User experiences with second-generation 32-gauge x 4 mm vs. thinner comparator pen needles: prospective randomized trial

Objective Two similarly designed studies compared user experiences with a second-generation extra-thin-wall, 5-bevel 32 G x 4 mm pen needle (PN) with redesigned hub versus four thinner commercially available PNs. Methods Adults (18-75 years old) with type 1 or type 2 diabetes and >= 3 months of experience with pen injectors qualified for single-visit, single-blinded randomized studies. The investigational 32 G PN was compared with three 33-34 G x 3.5-4 mm PNs in Study 1 and one 34 G x 4 mm PN in Study 2. Participants completed 12 abdominal injections of 0.3 mL sterile saline using insulin pens in 6 pairs, each comprising one investigational 32 G PN and one comparator PN in random order. After each injection pair, participants compared injection pain via relative 150 mm visual analog scale (VAS) and perceived dose delivery force via relative 5 point Likert scale. Adjusted models tested injection pain scores (primary endpoint) for noninferiority and, if met, then for superiority. ClinicalTrials.gov identifiers: NCT03878758 and NCT03878745. Results The investigational 32 G PN met noninferiority as well as superiority criteria for less injection pain vs. each comparator (p< .01), with adjusted mean relative VAS scores 9.1-17.6 in Study 1 (n = 154) and 7.3 in Study 2 (n = 55). The investigational 32 G PN was also superior vs. each comparator PN in requiring less relative perceived force to deliver the dose (p< .01). Conclusions The investigational 32 G PN was associated with less participant-reported injection pain and less perceived dose delivery force compared with four thinner PNs, suggesting no additional pain reduction or force reduction benefit conferred by the thinner PNs.