systemic lupus erythematosus ( sle ) is a chronic disease with relapsing - remitting periods leading to high morbidity and disability in many of the patients . a comprehensive evaluation of the disease state should contain disease activity , cumulative damage , and patients ' quality of life ( qol ) . therefore , according to international consensus recommendations on outcome measures in rheumatology clinical trials , qol is among the major domains that should be assessed in clinical trials and cohorts on sle . generic measures , such as the short - form health survey-36 ( sf-36 ) , assess the patient condition in a more comprehensive manner and allow comparison between different groups ( patients and healthy individuals ) . however , these measures are not focused on aspects of a specific disease and might not be sensitive to important clinical changes during treatment . therefore , disease specific measures are developed not only to focus on those aspects of life being affected by the disease but also to evaluate the efficacy of different treatments . in terms of the qol in sle patients , some disease - specific instruments are developed and applied in various studies up to now including the sleqol , sle symptom checklist , l - qol , lupusqol , and some other instruments . the lupusqol questionnaire is widely used according to relatively better psychometric characteristics compared with other measures [ 9 , 10 ] . the questionnaire was initially developed in uk and was then validated for use in the united states and canada . there is no specific instrument designed to assess qol of sle patients in iranian population . translation process of a questionnaire , specifically qol questionnaires , should be as precise as the developing process and should be done on the basis of standard linguistic validation methods . the aim of this study was to linguistically validate the lupusqol and to evaluate its psychometric characteristics in iranian population . this linguistic validation study was conducted on women with sle referring to an outpatient clinic of rheumatology in isfahan city ( iran ) between january and july 2013 . after a primary report , we further continued the study with a relatively larger sample of patients with more precise data , including data of a generic qol measure for comparisons . known sle patients , according to the american college of rheumatology ( acr ) revised criteria for sle , who were at least 18 years of age and had no major cognitive deficits that would interfere questionnaire completion were consecutively included into the study . the study was approved by ethical committee of the isfahan university of medical sciences and oral consent was obtained from the patients . the lupusqol questionnaire is developed by mcelhone and colleagues to specifically evaluate qol of the sle patients . it consists of 34 items in 8 different domains evaluating physical health ( 8 items ) , emotional health ( 6 items ) , body image ( 5 items ) , pain ( 3 items ) , planning ( 3 items ) , fatigue ( 4 items ) , intimate relationship ( 2 items ) , and burden to others ( 3 items ) in the preceding 4 weeks . the answers are scored through a 5-point likert response format from 0 to 4 . to facilitate analysis and result interpretation , the final score is then transformed from 0 to 100 scale in which a higher score demonstrates a better qol state . after permission from the original developer , linguistic validation of the lupusqol was performed by the standard method of forward - backward translation . we followed the following stages : ( 1 ) conceptual definition of each item , ( 2 ) forward translation , ( 3 ) backward translation , ( 4 ) pilot study to assess cognitive debriefing and clinician 's review , and ( 5 ) proofreading . the team members in validating process consisted of a rheumatologist , four professional translators who were also physicians , and the main investigators . in a pilot study with 10 participants , patients completed the translated lupusqol and responded to a set of questions that assessed the level of difficulty and readability of the questionnaire . based on the pilot study , the final persian version of the lupusqol ( lupusqol - p ) data including age , education level , sle duration , comorbidities , and laboratory data were gathered by reviewing patients ' documents interview . disease activity , cumulative disease damage , and qol were assessed by the following standard measures . the systemic lupus erythematosus disease activity index 2000 ( sledai-2k ) was used to measure the sle activity . the sledai-2k covers clinical ( 16 items ) as well as laboratory ( 8 items ) variables covering events in the preceding 1030 days ( the 30-day version was applied ) . based on the total score , disease activity is divided into inactive ( sledai-2k < 6 ) and active ( sledai-2k  6 ) disease state . the systemic lupus international collaborative clinics / american college of rheumatology damage index ( sdi ) was used to estimate the accumulated damage since the onset of the disease . the sdi evaluates 12 organs and lupus - related complications as well as treatment - related complications . the short - form health survey ( sf-36 ) was applied to measure general qol . the sf-36 contains 36 items with likert - type as well as binary response questions . the instrument yields an 8-scale profile of physical and emotional health including physical functioning , role - physical , bodily pain , general health , vitality , social functioning , role - emotional , and mental health . all scores are converted to a range of 0 to 100 in which higher scores indicate better qol status . reliability was assessed by determining the internal consistency ( cronbach 's alpha ) of the total lupusqol and the subscales . convergent validity was assessed by determining corrected item - subscale and subscale - total correlations as well as intersubscale correlations . concurrent validity was assessed by testing the correlations between the lupusqol and the sf-36 comparable domains . discriminant validity was assessed by comparison between patients with active and inactive disease , as well as comparison between patients with no disease damage and patients with damage index of 1 . in all analyses , a p value ( two - tailed ) of less than 0.05 was considered statistically significant . one hundred sle patients were invited to participate in this survey , of whom six patients refused to enroll in the study and six other patients partially filled the questionnaires and therefore were excluded . ten patients were enrolled in the pilot study and 78 patients were enrolled in the main survey . the data of the 10 patients from