Psychometric properties of Persian Diabetes-Mellitus Specific Quality of Life (DMQoL) questionnaire in a population-based sample of Iranians

  • Mohsen Saffari
  • Chung-Ying Lin
  • Keisha O’Garo
  • Harold G. Koenig
  • Hormoz Sanaeinasab
  • Amir H. PakpourEmail author
Original Article


Health-related quality of life (HRQoL) among patients with diabetes mellitus is often poorer than in those with other chronic medical conditions. Appropriate disease specific measures are needed to measure HRQoL in these patients. This study sought to validate a culturally adapted version of the Diabetes-Mellitus Specific Quality of Life (DMQoL) questionnaire module in Persian. Concurrent validity of the scale was assessed by the Diabetes Quality of Life (DQOL) questionnaire. Convergent and discriminative validity of the DMQoL was determined using a brief version of World Health Organization’s Quality of Life Scale Brief version (WHOQOL-BREF), Hospital Anxiety and Depression Scales (HADS), and Medication Adherence Report Scale (MARS). Construct validity was examined using confirmatory factor analysis. Rasch analysis was also performed to examine the unidimensionality of the DMQoL. Known-group method was used to examine the ability of the scale to differentiate between different categories of patients. A sample of 824 patients (512 females) with diabetes mellitus was recruited from diabetic care centers located in Qazvin, Iran. The mean age of participants was 54.1 (SD 6.3) and 27% were smokers. All items loaded on a single factor (factor loadings ≥ 0.6) and internal consistency of the scale was acceptable (α = 0.89). Significant associations were found between the scale and DQOL, indicating concurrent validity (p < 0.001). The DMQoL was able to differentiate subgroups of patients with hypertension, HbA1c, cholesterol, and diabetic diet. All items were appropriate with regard to difficulty level and confirmatory factor analysis verified the scale’s single dimension (CFI = 0.927; RMSEA = 0.067). Persian DMQoL is a reliable and valid measure of HRQoL in a Persian-speaking population with type II diabetes. Further assessment is needed to confirm the psychometric properties of the scale in other cultures and languages. Future studies are needed to determine the sensitivity of the scale to change over time in response to treatment.


Diabetes mellitus Health-related quality of life Psychometrics Validity Reliability 



The authors would like to thank Huang-tzOu and her colleagues who granted us permission to use the DMQoL. Also, we are grateful for the support from Qazvin University of Medical Sciences, Deputy of Health that facilitated data collection for this study.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

The study was approved by the Ethic Committee at Qazvin University of Medical Sciences, and all patients gave written informed consent prior to participation.


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Copyright information

© Research Society for Study of Diabetes in India 2018

Authors and Affiliations

  1. 1.Health Research Center, Life Style InstituteBaqiyatallah University of Medical SciencesTehranIran
  2. 2.Health Education Department, School of HealthBaqiyatallah University of Medical SciencesTehranIran
  3. 3.Department of Rehabilitation SciencesThe Hong Kong Polytechnic UniversityHung HomHong Kong
  4. 4.Division of Psychology, Department of PsychiatryDuke University Medical CenterDurhamUSA
  5. 5.Duke University Medical CenterDurhamUSA
  6. 6.King Abdulaziz UniversityJeddahSaudi Arabia
  7. 7.Ningxia Medical UniversityYinchuanChina
  8. 8.Social Determinants of Health Research Center (SDH)Qazvin University of Medical SciencesQazvinIran
  9. 9.Department of Nursing, School of Health and WelfareJönköping UniversityJönköpingSweden

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