Persian adaptation of Quality of Life Profile for Spinal Deformities questionnaire

Abstract

BACKGROUND:

The Quality of Life Profile for Spinal Deformities (QLPSD) is the first specific questionnaire to evaluate health-related quality-of-life (HRQoL) in adolescents with spinal deformities. Measuring HRQoL is important because spinal deformities and their management may negatively affect quality of life (QoL), thereby importantly affecting treatment effectiveness.

OBJECTIVE:

This study aimed to examine the validity and reliability of a Persian version of the QLPSD through patients with adolescent idiopathic scoliosis and Scheuermann’s kyphosis.

METHODS:

A cross-sectional design was used to determine the validity and reliability of the Persian version of the QLPSD based on the IQOLA protocols.

RESULTS:

The QLPSD was successfully culturally adapted, showing acceptable internal consistency (cronbach’s $\alpha=$ 0.88) and intraclass correlation coefficients (ICC $=$ 0.91). Concurrent validity was supported by comparing scores on corresponding dimensions of the Persian versions of QLPSD and the Scoliosis Research Society-22r (SRS-22r) questionnaires (function, pain, and body-image). Discriminant validity was supported though observation of significant differences between participants who had different clinical characteristics ( $p<$ 0.05).

CONCLUSIONS:

The Persian QLPSD is valid and reliably measures QoL among adolescents with spinal deformities; it may be used in clinical evaluations and future research.

Keywords

QLPSD quality of life spinal deformities adaptation validity reliability

1. Introduction

Spinal deformities place individuals in an ill-defined position between illness and health; they involve deviation from the spine’s natural alignment and often cause the patient to consider his or her situation abnormal [1]. Most treatments aim to prevent progression of the deformity; however, these treatments may negatively affect health-related quality of life (HRQoL) among adolescents with spinal deformities [2].

The Quality of Life Profile for Spinal Deformities (QLPSD), developed in Spain, was the first questionnaire designed to evaluate HRQoL in adolescents with spinal deformities [3]. The QLPSD has shown good validity and reliability. English and French versions of the QLPSD have been developed and validated. Good reliability and ease of use are mentioned in these versions [4, 5]. The QLPSD was designed to examine adolescents with spinal deformities and measure the effect of orthotic and surgical treatments on QoL [6].

Linguistic and cultural differences between nations may affect the perception of items in the QLPSD; Idiopathic scoliosis (IS) and Scheuermann’s kyphosis (SK) are the most common types of spinal deformity among adolescents aged 10 to 16. Therefore, this study aimed to translate and trans-culturally adapt the QLPSD to the Persian language and context and test the adapted version’s reliability and validity in adolescents with IS and SK.

2. Methods

2.1 Study design

Following the guidelines given by the International Quality of Life Association (IQOLA), the study protocol involved cross-cultural adaptation of the QLPSD and examination of its reliability and concurrent and discriminant validity [7].

2.2 Tools

The QLPSD contains 21 items in five dimensions: psychosocial functioning (7 items), sleep disturbances (4 items), back pain (3 items), body image (4 items), and back flexibility (3 items). Responses to items use a 5-point Likert scale. The possible score range is 21–105. Higher scores indicate poorer QoL.

The SRS-22 questionnaire covers the following five domains: function/activity (five items); pain (five items); self-image/appearance (five items); mental he- alth (five items); and satisfaction with management (two items). For each item of the domains, the score ranges from 1 (worst) to 5 (best).

2.3 Translation

Two bilingual certified translators whose native language was Persian produced independent Persian translations of the Spanish original. One translator was aware of the study’s aims and the characteristics of spinal deformities. The second translator received no background information concerning the study or the character of spinal deformities. The authors and the translators compared the translations and produced a single version of the questionnaire. Two other professional translators translated the Persian questionnaire back into Spanish; these translators were unaware of the original version of the questionnaire. An expert committee (the translators, the researchers, an orthopedic surgeon, a psychologist, and an outcome methodologist) supervised all translation and cultural adaptation processes. The committee verified that the Persian QLPSD was culturally, semantically, idiomatically, experientially and conceptually equivalent to the original. The pre-final Persian version of the QLPSD was given to 20 Persian-speaking persons with no history of spinal disorder as a pretest to identify any spelling or equivocation errors. One change was made: item 15 was revised from I am ashamed to be seen in a swimsuit to I am ashamed about my back being seen (e.g. in a swimsuit). Subsequently, the Persian QLPSD was finalized and its psychometric properties tested.

