Mapping EQ-5D utility scores from the Incontinence Quality of Life Questionnaire among patients with neurogenic and idiopathic overactive bladder

Questionnaires for Neurogenic Lower Urinary Tract Dysfunction

The evaluation of people with neurogenic lower urinary tract dysfunction (NLUTD) often involves objective parameters, however quality of life (QOL) assessments are crucial for patient-centered care. This article discusses how to measure QOL and urinary symptoms in NLUTD and highlights various questionnaires such as the Qualiveen, Neurogenic Bladder Symptom Score (NBSS), and the Incontinence Quality of Life Questionnaire (I-QOL). These questionnaires focus on bladder-related QOL or symptoms and have been validated in multiple NLUTD populations. These tools are important for advancing research and the clinical care of NLUTD patients, and have the potential to impact decision-making and improve patient outcomes.

Mapping from SIBDQ to EQ-5D-5L for patients with inflammatory bowel disease

OBJECTIVE

Clinical studies commonly use disease-specific measures to assess patients' health-related quality of life. However, economic evaluation often requires preference-based utility index scores to calculate cost per quality-adjusted life-year (QALY). When utility index scores are not directly available, mappings are useful. To our knowledge, no mapping exists for the Short Inflammatory Bowel Disease Questionnaire (SIBDQ). Our aim was to develop a mapping from SIBDQ to the EQ-5D-5L index score with German weights for inflammatory bowel disease (IBD) patients.

METHODS

We used 3856 observations of 1055 IBD patients who participated in a randomised controlled trial in Germany on the effect of introducing regular appointments with an IBD nurse specialist in addition to standard care with biologics. We considered five data availability scenarios. For each scenario, we estimated different regression and machine learning models: linear mixed-effects regression, mixed-effects Tobit regression, an adjusted limited dependent variable mixture model and a mixed-effects regression forest. We selected the final models with tenfold cross-validation based on a model subset and validated these with observations in a validation subset.

RESULTS

For the first four data availability scenarios, we selected mixed-effects Tobit regressions as final models. For the fifth scenario, mixed-effects regression forest performed best. Our findings suggest that the demographic variables age and gender do not improve the mapping, while including SIBDQ subscales, IBD disease type, BMI and smoking status leads to better predictions.

CONCLUSION

We developed an algorithm mapping SIBDQ values to EQ-5D-5L index scores for different sets of covariates in IBD patients. It is implemented in the following web application: https://www.bwl.uni-hamburg.de/hcm/forschung/mapping.html .

Real-world evidence generation from patients, their caregivers and physicians supporting clinical, regulatory and guideline decisions: an update on Disease Specific Programmes

OBJECTIVE

To update on and describe the role of Disease Specific Programmes (DSPs), a multi-perspective real-world data (RWD) source, in the context of the evolution of the value and acceptance of real-world evidence (RWE) in clinical, regulatory and guideline decision-making.

METHODS

DSPs are multi-national, multi-subscriber, multi-therapy cross-sectional surveys incorporating retrospective data collection from patient, caregiver and physician perspectives. Information collected covers the patient journey, including treatment/prescribing patterns and rationale, patient-reported outcomes, impact on work and everyday activities, attitudes towards and perceptions of the condition, adherence to treatment and burden of illness. Published peer-reviewed DSP papers were aligned with current key RWE themes identified in the literature, alongside their contribution to RWE.

RESULTS

RWE themes examined were: using RWE to inform clinical practice, patient and caregiver engagement, RWE role in supporting health technology assessments and regulatory submissions, informing value-driven healthcare decisions, real-world patient subgroup differences and therapeutic inertia/unmet needs; highlighting patients' and caregivers' experience of living with a disease, disconnect from their physicians, unmet needs and educational gaps.

CONCLUSIONS

DSPs provide a wealth of RWD in addition to evidence generated by registries, clinical trials and observational research, with wide use for the pharmaceutical industry, government, funding/regulatory bodies, clinical practice guideline insights and, most importantly, informing improvements in people's lives. The depth, breadth and heritage of information collected via DSPs since 1995 is unparalleled, extending understanding of how diseases are managed by physicians in routine clinical practice and why treatment choices are made, patients' perceptions of their disease management, and caregiver burden.

Cross-walk of the Chronic Liver Disease Questionnaire for Nonalcoholic Steatohepatitis (CLDQ-NASH) and the EuroQol EQ-5D-5L in patients with NASH

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is a chronic progression of nonalcoholic fatty liver disease, which can negatively impact the health-related quality of life (HRQoL) of affected individuals. HRQoL in NASH has been assessed using the disease-specific Chronic Liver Disease Questionnaire for NASH (CLDQ-NASH) and the generic EuroQol EQ-5D-5L. As the performance of these instruments relative to each other is unknown, we performed a cross-walk analysis of CLDQ-NASH to EQ-5D-5L using data from a real-world NASH population.

METHODS

Data were drawn from the Adelphi Real World 2019 NASH Disease Specific Programme, a cross-sectional survey of physicians and their patients in the United States. Patients with physician-diagnosed NASH completed a questionnaire that included the CLDQ-NASH and EQ-5D-5L. Mapping from CLDQ-NASH to EQ-5D-5L was done using tenfold cross-validation; performance was assessed using root-mean squared error as accuracy measure. Subgroup analyses compared performance of the models in obese versus non-obese patients and patients with versus without type 2 diabetes (T2D).

RESULTS

Data from 347 patients were included in this analysis. Overall, 2172 models were tested for predicting EQ-5D-5L index score from CLDQ-NASH score. The best model for this mapping was a generalized linear model using Gaussian distribution and a power link. The best model for mapping from CLDQ-NASH domains to the EQ-5D-5L was a fractional logistic model. Models performed better at predicting upper versus lower values of EQ-5D-5L, for non-obese versus obese patients, and for patients without versus with T2D.

