KINDL Quality Of Life Questionnaire In Serbia: Referent Values For Healthy Children And Adolescents

Article ID: WC001342 2046-1690 KINDL Quality Of Life Questionnaire In Serbia: Referent Values For Healthy Children And Adolescents Corresponding Author: Dr. Dejan Stevanovic, Researcher/clinician, Psychiatry, General Hospital Sombor Submitting Author: Dr. Dejan Stevanovic, Researcher/Clinician, Department of Psychiatry, General Hospital Sombor, Apatinski put 38, 25000 - Serbia Article ID: WC001342 Article Type: Original Articles Submitted on:11-dec-2010, 04:55:12 P GT Article URL: http://www.webmedcentral.com/article_view/1342 Subject Categories:PAEDIATRICS Keywords:KINDL, questionnaire, quality of life, children, adolescents Published on: 13-Dec-2010, 02:48:27 P GT How to cite the article:stevanovic D. KINDL Quality Of Life Questionnaire In Serbia: Referent Values For Healthy Children And Adolescents. WebmedCentral PAEDIATRICS 2010;1(12):WC001342 Source(s) of Funding: None Webmedcentral > Original Articles Page 1 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A KINDL Quality Of Life Questionnaire In Serbia: Referent Values For Healthy Children And Adolescents Author(s): Stevanovic D Abstract The objective of this report was to present the referent values of the Serbian KINDL for healthy children and adolescents. The data from 756 children and adolescents and 618 parents were used. The mean values with standard deviations, 95% confidence intervals, and percentiles were calculated for KINDL. Additionally, the differences between genders, children and parents, and the correlations of age with the KINDL scores were given. The mean values of the subscales ranged 59.51 76.39 for the children and 68.96 79.97 for the parents. The total scores were 76.29 and 79.86, respectfully. Between the male and female subjects, no significant differences were observed. However, the majority of the scores significantly, but inversely, correlated with age. The referent values were given for gender and age. Introduction The KINDL, a generic quality of life (QOL) questionnaire, is frequently used to evaluate everyday living in children and adolescents [1, 2]. This measure considers QOL as a psychological construct including physical, psychosocial, and functional aspects of well-being and daily functioning [3]. From measurement perspectives, the KINDL provide reliable and valid QOL assessments in screening or evaluative purposes [2]. The KINDL was translated into Serbian and psychometrically validated during 2005/06. Three validation studies were organized in order to evaluate measurement properties of the version in the general populations a basic psychometric, replication and confirmatory factor analysis study [4, 5]. In the current projects, the KINDL is being evaluated in populations with chronic illnesses/conditions. The objective of this report was to present the referent values of the Serbian KINDL for healthy children and adolescents. ethods KINDL questionnaire The Serbian KINDL questionnaire (KINDL S) is developed in two forms Kid-KINDL (8 12 year-olds) and Kiddo-KINDL (13 16 year-olds), both as a self-report and parent questionnaire [4]. Twenty-four items are classified into six sub-scales: Physical well-being PW, Emotional well-being EW, Self-esteem SE, Family FA, Friends FRI, and School SC. All items are five-likert-scaled, 1 = never to 5 = all the time. The total subscale score is created as the mean value of all answered items in that scale, while the total KINDL is the mean value of all answered items. The scores are transformed into a 0 100 scale, with the higher the value, the better QOL is. The parent version represents an equivalent to the self-report. The Serbian KINDL possesses satisfactory measurement characteristics as a screening QOL questionnaire [4]. It is a feasible measure with appropriate face and content validity. The internal consistency coefficients ranged 0.45 0.74 for the subscales and it was above 0.8 for the total, while the reliability in the form of measurement