Correspondence between symptoms and preference-based health status measures in the STOP study

The estimation of health state utility values in rare diseases: do the approaches in submissions for NICE technology appraisals reflect the existing literature? A scoping review

BACKGROUND

Rare diseases negatively impact patients' quality of life, but the estimation of health state utility values (HSUVs) in research studies and cost-utility models for health technology assessment is challenging.

OBJECTIVES

This study compared the methods for estimating the HSUVs included in manufacturers' submissions of orphan drugs to the National Institute for Health and Care Excellence (NICE) with those of published studies addressing the same rare diseases to understand whether manufacturers fully exploited the existing literature in developing their economic models.

METHODS

All NICE Technology Appraisal (TA) and Highly Specialized Technologies (HST) guidance documents of non-cancer European Medicines Agency (EMA) orphan medicinal products were reviewed and compared with any published primary studies, retrieved via PubMed until November 2020, and estimating HSUVs for the same conditions addressed in manufacturers' submissions.

RESULTS

We identified 22 NICE TA/HST appraisal reports addressing 19 different rare diseases. Sixteen reports presented original HSUVs estimated using EQ-5D or Health Utility Index (n = 12), direct methods (n = 2) or mapping (n = 2), while the other six included values obtained from the literature only. In parallel, we identified 111 published studies: 86.6% used preference-based measures (mainly EQ-5D, 60.7%), 12.5% direct techniques, and 2.7% mapping. The collection of values from non-patient populations (using 'vignettes') was more frequent in manufacturers' submissions than in the literature (22.7% vs. 8.0%).

CONCLUSIONS

The agreement on methodological choices between manufacturers' submissions and published literature was only partial. More efforts should be made by manufacturers to accurately reflect the academic literature and its methodological recommendations in orphan drugs submissions.

Development of the Cystic Fibrosis Questionnaire-Revised-8 Dimensions: Estimating Utilities From the Cystic Fibrosis Questionnaire-Revised

OBJECTIVES

Cystic fibrosis (CF) limits survival and negatively affects health-related quality of life (HRQOL). Cost-effectiveness analysis (CEA) may be used to make reimbursement decisions for new CF treatments; nevertheless, generic utility measures used in CEA, such as EQ-5D, are insensitive to meaningful changes in lung function and HRQOL in CF. Here we develop a new, CF disease-specific, preference-based utility measure based on the adolescent/adult version of the Cystic Fibrosis Questionnaire-Revised (CFQ-R), a widely used, CF-specific, patient-reported measure of HRQOL.

METHODS

Blinded CFQ-R data from 4 clinical trials (NCT02347657, NCT02392234, NCT01807923, and NCT01807949) were used to identify discriminating items for a classification system using psychometric (eg, factor and Rasch) analyses. Thirty-two health states were selected for a time trade-off (TTO) exercise with a representative sample of the UK general population. TTO utilities were used to estimate a preference-based scoring algorithm by regression analysis (tobit models with robust standard errors clustered on participants with censoring at -1).

RESULTS

A classification system with 8 dimensions (CFQ-R-8 dimensions; physical functioning, vitality, emotion, role functioning, breathing difficulty, cough, abdominal pain, and body image) was generated. TTO was completed by 400 participants (mean age, 47.3 years; 49.8% female). Among the regression models evaluated, the tobit heteroscedastic-ordered model was preferred, with a predicted utility range from 0.236 to 1, no logical inconsistencies, and a mean absolute error of 0.032.

CONCLUSION

The CFQ-R-8 dimensions is the first disease-specific, preference-based scoring algorithm for CF, enabling estimation of disease-specific utilities for CEA based on the well-validated and widely used CFQ-R.

Comparative analysis of respiratory symptom scores to detect acute respiratory events in children with cystic fibrosis

BACKGROUND

Patient-reported outcomes (PROs) are important outcome measures in research and clinical practice. This study describes the longitudinal variability the Cystic Fibrosis Questionnaire-Revised (CFQ-R) Respiratory score and the Chronic Respiratory Infection Symptom Score (CRISS), as well as their ability to identify acute respiratory events in children with CF.

METHODS

In this prospective observational study, the parent-proxy (6 -13 years) and self-reported (6-18 years) CFQ-R Respiratory score and CRISS (6-18 years) were measured every 3 months over 2 years. The lung clearance index (LCI) and FEV₁ were also measured. We compared the diagnostic accuracy of the PROs in distinguishing acute respiratory events and clinically stable visits, using the minimal important difference of each PRO as the threshold.

