Background: Optimal needle length for subcutaneous insulin injection may differ for obese and nonobese patients, which could affect management of diabetes mellitus (DM).
Objective: The aim of this study was to determine whether 31 gauge (G) x 6 mm (shorter) needles are appropriate alternatives to 29 G x 12.7 mm (longer) needles in obese patients with DM.
Methods: A multicenter, open-label, randomized, 2-period crossover trial was conducted in insulin-treated patients with type 1 or 2 DM with body mass index >or=30 kg/m(2) and glycosylated hemoglobin A(1c) (HbA(1c)) concentration <or=10%. All patients used the same injection device and were randomized to receive 12 weeks of therapy with 1 injection site (thigh or abdomen) and 1 of the 2 needle lengths. Patients used the same injection site but the alternate needle during the second 12-week period.
Results: Sixty-two patients (31 men, 31 women; mean [SD] age, 50.5 [10.6] years; age range, 20-73 years) received treatment. Fifty-six patients completed all 24 weeks of treatment. No differences in glycemic control were found. Double-blind assessments of pain scores and leakage measurements, and results from the World Health Organization Diabetes Treatment Satisfaction Questionnaire and most sections of the Insulin Treatment Satisfaction Questionnaire (ITSQ), indicated no differences. However, patients indicated greater satisfaction with the shorter needle on the ITSQ (P < 0.001). The most common adverse event was injection-site bruising (51% [30/59] for the longer needle vs 34% [21/61] for the shorter needle; P = NS). Eighty-nine percent of patients (49/55) preferred the shorter needle (P < 0.001), and 76% (42/55) had a strong, very strong, or extremely strong preference for it.
Conclusions: In obese patients, use of 31 G x 6 mm and 29 G x 12.7 mm needles produced comparable HbA(1c) values, double-blind pain and leakage scores, convenience, and ease of use. However, patients preferred the shorter needle.