Psychometric evaluation of a Brazilian version of the impact of weight on quality of life (IWQOL‐Lite) instrument

Abstract

The IWQOL-Lite is the first specific instrument validated in Brazil for assessing quality of life in obesity. The results reveal that IWQOL-Lite is an instrument with good psychometric properties. Nevertheless, in some cases results were dissimilar to those reported in earlier studies using the original American English.

Psychometric Evaluation of the IWQOL-Lite (Spanish Version) When Applied to a Sample of Obese Patients Awaiting Bariatric Surgery

“…Similarly, these Spanish patients scored slightly higher on physical function, self-esteem, and work and had higher total transformed scores, than did the severely obese patients studied in the German validation [13] of the IWQOL-Lite (A. Mueller, personal communication). By contrast, the present study found lower quality of life in the sexual life and public distress domains compared with the German data, as well as in comparison to clinical and community samples from Brazil and Portugal [12,18]. These differences are likely due to the different nature of the samples used in these studies, since subjects seeking surgery to correct their weight problem would be expected to be more negatively affected by obesity than would other obese patients [3,35].…”

“…Scores for each subscale and a total score are obtained. Previous studies have reported adequate corrected item-total correlations and internal consistency coefficients in bariatric surgery patients, as well as in a variety of clinical and community samples [12,13,[15][16][17][18]25]. Factor analysis has also supported the construct validity of the questionnaire [15][16][17][18].…”

“…In this context, the advent of anti-obesity medications and surgical treatments [8,9] has shown that weight reduction is associated with an improvement in HRQOL [10,11], and therefore, its assessment has become important. Although generic HRQOL assessment instruments are available, the use of obesity-specific assessment tools is recommended, since they are capable of assessing particular aspects of quality of life [12]. Disorder-specific questionnaires contain items of particular relevance to a certain disease and, therefore, are better able to detect improvement or deterioration in specific aspects related to it [12,13].…”

“…Although generic HRQOL assessment instruments are available, the use of obesity-specific assessment tools is recommended, since they are capable of assessing particular aspects of quality of life [12]. Disorder-specific questionnaires contain items of particular relevance to a certain disease and, therefore, are better able to detect improvement or deterioration in specific aspects related to it [12,13].…”

“…Faced with the need for a brief and obesity-specific tool to assess HRQOL in the clinical setting, the IWQOLLite, a reduced version of the former, was subsequently developed [15]. To date, the IWQOL-Lite has demonstrated adequate psychometric properties in a variety of populations and settings [15][16][17], and it has also been validated and adapted for use in Portuguese [18], Brazilian Portuguese [12], and German [13] samples. The factor analysis of the IWQOL-Lite confirmed the existence of five domains and a total score that were related to HRQOL in obesity.…”