CONCLUSION

We describe a scoring algorithm for cross-walking the CLDQ-NASH to the EQ-5D-5L enabling health status comparisons of HRQoL across studies.

Rationale and design of an implant procedure and pivotal study to evaluate safety and effectiveness of Medtronic's tibial neuromodulation device

Percutaneous tibial neuromodulation is a medical guideline recommended therapy for treating symptoms of overactive bladder. Stimulation is delivered to the tibial nerve via a thin needle placed percutaneously for 30 min once a week for 12-weeks, and monthly thereafter. Studies have shown that this therapy can effectively relieve symptoms of overactive bladder; however, the frequent office visits present a barrier to patients and can impact therapy effectiveness. To mitigate the burden of frequent clinic visits, small implantable devices are being developed to deliver tibial neuromodulation. These devices are implanted during a single minimally invasive procedure and deliver stimulation intermittently, similar to percutaneous tibial neuromodulation. Here, we describe the implant procedure and design of a pivotal study evaluating the safety and effectiveness for an implantable tibial neuromodulation device. The Evaluation of Implantable Tibial Neuromodulation (TITAN 2) pivotal study is a prospective, multicenter, investigational device exemption study being conducted at up to 30 sites in the United States and enrolling subjects with symptoms of overactive bladder.

Mapping Studies to Estimate Health-State Utilities From Nonpreference-Based Outcome Measures: A Systematic Review on How Repeated Measurements are Taken Into Account

OBJECTIVES

Mapping algorithms are developed using data sets containing patient responses to a preference-based questionnaire and another health-related quality-of-life questionnaire. When data sets include repeated measurements from the same individuals over time, the assumption of observations' independence, required by standard models, is violated, and standard errors are underestimated. This review aimed to identify how studies deal with methodological challenges of repeated measurements, provide an overview of practice to date, and potential implications for future work.

METHODS

We conducted a systematic literature search of MEDLINE, Cumulative Index to Nursing and Allied Health Literature, specialized databases, and previous systematic reviews. A data template was used to extract, among others, start and target instruments if the data set(s) used for estimation and validation had repeated measurements per patient, used regression techniques, and which (if any) adjustments were made for repeated measurements.

RESULTS

We identified 278 publications developing at least 1 mapping algorithm. Of the 278 publications, 121 used a data set with repeated measurements, among which 92 used multiple time points for estimation, and 39 selected specific time points to have 1 observation per participant. A total of 36 studies did not account for repeated measurements. An adjustment was conducted using cluster-robust standard errors (21), random-effects models (30), generalized estimating equations (7), and other methods (7).

CONCLUSIONS

The inconsistent use of methods to account for interdependent observations in the literature indicates that mapping guidelines should include recommendations on how to deal with repeated measurements, and journals should update their guidelines accordingly.

Cost-effectiveness of overactive bladder treatments from a US commercial and payer perspective

Aim: The cost-effectiveness of treatment options (anticholinergics, β3-adrenoceptor agonists, onabotulinumtoxinA, sacral nerve stimulation and percutaneous tibial stimulation [the latter two including new rechargeable neurostimulators]) for the management of overactive bladder (OAB) were compared with best supportive care (BSC) using a previously published Markov model. Materials & methods: Cost-effectiveness was evaluated over a 15-year time horizon, and sensitivity analyses were performed using 2- and 5-year horizons. Discontinuation rates, resource utilization, and costs were derived from published sources. Results: Using Medicare and commercial costs over a 15-year time period, onabotulinumtoxinA 100U had incremental cost-effectiveness ratios (ICERs) gained of $39,591/quality-adjusted life-year (QALY) and $42,255/QALY, respectively, versus BSC, which were the lowest ICERs of all assessed treatments. The sensitivity analyses at 2- and 5-year horizons also showed onabotulinumtoxinA to be the most cost-effective of all assessed treatments versus BSC. Conclusion: OnabotulinumtoxinA 100U is currently the most cost-effective treatment for OAB.

Cost-Utility Analysis of Oxybutynin vs. OnabotulinumtoxinA (Botox) in the Treatment of Overactive Bladder Syndrome

Background: The UK National Health Service (NHS) propose the use of oxybutynin prior to onabotulinumtoxinA (Botox) in the management of overactive bladder syndrome (OAB). Oxybutynin is costly and associated with poor adherence, which may not occur with Botox. We conducted a cost-utility analysis (CUA) to compare the medications. Methods: we compared the two treatments in quality-adjusted life years (QALYS), through the NHS’s perspective. Costs were obtained from UK-based sources and were discounted. Total costs were determined by adding the treatment cost and management cost for complications on each branch. A 12-month time frame was used to model the data into a decision tree. Results: Our results found that using Botox first-line had greater cost utility than oxybutynin. The health net benefit calculation showed an increase in 0.22 QALYs when Botox was used first-line. Botox also had greater cost-effectiveness, with the exception of pediatric patients with an ICER of £42,272.14, which is above the NICE threshold of £30,000. Conclusion: Botox was found to be more cost-effective than antimuscarinics in the management of OAB in adults, however less cost-effective in younger patients. This predicates the need for further research to ascertain the age at which Botox becomes cost-effective in the management of OAB.

