Cross-Cultural Application of the Korean Version of Ureteral Stent Symptoms Questionnaire

Abstract

Purpose:

We validated the Korean version of the Ureteral Stent Symptoms Questionnaire (USSQ) in patients with an indwelling ureteral stent.

Materials and Methods:

Linguistic validation of the original USSQ was performed through a standard process including translation, back translation, and pilot study. A total of 65 patients who underwent ureteroscopic surgery were asked to complete the Korean USSQ as well as EuroQOL (male and female), the International Prostate Symptom Score (male), and Urogenital Distress Inventory-6 (female). Patients were evaluated at weeks 1 and 2 after stent placement and at week 4 after removal. Sixty-four healthy subjects without a ureteral stent were also asked to complete the Korean USSQ once. The psychometric properties of the questionnaire were analyzed.

Results:

Internal consistencies (Cronbach α coefficients: 0.73–0.83) and test-retest reliability (Spearman correlation coefficient: ≥0.6) were satisfactory for urinary symptom, body pain, general health, and work performance domains. Most USSQ domains showed moderate correlations with each other. Convergent validity determined by correlation between other instruments and corresponding USSQ domain was satisfactory. Sensitivity to change and discriminant validity were also good in most domains (P<0.01). Only a small proportion of the study population had an active sexual life, with the stent in situ, limiting its analysis.

Conclusions:

The Korean version of the USSQ is a reliable and valid instrument that can be self-administered by Korean patients with a ureteral stent in the clinical and research settings. Further clinical studies in the Korean settings would be useful to provide robust data on sensitivity to change.

Introduction

U reteral stent plcement for ensuring urinary flow in various conditions is one of the common urologic procedures. Indications and use of stent placement have continued to expand. Ureteral stent placement, however, is associated with various side effects and patient morbidity, which consequently result in decreased patient quality of life (QoL).^1
–3 A reliable and valid measure of such patient experience is therefore becoming a more important assessment of clinical outcomes and would form the basis for the research and development of better treatment methods.⁴

To address such needs, in 2003, Joshi and associates⁴ developed and validated the Ureteral Stent Symptoms Questionnaire (USSQ), a self-administered, multidimensional instrument exploring stent-related morbidity in six domains, including urinary symptoms, body pain, general health, work performance, sexual matters, and additional problems. The original English version of USSQ was then translated and validated in European countries, such as in Italy⁵ and France.⁶ Is applicability in different cultures, however, has not been reported. While there are limited studies that evaluated clinical outcomes with USSQ in Korea⁷ the process of questionnaire translation and psychometric validation was not systematically performed.

In this study, we developed a Korean version of the USSQ and evaluated its psychometric properties to determine if it is appropriate for evaluating the outcomes of ureteral stent placement in Korean patients.

Materials and Methods

Translation process and pilot study

Linguistic validation of the USSQ was performed through a standard, multistep process. The questionnaire was initially forward translated from English into Korean by two independent translators (one M.D., one Master of Education majoring in English) who are fluent in both English and Korean. A first consensus meeting among the translators and two of the investigators (JP and DWS) with a good command of English was done to reconcile the two versions, yielding a first consensus Korean version. Back-translation of the synthesized version was performed in parallel by two independent M.D.s, bilingual in English and Korean, without referring to the original questionnaire.

A second consensus meeting was held between the translators and all investigators, during which the original and back-translated versions were compared and their minor discordances were debated. At this meeting, we decided that several questions needed slight modification because of the difference in the health system and cultural background, and made a revision of the first consensus version. The original author (HBJ) of the English USSQ was invited to compare the back translation and original English version. This revised translation was subsequently corrected for spelling and grammar and the definitive version was edited and drafted. Finally, a pilot test was performed by an urologist (JP) to assess whether the questionnaire was clear and appropriate by face-to-face interviews in three men and three women patients with an indwelling ureteral stent.

