The research has been designed as cross-sectional and was conducted by interviewing respondents using the two questionnaires. The first questionnaire included basic information about the patient: age, gender, work and marital status, body weight and height, BMI, self-assessment of the body weight’s impact on the health and quality of life. The second questionnaire evaluated the quality of life (WHOQoL-BREF). We have conducted the pilot study on 232 respondents with the purpose of the questionnaire validation, and based on those answers the questionnaire was updated.
Interviewing was conducted during one month of September 2019 n 10 outpatient clinics of Health Care Center Mostar. All the patients who visited the outpatient clinic in that period were interviewed, regardless of the reason for the visit. Patients with severe mental illnesses (severe depression, schizophrenia, mental retardation or impaired development), cancer (within 5 years of illness development), impaired cognition, pregnant women, handicapped patients and people who did not want to participate were excluded from the study. Overall, 1300 questionnaires were distributed, and 1067 were valid for analysis. The response rate was 82.08 %.
Respondents were divided into categories by gender, age in decades (from 30 to 70 and more), education degree (elementary, high school, college and faculty), marital status (married or other) and working status (employed, unemployed/employment bureau, retired). Results were observed in all individual groups.
Respondents were provided with an informational sheet to be familiarized with the research aims to which they have given their consent. The researcher filled the socio-demographic data (age, gender, education degree, working and marital status) based on patient’s statement. Further, anthropometric measurements, height and weight, were performed and BMI was calculated. Respondents were categorized by BMI into the following groups: BMI <18.5 kg/m2, BMI 18.5 – 24.9 kg/m2, BMI 25 – 29.9 kg/m2, BMI 30 – 34.9 kg/m2 and BMI >35 kg/m2 (14).
To evaluate the quality of life, the World Health Organization WHOQoL-BREF questionnaire, consisting of 26 questions with structured responses on a Likert scale of five points, was used. The questionnaire was self-administered, based on the perception of the last two weeks. Of the 26 questions, 24 questions comprise the physical, psychological, social and environmental domains and the other two assess the perception of quality of life and patient’s health [15-16]. The physical domain includes the questions related to daily activities such as pain and discomfort, energy and fatigue, sleep and rest, dependence on the medications, work and mobility. The psychological domain consists of questions regarding the positive and negative feelings, meaning of life, self-esteem, body image, physical appearance, personal beliefs and ability to concentrate. The domain of social relationship is related to personal relationships, social support and sexual activity. The environmental domain investigates the physical security and safety, financial resources, physical and home environment, availability of health and social care, leisure activities, opportunities for new information and skills acquisition as well as opportunities for recreation and transport and participation in those.
Statistical analysis
The collected data were analyzed in Microsoft Excel 2007 (Microsoft Corporation, Redmond, WA, USA) and SPSS for Windows (version 17.0., SPSS Inc. Chicago, Illinois, USA). Descriptive analyses were performed including absolute frequencies, relative frequencies (percentages, %), means (M) and standard deviations (SD). Cronbach's alpha (internal consistency index) was used to estimate the reliability of the WHOQoL-BREF (Cronbach's alpha values of 0.70 and over were deemed acceptable). Pearson's correlation coefficient was used to investigate the correlation between BMI and QoL domains.
Independent t-test and ANOVA were used to investigate the difference ih QoL regarding participants’ socio-demographic characteristics. Original scores of QoL domains were used for statistical analyses. The level of significance was set at p <0.05. P values that cannot be expressed up to three decimal places are shown as p <0.001.
The Cronbach's alpha coefficient of WHOQoL-BREF in general and of their domains was adequate: 0.935 for all 26 questions, 0.928 for 24 questions, 0.862 for Physical health domain, 0.843 for Mental health domain, 0.686 for Social relationship domain and 0.810 for Environmental health domain. There are statistically significant correlations between overall QoL, overall health and all QoL domains (Table 1).