Mapping the Edmonton Symptom Assessment System-Revised: Renal to the EQ-5D-5L in patients with chronic kidney disease

PURPOSE

The Edmonton Symptom Assessment System-Revised: Renal (ESAS-r: Renal) is a disease-specific patient-reported outcome measure (PROM) that assesses symptoms common in chronic kidney disease (CKD). There is no preference-based scoring system for the ESAS-r: Renal or a mapping algorithm to predict health utility values. We aimed to develop a mapping algorithm from the ESAS-r: Renal to the Canadian EQ-5D-5L index scores.

METHODS

We used data from a multi-centre cluster randomized-controlled trial of the routine measurement and reporting of PROMs in hemodialysis units in Northern Alberta, Canada. In two arms of the trial, both the ESAS-r: Renal and the EQ-5D-5L were administered to CKD patients undergoing hemodialysis. We used data from one arm for model estimation, and data from the other for validation. We explored direct and indirect mapping models; model selection was based on statistical fit and predictive power.

RESULTS

Complete data were available for 506 patient records in the estimation sample and 242 in the validation sample. All models tended to perform better in patients with good health, and worse in those with poor health. Generalized estimating equations (GEE) and generalized linear model (GLM) on selected ESAS-r: Renal items were selected as final models as they fitted the best in estimation and validation sample.

CONCLUSION

When only ESAS-r: Renal data are available, one could use GEE and GLM to predict EQ-5D-5L index scores for use in economic evaluation. External validation on populations with different characteristics is warranted, especially where renal-specific symptoms are more prevalent.

Current Status of Research on the Mapping Function of Health Utility Values in the Asia Pacific Region: A Systematic Review

OBJECTIVES

This systematic review aimed to analyze the published studies on the use of the mapping method between generic scales and disease-specific scales as well as between 2 universal scales.

METHODS

A systematic literature search was conducted using PubMed, ScienceDirect, Web of Science, CNKI, Weipa Database, Wanfang Database, and HERC Database to collect articles about the application of the mapping method to the measurement of health utility value from January 2000 to December 2019.

RESULTS

Overall, 59 articles met the inclusion requirements, and most of them were a mapping study between a disease-specific scale and a generic scale. Then all these articles were classified by the following study types: a clear functional relationship; unclear functional relationship; disease-specific scale and universality; mapping between generic scales and disease-specific scales, and mapping between universal scales. Most studies derived the best mapping model from the ordinary least squares regression, and fewer studies chose to use new regression methods. Sample sizes in the retrieved studies generally affected the reliability of the study results.

CONCLUSIONS

In recent years, as more attention has been paid to the research of the mapping method, a large number of problems have followed, such as the selection of scale types, the coverage of the study sample, and the selection of evaluation index of model performance and sample size. It is hoped that these problems can be properly solved in the future research.

An Updated Systematic Review of Studies Mapping (or Cross-Walking) Measures of Health-Related Quality of Life to Generic Preference-Based Measures to Generate Utility Values

BACKGROUND

Mapping is an increasingly common method used to predict instrument-specific preference-based health-state utility values (HSUVs) from data obtained from another health-related quality of life (HRQoL) measure. There have been several methodological developments in this area since a previous review up to 2007.

OBJECTIVE

To provide an updated review of all mapping studies that map from HRQoL measures to target generic preference-based measures (EQ-5D measures, SF-6D, HUI measures, QWB, AQoL measures, 15D/16D/17D, CHU-9D) published from January 2007 to October 2018.

DATA SOURCES

A systematic review of English language articles using a variety of approaches: searching electronic and utilities databases, citation searching, targeted journal and website searches.

STUDY SELECTION

Full papers of studies that mapped from one health measure to a target preference-based measure using formal statistical regression techniques.

DATA EXTRACTION

Undertaken by four authors using predefined data fields including measures, data used, econometric models and assessment of predictive ability.

RESULTS

There were 180 papers with 233 mapping functions in total. Mapping functions were generated to obtain EQ-5D-3L/EQ-5D-5L-EQ-5D-Y (n = 147), SF-6D (n = 45), AQoL-4D/AQoL-8D (n = 12), HUI2/HUI3 (n = 13), 15D (n = 8) CHU-9D (n = 4) and QWB-SA (n = 4) HSUVs. A large number of different regression methods were used with ordinary least squares (OLS) still being the most common approach (used ≥ 75% times within each preference-based measure). The majority of studies assessed the predictive ability of the mapping functions using mean absolute or root mean squared errors (n = 192, 82%), but this was lower when considering errors across different categories of severity (n = 92, 39%) and plots of predictions (n = 120, 52%).

CONCLUSIONS

The last 10 years has seen a substantial increase in the number of mapping studies and some evidence of advancement in methods with consideration of models beyond OLS and greater reporting of predictive ability of mapping functions.

Mapping the Strengths and Difficulties Questionnaire onto the Child Health Utility 9D in a large study of children

PURPOSE

Non-preference-based measures cannot be used to directly obtain utilities but can be converted to preference-based measures through mapping. The only mapping algorithm for estimating Child Health Utility-9D (CHU9D) utilities from Strengths and Difficulties Questionnaire (SDQ) responses has limitations. This study aimed to develop a more accurate algorithm.

METHODS

We used a large sample of children (n = 6898), with negligible missing data, from the Longitudinal Study of Australian Children. Exploratory factor analysis (EFA) and Spearman's rank correlation coefficients were used to assess conceptual overlap between SDQ and CHU9D. Direct mapping (involving seven regression methods) and response mapping (involving one regression method) approaches were considered. The final model was selected by ranking the performance of each method by averaging the following across tenfold cross-validation iterations: mean absolute error (MAE), mean squared error (MSE), and MAE and MSE for two subsamples where predicted utility values were < 0.50 (poor health) or > 0.90 (healthy). External validation was conducted using data from the Child and Adolescent Mental Health Services study.