stability is satisfactory for almost all scores (above 0.6) [5]. However, although the discriminative validity of the subscales is appropriate, they are overlapped substantially and the construct validity is not supported [5]. Additionally, the KINDL parent form possesses better measurement properties than the self-report (D. Stevanovic, unpublished results). Following these findings, it is suggested to consider the subscales for preliminary decisions and/or subjects sorting, while the total KINDL score could be used for comparative purposes, mainly for the screening assessments of QOL. Details about the questionnaire will be obtained in the Serbian KINDL manual that is in preparation. Sample The total number of healthy children/adolescents and their parents from three studies who completed the KINDL was 756 and 618, respectfully. The children and adolescents were randomly recruited and the representativeness was ensured in the way of the subjects recruitment from the urban areas of Belgrade to the mid-urban and rural societies of Western Webmedcentral > Original Articles Page 2 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Vojvodina, Odzaci. The mean age was 12.34 ± 1.84 years, range 8-16, and 385 were males. For the detailed description of the samples, the reader is referred to the primary references [4, 5]. Statistical analysis The mean values (), standard deviations, 95% confidence intervals (CI), percentiles (25, 50, 75), and floor and ceiling effects were calculated for the subscale and total KINDL score [6]. Considering the skewness of the data reported in the first study [4], one-sample Kolmogorov-Smirnov test was run to confirming the significant violation of the normal distribution for the sample (p < 0.001). Consequently, ann-whitney test was used to evaluate the differences between gender and between children and parents, while Spearman's rho coefficient was used to evaluate the correlations of age and the KINDL scores. Internal consistency was demonstrated using Cronbach s α coefficient. The referent values were given for gender and age. According to age, the referent values were presented so to represent a school grade. The children and parents scores were presented separately. Results The mean values of the subscales ranged from 59.51 to 76.39 for the children and from 68.96 to 79.97 for the parents. The total scores were 76.29 and 79.86, respectfully. Important ceiling effects were observed for the EW and FA subscale (Table 1). Between the male and female subjects, no significant differences were observed in the KINDL scores, as self- or proxy-reported. The majority of the scores significantly, but inversely correlated with age. Finally, Cronbach s α coefficient ranged from 0.51 to 0.86 (Table 2). The referent values for gender and age were presented in Table 3 and 4. Discussion The KINDL is a generic pediatric QOL questionnaire validated for the Serbian language. It was culturally adapted and acceptable measurement properties were demonstrated for QOL screening in healthy children and adolescents. The referent values for gender and age provided in this study could be used as a preliminary reference until standardized norms are developed. Up-to-date, only the German and Spanish norms were reported [7, 8]. Several important observations from the study should be considered when using the referent values. First, although sufficiently large and randomly selected, the subjects from whom the referent values were derived are not necessary representative of gender and age. Notably, the males slightly predominated and the age groups were not equal. Then, the mean values are deferent among the subscales, the range of scores and standard deviations are large, what suggest a broad range for the KINDL scores within normal limits [6]. Second, between genders no significant differences were reported in the KINDL scores as self- and/or proxy-reported. Additionally, whilst there was a statistically significant negative correlation between the children age and the