Objective:
This paper describes the processes involved to ensure a diabetes-specific
quality of life questionnaire [the “Audit of Diabetes Dependent
Quality of Life” (ADDQoL)] retained the psychometric properties
following cross-cultural adaptation from English to Portuguese.
Methods: One hundred patients were recruited through community
pharmacies located in Lisbon through a cross-sectional study design.
Patients were asked to respond to the questionnaire on one occasion
in time. Data were subjected to factor analysis, and internal
consistency and discriminatory power analyses were undertaken.
Results: In the Portuguese sample, 17 items loaded into one factor,
with factor loadings above 0.43. The item “worries about the future”
loaded weekly into this factor but if removed its internal consistency
estimate increased very slightly (Cronbach’s alpha=0.89 to 0.90).
A greater negative impact of diabetes on 16 of the 18 quality
of life domains was detected for insulin-treated patients, together
with a greater negative impact on 14 of the 18 quality of life
domains for patients with diabetic complications. The domain “freedom
to eat” revealed the greatest negative impact in all patient subgroups,
as described in its original version, so the psychometric properties
were retained.
Additionally, patients without diabetic complications reported
a worse quality of life (greater negative impact) on the first
overview item, present quality of life (Z=-2.25; p=0.024); whilst
patients on insulin reported a greater negative impact of diabetes
on their quality of life (Z=-1.94; p=0.053).
Conclusion: Generally, the Portuguese version for Portugal of
the ADDQoL has shown to maintain its original psychometric properties,
and could be recommended for use and further evaluation in subsequent
studies.
