A comparison of two measures of quality of life of Nigerian clinic patients with type 2 diabetes mellitus.

BACKGROUND We present data comparing the quality of life effects of type 2 diabetes determined by the Bradley well-being questionnaire and the WHOQOL-BREF, a generic instrument. We also present data on the reliability and validity of these instruments. METHOD The Well-being and the WHO-bref were administered on fifty-three consecutive type 2 diabetics. The internal consistency of the quality of life scales was assessed using Cronbach's alpha. Convergent, discriminant, and known groups validity were determined and compared. RESULTS Our patients had a mean age of 55.8+/-13 years. 31(58.5%) were males and all patients had been diabetic for 7.9+/-7.1 years. 13(24.5%) were being treated with oral agents, 14(26.4%) were on insulin and 26(49.1%) were on combined therapy. The Cronbach alpha coefficients ranged from 0.31 to 0.72 on the Well-being subscales and from 0.47 to 0.78 on the WHOQOL-BREF subscales. Both scales were modestly related to one another. In general the quality of life measures were not influenced by characteristics such as age, gender, marital or educational status. Both scales were not influenced significantly by treatment type or the severity or number of complications. CONCLUSION Our study has shown how two different measures of quality of life perform in patients with type 2 diabetes. Even though the subscales of the Well-being and WHOQOL-BREF were not very sensitive to external criteria of disease impact (complications) casting a doubt on their utility as psychological outcome measures, they demonstrated fairly reasonable internal consistency in our patients with type 2 diabetes. Further larger studies are thus required to clarify this given our present limitations.