RESULTS

SDQ and CHU9D were moderately correlated (ρ = - 0.52, p < 0.001). EFA demonstrated that all CHU9D domains were associated with four SDQ subscales. The best-performing model was the Generalized Linear Model with SDQ items and gender as predictors (full sample MAE: 0.1149; MSE: 0.0227). The new algorithm performed well in the external validation.

CONCLUSIONS

The proposed mapping algorithm can produce robust estimates of CHU9D utilities from SDQ data for economic evaluations. Further research is warranted to assess the applicability of the algorithm among children with severe health problems.

Mapping health-related quality of life scores from FACT-G, FAACT, and FACIT-F onto preference-based EQ-5D-5L utilities in non-small cell lung cancer cachexia

BACKGROUND

Health-related quality of life (HRQoL) measurements from disease-specific tools cannot be directly used in economic evaluations. This study aimed to develop and validate mapping algorithms that predicted EuroQol 5-Dimensions 5-Levels (EQ-5D-5L) utilities from Functional Assessment of Anorexia-Cachexia Therapy (FAACT) and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) and their common component (Functional Assessment of Cancer Therapy-General-FACT-G) in patients with non-small cell lung cancer cachexia.

METHODS

Data were collected on five occasions over a 12-week period in two multicenter placebo-controlled trials. EQ-5D-5L utilities were calculated using both English and Dutch value sets. The study sample was divided into development and validation datasets according to patients' geographical residence. Generalized estimating equations were applied to five different sets of independent variables including overall, Trial Outcome Index (TOI), and individual subscales results. The best performing models were selected based on mean absolute error (MAE) and root-mean square error (RMSE).

RESULTS

EQ-5D-5L and FAACT/FACIT-F results were available for 96 patients. The developed algorithms showed a good predictive performance, with acceptable MAE/RMSE and small differences between mean observed and predicted EQ-5D-5L utilities. In FACT-G models, Physical Well-Being had the highest explanatory value, while Emotional Well-Being did not significantly affect the EQ-5D-5L score; Anorexia-Cachexia and Fatigue subscales were highly statistically significant in FAACT and FACIT-F models, respectively, as well as the TOI scores. The Eastern Cooperative Oncology Group status was included as covariate in all models.

CONCLUSION

The developed algorithms enable the estimation of EQ-5D-5L utilities from three cancer-specific instruments when preference-based HRQoL data are missing.

Cost–effectiveness of overactive bladder treatments: from the US payer perspective

Aim: To assess the cost–effectiveness of onabotulinumtoxinA (onabotA), implantable sacral nerve stimulation devices, percutaneous tibial nerve stimulation, anticholinergic medications and mirabegron compared with best supportive care (BSC) for management of refractory overactive bladder (OAB). Methods: A Markov model was developed to compare the cost–effectiveness of treatment options with BSC over a 10-year time horizon. Resource utilization, discontinuation rates and costs were derived from unpublished and published sources. Quality-adjusted life-years (QALYs) and incremental cost–effectiveness ratios were reported. Results: Treatment with onabotA 100U produced the largest gain in QALYs (7.179) and lowest estimated incremental cost–effectiveness ratio ($32,680/QALY) of all assessed treatments compared with BSC. Conclusion: Compared with BSC, onabotA 100U was the most cost-effective treatment option for patients with refractory OAB.

Does Selecting Covariates Using Factor Analysis in Mapping Algorithms Improve Predictive Accuracy? A Case of Predicting EQ-5D-5L and SF-6D Utilities from the Women's Health Questionnaire

BACKGROUND

In addition to theoretical justifications, many statistical methods have been used for selecting covariates to include in algorithms mapping nonutility measures onto utilities. However, it is not clear whether using exploratory factor analysis (EFA) as one such method improves the predictive ability of these algorithms.

OBJECTIVE

This question is addressed within the context of mapping a non-utility-based outcome, the core 23-item Women's Health Questionnaire (WHQ-23), onto two utility instruments: five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) and the six-dimensional health state short form (derived from short form 36 health survey) (SF-6D).

METHODS

Data on all three outcomes were collected from 455 women from the Australian general population participating in a study assessing attitudes toward in vitro fertilization. Statistical methods for selecting covariates included stepwise regression (SW), including all covariates (Include all), multivariable fractional polynomial (MFP), and EFA. The predictive accuracy of 108 regression models was assessed using five criteria: mean absolute error, root mean squared error, correlation, distribution of predicted utilities, and proportion of predictions with absolute errors of less than 0.0.5. Validation of "primary" models was carried out on random samples of the in vitro fertilization study.

RESULTS

The best results for EQ-5D-5L and SF-6D predictions were obtained from models using SW, "Include all," and MFP covariate-selection approaches. Root mean squared error (0.0762-0.1434) and mean absolute error (0.0590-0.0924) estimates for these models were within the range of published estimates. EFA was outperformed by other covariate-selection methods.

CONCLUSIONS

It is possible to predict valid utilities from the WHQ-23 using regression methods based on SW, "Include all," and MFP covariate-selection techniques.

The Relationship Between Improvements in Myelopathy and Sagittal Realignment in Cervical Deformity Surgery Outcomes

STUDY DESIGN

Retrospective review.

OBJECTIVE

Determine whether alignment or myelopathy improvement drives patient outcomes after cervical deformity (CD) corrective surgery.

SUMMARY OF BACKGROUND DATA

CD correction involves radiographic malalignment correction and procedures to improve motor function and pain. It is unknown whether alignment or myelopathy improvement drives patient outcomes.

