Usability of a microtapered needle (TN3305) for insulin treatment in japanese patients with diabetes mellitus: a comparative clinical study with a standard thin wall needle

We evaluated the clinical usability of a microtapered needle (TN3305, "Needle T," Terumo Corp., Tokyo, Japan) by comparing it with a standard needle (Micro-Fine +, 31 gauge, 5 mm, thin wall, "Needle B," Nippon Becton Dickinson Co., Ltd., Tokyo) in a multicenter study.Ninety-nine patients with diabetes mellitus being treated in 11 Japanese hospitals were enrolled in the study. Written consent was obtained from all patients. They were allocated randomly to two groups by an envelope (crossover) method. Injections were performed using one needle first, followed by the other needle 4 or 5 days later. Pain caused by injection was evaluated using a visual analogue scale (VAS).In the overall evaluation, Needle T was chosen by 40 patients (44.4%) and Needle B by 17 (18.8%); 33 patients (36.7%) expressed no preference. VAS scores for Needles T and B were 1.48 +/- 0.18 and 2.47 +/- 0.24 cm, respectively (P0.001). In this study, lower VAS indicated less pain.The preferences and VAS scores suggested that Needle T caused less pain than Needle B. The incidence of adverse events and safety were equivalent for both needles. We believe that usability of Needle T by patients for self-injection is better.