Study subjects

A total of 65 consecutive male (n=31) and female (n=34) patients who underwent ureteral stent placement after ureteroscopic surgery for ureteral calculi between December 2010 and September 2011 at four university hospitals were enrolled. Inclusion criteria were adult patients older than 18 years who underwent unilateral temporary stent insertion after ureteroscopy for ureteral calculi. Exclusion criteria were (1) a history of or current treatment for lower urinary tract symptoms, chronic prostatitis, chronic pelvic pain syndrome, and prostate cancer in men, (2) a history of or current treatment for stress/urge/mixed urinary incontinence, (3) lower urinary tract dysfunction and pregnancy in women, (4) chronic ureteral obstruction, bleeding diathesis, recurrent urinary tract infections, (5) overactive bladder syndrome, neurologic and psychiatric diseases, and (6) concomitant medication with α-blockers, anticholinergics, analgesics, and other drugs, possibly interfering with lower urinary tract function. We also excluded patients with major complications after ureteroscopy and stent insertion whose clinical course was significantly affected by the complications.

The same type of 6F double-pigtail ureteral stent (Percuflex,^® Boston Scientific) of four lengths (22, 24, 26, and 28 cm, respectively) was inserted in all cases according to patient height. Because inappropriate stent location was associated with severe lower urinary tract symptoms in our previous study,⁸ we took into consideration the length of the stent according to the patient's height not to cross the midline of the bladder, and we also evaluated its correct position with radiography of the kidneys, ureters, and bladder on the day of stent removal.

During the study period, 64 persons (30 men and 34 women) who visited the university hospital for routine health examination were recruited as controls. They were enrolled if they were apparently healthy at the time of the visit and without a urinary disease necessitating placement of a ureteral stent. To ensure comparability with the subjects, we purposefully selected control persons considering age and sex distribution of the enrolled subject.

Required sample size was predetermined before the study based on the assessment of convergent validity between the USSQ and other validated questionnaires. The minimum number of subjects with stent per each sex was estimated to test the correlation coefficient of 0.56 (the lowest found in the Italian validation of the USSQ⁵), with the assumption of α=0.05, β=0.10, and a response rate of at least 80%. The required number was 30 for each man and woman.

Institutional Review Board of each participating center approved the study protocol, and all study subjects were fully informed about the purpose of the study and provided written consent for their participation.

Data collection

The Korean version of the USSQ was self-administered by all patients at weeks 1, 2 (the day of stent removal) after stent placement, and at week 6 (4 weeks after stent removal). In addition, all patients were asked to complete the EuroQoL questionnaire⁹ for general QoL, the International Prostate Symptom Score (IPSS)¹⁰ in men, and the Urogenital Distress Inventory-6 (UDI-6)¹¹ in women at weeks 2 and 6. The Korean version of the EuroQoL questionnaire¹² and IPSS had been previously validated. Because a validated Korean version of the UDI-6 questionnaires was not available at enrollment, a Korean translated version was administered.

Healthy control subjects were evaluated with the Korean version of USSQ only once. Therefore, test-retest reliability was performed in patients only. No other questionnaires were administered in control subjects.

Statistical analysis

The characteristics of the participants were analyzed using descriptive statistics. Response rates for each item were calculated to evaluate feasibility and acceptability. For the statistical analysis, domain scores were calculated according to established scoring guidelines by the original author (HBJ).⁴ According to the original author's guide, imputing the individual's mean is used for the small number of missing data, and unanswered whole domain was omitted in the analysis; meanwhile the rest of the data was used.

Reliability was evaluated by internal consistency (tested by Cronbach α) and test-retest reliability between week 1 and 2 (tested by Spearman correlation). Domain structures were examined by interdomain correlations using Spearman correlation coefficient. Convergent validity was assessed by correlating the scores of urinary symptom domain to the IPSS in men or UDI-6 in women, and by correlating the scores of general health domain to the visual analogue scale of the EuroQoL questionnaire. Sensitivity to change was assessed by comparing scores with the stent in situ and after removal with the Wilcoxon signed rank test. Discriminant validity was evaluated by comparing the results of patients at week 2 with those of healthy subjects with Wilcoxon-rank sum tests. All statistical analyses were performed using STATA version 12.0 (STATA Corp, Houston, TX) and were two-sided with P<0.05 defined as statistically significant.

Results

The original author confirmed that no significant differences existed between the backward-translated version and the original English version. The pilot test confirmed that the instructions, questions, and response options were clearly understood by the subjects; thus, no change was made.

