Development and Validation of the Continuous Subcutaneous Insulin Infusion-Related Quality-of-Life (CSII-QOL) Scale

Background: Continuous subcutaneous insulin infusion (CSII) is associated with improved glycemic control, a reduced incidence of hypoglycemia, and improved quality of life (QOL). To date, however, there has been no QOL scale specific to CSII. The objective of this study was to develop and validate a scale to measure CSII-QOL for people with type 1 diabetes (T1D). Methods: A total of 50 people with T1D aged >= 15 years who used CSII (28% males; age, 47.6 +/- 17.0 years; duration of diabetes, 14.7 +/- 9.7 years; duration of CSII use, 6.1 +/- 3.3 years; HbA1c, 7.4% +/- 0.8%) took part in the CSII-QOL study. Twenty-eight potential CSII-QOL items were developed in a combined approach consisting of semistructured patient interviews, expert input, and a literature search. The resulting CSII-QOL was tested for factor analysis, validity, reliability, and influencing factors. Results: The final 25-item questionnaire had a 3-domain structure ("convenience," "social restriction," and "psychological problems"), high internal consistency (Cronbach's alpha = 0.870), and substantial test-retest reliability (intraclass correlation coefficient = 0.65). The CSII-QOL score was correlated negatively with the Problem Areas in Diabetes score. Conclusion: The CSII-QOL is the first CSII-related QOL scale for people with T1D. This short, validated, and reliable instrument might potentially be useful in future clinical studies and routine clinical patient care. Further validation is required to confirm these issues because of the small and potentially biased sample (UMIN-CTR: UMIN000031595).