self-perceived scores, the correlation coefficient was relatively small to consider the correlation clinically significant. This indicates the KINDL is suitable for using with children over a large age range (8±16 years) without the scores being confounded by the age of the child [6]. However, the effect of age and gender differences on the KINDL should be further explored. Third, there were significant differences between the children and parents KINDL scores, signifying different perceptions of QOL. Differences between children and parents QOL evaluations were well documented and this must be followed when selecting who will complete the KINDL and how to use observations [3, 9]. Forth, the internal consistency coefficient of the KINDL varied among the subscales, from 0.51 to 0.73. For the total, it was above 0.8, high enough to suggest the items are looking at the same construct, yet low enough to suggest sufficient variation between the items [6, 10]. Additionally, although the level of internal consistency is acceptable for QOL measures, the data confirmed that the subscales should be only used for preliminary decisions and/or subjects sorting, while the total score could be used confidentially for screening and descriptive purposes [5]. How one should use these referent values? We advise a KINDL evaluator to use the and percentiles, although there are other useful methods []. For example, let us say that a 11-year-old healthy boy obtained the total KINDL score of 70 during a screening assessment. From Table 3, this is below the lower end of for the entire population and in Table 1 this score is on the 25 percentile. The evaluator therefore should conclude the boy probably has disturbed QOL, and depending on occasions, further evaluations should be advised, let us say to screen for the risk factors affecting his QOL or another measure should be used to explore more thoroughly Webmedcentral > Original Articles Page 3 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A his QOL. Conclusion(s) In summary, the KINDL is a useful measure for assessing a child's and/or an adolescent s quality of life and the referent values provided could be used for different clinical and research purposes, but only screening or descriptive. Additionally, all potential users are advised to follow the above observations and give sufficient priority to the total KINDL score. In incoming projects, the Serbian version will be further evaluated in diverse groups of chronically diseased children and adolescents and fully standardized norms will be developed soon. Abbreviation(s) Adolescents in Germany. Norm Data from the German Health Interview and Examination Survey (KiGGS). Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2007; 50: 810 8. 8. Serra-Sutton V, Ferrer, Rajmil L, Tebe C, Simeoni C, Ravens-Sieberer U. Population norms and cut-off-points for suboptimal health related quality of life in two generic measures for adolescents: the Spanish VSP-A and KINDL-R. Health Qual Life Outcomes 2009; 7: 35. 9. De Civita, Regier D, Alamgir, AH, Anis AH, Fitzgerald J, arra CA. Evaluating health-related quality-of-life studies in paediatric populations: some conceptual, methodological, and developmental considerations and recent applications. Pharmacoeconomic 2005; 23: 659 685. 10. Streiner D, Norman G. Health measurement scales: A practical guide to their development and use, 3rd ed. Oxford: Oxford University Press; 2003. QOL - quality of life, KINDL - quality of life measure for children and adolescents References 1. Ravens-Sieberer U, Bullinger. Assessing health-related quality of life in chronically ill children with the German KINDL: First psychometric and content analytical results. Qual Life Res 1998; 7: 399 407. 2. Bullinger, Brütt AL, Erhart, Ravens-Sieberer U, BELLA Study Group. Psychometric properties of the KINDL-R questionnaire: results of the BELLA study. Eur Child Adolesc Psychiatr 2008; 17: S125 S32. 