/32) felt confident using FP without instruction. FP was the device of overall preference in both groups.

FP was the device that was most intuitive, easiest to use and the device of overall preference.