METHODS

Inclusion: Patients with CD with baseline/1-year radiographic and outcome scores. Cervical alignment improvement was defined by improvement in Ames CD modifiers. modified Japanese Orthopaedic Association (mJOA) improvement was defined as mild [15-17], moderate [12-14], severe [<12]. Patient groups included those who only improved in alignment, those who only improved in mJOA, those who improved in both, and those who did not improve. Changes in quality-of-life scores (neck disability index [NDI], EuroQuol-5 dimensions [EQ-5D], mJOA) were evaluated between groups.

RESULTS

A total of 70 patients (62 yr, 51% F) were included. Overall preoperative mJOA score was 13.04 ± 2.35. At baseline, 21 (30%) patients had mild myelopathy, 33 (47%) moderate, and 16 (23%) severe. Out of 70 patients 30 (44%) improved in mJOA and 13 (18.6%) met 1-year mJOA minimal clinically important difference. Distribution of improvement groups: 16/70 (23%) alignment-only improvement, 13 (19%) myelopathy-only improvement, 18 (26%) alignment and myelopathy improvement, and 23 (33%) no improvement. EQ-5D improved in 11 of 16 (69%) alignment-only patients, 11 of 18 (61%) myelopathy/alignment improvement, 13 of 13 (100%) myelopathy-only, and 10 of 23 (44%) no myelopathy/alignment improvement. There were no differences in decompression, baseline alignment, mJOA, EQ-5D, or NDI between groups. Patients who improved only in myelopathy showed significant differences in baseline-1Y EQ-5D (baseline: 0.74, 1 yr:0.83, P < 0.001). One-year C2-S1 sagittal vertical axis (SVA; mJOA r = -0.424, P = 0.002; EQ-5D r = -0.261, P = 0.050; NDI r = 0.321, P = 0.015) and C7-S1 SVA (mJOA r = -0.494, P < 0.001; EQ-5D r = -0.284, P = 0.031; NDI r = 0.334, P = 0.010) were correlated with improvement in health-related qualities of life.

CONCLUSION

After CD-corrective surgery, improvements in myelopathy symptoms and functional score were associated with superior 1-year patient-reported outcomes. Although there were no relationships between cervical-specific sagittal parameters and patient outcomes, global parameters of C2-S1 SVA and C7-S1 SVA showed significant correlations with overall 1-year mJOA, EQ-5D, and NDI. These results highlight myelopathy improvement as a key driver of patient-reported outcomes, and confirm the importance of sagittal alignment in patients with CD.

LEVEL OF EVIDENCE

3.

Impact of clean intermittent catheterization on quality adjusted life years (QALYs) in spinal cord injury patients with neurogenic urinary incontinence

AIMS

The impact of clean intermittent catheterization (CIC) on quality adjusted life years (QALYs) gained in adults' spinal cord injury population with neurogenic urinary incontinence (UI).

METHODS

Patients were recruited from the national registry January-June 2014. The inclusion criteria were adults, neurogenic UI due to spinal cord injury (SCI), use of collection devices and CIC for more than 6 months. The exclusion criteria were inability to perform CIC, cancer of the lower urinary tract and fistulas formation. Measurement tools were the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) and an estimation of life expectancy by the national registry. The calculation of the weighting factor (WF) was obtained by linear transformation of the ICIQ-UI SF total score. A score was transformed to the range from 0 (worst impact) to 1 (no impact). The QALYs was calculated as the weighting factor × life expectancy in years.

RESULTS

A total of 229/365 patients were involved in this study (63%). Patients before CIC reached an ICIQ mean score of 14.83, WF of 0.29, and QALYs of 9.02 during life expectancy. After 6 months of follow-up using CIC, ICIQ reached 9.12, WF 0.57 and QALYs 17.45. The number of QALYs increased by 93.5% and UI evaluated with the ICIQ-UI SF decreased by 38.5% (P < 0.01).

CONCLUSIONS

The CIC of the urinary bladder statistically significantly increased the number of QALYs and reduced the degree of UI in SCI patients.

Mapping of the OAB-SF Questionnaire onto EQ-5D in Spanish Patients with Overactive Bladder

BACKGROUND AND OBJECTIVE

Mapping disease-specific measures onto generic preference-based indexes allows estimating utility values in specific conditions to determine gain of quality-adjusted-life-years when the status of condition varies. The aim of this study was to map a disease specific scale, the Overactive Bladder Questionnaire 5-dimensional health classification system (OAB-5D) derived from the Overactive Bladder questionnaire-Short Form (OABq-SF), onto a preference-based scale, the EuroQol-5D (EQ-5D), in a sample of patients with overactive bladder (OAB) in a Spanish population.

METHOD

A survey addressed to value the health states was conducted among 246 patients at 18 clinics of urology from Spain. A total of 43 out of 243 possible health states have been valued, using VAS (Visual Analog Scale) and TTO (time trade-off) techniques. In addition, ordinary least squares (OLS), generalized linear models (GLM) and Tobit models were estimated. Resulting models were compared and the best one was selected in terms of goodness of fit measures, attribute sign, coefficient magnitude, and statistical significance of regression coefficients. Finally, the internal validity of the best model was calculated by bootstrap resampling.

RESULTS

The best model to map the OAB-5D onto EQ-5D could be estimated and the stability of parameter estimations was proved. The mentioned model estimated through OLS regression attained R (2) value of 0.892, with the aggregated data; with GLM (efficient maximum likelihood regression), Pearson χ (2) of 15.3 has been obtained; AIC (Akaike information criterion) = -550.9 and BIC (Bayesian information criterion) = -475.4. OLS model included the following OABq-SF items (and range of weights): A1 (0.102, 0.216); A3 (0.070, 0.171); B3 (0.071, 0.078); B1 (0.076, 0.136); B2 (-0.132, -0.028).

