ureteral stent sympton questionnaire (english)

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URETERAL STENT SYMPTOM QUESTIONNAIRE: DEVELOPMENT AND VALIDATION OF A MULTIDIMENSIONAL QUALITY OF LIFE MEASURE

H. B. JOSHI, N. NEWNS, A. STAINTHORPE, R. P. M ACDONAGH, F. X. KEELEY, JR.

AND A. G. TIMONEY

From the Bristol Urological Institute, Southmead Hospital, Bristol, and Taunton and Somerset National Health Service Trust, Taunton,

United Kingdom

AB ST RA CT

Purpose: We developed the ureteral stent symptom questionnaire (USSQ), a psychometrically valid measure to evaluate symptoms and impact on quality of life of ureteral stents.

Materials and Methods: A total of 309 patients were asked to participate during differentphases of our study. In phase 1 a structured literature search, 9 patient interviews and studiesof 90 patients using existing instruments formed the foundation for the initial draft of our newquestionnaire. In phase 2 the USSQ was pilot tested, reviewed by experts and field tested in 40patients to produce a final 38-item draft. In phase 3 formal validation studies were performed in55 patients to assess validity, reliability and sensitivity to change. Discriminant validation wasperformed by administering the questionnaire to 3 groups of patients without stents.

Results: The final draft addressed various domains of health (6 sections and 38 items) affectedby stents covering urinary symptoms, pain, general health, work performance, sexual mattersand additional problems. The validation studies showed the questionnaire to be internallyconsistent (Cronbach’s 0.7) with good test-retest reliability (Pearson’s coefficient0.84). Thequestionnaire demonstrated good construct validity and sensitivity to change shown by signifi-cant changes in the score with and after removal of stents. The new USSQ discriminated patientswith stents from healthy controls (p 0.001) and patients with urinary calculi without stents andlower urinary tract symptoms.

Conclusions: Indwelling ureteral stents have a significant impact on health related quality of life. The new USSQ is a valid and reliable instrument that is expected to become a standardoutcome measure to evaluate the impact and compare different types of stents.

K EY WORDS: stents, ureter, quality of life, questionnaires, treatment outcome

Placement of a ureteral stent is a common urological in-tervention. It has been more than 3 decades since the firstdescription of a cystoscopically placed temporary ureteralstent,1 and indications and use have continued to expand.However, side effects and patient morbidity associated withstents have been identified as major problems.2–9 Despiteimprovements in stent designs and composition, in an effortto improve patient comfort and little or no morbidity, struc-tured in-depth assessment of symptoms due to stents andtheir impact on daily life has not previously been performedto our knowledge. Such an assessment is best performedusing patient self-report techniques, which measure subjec-tive quality of life objectively and forms an important validoutcome measure, as long as the tool is appropriate, well

developed and reliable.10,11

There are no such valid measures available to assess qualityof life issues in patients with ureteral stents, which has ham-pered our understanding of such symptoms and their true im-pact. We developed a comprehensive, reliable and psychomet-rically valid multidimensional measure to evaluate healthrelated quality of life in patients with ureteral stents. We de-scribe the development and validation of the ureteral stentsymptom questionnaire (USSQ), which is a self-administeredmeasure designed for use in clinical and research settings.

PATIENTS AND METHODS

A total of 194 patients with and 115 without indwelling ureteral stents were asked to participate at various stagesduring the development and validation of the new question-

naire. The developmental phase included qualitative re-search methods. Only adults with unilateral ureteral stentsplaced for urinary calculi or ureteropelvic junction obstruc-tion were included in this phase.

Phase 1. We performed a structured literature review us-ing electronic data bases, hand searches and cross referenc-ing to identify issues related to the use, symptoms and com-plications of ureteral stents.

We then conducted detailed interviews of 6 men and 3women 18 to 70 years old. The interviews were audiotapedand transcribed to identify important themes related to theuse of and problems with ureteral stents. Participants wereallowed adequate opportunity to describe individual experi-ences with stents with emphasis on patient views and per-

ception about stents. The interviews tried to identify themost appropriate words to describe symptoms, severity andbothersomeness. Frequency, patterns and daily variation of symptoms and their impact on quality of life were evaluated.

The transcripts were analyzed and the themes were identi-fied by content analysis. The themes were grouped under symp-tom complexes or the broad health domains to which they werethought to be most appropriate (for example urinary symptoms,pain, general health and so forth). The transcripts and themeswere reviewed by a panel of 3 clinicians (urologists), a staff nurse and a social science advisor so that further agreementcould be sought about content analysis and categorization of thethemes. Additional prospective studies were conducted to as-sess whether the existing instruments could identify the effects

of stents on various domains of health, and were sufficientlyspecific and sensitive for this group of patients. Accepted for publication September 6, 2002.

