A multicenter, randomized, open-label, comparative, two-period crossover trial of preference, efficacy, and safety profiles of a prefilled, disposable pen and conventional vial/syringe for insulin injection in patients with type 1 or 2 diabetes mellitus

Clin Ther. 2003 Nov;25(11):2836-48. doi: 10.1016/s0149-2918(03)80337-5.


Background: The accuracy and convenience of pen devices for insulin injection have improved quality of life for patients with insulin-treated diabetes mellitus (DM). Prefilled, disposable pens have the advantage of simplicity, with minimal training and attention required and no installation of new cartridges necessary.

Objective: The aim of this study was to assess patient preference, efficacy, and safety profiles of a prefilled, disposable pen (FlexPen) and conventional vial/syringe injection method for insulin injection therapy among patients with DM.

Methods: In a multicenter, randomized, open-label, crossover study, patients with type 1 or 2 DM were transferred from previous QD or BID conventional insulin therapy to a mixture of 70% insulin aspart protamine suspension and 30% insulin aspart injection (NovoLog Mix 7030) for 4 weeks of dose optimization using their usual type of syringe. Patients were then randomly assigned to use either vial/syringe or a prefilled, disposable pen to inject the biphasic insulin aspart 7030 mixture for the next 4 weeks, followed by 4 weeks of use of the other injection device. Efficacy, safety profiles, and patient preference for the delivery systems were compared.

Results: A total of 121 patients (mean [SD] age, 57.0 [12.4] years; age range, 28-81 years; mean [SD] body mass index, 31 [5.5] kg/m(2)) were enrolled. One hundred three patients completed the study. Seventy-four percent of patients (78105) indicated a preference for the pen over the vial/syringe method (95% CI, 71%-87%), compared with 20% (21105) who preferred the vial/syringe. Eighty-five percent (88104) considered the pen more discreet for use in public (compared with 9% [9104] for the vial/syringe), 74% (77104) considered it easier to use overall (compared with 21% [22104] for the vial/syringe), and 85% (89105) found the insulin dose scale on the pen easier to read (compared with 10% [10105] for the vial/syringe). Patients had statistically significant improvement in glycosylated hemoglobin values during the study (P < 0.05). No statistically significant differences in fasting plasma glucose, mean 4-point blood glucose profiles, or serum fructosamine values were found between groups. Overall, the safety profiles during treatment periods with the pen were comparable to those with the vial/syringe.

Conclusions: In this trial, differences in efficacy and safety profiles between the vial/syringe and prefilled, disposable pen appeared negligible. However, more patients expressed a preference to continue use of the pen.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cross-Over Studies
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Disposable Equipment
  • Female
  • Humans
  • Injections, Subcutaneous / instrumentation
  • Insulin / administration & dosage*
  • Insulin / analogs & derivatives*
  • Insulin / therapeutic use
  • Insulin Aspart
  • Male
  • Middle Aged
  • Patient Compliance
  • Patient Satisfaction
  • Quality of Life
  • Syringes*


  • Insulin
  • Insulin Aspart