RESULTS

A total of 98 children with CF were included. On average, the symptom scores did not change between clinically stable visits. The positive predictive value (PPV) and negative predictive value (NPV) of a ≥8.5-point worsening in the parent-proxy CFQ-R score to identify acute respiratory events (n=119) (PPV 70.2% and NPV 87.0%) were higher than for the self-reported CFQ-R score (PPV 58.9% and NPV 72.2%). The PPV and NPV of an ≥11-point change in the CRISS for acute respiratory events (n=137) was 56.5% and 79.6%, respectively. The PPV and NPV of all PROs were increased when combined with the LCI and/or FEV₁pp.

CONCLUSION

Symptoms scores differ in their ability to identify acute respiratory events in children with CF; PPV and NPV of all PROs were improved when combined with lung function outcomes.

Health care costs related to home spirometry in the eICE randomized trial

BACKGROUND

Home spirometry with regular symptom assessment is one strategy to track lung health to intervene early in episodes of pulmonary exacerbations (PE). In a multi-center randomized controlled trial home spirometry and symptom tracking demonstrated no significant differences regarding the primary clinical endpoint, FEV₁, compared to usual care, but did identify differences in healthcare utilization. We used data from the Early Intervention in Cystic Fibrosis Exacerbation (eICE) study to evaluate whether home monitoring of PE is a cost-minimizing intervention in the context of this randomized trial.

METHODS

We reviewed healthcare resource utilization of all 267 eICE participants, including outpatient visits, antibiotics and hospitalizations. Prices were identified in the IBM/Watson MarketScan^Ⓡ Commercial Claims and Encounters Databases and averaged over the 2014-2017 period. Using total healthcare utilization costs, we generated summary statistics by intervention and protocol arm (total cost, mean cost, standard deviation). We performed Welch Two Sample t-tests to determine if total costs and cost by type of utilization differed significantly between groups.

RESULTS

Outpatient visit costs were significantly higher by 13% in the Early Intervention (EI) than in the usual care (UC) arm ($3,345 vs. $2,966). We found no significant differences in outpatient antibiotic, hospitalization, or total health care costs between the arms.

CONCLUSIONS

Within the context of the eICE trial, outpatient visits were significantly higher in those with experimental home spirometry care, but that did not translate into statistically significant differences of overall health care costs between the two arms.

A Randomized Trial of Antimicrobial Duration for Cystic Fibrosis Pulmonary Exacerbation Treatment

RATIONALE

People with cystic fibrosis (CF) experience acute worsening of respiratory symptoms and lung function known as pulmonary exacerbations. Treatment with intravenous antimicrobials is common; however, there is scant evidence to support a standard treatment duration.

OBJECTIVE

Test differing durations of intravenous antimicrobials for CF exacerbations.

METHODS

STOP2 was a multi-center, randomized, controlled, clinical trial in exacerbation among adults with CF. After 7-10-days of treatment, participants exhibiting pre-defined lung function and symptom improvements were randomized to 10- or 14-days total antimicrobial duration; all others were randomized to 14- or 21-days.

MEASUREMENTS

The primary outcome was percent predicted forced expiratory volume in 1 second (ppFEV1) change from treatment initiation to two weeks after cessation. Among early responders non-inferiority of 10-days to 14-days was tested; superiority of 21-days compared to 14-days was compared for the others. Symptoms, weight, and adverse events were secondary.

RESULTS

Among 982 randomized, 277 met improvement criteria and were randomized to 10- or 14-days treatment; the remaining 705 received 21- or 14-days. Mean ppFEV1 change was 12.8 and 13.4 for 10- and 14-days, respectively, a ‒0.65 difference [95%CI ‒3.3, 2.0], excluding the pre-defined noninferiority margin. The 21- and 14-day arms experienced 3.3 and 3.4 mean ppFEV1 changes, a difference of ‒0.10 [‒1.3, 1.1]. Secondary endpoints and sensitivity analyses were supportive.

CONCLUSIONS

Among CF adults with early treatment improvement during exacerbation, ppFEV1 after 10-days of intravenous antimicrobials is not inferior to 14-days. For those with less improvement after one week, 21-days is not superior to 14-days. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT02781610.