0022-5347/03/1693-1060/0 Vol. 169, 1060 –1064, March 2003THE JOURNAL OF UROLOGY ® Printed in U.S.A.

Copyright © 2003 by A MERICAN UROLOGICAL A SSOCIATION DOI: 10.1097/01.ju.0000049198.53424.1d

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Phase 2. Based on the results of phase 1, an initial draft of the USSQ was developed. This version included a large pool of questions divided into 4 multi-item sections along with a vali-dated generic measure Functional Status Questionnaire.11 Theinvestigators, clinicians and a select group of 5 patients reviewed this draft for content adequacy and relevance. It wasrevised to delete duplicated or obvious redundant items, andpilot tested by face-to-face interviews of 10 patients to identifyproblems or ambiguity related to the wording and clarity of thequestions. The draft was further modified and administered to40 patients with ureteral stents to evaluate its psychometriccharacteristics, and identify and retain the items that weremost relevant and sensitive for the final version.

Phase 3. We evaluated the final draft with formal validationtesting. The studies were performed to assess validity and re-liability (internal consistency and test-retest repeatability) of the USSQ and its sensitivity to change by administering it to 55patients with the stent (1 and/or 4 weeks after insertion) and 4weeks after removal. Internal consistency was assessed(Cronbach’s ) for the stent in situ scores. Test-retest reliabilitywas evaluated by readministering the questionnaire 1 weekafter completion of the week 4 stent in situ questionnaire (25patients). Sensitivity to change was assessed by comparing scores with and after removal of stents.

Validity was assessed using face content and construct (con- vergence and discriminant) assessments. Convergent validitywas evaluated by correlating the responses to the questions inthe USSQ to those assessing similar domains from the existing validated measures of Dartmouth COOP charts,12 EuroQol13

and Danish Prostate Symptom Score14 questionnaires. Dis-criminant properties were evaluated by comparing the resultsfrom patients with ureteral stents to those from healthy volun-teers, the cohort of patients with urinary (renal and/or ureteral)calculi who did not have stents and patients with lower urinarytract symptoms (45 in each group).

Statistical analysis. The questionnaire responses were an-alyzed using cross tabulations and descriptive statistics. Thesign and t tests were used to assess questionnaire respon-siveness to change (comparison between stent in situ and

after removal) and discriminant properties. Test-retest reli-ability and item associations were calculated using Pearson’sproduct moment correlation coefficients. Cronbach’s wasused to assess the internal consistency of the USSQ. Analy-ses were performed using the SAS statistical software (SASInstitute, Carey, North Carolina).

RESULTS

Phase 1. Patient interviews identified a range of symptomsand various issues affecting health related quality of life,including pain in the loin, bladder or other areas; mild tosevere sexual dysfunction; bothersome storage, and voiding symptoms and incontinence. The stents appeared to have a

significant impact on daily activities and general health thataffected work performance. Due to differences in the assess-ment methods and lack of validated questionnaires, none of thestudies in the literature was able to capture the whole impactreliably. The results of the studies, using existing question-naires, identified a number of health domains affected by stentsbut none of the existing questionnaires revealed the completeimpact and was intervention specific.15,16

Phase 2. The initial draft of the USSQ included 116 ques-tions consisting of 48 symptom prevalence and 33 botherquestions along with a 35-item Functional Status Question-naire, an existing measure. The pilot testing resulted inchanges to the wording of questions, resolved ambiguities,and improved patient understanding and acceptability. Onfurther field testing, items with low (less than 0.20) or high

endorsement frequencies and high Pearson’s correlation co-efficients (0.95) were deleted. Similarly, the items thatshowed poor sensitivity to change (p 0.05) were deleted.

Apart from urinary symptoms, a high correlation betweenoccurrence and associated bother of these symptoms wasnoted. Hence, the separate bother questions relating to thesesymptoms were eliminated.

Thus, a final draft of the USSQ with 38 scoring items wasdeveloped, which addressed various domains of health (6sections) covering urinary symptoms, pain, general health,work performance and sexual matters with additional prob-lems (see Appendix). The urinary symptom section included11 items assessing storage and voiding symptoms along withincontinence, hematuria and dysuria. Two items assessedthe impact of urinary symptoms on quality of life. The sectionon body pain retained 8 scoring items evaluating differentdimensions of pain. A diagram with defined body zones wasdeveloped and the site(s) of pain was linked to the intensitylevels using a Visual Analog Scale. The section on sexualmatters included 3 comprehensive issues (“pain during sex,”“overall satisfaction” and transient but “complete sexual dys-function”) applicable to both sexes.

