BMC Public Health 2006, 6:268 http://www.biomedcentral.com/1471-2458/6/268 of life (HRQOL), especially in the presence of complica- tions [3-9]. However, most of the studies on diabetes and HRQOL have been conducted in developed countries (review in [10]) and studies of the HRQOL in diabetic patients in developing countries are rare [11-14]. In the Gaza strip, more than one third of the Palestinian population lives in eight very densely populated camps [15]. The prevalence of diabetes was estimated at 11% in the rural and 14% in the urban population of the West- Bank [16]. The prevalence of complications of diabetes in this population is high [17] and complications of diabetes are known to negatively affect the HRQOL of diabetic patients. In an Iranian randomized trial a health educa- tion programme considerably improved the HRQOL of diabetic patients in the intervention group [14]. However, because of the lack of controls without diabetes living under the same conditions, the authors were not able to assess to which extent the intervention reduced the gap between diabetic patients and healthy controls. In a pop- ulation-based Dutch study diabetic patients without com- plications had only slightly lower HRQOL than age matched persons in the general population [4]. However, the effects of socio-economic differences may be weaker in developed countries than in conditions of poverty in developing countries. The negative impact of socio-eco- nomic conditions on HRQOL among diabetic patients can be even stronger in refugees. The aim of our study was to examine the HRQOL of diabetic patients in a large and long-term refugee community in camps in the Gaza strip in comparison to controls living in similar conditions. We focussed on the question whether variables potentially affecting HRQOL in healthy controls have a different impact in diabetic patients. The secondary aim of the anal- ysis was to evaluate the psychometric properties of the Arabic version of a HRQOL instrument. Methods Sample For the purpose of comparison we aimed at recruiting about 200 patients with diabetes and 200 controls with- out diabetes living in the camps in the Gaza strip. We started with diabetic refugees who were randomly selected from the files in "United Nations Relief and Works Agency for Palestine" clinics (UNRWA) in the biggest three refu- gee camps in the Gaza strip: Jabalia in the North, Nuseirat in the Middle, and Rafah in the South. The sample obtained at each site was proportional to the population living in the respective regions. Inclusion criteria for patients were: being a resident of one of the three refugee camps, a diagnosis of type 1 or type 2 diabetes with treat- ment initiated at least six months prior to the study. Exclu- sion criteria were having any co-morbidities (any chronic disease not clearly related to diabetes, patients with com- plications of diabetes were not excluded) and pregnancy at the time of the survey. The distinction between co-mor- bidities and complications of diabetes was based on med- ical records of the patient. Diabetes was diagnosed according to any one of the following criteria: (1) symp- toms of diabetes and random plasma glucose concentra- tion ≥ 200 mg/dl (11.1 mmol/l), (2) fasting plasma glucose ≥ 126 mg/dl (7.0 mmol/l), (3) 2-hours plasma glucose ≥ 200 mg/dl (11.1 mmol/l) during an oral glucose tolerance test. The first 20 patients were recruited for pilot-testing the survey and were therefore excluded from the main study. Of the following 299 patients with diabetes, 67 suffered from other diseases and 7 were pregnant, leaving 225 eli- gible patients for participation. 28 patients refused to par- ticipate, resulting in a final sample of 197 (response rate of 88%). Through referrals by diabetic patients we recruited 197 refugees without diabetes or any other chronic disease living in the same camps that were matched to patients by age groups and gender. For logistic reasons the number of controls refusing participation could not be obtained. All participants were asked to com- plete a self-administered questionnaire. Data were col- lected from November 2003 to December 2004. Written informed consent was obtained from all participants. The study was approved by the Ministry of Health and the United Nations Health Office in the Gaza strip. Questionnaire We used the World Health Organization Quality of Life Questionnaire – short version (WHOQOL-BREF) to assess quality of life [18,19]. This questionnaire was developed with 15 international field centres to obtain an assessment tool that is applicable cross-culturally. It was used in 212 publications currently referenced in Medline (search term: "WHOQOL", April 2006), 4 of them dealing with diabetic patients (search term: "WHOQOL diabe- tes"). The four domains of the WHOQOL-BREF are phys- ical health, psychological (e.g. self-esteem), social relationships (e.g. social support) and environment (e.g. freedom, physical safety). Subjects rated all items on a 5 point Likert-type scale. The questionnaire was translated into Arabic language using two independent translations from English to Arabic. The translations were reviewed by the first author (A.E.) and synthesised into one version. This preliminary Arabic questionnaire was back-trans- lated into English by two independent translators. Both versions were compared and the Arabic version was revised where necessary. Raw scores for the domains of WHOQOL-BREF were cal- culated by adding values of single items and were trans- formed on the scale ranging from 0 to 100, where 100 is the highest and 0 the lowest HRQOL [20]. Additionally to the variables used for matching (gender, age and place of Page 2 of 7 (page number not for citation purposes)