3. Ravens-Sieberer U, Erhart, Wille N, Wetzel R, Nickel J, Bullinger. Generic health-related quality-of-life assessment in children and adolescents: ethodological considerations. Pharmacoeconomic 2006; 24: 1199 20. 4. Stevanovic D, Lakic A, Vilotic J. The psychometric study of the Serbian KINDL questionnaire for health-related quality of life assessment in children and adolescents. Scand J Caring Sci 2009; 23; 361 368. 5. Stevanovic D. Serbian KINDL quality of life questionnaire: Results from a replication and confirmatory factor analysis study. Health Qual Life Outcomes 2009; 7: 79. 6. Fayers P, achin D. Quality of Life: The assessment, analysis and interpretation of patient-reported outcomes, 2nd ed. Chichester: John Wiley & Sons; 2007. 7. Ravens-Sieberer U, Ellert U, Erhart. Health-Related Quality of Life of Children and Webmedcentral > Original Articles Page 4 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Illustrations Illustration 1 Tables Table 1. Descriptive statistics of the KINDL S self-report and parent questionnaire (mean score, standard deviation SD, confidence interval CI) Physical well-bein g Emotional Self-estee well-being m Family Friends School Total QOL KINDL S self-report (N = 756) 76.39 (16.4) 83.93 (15.2) 72.11 (18) 86.74 (13.7) 79.04 (16) 59.51 (20.6) 76.29 (10.9) 75.22 77. 57 Percentiles 82.84 85. 01 70.82 73. 41 85.76 87. 71 77.89 80. 18 58.04 61 75.5 77.0 7 25 68.75 75 62.5 81.25 68.75 43.75 69.79 50 81.25 87.5 87.5 93.75 75 87.5 87.5 100 81.25 93.75 56.25 75 77.08 84.38 75 Ceiling % 9.4 17.7 8.6 26.1 11.9 3.3 0.5 Webmedcentral > Original Articles Page 5 of 19 Floor % 0 0 0 0 0 0 0

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Ceiling % 12.3 19.1 9.1 26.1 13.3 4.7 0.6 Floor % 0 0 0 0 0 0 0 Table 2. Cronbach s α coefficient, ann-whitney test and Spearman's rho coefficient for the KINDL S self-report and parent questionnaire (mean score, standard deviation SD) Physical well-bei ng Emotional Self-este well-being em Family Friends School Total QOL KINDL S self-report ale, n = 385 76.8 (16.8) 83.16 (16.5) 71.96 (18.3) 86.1(13.8)79.17(15.8)59.45(21) 76.11(11.3) Female, n = 371 76 (16) 84.72 (13.8) 72.28 (17.8) 87.4(13.6)78.9(16.2) 59.6 (20.3) 76.47 (10.5) ann-whit ney 68396.5 (0.31) (p value) 70006.5 (0.63) 71327 (0.97) 66634.5 (0.1) 71250 (0.95) 71204 (0.94) 70544.5 (0.77) Spearman's -0.11 rho (p (0.002) value) 0.041 (0.26) -0.05 (0.2) 0.1 (0.013) 0.1 (0.005) -0.31 (0.00) -0.11 (0.003) α coefficient Webmedcentral > Original Articles Page 6 of 19 0.64 0.56 0.7 0.6 0.51 0.51 0.83

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A (14.7) (13.7) (14.7) ann-whit ney 45737.5 (0.36) (p value) 46066 (0.44) 45557.5 (0.32) 47011 (0.74) 46606 (0.61) 47453 (0.89) 46786 (0.67) Spearman's -0.11 rho (p (0.007) value) -0.01 (0.72) -0.02 (0.61) 0.07 (0.06) 0.04 (0.27) -0.21(0.000-0.1 ) (0.023) α coefficient n = 618 0.7 0.68 0.73 0.7 0.68 0.53 0.86 ann-whit ney (p value)[1] 205200.5 222658 (0.000) (0.13) 216103.5 233596 (0.016) (0.99) 202369.5 (0.000) 170756 (0.000) 188920 (0.000) [1] Differences between the children s and parents scores Table 3. Age and gender referent values of the KINDL S self-report questionnaire (mean score, standard deviation SD, confidence interval CI, years y, mounts m) Age span & gender Physical Emotional Self-este well-bei Family well-being em ng Friends School Webmedcentral > Original Articles Page 7 of 19 8y 9y 6m Total QOL

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A 78.75 (16.2) 83.21 (15.1) 74.73 (17.7) 85.09 (13) 78.03 (15.7) 69.73 (18.6) 78.16 (11) n = 70 74.88 8 2.62 79.62 86. 81 70.51 7 8.95 81.9 88. 19 74.29 8 1.78 65.29 74.1 7 75.63 80.9 9y 7m 10y 6m ale 82.13 (17.3) 83.63 (18.7) 76 (18.4)86 (13) 79.25 (17.8) 70.75 (18.2) 79.63 (12.7) n = 50 77.22 8 7.03 78.32 88. 93 70.76 8 1.24 82.31 8 9.69 74.19 8 4.3 65.6 75.03 76 83.25 Female 74.34 (15) 80.91 (16) 70.23 (18.3) 89 (12.5) 74.51 (20.3) 67.11 (19.9) 76.01 (11.4) n = 38 69.41 7 9.23 75.67 86. 17 64.2 76. 26 84.86 9 3.1 67.83 8 1.18 60.6 73.63 72.25 79.77 78.76 (16.7) 82.46 (17.5) 73.51 (18.5) 87.29 (12.8) 77.2 (19) 69.18 (19) 78.08 (12.3) n = 88 75.23 8 2.3 78.75 86. 17 69.58 7 7.43 84.57 9 0 73.19 8 1.22 65.17 73.1 9 75.5 80. 66 10y 7m 11y 6m ale 78.07 (15.8) 84.32 (13.8) 73.23 (16.7) 85.73 (12.2) 75.83 (15.5) 66.5 (19.8) 77.28 (10.2) n = 53 73.7 82. 43 80.53 88. 1 68.63 7 7.83 82.36 8 9.1 71.56 8 0.1 61.05 72 74.5 80. 1 Webmedcentral > Original Articles Page 8 of 19 Female 76.7 (14.1) 86.6 (11.2) 72.27 (15.8) 88.41 (12.7) 80 (12.2) 61.25 (20.1) 77.54 (7.4)