The most relevant and sensitive items evaluating generalhealth were selected and grouped into 2 separate sectionsevaluating work performance issues and general health do-mains. The section on work performance (7 items) includedevaluation of functional limitation and quality of the work.

The general health section (6 items) evaluated physicalhealth, vitality, psychosocial impact and dependence. Thesection on additional problems (5 items) included a questionto assess patient views on a balance between the need for andside effects of, stents.

Phase 3. The validation studies showed satisfactory resultsfor both aspects of reliability testing (table 1). A high degree of internal consistency was observed for the majority of sectionswith the lowest results for the section on additional problems.The questionnaire demonstrated good test-retest reliability forall sections. Table 2 shows the results of interdomain (section)correlations for weeks 1 and 4 with the stent, and demonstrates variable relations between different sections.

The questionnaire had good convergent validity. TheUSSQ showed satisfactory correlation to the individual ques-

tions assessing similar domains (coefficients 0.61– 0.85, p 0.001) and total score (0.71, p 0.001) from the DanishProstate Symptom Score-I. Satisfactory correlations were ob-served between the USSQ and the Dartmouth COOP charts(0.64 – 0.83, P 0.001) and the EuroQol questionnaire (0.56 –0.77, p 0.001). Significant changes in the score (p 0.005)were observed across all domains with the stent (weeks 1 and4) scores versus, after its removal, indicating good sensitivityexcept sexual domain scores (table 3).

The demographic characteristics of patients along withresults of the discriminant validation are shown in table 4.Highly significant differences were observed for all domainscores between patients with stents and healthy volunteers.Clinically important sections in the USSQ (except for the

total pain index score for the stone group) discriminatedbetween patients with stents and those with stones andlower urinary tract symptoms. The scores for the section onsexual matters were high for the patients with stents, al-though the differences were not statistically significant whencompared with the nonstent groups.

T ABLE 1. Reliability of USSQ section characteristics

Domain

Internal Consistency(Cronbach’s ) Test-Retest Reliability

(Pearson’s correlationcoefficient)Wk. 1 Stent

In SituWk. 4 Stent

In Situ

Urinary symptoms 0.96 0.94 0.97Body pain 0.88 0.81 0.88General health 0.90 0.89 0.96

Work performance 0.78 0.76 0.84Sexual matters 0.70 0.71 0.92 Additional problems 0.60 0.61 0.82

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Scoring of the questionnaire. The scoring system for thequestionnaire consists of a simple sum of the scores for individual questions in each section. Each section had a sum-mary (index) score except for the questions on additional

problems. Simple sum and multiplicative composite scoring systems were tried before finalizing the simple scoring,which was justified by the high degree of internal consistencyfor these sections. The high scores indicate worse outcomes.

DISCUSSION:

The new USSQ is a reliable and comprehensive instrumentfor evaluating the symptoms and impact on health relatedquality of life due to ureteral stents. Compared to other studiesin the literature, we demonstrated that a combination of uri-nary symptoms and pain that affect physical and psychosocialhealth together with additional problems characterize a broadspectrum of impact associated with stents. The new USSQ hassatisfactory validity with good evaluative and discriminant

properties, which make it a valid outcome measure.We tried to evaluate the need to develop a new instrumentby asking patients and clinicians to assess suitability of theexisting instruments and conducting prospective studies us-ing those measures (phase 1), and the results justified theneed. The USSQ was developed using a multi-step, multidis-ciplinary approach and adhered to the standard methods andrigorous guidelines of instrument development used in the fieldof measurement psychology.17,18 The cognitive testing and val-idation studies of the USSQ gained the approval of patients andclinicians, which was further confirmed by statistical analysisof correlation and reliability assessments.

The selection of items for the urinary symptom section wasbased on objective and subjective evidence.16 The features of the urinary symptoms, such as frequency, urge incontinence,

hematuria and dysuria, which characterized stent experiencewere well captured in the USSQ. Pain associated with stentshas remained a dynamic multidimensional experience, mak-

ing it difficult to capture precisely and in a quantifiableformat. We tried to capture different dimensions of pain,including behavioral measurement of pain, and symptomsthat are supposed to characterize the experience of stent

pain, such as pain related to micturition.Patients were able to understand the scheme of answering

the questions on the site(s) and severity of pain as notedduring pilot testing and subsequent validation phases, with aless than 2% nonresponse rate. The responses to individualquestions demonstrated that the diversity in the sites andintensity of pain, pain on voiding and interference in life wereitems characteristic for the patients with stents. Due to thepresence or radiation of the pain associated with stents toexternal genitalia, especially in men, the diagram wherepatients mark the site(s) of the pain had to be different forthe 2 genders but this is the only aspect of the questionnairethat distinguishes between the sexes.

