Reliability and validity of the adapted Spanish version of the Early Onset Scoliosis-24 questionnaire María del Mar Pozo-Balado, PhD Hiroko Matsumoto PhD Michael G Vitale, MD Juan Manuel Praena-Fernández David M Farrington, MD

INTRODUCTION Early Onset Scoliosis (EOS) EOS may negatively impact life expectancy of children. Even without severe progression, the deformity may interfere with daily life and might have significant effects on health-related quality of life. Radiographic parameters are insufficient to evaluate the severity and efficacy of treatment in these patients. Early Onset Scoliosis Questionnaire (EOSQ-24) EOSQ-24 is a health-related quality of life disease specific measure for EOS. It needs to be translated into many languages, while maintaining the original meaning.

OBJECTIVE To translate and transculturally adapt the original EOSQ-24 to produce a Spanish version according to internationally published recommendations and to test the reliability and discriminative validity of the Spanish version of EOSQ-24.

PATIENTS AND METHODS I Study Design Translation and transcultural adaptation of EOSQ into the European Spanish language. Beaton et al., Spine (2000) Validity testing of the Spanish version of EOSQ in a cross-sectional study validation. The EOSQ-24 Principal disease-specific instrument to be used for studies involving children with EOS. Comprised of 24 items in 11 domains. Item scores ranged between 1 and 5 for all items, with lower scores meaning higher disability. Domain scores were calculated as (value of item choice-1)/4 *100 for 1 item domains and (algebraic mean of items-1)/4*100 for domains composed for more than 1 item, ranging from 0 to 100. The 11 domains were also averaged into a summary score called total score, which also may range from 0 to 100.

PATIENTS AND METHODS II Cross-cultural adaptation and translation process Translation Synthesis Back Translation Expert Committee Review Pretesting Beaton et al., Spine (2000) Reliability Cronbach’s a and Cronbach’s a if item/domain deleted (0.7-0.95 indicates good internal consistency). Item-total correlations (>0.3 indicates good internal consistency). Inter-item correlations (0.2-0.8 indicates good internal consistency). Terwee et al, J Clin Epidemiol (2007) Floor and ceiling effects Values lower than 30% were considered acceptable. Kane, Aspen Publishers (2007)

PATIENTS AND METHODS III Discriminative validity Analysis of the relationship between clinical and demographical variables and questionnaire total scores, under the assumption that unfavorable characteristics are associated with poor scores. Kruskar Wallis and Bonferroni corrections for multiple comparisons and Mann Whitney-U test for comparisons between two groups. Spearman correlations for quantitative variables. p<0.05 considered statistically significant for all tests.

RESULTS I Demographic and clinical characteristics of 44 children with EOS. Characteristic Value Male sex (%) 22 (50) Age, median months (IQR) 76 [44 - 92] Age at diagnosis, median months (IQR) 39 [16 -69] Age at surgery, median months (IQR) 76 [58 – 91] Cobb angle, median degrees (IQR) 31.1 [24.8 – 45.3] Diagnose (%) Congenital 18 (40.9) Neuromuscular 10 (22.7) Idiopathic 9 (20.5) Syndromic 7 (15.9) Treatment (%) Observation 24 (54.5) Bracing 2 (4.6) Casting 4 (9.1) Surgical 14 (31.8) Ambulation Status (%) Non-ambulatory 8 (18.2) Ambulatory 36 (81.8)

Good internal consistency for items and domains. RESULTS II Domains Corrected Item-total Correlation Cronbach’s a if Item Deleted General Health 0.415 0.825 Q1 0.496 0.893 Q2 0.413 0.895 Pain 0.553 0.816 Q3 0.502 Q4 0.455 0.894 Pulmonary Function 0.472 0.821 Q5 0.254 0.898 Q6 0.412 Mobility 0.826 Q7 0.435 Physical function 0.607 0.808 Q8 0.482 Q9 0.484 Q10 0.661 0.888 Daily living 0.675 0.802 Q11 0.689 0.887 Q12 0.691 Fatigue 0.522 Q13 0.476 Q14 0.474 Emotion 0.592 0.812 Q15 0.471 Q16 0.519 0.892 Parental Burden 0.655 Q17 0.670 0.890 Q18 0.518 Q19 0.550 0.891 Q20 0.724 Q21 0.179 Financial Burden 0.353 0.831 Q22 0.356 0.896 Satisfaction 0.418 Q23 Q24 0.392 Demographic and clinical characteristics of 44 children with EOS. Cronbach’s a for 24 items = 0.897 Cronbach’s a for domains = 0.832 Good internal consistency for items and domains.

RESULTS III RESULTS IV Domains Mean (SD) Median Missing (n) Missing (%) Floor (%) Ceiling (%) General Health 65.6 62.5 11.4 Q1 3.50 (1.04) 4 4.5 15.9 Q2 3.79 (0.89) 1 2.3 7 23.3 Pain 77.9 75.0 31.8 Q3 4.02 (0.86) 32.6 Q4 4.22 (0.69) 3 6.8 36.6 Pulmonary Function 86.3 100 59.1 Q5 4.40 (1.18) 5 4.7 74.4 Q6 4.50 (0.86) 68.2 Transfer 90.9 72.7 Q7 4.64 (0.65) Physical function 72.2 83.3 29.5 Q8 3.82 (1.38) 9.2 45.5 Q9 4.23 (1.41) Q10 3.74 (1.53) 2 11.9 52.4 Daily living 56.8 13.6 25.0 Q11 3.05 (1.57) 22.7 27.3 Q12 3.50 (1.80) 52.3 Fatigue 73.3 Q13 3.95 (0.94) 36.4 Q14 3.88 (1.28) 46.5 Emotion 76.4 Q15 4.11 (0.87) 40.9 Q16 4.00 (1.03) Parental Burden 61.3 65.0 Q17 2.98 (0.93) 9.1 Q18 3.16 (1.16) Q19 3.23 (1.33) Q20 3.68 (1.27) 34.1 Q21 4.26 (0.79) 44.2 Financial Burden 75.6 Q22 4.02 (1.13) Satisfaction Q23 3.98 (1.08) 41.9 Q24 3.93 (1.23) 43.2 Data quality with the Floor and Ceiling Effect of the EOSQ-24. No floor effects, but ceiling effects observed in some items and domains, probably because… Young age Mostly mild curves More than 50% under observation

RESULTS IV RESULTS II Discriminative validity of the EOSQ-24 questionnaire: Total Score and Cobb Angle. p=0.001 Comparison of total scores between EOS patients with Cobb angle >30° and ≤30° were performed using Mann Whitney U-test, and correlations between total scores and Cobb angles were evaluated using a Spearman rank correlation coefficient test .

RESULTS V RESULTS II Discriminative validity of the EOSQ-24 questionnaire: Total Score and Diagnosis K-W *p=0.006 * * * * C=Congenital; I= Idiopathic; N= Neurological; S= Syndromic Comparisons were made by using Kruskal-Wallis test and Mann Whitney U-test *p<0.05

CONCLUSIONS The Spanish version of the EOSQ-24 is reliable and a valid tool for the psychometric assessment of children with EOS, and can be applied in routine clinical practice and for research purposes.