2.4 Sample

Recruited participants were 105 patients attending three spine centers in Tehran, Iran for a regular brace check-up; they completed the Persian QLPSD and Persian SRS-22r questionnaire [8]. Forty of these participants were randomly selected to complete a retest. The inclusion criteria were as follows: patients with adolescent idiopathic scoliosis (AIS) or mid-thoracic SK aged 10–19 years, who wore a brace fo $r\geqslant$ 12 hours a day according to the patient and their parents’ report. At the time of participation, all participants used a Milwaukee brace and had no history of surgery. A brace was prescribed to any participants with AIS and a Cobb angle $>$ 45 ${}^{\circ}$ or with SK and a Cobb angle $>$ 74 ${}^{\circ}$ who had refused surgery. Ninety-seven participants completed the first round of surveying; 35 completed the retest. All participants voluntarily provided a written indication of informed consent. This study was approved by the ethics committee at the Iran University of Medical Sciences and carried out in accordance with the Declaration of Helsinki.

2.5 Statistical analysis

Statistical analysis was conducted using SPSS v. 16 (SPSS Inc., Chicago IL, USA). Scores were distributed normally except regarding sleep disturbance and back flexibility; therefore, parametric and nonparametric tests were used. Statistical significance was set at $<$ 0.05. Construct validity was examined through convergent and discriminant validity. Convergent validity was examined by comparing the Persian QLPSD with the Persian SRS-22r using a multitrait-multimethod matrix and correlation coefficients calculated between the instruments’ relevant dimensions [9]. Correlation values $\geqslant$ 0.40 were considered satisfactory ( $r\geqslant$ 0.81–1.0, excellent; 0.61–0.80, very good; 0.41–0.60, good; 0.21–0.40, fair; 0–0.20, poor) [10]. Discriminant validity was examined by testing if the Persian QLPSD could discriminate between participants who differed regarding type of deformity, gender, Cobb angle, and duration of bracing (independent-sample t-tests). Test-retest reliability was examined by calculating the intraclass correlation coefficient (ICC) with 35 participants who completed a retest after a two-week interval. Internal consistency was estimated using Cronbach’s alpha in each dimension; values $>$ 0.7 were considered acceptable [11].

Table 1
The internal consistency and test-retest reliability of the Persian QLPSD

Persian QLPSD	Cronbach’s $\alpha$	ICC (95% confidence interval)
Psychosocial functioning	0.75	0.91 (0.83–0.95)
Sleep disturbances	0.76	0.81 (0.63–0.90)
Back pain	0.72	0.84 (0.69–0.92)
Body image	0.76	0.89 (0.77–0.94)
Back flexibility	0.82	0.78 (0.56–0.88)
Total	0.88	0.91 (0.83–0.95)

Table 2

Multitrait-multimethod matrix of correlation between the QLPSD and the SRS-22r

	Psychosocial functioning	Back pain	Body image
Function	$-$ 0.62	$-$ 0.40	$-$ 0.57
Pain	$-$ 0.51	$-$ 0.57	$-$ 0.26
Self image	$-$ 0.49	$-$ 0.30	$-$ 0.57

$P<$ 0.05.

Table 3

QLPSD scores by Cobb angle and bracing duration among participants with AIS

Characteristics	QLPSD dimensions
	Psychosocial	Sleep disturbances	Back pain	Body image	Back flexibility
	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)
Cobb angle
$\geqslant$ 40 ${}^{\circ}$	22.20 (9.79)	10.67 (3.47)	10.73 (3.32)	13.67 (4.83)	11.13 (3.79)
$<$ 40 ${}^{\circ}$	17.09 (5.35)	8.94 (3.86)	7.63 (2.74)	10.46 (3.50)	11.04 (3.691)
$P$	0.001	NS	0.001	0.027	NS
Bracing duration
$>$ 3 months	17.24 (5.55)	8.82 (3.86)	7.96 (3.30)	10.59 (4.33)	10.37 (3.81)
$\leqslant$ 3 months	20.55 (5.18)	10.55 (3.54)	9.15 (2.56)	12.55 (2.72)	12.75 (2.77)
$P$	0.026	NS	NS	0.028	0.008
$>$ 6 months	16.82 (5.71)	9.09 (4.00)	7.82 (3.28)	9.88 (4.21)	9.74 (3.72)
$\leqslant$ 6 months	19.54 (5.26)	9.54 (3.69)	8.77 (2.95)	12.40 (3.44)	12.34 (3.19)
$P$	0.044	NS	NS	0.008	0.002

SD, standard deviation; NS, not significant.

