An assessment of factorial structure and health-related quality of life in problem drug users using the Short Form 36 Health Survey

Abstract

To confirm the factorial structure of the Short Form 36 Health Survey (SF-36) in problem drug users and to compare their health-related quality of life (HRQOL) with general Dutch population norms. Data of 394 participants from the Amsterdam Cohort Study among drug users, who had completed once the SF-36 standard form (4 weeks recall) between February and August 2005, were analyzed. The factorial structure of the SF-36 was investigated by confirmatory factor analysis. Subsequently, sum scores of the eight SF-36 health dimensions were converted into z-scores by standardizing them with the mean and standard deviation of the corresponding general Dutch population age and gender group. The factor structure was acceptable and also comparable with previous findings. Compared with the general population, participants had significantly lower z-scores on all of the eight SF-36 dimensions, with largest deviations in social functioning (M = -1.13) and mental health (M = -1.01), and smallest deviations in bodily pain (M = -0.32). The results corroborate the factorial structure and reliability of the answers of problem drug users to the SF-36. Their HRQOL was low, even though it was assessed irrespective of substance abuse treatment settings.