Objective: The shortest pen needle (PN) for subcutaneous insulin therapy is 4 mm. Clinicians may hesitate to use it in obese patients. We report a post hoc analysis of a previously published study of the 4 mm × 32 G PN, evaluating responses in obese (≥30 kg/m(2)) and non-obese (<30 kg/m(2)).
Methods: Subjects (BMI 20 to 49 kg/m(2), 52% obese) with diabetes used 4 mm × 32 G PNs and either 5 mm or 8 mm PNs (both 31 G) in two, 3-week treatment periods in a randomized noninferiority cross-over trial. Percentage absolute change in fructosamine (%│Δ Fru│) was the primary endpoint. Equivalent glycemic control was defined as %│Δ Fru│ within 20% (including 95% CI). The impact of obesity on change in fructosamine, pain and reported insulin leakage from the skin is described.
Clinical trial registration: Clinicaltrials.gov - identifier: NCT00928057.
Limitations: This report is a post hoc analysis of two BMI subgroups resulting in smaller sample sizes.
Results: Of 168 who completed the study, 163 were included in the fructosamine analyses - 83 and 80 in the 4/5 mm and 4/8 mm groups, respectively. For the 4/5 mm group, mean BMI ± SD in non-obese and obese groups were 25.9 ± 2.3 and 35.0 ± 4.9 kg/m(2), respectively; 4/8 mm group 25.2 ± 2.6 and 35.6 ± 4.2 kg/m(2). BMI group was not significant for %│Δ Fru│ for either 4/5 mm or 4/8 mm. Between BMI groups, the difference of the means in %│Δ Fru│ was 0.4% (4/5 mm) and 0.3% (4/8 mm). The 4 mm PN was significantly less painful in all subject groups, except non-obese in 4/5 mm. Regardless of needle size, obese subjects reported more leakage events. For both BMI groups, there were fewer total reported leakage events when using the 4 mm vs 5 mm and 8 mm needles.
Conclusions: The 4 mm pen needle provided equivalent glycemic control in both obese and non-obese patients compared to 5 mm and 8 mm needles with no increase in reports of skin leakage, in this post-hoc analysis. These findings should be confirmed in a prospective randomized controlled trial.