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A ale 76.63 (17) 81.25 (17.9) 69.26 (19.2) 83.82 (15.1) 76.54 (14.8) 61.47 (21.2) 74.83 (11.8) n = 73 72.65 8 0.6 77.1 85.4 2 64.78 7 3.74 80.23 8 7.34 73.08 8 0 56.53 66.4 1 72.07 77.6 Female 76.9 (18) 84 (14.9) 72.88 (19.5) 87.28 (12.1) 76.16 (15.7) 59.11 (20.4) 76.06 (11.2) n = 59 72.2 81. 6 80.11 87. 9 67.8 78 84.13 9 0.4 72.06 8 0.26 53.8 64.42 73.15 79 n = 132 76.57 (17.4) 73.75 7 9.75 82.48 (16.6) 79.62 85. 34 70.88 (19.3) 67.55 7 4.21 85.37 (14) 83 87.7 6 76.37 (15.2) 73.76 7 9 60.41 (20.8) 56.84 64 75.38 (11.5) 73.4 77. 36 12y 7m 13y 6m ale 77.56 (15.1) 83.59 (16.7) 72.3 (17.7) 88.28 (11.9) 83.02 (14.4) 54.47 (17.9) 76.54 (10.6) n = 88 74.36 8 0.75 80.06 87. 13 68.54 7 6.06 85.75 9 0.81 80 86.8 50.67 58.2 8 74.3 78. 78 Female 73.9 (16.2) 84.05 (12) 71.22 (16.1) 86.64 (11.8) 79.85 (16.9) 60.13 (19) 76 (9) n = 58 69.66 7 8.2 80.9 87.2 67 75.4 8 83.54 8 9.74 75.4 84. 23 55.14 65.1 2 73.6 78. 34 n = 146 76.11 (15.6) 83.78 (15) 71.88 (17.1) 87.63 (11.9) 81.76 (15.5) 56.72 (18.5) Webmedcentral > Original Articles Page 9 of 19 73.56 7 8.66 81.3 86.2 2 69.08 7 5.67 85.69 8 9.57 79.23 8 4.3 76.31 (9.9) 53.7 59.75 74.69 77.94

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Female 77.65 (15.7) 86.56 (15.5) 72.35 (17.5) 86.23 (17) 78.28 (18.6) 52.43(20.8) 75.58 (12.6) n = 59 73.55 8 1.74 82.51 90. 56 67.8 76. 91 81.8 90. 67 73.43 8 3.14 47 57.87 72.31 78.86 n = 115 74.62 (17.8) 71.32 7 7.91 84.24 (16.6) 81.17 87. 3 70.38 (18.4) 67 73.7 8 85.76 (16.4) 82.74 8 8.8 78.6 (18) 49.4 (20.7) 73.83 (12.1) 75.3 81. 9 45.57 53.2 2 71.58 76.08 14y 7m 16y ale 70.41 (17) 87.7 (10.8)70 (19.7) 91.67 (11.5) 82.71 (14.2) 52.29 (21.1) 75.8 (10.4) n = 30 64.07 7 6.75 83.67 91. 75 62.63 7 7.36 87.36 9 6 77.41 8 8 44.43 60.1 5 71.93 79.67 Female 74.9 (15.6) 85.07 (12.9) 73.41 (19.3) 87.41 (15.8) 82.74 (14.4) 54.1 (18.2) 76.27 (10.6) n = 67 71.1 78. 71 81.92 88. 22 68.7 78. 12 83.54 9 1.27 79.22 8 6.26 49.66 58.5 5 73.7 78. 86 73.52 (16.1) 85.89 (12.3) 72.36 (19.4) 88.72 (14.7) 82.73 (14.3) 53.54 (19) 76.12 (10.5) n = 97 70.27 7 6.76 83.41 88. 37 68.44 7 6.27 85.75 9 1.69 79.85 8 5.61 49.7 57.38 74.01 78.24 Webmedcentral > Original Articles Page 10 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Table 4. Age and gender referent values of the KINDL S parent questionnaire (mean score, standard deviation SD, confidence interval CI, years y, mounts m) Age span & gender Physical well-bei ng Emotional Self-este well-being em Family Friends School Total QOL 8y 9y 6m ale 82.26 (14.4) 87.50 (11.8) 80.24 (14.2) 87.3 (11.2) 84.88 (13.2) 68.35 (18.2) 81.75 (8.7) n = 31 76.96 87 83.15 91..55 85 75.04 85.44 83.18 91 80.04 89 61.65 75 78.54 84.42.79.04.96 Female 82.22 (14.4) 84.18 (12.6) 72.06 (13.8) 85.94 (13.5) 80.66 (14.8) 73.24 (17) 79.72 (10) n = 32 76.82 87 79.6 88.7.62 6 67.08 77.06 81.08 90 75.31 86 67.1 79..78.01 39 76.11 83.32 n = 63 82.24 (14.6) 78.56 85.92 85.81 (12.3) 82.71 88. 91 76.09 (14.5) 72.44 79.74 86.61 (12.3) 83.5 89. 71 82.74 (14.1) Webmedcentral > Original Articles Page 11 of 19 79.18 86.28 70.83 (17.6) 80.72 (9.4) 66.38 75 78.35 83.28.03