the pilot study was not considered for the psychometric analyses . ceiling effect was observed for item 3 ( 69.2% ) and item 33 ( 59% ) . no floor effect was observed . the cronbach 's alpha was 0.97 for the total lupusqol and from 0.82 to 0.93 for the subscales . total alpha remained stable at 0.97 by deleting each of the items . deleting none of the items increased the corresponding subscale alpha . corrected item - total correlations were above 0.4 for all items except items 10 and 33 ( r = 0.39 ) . the corrected item - subscale correlations were 0.5 for all items ( range from 0.50 to 0.91 ) . all subscales had the corrected subscale - total correlations of > 0.6 ( range from 0.61 to 0.89 , table 2 ) . also , there were strong correlations between different subscales ( range from 0.51 between pain and intimate relationship to 0.81 between pain and fatigue ) . for the 4 comparable domains , the 2 measures correlated well ; r = 0.80 for physical health / physical functioning , r = 0.70 for emotional health / mental health , r = 0.73 for pain / bodily pain , and r = 0.55 for fatigue / vitality . comparison of patients ' qol according to disease activity and cumulative disease damage is summarized in table 4 . patients with active disease had significantly lower scores in domains of planning ( p = 0.041 ) , emotional health ( p = 0.044 ) , and body image ( p = 0.019 ) than patients with inactive disease . also , patients with damage index of 1 had significantly lower scores for planning ( p = 0.002 ) , burden to others ( p = 0.039 ) , and body image ( p = 0.012 ) than those with no disease damage . we aimed to linguistically validate the lupusqol and determine its psychometric characteristics in iranian sle patients with persian language . our results revealed that the lupusqol - p is a valid and reliable disease - specific instrument for assessing qol in iranian sle patients . in this survey , patients ' cooperation was acceptable and there was limited number of missing data for most of the items implying good acceptance and understanding of patients towards the translation . in our study , no floor effect was observed . the minimal observed ceiling effect could be explained by the homogenicity of the studied sample . the calculated cronbach 's alpha for the whole questionnaire ( 0.97 ) and its different domains ( 0.82 to 0.93 ) demonstrates a good internal consistency . lack of change in alpha coefficients following removal of each item showed that all the items were consistent with the whole questionnaire . in the main questionnaire designed by mcelhone et al . , alpha coefficient ranged from 0.88 to 0.96 for different domains of the instrument . also the american version of the lupusqol reported alpha coefficient between 0.85 and 0.94 . surveys on other versions of the questionnaire such as french , chinese , and italian translations also reported similar results [ 1114 ] . consistently with other validation surveys [ 1114 ] , we found that each item of the lupusqol - p has a high correlation with its corresponding domain . also , there was strong correlation between the lupusqol - p and the corresponding sf-36 domains , especially those of physical health , emotional health , pain , and fatigue . the validity of the lupusqol against generic qol measures is also confirmed by other validation studies [ 1114 ] . we expected to find a difference between patients with and without active disease state and also between those with and without disease damage regarding their qol . in our study , several but not all domains of the lupusqol - p were affected by disease activity and disease damage including planning , burden to others , emotional health , and body image . although the original study has reported weak correlations between the scores of the lupusqol domains and disease activity and damage scores , later linguistic validation studies have shown appropriate discriminant validity of the scale . in this regard , conti and colleagues found a difference in the domains of physical health , planning , burden to others , and fatigue between patients with and without active disease . wang and colleagues found a difference in almost all domains of the lupusqol - china ( except body image and burden to others ) between patients with different disease activity and damage state . also , devilliers et al . reported a difference in domains of physical health , pain , and intimate relationship between patients with active and inactive disease . differences among the previous studies might be related to differences in patients ' characteristics and the disease activity measures . to evaluate the discriminant validity of the scale , a heterogeneous sample of patients with various stages of the disease activity and damage is required . it should be noted that our study sample size was small in this regard and not many of our patients had active disease or considerable disease damage . the persian version of the lupusqol ( lupusqol - p ) has appropriate validity and reliability among iranian patients with sle . while this linguistic validation study is done in a single care center , further multicenter studies are needed to evaluate iranian sle patients ' qol and contributing factors . such data would be useful for healthcare providers in designing and implementing strategies to improve qol of the patients .
objectives . we evaluated the psychometric properties of the persian lupusqol for the evaluation of quality of life in iranian systemic lupus erythematosus ( sle ) patients . methods . 
 the lupusqol was translated to persian language . 
 patients with sle ( n = 78 ) completed the lupusqol and the short - form health survey ( sf-36 ) . 
 disease activity and cumulative disease damage were assessed with standard indices . 
 the psychometric properties of the scale were evaluated . 
 results . 
 the cronbach 's alpha was 0.97 for the total lupusqol ( above 0.8 for subscales ) . 
 there were strong corrected item - total ( r > 0.4 ) , item - subscale ( r  0.5 ) , and subscale - total correlations ( r > 0.6 ) , as well as intersubscale correlations ( r > 0.5 ) . 
 patients with active disease and patients with disease damage index of 1 had lower scores in domains of planning , emotional health , burden to others , and body image than patients with inactive disease and those with no disease damage , respectively ( p < 0.05 ) . 
 the lupusqol and the sf-36 correlated well regarding comparable domains ( r > 0.4 ) . conclusion . 
 the psychometric characteristics of the persian version of lupusqol questionnaire are acceptable in iranian population . 
 this instrument can be used to evaluate quality of life in iranian sle patients .