Table 4

QLPSD scores by Cobb angle and bracing duration among participants with SK

Characteristics	QLPSD dimensions
	Psychosocial	Sleep disturbances	Back pain	Body image	Back flexibility
	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)
Cobb angle
$\geqslant$ 45 ${}^{\circ}$	18.13 (5.40)	12.06 (3.66)	8.88 (3.20)	9.75 (3.66)	11.31 (2.549)
$<$ 45 ${}^{\circ}$	14.33 (5.26)	7.00 (2.82)	6.00 (2.33)	8.42 (3.20)	8.33 (3.82)
$P$	NS	0.001	0.014	NS	0.039
Bracing duration
$>$ 3 months	16.00 (5.36)	9.58 (4.03)	7.21 (3.12)	8.88 (3.15)	9.50 (3.38)
$\leqslant$ 3 months	19.50 (6.75)	11.75 (4.99)	10.25 (2.21)	11.00 (5.22)	13.25 (1.50)
$P$	NS	NS	NS	NS	0.014
$>$ 6 months	13.87 (4.62)	8.47 (3.98)	6.40 (3.20)	8.20 (3.25)	8.93 (3.49)
$\leqslant$ 6 months	19.54 (5.14)	11.54 (3.84)	9.08 (2.53)	10.31 (3.49)	11.31 (3.01)
$P$	0.005	0.044	0.023	NS	NS

SD, standard deviation; NS, not significant.

3. Results

From May 2015 to February 2016, 97 participants with spinal deformities (63 females and 34 males) with a mean age of 14.16 years (range: 10–19) at the time of study who met the inclusion criteria were recruited. Sixty-nine participants had AIS; 28 had SK. The AIS subgroup contained 47 females and 22 males with a mean age of 14.26 $\pm$ 2.19 years (range: 11–19). The mean in-brace Cobb angle in the AIS subgroup was 29.03 ${}^{\circ}$ $\pm$ 11.94 (range: 10 ${}^{\circ}$ –60 ${}^{\circ}$ ). The SK subgroup contained 16 females and 12 males with a mean age of 13.93 $\pm$ 1.99 years (range: 10–18). The mean in-brace Cobb angle in the SK subgroup was 47 ${}^{\circ}$ $\pm$ 8.233 (range: 36 ${}^{\circ}$ –70 ${}^{\circ}$ ). All participants responded to all items. No floor or ceiling effects were observed. Values of Cronbach’s $\alpha$ were 0.72–0.82 for each dimension of the QLPSD and 0.88 for the entire scale (Table 1). ICC values for each dimension of the QLPSD were 0.78–0.91 and 0.919 for the entire scale (Table 1).

Convergent validity was examined using multitrait-multimethod matrix analysis of domains that correspond between the QLPSD and SRS-22r (QLPSD: psychosocial functioning, back pain, and body image; SRS-22r: function, pain, and self-image). The resulting correlation coefficients were $-$ 0.30 to $-$ 0.62 ( $p<$ 0.01). A convergent matrix with higher coefficients in the diagonal indicates that the two scales represent similar characteristics [9]. The mean value of the coefficients in the diagonal (0.58, range: 0.57–0.62) exceeded that of those out of the diagonal (0.42, range: 0.30–0.57). The correlation coefficient between the instrument’s total scores was $-$ 0.77 ( $p<$ 0.01).

Participants with AIS had poorer body image scores than participants with SK (11.16 vs. 9.18, respectively; $p=$ 0.025). Male participants with SK had poorer psychosocial functioning and body image than females (psychosocial functioning: 19 vs. 14.63; body image: 12.17 vs. 6.94; $p=$ 0.037 and 0.001, respectively). Participants with AIS did not differ significantly by gender.

Among participants with SK, a Cobb angle $\geqslant$ 40 ${}^{\circ}$ predicted significantly poorer scores on psychosocial functioning ( $p=$ 0.001), back pain ( $p=$ 0.001), and body image ( $p=$ 0.027; Table 3). Among participants with SK, a Cobb angle $\geqslant$ 45 ${}^{\circ}$ predicted significantly poorer scores on sleep disturbance ( $p=$ 0.001), back pain ( $p=$ 0.014), and body image ( $p=$ 0.039; Table 4).

In this study, the average time of bracing was 10 $\pm$ 8.93 months among participants with AIS and 9.71 $\pm$ 7.15 months among participants with SK. Among participants with AIS, psychosocial functioning, body image, and back flexibility scores reduced from $\leqslant$ 3 to $>$ 3 months of bracing, and from $\leqslant$ 6 to $>$ 6 months of bracing (Table 3). Among participants with SK, back flexibility scores reduced from $\leqslant$ 3 to $>$ 3 months of bracing and psychosocial functioning, sleep disturbance, and back pain, scores reduced from $\leqslant$ 6 to $>$ 6 months of bracing (Table 4).

4. Discussion

This study tested the translated and culturally adap- ted Persian QLPSD. The Persian QLPSD’s alpha coefficient was 0.72–0.82, indicating acceptable internal consistency. Compared with the original, the Persian QLPSD showed inferior internal consistency regarding psychosocial functioning, sleep disturbances, and back pain [3]; this change resembles other transcultural adaptations of questionnaires [8, 12]. The Persian and original QLPSD showed similar overall internal consistency (0.88). The Persian QLPSD’s test-retest reliability was satisfactory to excellent (0.78–0.91), exceeding the original QLPSD except regarding the back pain dimension [3]. The Persian QLPSD’s overall ICC was 0.91, equaling the original.