Sex and age distribution between the 65 patients (31 men, 34 women; median age 53 years, interquartile range [IQR], 45 to 60 years) and 64 healthy subjects (30 men, 34 female; median age 53 years, IQR, 45 to 58 years) were similar (P=0.527, P=0.926, respectively). Most patients completed the questionnaire without many missing items and were suitable for further statistical analysis. There was a small number (1 to 4) of missing data in 12 (18.5%) patients and 11 (17.2%) controls, and whole item in several domains was not answered only in 2 (3.1%) patients. Unanswered questions, however, were not uniformly distributed throughout all USSQ domains. Reply to items on sexual matters showed that only small proportions of our patients had an active sex life during the study period. Only 7 (10.8%) and 12 (18.5%) patients had an active sex life at week 1 and 2 after stent placement; meanwhile, 21 (32.3%) patients were sexually active at week 4 after stent removal. Because sexual matters score (sum of S3 and S4 questions) was determined by such a small number of patients, estimates regarding sexual matters were not reliable; thus, they were omitted in further analysis.

Reliability and validity

Internal consistencies were satisfactory for urinary symptom, body pain, general health, and work performance domains, with Cronbach α coefficients ranging from 0.73 to 0.83 (Table 1). Test-retest reliability was also satisfactory (Spearman correlation coefficient ≥0.6 for all domains).

Table 1.

Internal Consistency and Test-Retest Reliability of Korean Ureteral Stent Symptoms Questionnaire

	Internal consistency (Cronbach α)		Test-retest reliability
	Week 1 with stent	Week 2 with stent	Spearman correlation coefficient	P value
Urinary symptom	0.77	0.83	0.74	<0.001
Body pain	0.73	0.78	0.63	<0.001
General health	0.77	0.8	0.60	<0.001
Work performance	0.74	0.79	0.60	<0.001
Global QoL	NA	NA	0.69	<0.001

QoL=quality of life, NA=not applicable.

Domain structure and convergent validity

Most USSQ domains showed moderate correlations with each other, except for that between urinary symptom and body pain (Spearman correlation coefficient=0.75) and that between work performance and global QoL (0.04) at week 2 (Table 2). At week 2, correlation was high for the urinary symptoms index compared with the IPSS total score and QoL score in men (correlation coefficients=0.74, P<0.001 and 0.83, P<0.001, respectively), and was moderate for the urinary symptoms index compared with the UDI-6 score in women (correlation coefficients=0.46, P=0.024, Table 3). The global QOL score of USSQ has weak-to-moderate correlation with the visual analogue scale of the EuroQOL questionnaire (correlation coefficients=−0.27, P=0.073).

Table 2.

Total Domain Correlations of Korean Ureteral Stent Symptoms Questionnaire Domain Scores in Patients with Indwelling Stent at Weeks 1 and 2

	Urinary symptom	Body pain	General health	Work performance	Global QoL
Urinary symptom	1.00/1.00
Bodily pain	0.65/0.75	1.00/1.00
General health	0.48/0.54	0.52/0.58	1.00/1.00
Work performance	0.26/0.33	0.32/0.30	0.55/0.64	1.00/1.00
Global QOL	0.36/0.45	0.22/0.46	0.46/0.43	0.37/0.04	1.00/1.00

QoL=quality of life.

Table 3.

Convergent Validity of Korean Ureteral Stent Symptoms Questionnaire

	Spearman correlation coefficient	P value
Correlation with urinary symptom domain
Male
IPSS total score	0.74	<0.001
IPSS storage symptom score	0.67	<0.001
IPSS voiding symptom score	0.70	<0.001
IPSS QoL score	0.83	<0.001
Female
UDI-6 sum	0.46	0.024
Correlation with global QoL score^*
EuroQoL, visual analogue scale score	−0.27	0.073

Response to the question GQ in additional problems domain.

IPSS=International Prostate Symptom Score; QoL=quality of life; UDI-6=Urogenital Distress Inventory-6.

Sensitivity to change and discriminant validity

Significant changes were observed in the score of all domains except global QoL domain when comparing patients with and without a stent (Table 4). Differences between patients and healthy controls are shown in Table 5; each domain scores were significantly different, indicating good discriminant validity of the Korean USSQ.