CONCLUSION

It is possible to map the OAB-5D scores onto EQ-5D in the Spanish population, allowing estimating EQ-5D utility scores from OAB specific health conditions.

Bladder ultrasonography for diagnosing detrusor overactivity: test accuracy study and economic evaluation

BACKGROUND

Urodynamics (UDS) has been considered the gold standard test for detrusor overactivity (DO) in women with an overactive bladder (OAB). Bladder ultrasonography to measure bladder wall thickness (BWT) is less invasive and has been proposed as an alternative test.

OBJECTIVES

To estimate the reliability, reproducibility, accuracy and acceptability of BWT in women with OAB, measured by ultrasonography, in the diagnosis of DO; to explore the role of UDS and its impact on treatment outcomes; and to conduct an economic evaluation of alternative care pathways.

DESIGN

A cross-sectional test accuracy study.

SETTING

22 UK hospitals.

PARTICIPANTS

687 women with OAB.

METHODS

BWT was measured using transvaginal ultrasonography, and DO was assessed using UDS, which was performed blind to ultrasonographic findings. Intraobserver and interobserver reproducibility were assessed by repeated measurements from scans in 37 and 57 women, respectively, and by repeated scans in 27 women. Sensitivity and specificity were computed at pre-specified thresholds. The smallest real differences detectable of BWT were estimated using one-way analysis of variance. The pain and acceptability of both tests were evaluated by a questionnaire. Patient symptoms were measured before testing and after 6 and 12 months using the International Consultation on Incontinence modular Questionnaire Overactive Bladder (short form) (ICIQ-OAB) questionnaire and a global impression of improvement elicited at 12 months. Interventions and patient outcomes were analysed according to urodynamic diagnoses and BWT measurements. A decision-analytic model compared the cost-effectiveness of care strategies using UDS, ultrasonography or clinical history, estimating the cost per woman successfully treated and the cost per quality-adjusted life-year (QALY).

RESULTS

BWT showed very low sensitivity and specificity at all pre-specified cut-off points, and there was no evidence of discrimination at any threshold (p = 0.25). Extensive sensitivity and subgroup analyses did not alter the interpretation of these findings. The smallest detectable difference in BWT was estimated to be 2 mm. Pain levels following both tests appeared relatively low. The proportion of women who found the test 'totally acceptable' was significantly higher with ultrasonography than UDS (81% vs. 56%; p < 0.001). Overall, subsequent treatment was highly associated with urodynamic diagnosis (p < 0.0001). There was no evidence that BWT had any relationship with the global impression of improvement responses at 20 months (p = 0.4). Bladder ultrasonography was more costly and less effective than the other strategies. The incremental cost-effectiveness ratio (ICER) of basing treatment on the primary clinical presentation compared with UDS was £491,500 per woman successfully treated and £60,200 per QALY. Performing a UDS in those women with a clinical history of mixed urinary incontinence had an ICER of £19,500 per woman successfully treated and £12,700 per QALY compared with the provision of urodynamic to all women. For DO cases detected, UDS was the most cost-effective strategy.

CONCLUSION

There was no evidence that BWT had any relationship with DO, regardless of the cut-off point, nor any relationship to symptoms as measured by the ICIQ-OAB. Bladder ultrasonography has no diagnostic or prognostic value as a test in this condition. Furthermore, despite its greater acceptability, BWT measurement was not sufficiently reliable or reproducible.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN46820623.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 7. See the NIHR Journals Library website for further project information.

OnabotulinumtoxinA in the treatment of overactive bladder: a cost-effectiveness analysis versus best supportive care in England and Wales

The cost-effectiveness of onabotulinumtoxinA (BOTOX(®)) 100 U + best supportive care (BSC) was compared with BSC alone in the management of idiopathic overactive bladder in adult patients who are not adequately managed with anticholinergics. BSC included incontinence pads and, for a proportion of patients, anticholinergics and/or occasional clean intermittent catheterisation. A five-state Markov model was used to estimate total costs and outcomes over a 10-year period. The cohort was based on data from two placebo-controlled trials and a long-term extension study of onabotulinumtoxinA. After discontinuation of initial treatment, a proportion of patients progressed to downstream sacral nerve stimulation (SNS). Cost and resource use was estimated from a National Health Service perspective in England and Wales using relevant reference sources for 2012 or 2013. Results showed that onabotulinumtoxinA was associated with lower costs and greater health benefits than BSC in the base case, with probabilistic sensitivity analysis indicating an 89 % probability that the incremental cost-effectiveness ratio would fall below £20,000. OnabotulinumtoxinA remained dominant over BSC in all but two scenarios tested; it was also economically dominant when compared directly with SNS therapy. In conclusion, onabotulinumtoxinA appears to be a cost-effective treatment for overactive bladder compared with BSC alone.

Testing and Treating Women after Unsuccessful Conservative Treatments for Overactive Bladder or Mixed Urinary Incontinence: A Model-Based Economic Evaluation Based on the BUS Study

Objective

To compare the cost-effectiveness of bladder ultrasonography, clinical history, and urodynamic testing in guiding treatment decisions in a secondary care setting for women failing first line conservative treatment for overactive bladder or urgency-predominant mixed urinary incontinence.

Design

Model-based economic evaluation from a UK National Health Service (NHS) perspective using data from the Bladder Ultrasound Study (BUS) and secondary sources.

Methods

Cost-effectiveness analysis using a decision tree and a 5-year time horizon based on the outcomes of cost per woman successfully treated and cost per Quality-Adjusted Life-Year (QALY). Deterministic and probabilistic sensitivity analyses, and a value of information analysis are also undertaken.