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A 78.1 87. 4 83.82 92. 04 64.2 76. 26 81.72 92 77 87.22 67.75 79 78.35 85.24.3 82.63 (12) 87.41 (10) 76.38 (14) 88.14 (11.8) 81.89 (12.7) 75.64 (14.9) 82.02 (7.9) n = 68 79.73 85.53 85 89.92 73 79.78 85.27 91 78.8 85 72.03 79 80.1 83..25 93 10y 7m 11y 6m ale 77.68 (16.3) 84.08 (13.2) 73.96 (15.8) 85.6 (12.2) 81.25 (12.2) 72.47 (15.8) 79.19 (9.5) n = 42 72.58 82 79.95 88..77 21 69.03 78.9 81.46 89 77.45 85 67.55 77 76.24 82.72.05.39.14 Female 80.9 (15.7) 87 (16.8) 75.36 (17.9) 85.6 (12.2) 86.28 (9.7) 73.96 (15.4) 81.51 (10.9) n = 36 75.6 86. 2 81.3 92.6 7 69.28 81.4 81.46 89 83.01 89 68.74 79 77.81 85.72.55.17.2 79.16 (16) 85.41 (15) 74.6 (16.7) 85.66 (11.6) 83.57 (11.3) 73.15 (15.5) 80.26 (10.2) n = 78 75.55 82 82.04 88..78 79 70.8 78. 34 83.04 88.27 81.02 86 69.65 76 77.97 82.12.66.55 11y 7m 12y 6m ale 81.68 (13.3) 69.26 (15.1) 74.14 (14.8) 84.48 (15.5) 81.36 (15.3) 72.73 (17.1) 79.78 (10) Webmedcentral > Original Articles Page 12 of 19 n = 58 78.17 85.19 80.3 88.2 3 70.25 78.05 80.39 88 77.32 85 68.23 77 77.13 82.5.39.23.42

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A 12y 7m 13y 6m ale 80.12 (12.2) 86.2 (10.8) 76.13 (14.3) 88.63 (11.8) 83.94 (11.9) 67.01 (16.2) 80.33 (8.4) n = 72 77.24 83 83.66 88. 73 72.75 79.5 85.84 91 81.13 86 63.2 70..4.75 83 78.36 82.32 Female 78.37 (15.7) 84.25 (15.8) 73.37 (14.2) 85.87 (14.1) 81.62 (16) 69.62 (14.8) 78.85 (10.9) n = 50 73.9 82. 84 79.76 88. 73 69.33 77.41 81.87 89 77.05 86 65.4 73..88.18 84 75.76 81.94 n = 122 79.4 (13.7) 85.4 (13) 75 (14.3) 87.5 (12.8) 76.94 81 83.06 87..87 74 72.45 77 85.2 89..56 8 83 (13.7) 68.04 (15.7) 80.52 85.46 79.73 (9.5) 65.28 70 78.03 81.9.43 13y 7m 14y 6m ale 75.81 (18.7) 83.8 (14.5) 72.81 (14.2) 87.63 (11.5) 81 (16.3) 59.1 (20.1) 76.7 (10.9) n = 46 70.26 81 79.5 88.1.37 6 68.6 77. 06 84.22 91.05 75.53 86 53.15 65 73.46 80.43.06 Female 83.25 (14.2) 85.75 (14) 77.37 (13) 88.12 (13.5) 84.5 (15.4) 65.9 (18.4) 80.81 (10.8) n = 50 79.21 87 81.78 89..28 71 73.68 81.07 84.28 92 80.13 88.68 60.64 71 77.74 83.1.9 Webmedcentral > Original Articles Page 13 of 19 79.62 (16.8) 84.83 (14.2) 75.2 (13.7) 87.9 (12.5) 82.81 (16.8) 62.63 (19.4) 78.84 (11)

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Female 76 (14.5) 85.7 (13.8) 73 (15) 90.68 (10.7) 83.05 (14.4) 63.13 (18.3) 78.58 (9.7) n = 59 72.18 79.73 82.2 89.3 69.08 76 87.8 93..9 47 78.93 87.16 58.35 67 76 81.13.92 75.52 (15.3) 85.49 (14.3) 74.55 (15.7) 88.62 (13.4) 83.63 (14.5) 63.1 (17.2) 78.48 (10) n = 84 72.2 78. 84 82.4 88.5 8 71.15 78 85.71 91.52 80.63 86 59.35 66 76.31 80.77.84.65 Webmedcentral > Original Articles Page 14 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Disclaimer This article has been downloaded from WebmedCentral. With our unique author driven post publication peer review, contents posted on this web portal do not undergo any prepublication peer or editorial review. It is completely the responsibility of the authors to ensure not only scientific and ethical standards of the manuscript but also its grammatical accuracy. Authors must ensure that they obtain all the necessary permissions before submitting any information that requires obtaining a consent or approval from a third party. Authors should also ensure not to submit any information which they do not have the copyright of or of which they have transferred the copyrights to a third party. Contents on WebmedCentral are purely for biomedical researchers and scientists. They are not meant to cater to the needs of an individual patient. The web portal or any content(s) therein is neither designed to support, nor replace, the relationship that exists between a patient/site visitor and his/her physician. Your use of the WebmedCentral site and its contents is entirely at your own risk. We do not take any responsibility for any harm that you may suffer or inflict on a third person by following the contents of this website. Webmedcentral > Original Articles Page 15 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Reviews Review 1 Review Title: Revision Serbian KINDL reference values Posted by Dr. Vicky Serra-Sutton on 06 ay 2011 02:28:09 P GT 1 Is the subject of the article within the scope of the subject category? Yes 2 Are the interpretations / conclusions sound and justified by the data? No 3 Is this a new and original contribution? No 4 Does this paper exemplify an awareness of other research on the topic? No 5 Are structure and length satisfactory? No 6 Can you suggest brief additions or amendments or an introductory statement that will increase the value of this paper for an international audience? 