Table 4.

Sensitivity To Change of Korean Ureteral Stent Symptom Questionnaire

	Median with stent (IQR)		Median without stent (IQR)	P value
	Week 1	Week 2	Week 6	Week 1 vs 6	Week 2 vs 6
Urinary symptom	28 (24–31)	27 (22–33)	18 (15–20)	<0.001	<0.001
Body pain	18.5 (13.5–24)	18 (7–23)	0 (0–0)	<0.001	<0.001
General health	12 (10–16)	11 (9–16)	8 (6–9)	<0.001	<0.001
Work performance	7.5 (5–10)	6 (4–10)	3 (3–4)	<0.001	0.001
Global QoL	4 (4–5)	5 (4–6)	4.5 (3–6)	0.76	0.41

IQR=interquartile range; QoL=quality of life.

Table 5.

Discriminant Validity of Korean Ureteral Stent Symptom Questionnaire

	Cases (Week 2 with stent)	Controls	P value
Median domain index score (IQR):
Urinary symptom	27 (22–33)	16 (13–18)	<0.001
Body pain	18 (7–23)	0 (0–0)	<0.001
General health	11 (9–16)	11 (9–13)	0.057
Work performance	6 (4–10)	4 (3–6)	0.001

IQR=interquartile range.

Discussion

Indwelling ureteral stents result in various stent-related symptoms and reduced QoL in about 80% of patients.² The USSQ, which was developed and validated in 2003, is a multidimensional instrument evaluating stent-related morbidity in six domains.⁴ In this study, we evaluated the psychometric properties of the Korean version of USSQ.

Our results show that the Korean version of USSQ is a reliable and valid instrument for measuring various stent-related symptoms in Korean patients with a ureteral stent. These findings demonstrate that this questionnaire has adequate levels of cross-cultural validity and might be applicable to other languages and cultures as well.

Internal consistencies were found to be satisfactory for most domains (Table 1), suggesting its reliability. While the original USSQ study⁴ and Italian study⁵ put a 4 weeks interval to avoid recall bias in assessing test-retest reliability, we assessed it with a 2 weeks interval because removal of the ureteral stent at postoperative 2 weeks was our routine practice. From our results, we believe that recall bias from a relatively shorter interval is minimal.

Moderate correlations in domain correlation analysis show that each domain of the Korean version of USSQ reflects different aspects of QoL in patients with an indwelling ureteral stent (Table 2). Only one exception was high correlation between urinary symptom and body pain. A similar finding was observed in the original USSQ study (Spearman correlation coefficient=0.82 at week 1, 0.67 at week 4).⁴ The reason for these findings remains to be elucidated. Whether patients with severe urinary symptoms are likely to have more severe body pain is uncertain. As noted by another study, however, urinary symptoms and stent-related pain were predominant symptoms affected by stents, which in turn had a marked impact on other aspects of QoL.²

Convergent validity of the Korean version of USSQ was confirmed by good correlations with other validated voiding symptom measures—the IPSS in men and the UDI-6 in women. In addition, the finding that the global QoL score had weak-to-moderate correlation with the visual analogue scale score of the EuroQOL questionnaire with marginally statistical significance indicates that the global QoL score reflects general QoL of patients to some degree.

The Korean version of USSQ was capable of discriminating among patients with stents and healthy controls. Of note, global QoL was not different between patients with and without a stent. We believe that the response to global QoL with the stent in situ (GQ question) reflects the stability of the patient decision for treatment re-choice rather than the patient's general QoL.

In our study, only small proportions of Korean patients with indwelling ureteral stents had answered that they had an active sexual life. In another study by an Italian group, 66.7% of patients had an active sexual life at 4 weeks after stent insertion,⁵ whereas only 10.8% and 18.5% of our patients had an active sex life at weeks 1 and 2 after stent placement. No previous USSQ validation studies so far have reported such low sexual activity during stent insertion. One possible explanation could be the Korean (Asian) patient's reluctance to discuss sexual issues with health professionals.^13
–15 Without proper education regarding the sexual safety issue after stent placement, patients might have concerns for safety if having sex, be unsure about the timing for resuming sex, or have fear that complications could occur as a result of sexual intercourse, which leads to abstinence while having a stent.¹⁴ We believe that sexual experience with the stent in situ could be assessed with the larger sample size. Similarly, complex issues such as cultural influences, social factors, as well as stent-related factors/illness could influence this domain and would need separate detailed evaluation that could not be encompassed within the span of the current study.