Results

Bladder ultrasonography is more costly and less effective test-treat strategy than clinical history and urodynamics. Treatment on the basis of clinical history alone has an incremental cost-effectiveness ratio (ICER) of £491,100 per woman successfully treated and an ICER of £60,200 per QALY compared with the treatment of all women on the basis of urodynamics. Restricting the use of urodynamics to women with a clinical history of mixed urinary incontinence only is the optimal test-treat strategy on cost-effectiveness grounds with ICERs of £19,500 per woman successfully treated and £12,700 per QALY compared with the treatment of all women based upon urodynamics. Conclusions remained robust to sensitivity analyses, but subject to large uncertainties.

Conclusions

Treatment based upon urodynamics can be seen as a cost-effective strategy, and particularly when targeted at women with clinical history of mixed urinary incontinence only. Further research is needed to resolve current decision uncertainty.

Modeling Health State Utility Values in Ankylosing Spondylitis: Comparisons of Direct and Indirect Methods

OBJECTIVES

Cost-effectiveness analyses of technologies for patients with ankylosing spondylitis frequently require estimates of health utilities as a function of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Bath Ankylosing Spondylitis Functional Index (BASFI).

METHODS

Linear regression, bespoke mixture models, and generalized ordered probit models were used to model the EuroQol five-dimensional questionnaire as a function of BASDAI and BASFI. Data were drawn from a large UK cohort study (n = 516 with up to five observations) spanning the full range of disease severity.

RESULTS

Linear regression was systematically biased. Three- and four-component mixture models and generalized probit models exhibit no such bias and improved fit to the data. The mean, median, mean error, and mean absolute error favored the mixture model approach. Root mean square error favored the generalized ordered probit model approach for the data as a whole. Model fit assessed using these same measures by disease severity quartiles tended to be best using the mixture models. The value of moving from good to poor health may differ substantially according to the chosen method. Simulated data from the mixture and probit models yield a very similar distribution to the original data set.

CONCLUSIONS

These results add to a body of evidence that the statistical model used to estimate health utilities matters. Linear models are not appropriate. The four-class bespoke mixture model approach provides the best performing method to estimate the EuroQol five-dimensional questionnaire values from BASDAI and BASFI.

Mapping between 6 Multiattribute Utility Instruments

Background: Cost-utility analyses commonly employ a multiattribute utility (MAU) instrument to estimate the health state utilities, which are needed to calculate quality-adjusted life years. Different MAU instruments predict significantly different utilities, which makes comparison of results from different evaluation studies problematical. Aim: This article presents mapping functions (“crosswalks”) from 6 MAU instruments (EQ-5D-5L, SF-6D, Health Utilities Index 3 [HUI 3], 15D, Quality of Well-Being [QWB], and Assessment of Quality of Life 8D [AQoL-8D]) to each of the other 5 instruments in the study: a total of 30 mapping functions. Methods: Data were obtained from a multi-instrument comparison survey of the public and patients in 7 disease areas conducted in 6 countries (Australia, Canada, Germany, Norway, United Kingdom, and United States). The 8022 respondents were administered each of the 6 study instruments. Mapping equations between each instrument pair were estimated using 4 econometric techniques: ordinary least squares, generalized linear model, censored least absolute deviations, and, for the first time, a robust MM-estimator. Results: Goodness-of-fit indicators for each of the results are within the range of published studies. Transformations reduced discrepancies between predicted utilities. Incremental utilities, which determine the value of quality-related health benefits, are almost perfectly aligned at the sample means. Conclusion: Transformations presented here align the measurement scales of MAU instruments. Their use will increase confidence in the comparability of evaluation studies, which have employed different MAU instruments.

Short-stretch inelastic compression bandage in knee swelling following total knee arthroplasty study (STICKS): study protocol for a randomised controlled feasibility study

Background

Enhanced recovery programmes in total knee arthroplasty are well established. Post-operative knee swelling is common and impairs early post-operative function. The use of a short-stretch, inelastic compression bandage is hypothesised to reduce knee swelling and improve pain and early function. A study was designed to test feasibility with a view to informing a larger, future trial and to provide preliminary data.

Methods/design

This is a randomised controlled feasibility study. Fifty consecutive patients selected for primary total knee arthroplasty will be enrolled in the trial. Patients with a BMI >35, latex allergy or neurological or peripheral vascular disease are excluded. Patients are randomised by distance randomisation to receive a compression bandage for 24 hours after surgery or a standard wool and crepe bandage. The bandages are applied by one of two consultant surgeons who have had training with their application. Knee swelling, range of motion and pain scores will be compared pre-operatively and at day 1, day 2 and at 6 weeks between groups. The Oxford knee score and EQ-5D health status will be compared pre-operatively and at 6 months between groups. Recruitment rates, retention rates, resource allocation, completeness of data collection, and tolerance and complications with the compression bandage are recorded. Descriptive statistics are used to calculate a standard deviation for post-operative knee swelling in the groups and to perform a power calculation incorporating anticipated patient retention rates to inform a future trial. Preliminary data will be analysed using the independent samples t-test for equal distributions and the Mann-Whitney U for unequal distributions with the significance denoted at P <0.05.

Discussion

Enhanced recovery programmes have revolutionized the management of total knee arthroplasty. There is a paucity of clinical data regarding the efficacy of compression bandages. Large, randomised controlled trials are uncommon in orthopaedic surgery. The results of this study will provide feasibility and preliminary data prior to the construction of a larger, multicentre study.

Trial registration

The study was registered with Current Controlled Trials (ISRCTN86903140) on 30 May 2013.