7 Can you suggest any reductions in the paper, or deletions of parts? Yes 8 Is the quality of the diction satisfactory? No 9 Are the illustrations and tables necessary and acceptable? No 10 Are the references adequate and are they all necessary? No 11 Are the keywords and abstract or summary informative? No Rating: 4 Comment: Review of manuscript: KINDL Quality of Life Questionnaire in Serbia. Referent Values for Healthy Children and Adolescents by Dr. Dejan Stevanovic. The aim of this study is to present the reference values of the Serbian version of the KINDL using a representative population based sample including children, parents and parents. The manuscript is of interest in the field of Quality of Life and for future applications of the Serbian KINDL. Nevertheless, to be published the manuscript need to be improved regarding English writing and clarification of methods, results and finding-conclusions. - Abstract The abstract should be revised to be more comprehensive and show the relevance of this study in the field of health related quality of life measurement and application in evaluative studies. English should be revised. The objective of this report was to present the referent values... should be changed for The objective of this study was to present the reference values... - Title and context-introduction The author mentions the term Quality of Life and in the introduction mentions that the KINDL is a quality of life (QoL) questionnaire, considered as a psychological construct including physical, psychological and functional aspects of well-being and daily function. The author should consider that Health Related Quality of Life is different from a broader sense of Quality of Life and argument why it includes a psychological construct instead of a multidimensional health construct. Briefly a more detailed description of potential uses of this study should be made in the introduction, explaining why norm values are used in the measurement of mental health and HRQL instruments and also potential uses in future applications of the KINDL normative values in Serbia. The aim of the study is not clear enough. It would be interesting to add comparison with original German version of the KINDL or other normative values of the KINDL in other countries. - ethods Yes Webmedcentral > Original Articles Page 16 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A ore clarification of the sentence The Serbian KINDL possesses satisfactory measurement characteristics as a screening QOL questionnaire and include additional information of uses of the instrument in the field of mental health or health services evaluation. The author should reference in the text either in methods or discussion the characteristics of a tool to be able to be used for group comparison and as individual screening instrument in terms of psychometric properties (Cronbach alpha, Intraclass Correlation, Validity and Sensitivity to Changes). Even if published in other papers, more description of the sample should be made specially when mentioning representativeness and random sampling. Is the sample representative of children in Serbia, of adolescents in Serbia? And parents? In discussion section, any limitation of the sampling method and final sample obtained should be described. Regarding the approach of analysis, internal consistency is an additional aim not mentioned in the introduction. Children and adolescents scores are presented aggregated and not separately for boys and girls. Reference values are given for each age (from 8-9, 9-10, 10-11, 11-12, 12-13, 14-15, 16-17) for the KINDL self-reported and parent s version. This introduces small numbers when stratifications are made by gender and introduces limitation regarfind representativeness of these subgroups and specially when mean comparison of means for each domain and global score are made by gender and age, this may have introduced limitation due to