Compared to many other groups of patients affected by

urological conditions, a large proportion who need stentplacement are actively employed. Hence, the impact of stentson functional capacity and work performance is covered sep-arately in the section on work performance. The USSQ can beused with additional methods of economic evaluations toperform more detailed health economic assessments.

Simplicity in scoring the questionnaire was achieved using asystem that added score of individual items to form an indexscore for each section. However, there is no single score for thewhole questionnaire, as individual section scores represent sep-arate domains and characteristics of the stent experience. Sim-ilarly, it is possible to interpret results of questions on anindividual item basis depending on clinical needs (for examplecharacteristics of hematuria or different sites of pain).

We validated the USSQ by administering the question-naire at weeks 1 and 4 with the stent in situ. However,4-week assessments, remained our main time frame to give

T ABLE 2. Total domain correlations at weeks 4 and 1 with stent

Domain Index Score Urinary Symptoms

Wk. 4/1Body Pain

Wk. 4/1General Health

Wk. 4/1Work Performance

Wk. 4/1Sexual Matters

Wk. 4/1 Additional Problems

Wk. 4/1Trade-Off

Wk. 4/1

Urinary symptoms 1.00/1.00Body pain 0.67/0.82 1.00/1.00General health 0.77/0.85 0.85/0.88 1.00/1.00Work performance 0.38/0.68 0.53/0.64 0.54/0.70 1.00/1.00Sexual matters 0.30/0.13 0.32/0.18 0.27/0.10 0.29/0.15 1.00/1.00 Additional problems 0.83/0.27 0.74/0.17 0.81/0.14 0.40/0.30 0.39/0.20 1.00/1.00Trade-off 0.81/0.69 0.72/0.54 0.83/0.56 0.44/0.30 0.21/0.21 0.76/0.81 1.00/1.00

T ABLE 3. Sensitivity to change: comparison of scores with stent and after its removal

Domain Wk. 1 Mean

SDWk. 4 Mean

SDPost-Stent Mean

SDp Value (wks. 1 and 4

vs. post-stent)

Urinary symptom index 26.9 8.9 28.3 7.8 16.2 3.0 0.001Pain symptom index 23.05 10.38 22.2 9.6 10.9 3.4 0.001General health index 10.73 6.99 12.8 5.0 7.25 3.1 0.001Work performance index 9.90 7.5 15.0 13.0 3.83 0.28 0.003Sexual matters 3.99 3.87 4.7 2.5 2.9 1.03 0.4 (wk. 1)/0.2 (wk. 4)

T ABLE 4. Discriminant properties of the ureteral stent symptoms questionnaire

Domain Stent Group (wk. 4) Control Group Stone Group Lower Urinary Tract

Symptom Group

No. pts. 44 20 37 36Mean age SD (median) 50.8 16.8 (50) 50 13.2 (50) 54 14.1 (56) 62.5 11 (64)Male-to-female ratio 3212 128 307 297Mean domain scores mean SD p values

for 3 nonstent groups vs. stent group:Urinary symptom index 28.3 7.8 14.9 2.4 (0.001) 20.9 5.5 (0.001) 23.3 5.8 (0.04)Pain symptom index 22.2 9.6 0.6 3.0 (0.001) 18.8 6.7 (0.11) 14.6 4.8 (0.002)General health index 12.8 5.0 9.5 2.2 (0.001) 10.6 3.8 (0.04) 10.3 2.3 (0.01)Work performance index 15.0 13.0 3.0 0.28 (0.001) 7.9 7.7 (0.02) 3.4 1.2 (0.001)Sexual matters 4.7 2.5 2.1 0.4 (0.02) 2.8 0.9 (0.1) 3.2 0.9 (0.6)

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patients adequate chance to experience the impact of stents.Similarly, in our experience assessment of symptoms 4 weeksafter stent removal represented patient baseline status sat-isfactorily. Adequate performance in test reliability, con-struct validity and treatment responsiveness needs to bedemonstrated during psychometric validation before a newscale is applicable for general research or clinical use.19 Over-all, the USSQ has shown a strong internal consistency andhigh test-retest reliability. Results evaluating responsive-ness to change, sensitivity and specificity indicated that thetool captures the impact of stents satisfactorily.