We acknowledge that our study has potential limitations. Most of all, we did not evaluate the psychometric properties regarding the sexual matters domain because of the aforementioned low proportions of sexually active patients with stents. Thus, this issue requires further examination. We believe that the results of studies that would use the Korean version of the USSQ would help demonstrate psychometric properties in a more robust way and would help validate the Korean USSQ further.

Conclusion

The Korean version of the USSQ is a generally reliable and robust instrument that can be self-administered by men and women Korean patients with an indwelling ureteral stent in the clinical and research settings. Further clinical studies in the Korean settings would be useful to provide robust data on sensitivity to change.

Footnotes

Acknowledgments

We thank Dr. W.J. Yoo, Dr. Sarah Kim, Ms. Y.H. Cho for their participation in the translation and back-translation process. We are also grateful to Ms. S.Y. Lee for her excellent assistance in managing the database.

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

References

Tolley

. Ureteric stents, far from ideal. Lancet, 2000; 356:872–873.

Joshi

, Stainthorpe

, MacDonagh

et al. Indwelling ureteral stents: Evaluation of symptoms, quality of life and utility. J Urol, 2003; 169:1065–1069.

Pollard

, Macfarlane

. Symptoms arising from Double-J ureteral stents. J Urol, 1988; 139:37–38.

Joshi

, Newns

, Stainthorpe

et al. Ureteral stent symptom questionnaire: Development and validation of a multidimensional quality of life measure. J Urol, 2003; 169:1060–1064.

Giannarini

, Keeley

Jr , Valent

et al. The Italian linguistic validation of the ureteral stent symptoms questionnaire. J Urol, 2008; 180:624–628.

Puichaud

, Larre

, Bruyere

et al.

[The French linguistic validation of the Ureteric Stent Symptom Questionnaire (USSQ)]

(Fre) Prog Urol, 2010; 20:210–213.

Park

, Jung

, Lee

, Rim

. The effects of tolterodine extended release and alfuzosin for the treatment of double-j stent-related symptoms. J Endourol, 2009; 23:1913–1917.

Lee

, Yoo

, Oh

et al. Stent position is more important than α-blockers or anticholinergics for stent-related lower urinary tract symptoms after ureteroscopic ureterolithotomy: A prospective randomized study. Korean J Urol, 2010; 51:636–641.

EuroQol—a new facility for the measurement of health-related quality of life. The EuroQol Group. Health Policy, 1990; 16:199–208.

10.

Badia

, Garcia-Losa

, Dal-Re

. Ten-language translation and harmonization of the International Prostate Symptom Score: Developing a methodology for multinational clinical trials. Eur Urol, 1997; 31:129–140.

11.

Uebersax

, Wyman

, Shumaker

et al. Short forms to assess life quality and symptom distress for urinary incontinence in women: The Incontinence Impact Questionnaire and the Urogenital Distress Inventory. Continence Program for Women Research Group. Neurourol Urodyn, 1995; 14:131–139.

12.

Lee

, Song

, Noh

et al. Health-related quality of life using the EuroQol 5D questionnaire in Korean patients with type 2 diabetes. J Korean Med Sci, 2012; 27:255–260.

13.

Moreira

Jr , Brock

, Glasser

et al. Help-seeking behaviour for sexual problems: The global study of sexual attitudes and behaviors. Int J Clin Pract, 2005; 59:6–16.

14.

Takahashi

, Kai

, Hisata

, Higashi

. Attitudes and practices of breast cancer consultations regarding sexual issues: A nationwide survey of Japanese surgeons. J Clin Oncol, 2006; 24:5763–5768.

15.

Shin

, Ahn

, Kim

et al. Cross-cultural application of the Korean version of the European Organization for Research and Treatment of Cancer quality of life questionnaire cervical cancer module. Oncology, 2009; 76:190–198.