lack of statistical power. It would be recommended to groups children and adolescents (age groups) scores differently by gender to present comparison of mean scores and 95% confidence intervals and also percentiles, similar to the original version of the KINDL, other published studies of HRQL measures such as the KINDSCREEN. It would be interesting to show the scores of normative/ reference values of the original KINDL questionnaire to see differences in scores in Serbia and Germany, perhaps in a figure. - Results ore detail should be included regarding results of the study shown in table. Also regarding sample characteristics. - Discussion and conclusion The author should include more references to other studies in the field and discuss the potential uses of the results of this study in more detail. Regarding interpretation strategies of HRQL measures, more detail should be given of the strategy of reference values for potential users of the instrument in research and clinical practice. Reasons for not finding differences in HRQL using the Serbian version of the KINDL should me mentioned including references of studies showing gender differences in children s and adolescent s physical, psychological, social or well-being. Competing interests: No Invited by the author to make a review on this article? : Yes Experience and credentials in the specific area of science: During some years my field of research was the development of questionnaires of health related quality of life for children and adolescents including the psychometric properties and interpretation strategies of these intruments for potential users. I participated in the adaptation and validation of the Spanish version of the KINDL and published in the field of HRQL. y actual field og interest involves the measurement of HRQL instruments for the assessment of effectiveness of health services in adult population. Publications in the same or a related area of science: Yes References: Serra Sutton V, Ferrer, Rajmil L, Tebe C, Simeoni C, Ravens-Siberer U. Population norms and cut-off-points for suboptimal health related quality of life in two generic measures for adolescents: the Spanish VSP-A and KINDL. Health and Quality of Life Outcomes 2009, 7. 35 available at: http:www.hqlo.com/content/7/1/35 Webmedcentral > Original Articles Page 17 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A How to cite: Serra-Sutton V.Revision Serbian KINDL reference values [Review of the article 'KINDL Quality Of Life Questionnaire In Serbia: Referent Values For Healthy Children And Adolescents ' by ].WebmedCentral 1970;2(5):REVIEW_REF_NU728 Webmedcentral > Original Articles Page 18 of 19

WC001342 Downloaded from http://www.webmedcentral.com on 28-Dec-2011, 07:01:31 A Disclaimer This article has been downloaded from WebmedCentral. With our unique author driven post publication peer review, contents posted on this web portal do not undergo any prepublication peer or editorial review. It is completely the responsibility of the authors to ensure not only scientific and ethical standards of the manuscript but also its grammatical accuracy. Authors must ensure that they obtain all the necessary permissions before submitting any information that requires obtaining a consent or approval from a third party. Authors should also ensure not to submit any information which they do not have the copyright of or of which they have transferred the copyrights to a third party. Contents on WebmedCentral are purely for biomedical researchers and scientists. They are not meant to cater to the needs of an individual patient. The web portal or any content(s) therein is neither designed to support, nor replace, the relationship that exists between a patient/site visitor and his/her physician. Your use of the WebmedCentral site and its contents is entirely at your own risk. We do not take any responsibility for any harm that you may suffer or inflict on a third person by following the contents of this website. Webmedcentral > Original Articles Page 19 of 19