Implications of the minimal clinically important difference for health-related quality-of-life outcomes: a comparison of sample size requirements for an incontinence treatment trial

BACKGROUND

Sample size calculations for treatment trials that aim to assess health-related quality-of-life (HRQOL) outcomes are often difficult to perform. Researchers must select a target minimal clinically important difference (MCID) in HRQOL for the trial, estimate the effect size of the intervention, and then consider the responsiveness of different HRQOL measures for detecting improvements. Generic preference-based HRQOL measures are usually less sensitive to gains in HRQOL than are disease-specific measures, but are nonetheless recommended to quantify an impact on HRQOL that can be translated into quality-adjusted life-years during cost-effectiveness analyses. Mapping disease-specific measures onto generic measures is a proposed method for yielding more efficient sample size requirements while retaining the ability to generate utility weights for cost-effectiveness analyses.

OBJECTIVES

This study sought to test this mapping strategy to calculate and compare the effect on sample size of three different methods.

METHODS

Three different methods were used for determining an MCID in HRQOL in patients with incontinence: 1) a global rating of improvement, 2) an incontinence-specific HRQOL instrument, and 3) a generic preference-based HRQOL instrument using mapping coefficients.

RESULTS

The sample size required to detect a 20% difference in the MCID for the global rating of improvement was 52 per trial arm, 172 per arm for the incontinence-specific HRQOL outcome, and 500 per arm for the generic preference-based HRQOL outcome.

CONCLUSIONS

We caution that treatment trials of conditions for which improvements are not easy to measure on generic HRQOL instruments will still require significantly greater sample size even when mapping functions are used to try to gain efficiency.

Development of the Incontinence Utility Index: estimating population-based utilities associated with urinary problems from the Incontinence Quality of Life Questionnaire and Neurogenic Module

Background

Generic utility instruments may not fully capture the impact and consequences of urinary problems. Condition-specific preference-based measures, developed from previously validated disease-specific patient-reported outcomes instruments, may add relevant information for economic evaluations. The aim of this study was to develop a condition-specific preference-based measure, the Incontinence Utility Index (IUI), for valuing health states associated with urinary problems.

Methods

A two-step process was implemented. First, an abbreviated health state classification system was developed from the Incontinence Quality of Life Questionnaire (I-QOL) and Neurogenic Module by applying Rasch modelling, classical psychometrical testing and expert criteria to data from two pivotal trials comprised of neurogenic detrusor overactivity (NDO) patients. Criterion, convergent validity and concordance with the original instrument was assessed in the abbreviated version. Then, a multi-attribute utility function (MAUF) was estimated from a representative sample of the UK non-institutionalized adult general population. Visual analogue and time-trade off (TTO) evaluations were applied in the elicitation process. Predictive validity of the MAUF was tested comparing estimated and direct utility scores.

Results

The abbreviated health state classification system generated from the NDO sample contained 5 attributes with 3 levels of response and had adequate psychometrical properties: significant differences in scores according to the reduction in the frequency of urinary incontinence episodes [UIE] (p < 0.001); Spearman correlation coefficient with number of daily UIE = −0.43; p < 0.01 and Intraclass Correlation Coefficient (ICC, 95% CI) with the original version = 0.90 (0.89-0.91; p < 0.001). Next, 442 participants were interviewed (398 cases were valid, generating 2,388 TTO evaluations) to estimate the social preferences for derived health states. Mean age was 44.75 years (interquartile range 33.5-55.5) and 60.1% were female. An overall algorithm for the IUI was estimated and transformed onto a dead = 0.00 and full health = 1.00 scale. Model fits were acceptable (R-squared = 0.923 and 0.978). Predictive validity was adequate: ICC (95% CI) = 0.928 (0.648-0.985) and Mean of Absolute Differences = 0.038.

Conclusions

The newly developed IUI is a preference-based measure for urinary problems related to NDO that provides general population-based utility scores with adequate predictive validity.

Trial registration

ClinicalTrials.gov: NCT00461292, NCT00311376.

Electronic supplementary material

The online version of this article (doi:10.1186/s12955-014-0147-7) contains supplementary material, which is available to authorized users.

Mapping of incontinence quality of life (I-QOL) scores to assessment of quality of life 8D (AQoL-8D) utilities in patients with idiopathic overactive bladder

Background

The Incontinence Quality of Life (I-QOL) questionnaire is a commonly used and validated incontinence specific QOL instrument. The objective of this study is to develop an algorithm to map I-QOL to the Assessment of Quality of Life (AQoL) 8D utility instrument in patients with idiopathic overactive bladder (iOAB).

Methods

I-QOL and AQoL-8D scores were collected in a survey of 177 Australian adults with urinary incontinence due to iOAB. Three statistical methods were used for estimation, namely ordinary least squares (OLS) regression, the robust MM-estimator, and the generalised linear models (GLM). Each included a range of explanatory variables. Model performance was assessed using key goodness-of-fit measures in the validation dataset.

Results

The I-QOL total score and AQoL-8D utility scores were positively correlated (r = 0.50, p < 0.0001). Similarly, the three sub-scales of the I-QOL were correlated with the eight dimensions and two super-dimensions of the AQoL-8D. The GLM estimator, with I-QOL total score as the explanatory variable exhibited the best precision (MAE = 0.15 and RMSE = 0.18) with a mapping function given by AQoL-8D = exp(−1.28666 + 1.011072*I-QOL/100).

Conclusions

The mapping algorithm developed in this study allows the derivation of AQoL-8D utilities from I-QOL scores. The algorithm allows the calculation of preference-based QOL scores for use in cost-utility analyses to assess the impact of interventions in urinary incontinence.

Electronic supplementary material

The online version of this article (doi:10.1186/s12955-014-0133-0) contains supplementary material, which is available to authorized users.