The USSQ differentiated patients with stents and healthycontrols well. The impact of stents represents a spectrum of symptoms, many of which are common to other urologicalconditions, especially urinary calculi and lower urinary tractsymptoms. However, when analyzed on an individual ques-tion basis, it became clear that many of the symptoms arehighly prevalent and remain specific to patients with stents(for example hematuria, different locations of pain, loin painduring voiding). The USSQ captured these symptoms well. Sim-ilarly, the overall impact of stents, when measured across alldomains of the USSQ, always discriminated patients withstents from all other groups. True criterion validation of theUSSQ was difficult due to absence of an existing gold standard

outcome measure for patients with ureteral stents.It was important to compare the stent with nonstent (base-line) health status. In theory, comparing stent status witheither pre-stent or post-stent status can achieve this objec-tive. However, the pre-stent questionnaire assessment doesnot reflect the baseline status generally, tends to produce asignificant noise-to-signal ratio and may not be psychomet-rically valid for the purposes of comparison. Hence, it isessential to evaluate patient baseline status by administer-ing the questionnaire after the stent has been removed, thuspatients act as their own controls.

There are certain limitations to our study. The developmentand validation study did not include patients with ureteral

obstruction due to malignant pathology or stents inserted forlong-term use (for example metal stents). The questionnaireperforms short and brief assessment of general health domainsand sexual function. In-depth evaluation of these domains canbe performed using additional validated instruments. The ques-tionnaire administration in a format other than paper, such ascomputer based administration, will need further evaluation.The current USSQ has been validated for use in the Englishspeaking population. We anticipate further use of the scoring

algorithms to define clinically significant change and stratifyscores as mild, moderate or severe.Overall, the results of this project highlighted the wide-

spread impact of stents on health related quality of life. Thenew instrument characterizes the stent experience that hasnot been evaluated by previous studies and helps to quantifyit satisfactorily. Details of the stent experience, based on its validation studies, along with its impact on work perfor-mance and utility analysis, are reported separately.20

The USSQ is now undergoing linguistic validation for usein languages other than English (German, Korean) and in-ternational evaluation within clinical trials to help evaluateits psychometric properties in further detail. Stents continueto evolve and new designs and materials are being tested.During all of this work assessment of patient morbidity and

health related quality of life will remain an important is-sue.21 This project has improved our understanding of vari-ous health related quality of life issues in patients withindwelling ureteral stents. Future studies using the USSQwill help us to understand the mechanisms underlying stentrelated symptoms and achieve effective patient communica-tion. We expect the new USSQ to serve as an importantoutcome measure for future ureteral stent studies and in thesearch for an ideal stent.

Dr. Jenny Donovan, Department of Social Sciences, Univer-sity of Bristol, provided advice on the design and conduct of study, and Dr. Vaughn Reed performed the statistical analysis.

APPENDIX

The following table can be considered as a guide to the calculation of the sample size for comparison of different types of stentswith the USSQ as a main outcome measure. The guidelines are based on the results from the validation studies of the USSQwhen the questionnaire was administered to patients with indwelling ureteral stents and a control group of (healthy)patients. Based on the differences in the mean domain score and standard deviation for the 3 important sections (urinarysymptoms, pain and general health) the sample size was decided using a 2-tailed test (p 0.05). The expected differencebetween different stent designs will need to be specified as a percentage difference (or difference in the index score) between1 or more of the 3 important domains of the USSQ (urinary symptoms, body pain and general health).

Domain% Difference in

Mean Total DomainScore for 2 Samples

Difference in MeanTotal Domain Score

for 2 Samples

Power (number of patients ineach arm)

80% 85% 90%

Urinary symptom index (difference between patients with the stents andcontrols 46%, a score difference of 12)

30% 8 14 16 1820% 5 29 33 3815% 4 53 60 7010% 3 129 148 173

Pain index (the difference between patients with the stents and controls 96.6%, a score difference of 19.30)

30% 6 64 73 8520% 4 129 148 17315% 3 252 288 33710% 2 700 800 935

General health index (the difference between patients with the stentsand controls 32%, a score difference of 4.3)

30% 4 38 43 5120% 2.6 79 90 105

15% 2.05 129 148 17310% 1.3 393 456 526

The complete USSQ is available at www.bui.ac.uk/endourology and www.endourology.org

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ureteral stent sympton questionnaire (english)

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