Adherence to treatment in children with growth hormone deficiency, small for gestational age and Turner syndrome in Mexico: results of the Easypod™ connect observational study (ECOS)

BACKGROUND: Assessing adherence to growth hormone (GH) is challenging. The Easypod™ connect device delivers pre-set doses of recombinant human GH (r-hGH) and stores a digital record of adherence that can be shared with healthcare provider. We assessed adherence to r-hGH delivered with Easypod™ according to the approved pediatric indications for r-hGH: growth hormone deficiency (GHD), born small for gestational age (SGA) who failed to show catch-up growth and Turner syndrome (TS). METHODS: ECOS (NCT01555528) was a multicenter (24 countries), 5-year, longitudinal, observational study, which aimed to evaluate country-specific adherence to r-hGH therapy prescribed via the Easypod™ electronic injection device. The primary endpoint was yearly adherence. Secondary endpoints were height velocity, height velocity standard deviation scores (SDS), height, height SDS and IGF-1 concentrations. Clinical and auxological data were obtained from medical records and adherence from Easypod™ logs. RESULTS: This study included 147 Easypod™-naïve Mexican children assessed during 3 years (mean age: 9.96 ± 3.41 years, 56.8% boys, mean height SDS at baseline: − 2.17 ± 0.97): 118 with GHD, 24 SGA and 5 with TS. A total of 105 (71.4%) patients were GH naïve. Overall median adherence was > 90% over the first year of treatment and > 80% at 3 years. Adherence was not different by r-hGH indication or between GH-naïve or experienced patients. At 1-year follow-up, mean change in height SDS was 0.57 ± 0.34, whereas mean height velocity SDS was 2.85 ± 2.51. In all, 84.7% patients had normal IGF-1 concentrations at 1-year follow-up. Adherence was associated with change in height SDS (r = 0.239, p = 0.005) and height velocity SDS (r = 0.194, p = 0.027). CONCLUSION: Adherence rates with the Easypod™ device are high and maintained over time in GHD, SGA and TS Easypod™-naïve Mexican patients. High adherence is associated with better outcomes. Easypod™ assists physicians in monitoring adherence to r-hGH.