The QLPSD and SRS-22r were strongly correlated regarding overall score and scores on comparable dimensions (function, pain, and body image), supporting the QLPSD’s convergent validity. The mean of the coefficients in the diagonal of the matrix was lower than in Climent (0.57 vs. 0.67); however, the coefficients were higher in the diagonal than out of it. Coefficients outside the diagonal should ideally be lower because they represent dissimilar characteristics [9]. The instruments’ other dimensions assess complementary aspects of QoL; therefore, both instruments should be used in conjunction to thoroughly assess spinal deformities and their treatment.

Participants’ scores differed significantly depending on their demographic and clinical characteristics, supporting the Person QLPSD’s discriminant validity. Body image was poorer among participants with AIS than among those with SK, although Lonner reported better body image among individuals with AIS [13]. Among participants with SK, females reported better psychosocial functioning and body image; this finding also contrasts with previous researches [13, 14] but may reflect a cultural effect: Iranian girls’ typical clothing facilitates concealment of the Milwaukee brace (especially the neck ring), likely leading to better body-image and thereby protecting psychosocial functioning. Similarly, during school hours, patients’ uniform effectively conceals the brace, and the school context reduces the importance of self-presentation through dress [15].

Among participants with AIS, those whose Cobb angle was $<$ 40 ${}^{\circ}$ showed better psychosocial functioning, less back pain, and better body image. Among participants with SK, those whose Cobb angle was $<$ 45 ${}^{\circ}$ reported fewer sleep disturbances, less back pain, and better back flexibility. These results support previous studies [8, 13] and indicate that Cobb angle is negatively correlated with QoL among adolescents with spinal deformities.

Among participants with AIS, psychosocial functioning, body image, and back pain improved from $\leqslant$ 3 to $>$ 3 months of bracing. Cheung reported that functioning and pain improved with increasing time in bracing (resembling the present findings) and that self-image worsened over time (contrasting with the present results) [16]. Among participants with SK, back flexibility improved from $\leqslant$ 3 to $>$ 3 months of bracing and psychosocial functioning, sleep disturbances, and back pain improved from $\leqslant$ 6 to $>$ 6 months of bracing. These results suggest that, after the initial shock of adapting to bracing, spinal deformity’s negative effect on participants’ QoL begins to diminish.

During transcultural adaptation, the item I am ash- amed to be seen in a swimsuit was replaced with I am ashamed about my back to be seen (e.g., in a swimsuit). This change was made because recreational and competitive swimming are uncommon and little known in the Iranian cultural context.

The Persian QLPSD showed no ceiling or floor effects; however, back flexibility was not normally distributed. Given the Milwaukee brace’s particular structure (i.e., the basket, metal uprights, and neck ring), most patients appear to have poor spinal flexibility [2].

This study has the following limitations. First, the sample was small, reducing the likelihood that it represented the population of people with AIS and SK in Iran; however, participants were referred from a range of regions and cities of Iran. Second, the sample consisted of non-operatively treated individuals with AIS and SK; therefore, future research should use the Persian QLPSD to examine surgically treated individuals with AIS, SK, and other spinal deformities. Based on our findings, the Persian version of this questionnaire can be used to evaluate the quality of life in the patients who suffer from idiopathic scoliosis and Scheuermann’s kyphosis.

5. Conclusion

The Persian QLPSD showed adequate transcultural adaptation, reliability, and convergent and discriminant validity; therefore, it is appropriate for examining the effect of spinal deformities and their managements on QoL among Iranian Persian-speaking adolescents.

Footnotes

Acknowledgments

The kind assistance of Payvand Orthotics Center, Iranian Red Crescent Society and Shafa Yahyaeian Orthopedic Hospital of Iran University of Medical Sciences is appreciated. Special thanks go to J.M. Climent, whose invaluable experience in the field was incredibly helpful to our work.

Conflict of interest

None to report.

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Persian adaptation of Quality of Life Profile for Spinal Deformities questionnaire

Abstract

BACKGROUND:

OBJECTIVE:

METHODS:

RESULTS:

CONCLUSIONS:

Keywords

1. Introduction

2. Methods

2.1 Study design

2.2 Tools

2.3 Translation

2.4 Sample

2.5 Statistical analysis

Table 1 The internal consistency and test-retest reliability of the Persian QLPSD

4. Discussion

5. Conclusion

Footnotes

Acknowledgments

Conflict of interest

References

Table 1
The internal consistency and test-retest reliability of the Persian QLPSD