| Background and ObjectivesChina is one of the countries with the highest prevalence of hepatitis B.The progress of chronic hepatitis B(CHB)and the economic burden caused by the long-term treatment seriously affect patients'daily life.Besides,Chinese patients also report more psycho-social problems,such as sense of inferiority,anxiety,discrimination,and reduced work ability.Health-related quality of life(HRQOL)is an important outcome measure,often used to evaluate the health status of patients and the effectiveness of intervention and treatment.HRQOL can surmount the limitation of traditional clinical practice that only focuses on diagnosis and physical symptoms.However,the suitable assessment tools for non-cirrhotic CHB patient under China's cultural background were currently lacking.This study aimed to develop a conceptual framework of QOL in the cultural context for Chinese CHB patients through individual in-deep qualitative interviews.This study also aimed to systematically develop a new disease-specific quality of life instrument and its brief version by combining the classical measurement theory(CTT)and item response theory(IRT),and provide sufficient evidence of its measurement performance.We hope the instruments can be used for evaluation of disease burden and treatment effect of CHB patients in population research and clinical practice and greatly improve patient-centered health services.MethodsThis study was conducted in three phrases.In phrase?,we developed the initial CHBQOL instrument.Based on Maslow's hierarchy of needs theory and the qualitative research technique of grounded theory,94CHB patients according to the saturated sampling principle were interviewed in depth to explore the living feelings,goals,concerns and worries related to the disease.Three rounds of patient cognitive interviews were conducted to test the suitability of the language,the correctness and acceptability of the content understanding of initial items,and modified correspondingly.Quantitative statistical methods such as discrete trend analysis,factor analysis,correlation coefficient and Cronbach's?coefficient method were used to select the items,and qualified items were reserved to construct the CHBQOL instrument.In phrase?,we evaluated the measurement properties of the CHBQOL instrument.From June 2017 to February 2018,a total of 578 patients with CHB who met the inclusion and exclusion criteria were recruited from 6 tertiary hospitals in Zhejiang province by means of quota sampling.CTT was mainly used to evaluate the measurement performance of the CHBQOL instrument normatively.In this study,internal consistency reliability,test-retest reliability and measurement error were considered for the reliability evaluation.To evaluate the test-retest reliability,sixty patients were randomly selected to fill in the initial CHBQOL instrument again 7-10days later.Content validity,structure validity(including convergent and discriminant validity),criterion validity and known-group validity were evaluated for validity.The SF-36 questionnaire was used as the criterion.A longitudinal study design was adopted for the assessing the responsiveness.All subjects participating in the cross-sectional survey were invited to fill in the questionnaires about quality of life,demographic characteristics and clinical information again 1 year later.The effect size(ES)and standardized response mean(SRM)were calculated.The distribution of scores in different population and the minimal important difference(MID)of each dimension were used to evaluate the interpretability.In phrase?,we developed the brief version of the CHBQOL instrument(CHBQOL-SF).The short form was developed on the basis of the original scale by using IRT.The partial credit model(PCM)in Rasch model was selected to model fit the cross-sectional sample data due to the ordered multi-score items.Items were further screened by item characteristic curve(ICC),item information function,individual item fit residual,category probability curve(CPC),threshold parameters,differential item functioning(DIF)analysis,item-person maps,etc.According to the content of the item and the experts'scores of the item's importance,the final short version was formed and its model fit was evaluated.Epidata software was used for data entry in this study.Descriptive statistical analysis was presented by the number of cases(percentage),meanąstandard deviation(SD)and coefficient of variation(CV)of data variables.The correlation coefficient of Pearson and Spearman was adopted.T test,analysis of variance and chi-square test were used for the comparison of the differences among the subgroups.Amos 20.0 software was used for the confirmatory factor analysis(CFA),and RUMM2030 software was used for the IRT analysis.Results1)This study constructed a conceptual framework for the quality of life of CHB patients in the context of Chinese culture by encoding the interview transcript and using thematic analysis,and formed an item pool of thirty initial items.The Likert 6-point scoring form was selected for the items by cognitive interviews.After item selction by CTT,the final CHBQOL instrument contains four dimensions,named Physical health(PH),Emotional symptoms(EM),Social stigma(SO),and Belief(BE),with a total of24 items.2)The scores of SF-36 Physical Component Summary(PCS)and Mental Component Summary(MCS)of the participants were lower than Hangzhou population norms,which showed the HRQo L of patients with CHB was lower than the general population.The CHBQOL instrument had a good internal consistency reliability with the Cronbach's?coefficients of all dimensions larger than 0.7.Except that the inter-calss correlation coefficient in the Belief dimension was low at 0.53,the test-retest reliability of the other three dimensions was good.The measurement error of the PH dimension was the smallest.There was no ceiling and floor effect in each dimension of the scale.The average completion time of CHBQOL instrument was 3.8 minutes,which indicated that the instrument had little measurenment burden.The results of CFA confirmed that the instrument had good structure validity,with the factor loadings ranging from 0.54 to 0.90.The goodness of fit of model was ideal(?~2/df=2.19,GFI=0.87,CFI=0.92,RMSEA=0.06,SRMR=0.05).The correlations between dimensions of the CHBQOL and SF-36 were from low to medium,and the correlation coefficients between the comparable dimensions with similar concepts were larger,which proved that the CHBQOL had good criterion validity.Known-group validity results verified the research hypothesis of the score differences in subgroups of gender,age,economic income,but failed to find that the scores of CHBQOL PH dimension in patients with liver function impairment were significantly worse.After one year of antiviral therapy,the mean HRQo L scores in PH,BE and SO dimension of CHB patients were significantly changed(P<0.05),but the ES and SRM of each dimension were all around 0.2,showing that the responsiveness of the CHBQOL remained to be further improved.In this study,the MID of the PH,EM,BE,SO dimension was 9.0,-12.0,-20.0 and 12.0,respectively.3)With the expert Delphi method and IRT used to further simplify the items,the CHBQOL-SF with a total of 10 items retained the dimension structure of the original instrument.The absolute values of individual item fit residuals were all smaller than 2.5,indicating that the items were good.There was no inverse threshold for each item,indicating that the item option setting was reasonable.Item BE1,SO6 and SO7 had uniform DIF in subgroups of different ALT levels,age and gender,respectively.ConclusionThe disease-specific CHBQOL instrument developed following system development procedure proved to be of good reliability and validity,which is suitable for evaluating the HRQo L of CHB patients in the context of Chinese culture.The responsiveness needs to be further observed and improved.The MIDs calculated by the anchor-based and the distribution-based methods provided a reasonable explanation for the changes of patients'HRQo L scores over time.The core short form with 10 items(CHBQOL-SF)retained the dimension structure of the original CHBQOL instrument,and it would reduce the measurement burden and promote the assessments of HRQOL in clinical practice. |
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