Diabetes Care, Vol 23, Issue 12 1799-1803, Copyright © 2000 by American Diabetes Association
Development and factor analysis of a questionnaire to measure patient satisfaction with injected and inhaled insulin for type 1 diabetes
JC Cappelleri, RA Gerber, IA Kourides and RA Gelfand
Pfizer Inc., Global Research and Development, Groton, Connecticut 06340, USA. joseph_c_cappelleri@groton.pfizer.com
OBJECTIVE: To develop a self-administered questionnaire to address
alternative delivery routes of insulin and to investigate aspects of
patient satisfaction that may be useful for subsequent assessment and
comparison of an inhaled insulin regimen and a subcutaneous insulin
regimen. RESEARCH DESIGN AND METHODS: Attributes of patient treatment
satisfaction with both inhaled and injected insulin therapy were derived
from five qualitative research studies to arrive at a 15-item
questionnaire. Each item was analyzed on a five-point Likert scale so that
higher item scores indicated a more favorable attitude. There were 69
subjects with type 1 diabetes previously taking injected insulin therapy
who were enrolled in a phase II clinical trial. Their baseline responses on
the questionnaire were evaluated and subjected to an exploratory factor
analysis. Meaningful factors were retained and interpreted based on their
psychometric properties. RESULTS: Exploratory factor analysis suggested a
two-factor solution accounting for 66 and 20% of the variance,
respectively. The first factor contained 10 reliable items (Cronbach's
alpha = 0.89) relating to convenience and ease of use, and the second
contained 5 reliable items (Cronbach's alpha = 0.82) relating to social
comfort. CONCLUSIONS: Among patients with type 1 diabetes, this analysis
highlighted and quantified two key factors contributing to patient
satisfaction: convenience/ease of use and social comfort. The questionnaire
underwent rigorous development, had reliable properties, and an
interpretable and rich factor structure. This report is intended to help
advance, in subsequent investigations, the understanding and measurement of
treatment satisfaction with novel and existing forms of insulin delivery.