INS and hereditary elliptocytosis: Insulin users who reported ≥1 HE also reported less adherence to their insulin than users who were free of HEs; the relationship between HEs and adherence was not observed in oral medications, perhaps because patients understand the potential for insulin to cause hypoglycaemia, and perhaps due to the injectable mode of administration, which is more aversive than swallowing a pill and also enables dose reduction.