Psychometric properties of the Polish version of SF-12v2 in the general population survey

ABSTRACT

Background

This study aimed to assess the psychometric properties of the SF-12 questionnaire (in comparison to the EQ-5D questionnaire also), based on a survey conducted on a sample representing the general population of Poland.

Methods

The respondents completed Polish versions of health-related quality of life (HRQoL) questionnaires: SF-12, EQ-5D-5L, EQ VAS, and EQ-5D-3L, together with demographic and socioeconomic characteristic items. The following psychometric properties were analyzed: informativity power, ceiling and floor effects, reliability, and construct validity. We also conducted an exploratory factor analysis.

Results

A total of 3,896 respondents (mean age 48.3 years, 53.2% female) were included in the analysis. The results showed exceptional informativity power of SF-12 items. We did not observe any ceiling and floor effects for the PCS and MCS components. The high values of the Cronbach’s alpha coefficients confirmed the reliability of SF-12. Our hypothesis about lower scores for the summary components among older respondents, females and patients having declared diabetes was confirmed. The results of factor analysis also provided evidence for a positive assessment of construct validity.

Conclusions

Our results confirmed that the Polish version of the SF-12 questionnaire is a valid instrument for use in HRQoL assessment among the general population of Poland.

KEYWORDS:

• General population
• health-related quality of life
• reliability
• SF-12
• validity

Article highlights

• Validation of a questionnaire serves to ensure the correct interpretation of its results.

• Although several references are describing the psychometric properties of the SF-12 questionnaire in general populations, much of this research comes from over five years ago, and with no focus on the Central and Eastern European countries.

• In our study, we observed great informativity power of SF-12 items and the high values of the Cronbach’s alpha coefficients for the PCS and MCS components.

• No ceiling and floor effects for the PCS and MCS were identified.

• The hypothesis about lower scores for the summary components among older respondents, females and patients having declared diabetes was confirmed.

• The two-factor analysis provided evidence for a positive assessment of construct validity.

• Our results confirmed that the Polish version of the SF-12 questionnaire is a valid instrument for use in HRQoL assessment among the general population of Poland.

Acknowledgments

We would like to thank Marcin Hermann from the CBOS market research company and Maciej Niewada from HealthQuest for coordinating the survey.

Declaration of interest

KM is an employee of HealthQuest (Warsaw, Poland). DG is a member of the EuroQol Group, a not-for-profit organization that develops and distributes instruments that assess and value health. DG is also a shareholder of HealthQuest. All authors did not receive funding for performing this study. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewers disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Author contributions

KM contributed to study design, preparation and critical interpretation of the analyses, statistical analysis, literature search, and manuscript draft. DG contributed to study design, data acquisition, critical interpretation of the analyses, and manuscript draft. All authors read and approved the final manuscript.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

HealthQuest, company spółka z ograniczoną odpowiedzialnością Sp. K (Warsaw, Poland) funded the collection of data.