Cross-cultural adaptation and validation of diabetes-39 in Turkish patients with type 2 diabetes

Abstract

Purpose

To translate Diabetes-39 quality of life scale (D-39) into Turkish, to accomplish a cross-cultural adaptation, to demonstrate validity and reliability of Turkish version (D-39-TR).

Methods

A total of 214 patients with type 2 diabetes were included, with an average age of 52.59 ± 14.83, a female/male ratio of 51/49%. Internal consistency and test–retest reliability were assessed by Cronbach’s alpha coefficient and intraclass correlation coefficient (ICC), respectively. For structural validity, factor analysis was used. The SF-36 was used for convergent validity, and hemoglobin A1c (HbA1c) was used for differential validity.

Results

The Cronbach’s alpha coefficient was over 0.70 for all subscales of D-39-TR and it was 0.93 for whole D-39-TR. No problematic items were detected in the scale. The ICC for test–retest reliability was 0.91 (95% CI 0.91–0.94). The test–retest consistency for the total score was r = 0.94, p < 0.001. D-39-TR was explained by five factors. The ratio of explaining the total variance of these 5 factors was determined as 53.97%. SF-36 (r=−0.48, p < 0.001) and HbA1c values (r = 0.31, p < 0.001) were moderately correlated with total score of D-39-TR. A significant difference was found between QoL values of patients with poor and good glycemic control (p < 0.001).

Conclusion

Turkish version of D-39 is a reliable and valid scale for measuring QoL in patients with type 2 diabetes.

IMPLICATIONS FOR REHABILITATION

• The Turkish version of the Diabetes-39 (D-39) is a valid and reliable questionnaire and can be used in patients with type 2 diabetes.

• The Turkish version of the D-39 offers a useful tool for better identifying quality of life of patients with type 2 diabetes who are at risk for adverse outcomes.

• The Turkish version of the D-39 can be used to evaluate the effectiveness of attempts to increase quality of life in patients with type 2 diabetes.

Keywords:

• Type 2 diabetes
• quality of life
• questionnaire
• validity
• reliability

Ethical approval

Our study was conducted in accordance with the Helsinki declaration. Permission has been obtained from J. Gregory Boyer, developer of the questionnaire, for the Turkish translation of D-39. The compliance of the study with the ethical principles was approved by the Cyprus Science University Ethics Committee.

Disclosure statement

No potential conflict of interest was reported by the author(s).