EQ-5D-5L Bulgarian population norms

The present study aimed to provide normative data for the EQ-5D-5L questionnaire in Bulgaria, based on a nationally representative sample.

Random sampling was used. In September 2018, a total of 1005 respondents (aged 18-89 years) completed the self-administered paper-based EQ-5D-5L questionnaire, including a visual analogue scale (EQ VAS). Health state utility index scores were derived using the directly measured Polish value set.

The study sample was representative of the general Bulgarian population in terms of age, sex, geographical region, educational level, social and professional status. Mean EQ-5D-5L and EQ VAS values decreased from 0.986 and 89.7 (age group 18-24 years) to 0.789 and 53.6 (age group ≥ 75 years), respectively. Perfect health (the "11,111" health state) was reported by half of the population (50.1%), more often by men than women (55.8% vs 44.9%). The most frequently reported complaints characterised pain/discomfort dimension (39.1%), followed by anxiety/depression (34.5%). Although the least commonly reported health limitations concerned the self-care dimension, their frequency (13.6%) was the highest among the seventeen identified EQ-5D-5L population norm studies. The mean severity index score for the whole study sample was 6.96. EQ-5D-5L index was higher in respondents from lower age groups and with a higher average income per household member.

Bulgarian population norms, which were developed for the descriptive part of the EQ-5D-5L and EQ VAS, can be used as reference values. The availability of such normative data should encourage the use of the EQ-5D-5L questionnaire in health-related quality-of-life studies in Bulgaria.