A pilot study of cystic fibrosis exacerbation response phenotypes reveals contrasting serum and sputum iron trends

The cystic fibrosis (CF) community seeks to explain heterogeneous outcomes of pulmonary exacerbation (PEX) treatment. Serum and sputum inflammatory mediators may identify people with CF (PwCF) at risk for suboptimal responses. However, lack of an established association between response phenotypes and these mediators limits clinical application. In this pilot study, we prospectively characterized treatment response phenotypes by assessing health-related quality-of-life (HRQoL) during PEX. We also measured lung function and iron-related biochemical parameters in serum and sputum. We classified subjects as sustained symptom-responders (SRs) or non-sustained symptom-responders (NSRs) based on the absence or presence, respectively, of worsened symptom scores after initial improvement. We used linear mixed models (LMMs) to determine whether trends in lung function, hematologic, serum, and sputum indices of inflammation differed between response cohorts. In 20 PwCF, we identified 10 SRs and 10 NSRs with no significant differences in lung function at PEX onset and treatment durations. SRs had better model-predicted trends in lung function than NSRs during PEX. Non-linear trends in serum and sputum iron levels significantly differed between SRs and NSRs. In adults with cystic fibrosis, PEX treatment response phenotypes may be correlated with distinctive trends in serum and sputum iron concentrations.

Changes in symptom scores as a potential clinical endpoint for studies of cystic fibrosis pulmonary exacerbation treatment

INTRODUCTION

Symptom improvement was assessed as changes in the Chronic Respiratory Infection Symptom Score (CRISS) during intravenous antimicrobial exacerbation treatments among subjects from study NCT02109822.

METHODS

Median daily CRISS reduction (i.e., improvement) and covariates associated with CRISS reduction by Day 14 were assessed by logistic regression.

RESULTS

Among 173 subjects, median baseline CRISS was 49 [IQR 41, 56]; 93.6% had a CRISS reduction of ≥11 (minimal clinically important difference); median time to -11 reduction was 2 days [95% CI 2, 3]. The greatest median CRISS difference from baseline, on Day 17, was -26 [-29, -23]. Odds of -26 CRISS change by Day 14 were greater in subjects with higher baseline CRISS (P=.006) and younger ages (P=.041).

CONCLUSIONS

CRISS response has good dynamic range and may be a useful efficacy endpoint for PEx interventional trials. The optimal use of CRISS change as an endpoint remains uncharacterized.

Health State Utility Data in Cystic Fibrosis: A Systematic Review

INTRODUCTION

Cystic fibrosis (CF) is a life-limiting, hereditable condition, with the highest prevalence in Europe. CF treatments have led to improvements in clinical symptoms, disease management and decelerated disease progression. However, little is known about the health state utility (HSU) associated with CF disease states, adverse events, and changes in disease severity. Although HSU data have contributed to existing health economic modelling studies, a lack of such data have been highlighted. This systematic review aims to provide a summary of HSU-related research in CF and highlight related research gaps.

METHODS

Online searches were performed in six databases and studies in any of the following categories were included: (1) estimation of HSUs in CF; (2) mapping studies between patient-reported outcome measures (PROMs) and HSUs; (3) economic evaluations on the management of CF that report primary HSU data; and (4) any CF clinical trial that reported HSU as an outcome.

RESULTS

A total of 17 studies were reviewed, of which 12 provided HSU values for specific CF populations. The remaining five articles provided HSU data that were broken down by CF relevant health states, including lung transplantations, pulmonary exacerbation (PEx) events and forced expiratory volume in 1 s (FEV₁).

CONCLUSION

Current HSU data in CF are limited and there is considerable scope for further research, both in providing HSU values for CF and in investigating methods for HSU elicitation/evaluation in CF populations.

Correspondence between lung function and symptom measures from the Cystic Fibrosis Respiratory Symptom Diary-Chronic Respiratory Infection Symptom Score (CFRSD-CRISS)

BACKGROUND

Pulmonary exacerbations (PEx) in cystic fibrosis (CF) patients reduce quality of life. Lung function, measured by the percent predicted forced expiratory volume in 1 s (ppFEV1), is widely used to evaluate PEx treatments. We analyzed the correspondence of ppFEV1 with 8 patient-reported symptom-based questions from the Cystic Fibrosis Respiratory Symptom Diary-Chronic Respiratory Infection Symptom Score (CFRSD-CRISS).

METHODS

Data were derived from the observational Standardized Treatment of Pulmonary Exacerbations (STOP) study. CF patients who had CFRSD-CRISS and ppFEV1 measurements on ≥2 timepoints were included: 1) day of initial PEx, 2) 7 days later, and/or 3) end of PEx. We calculated age-stratified Spearman correlation coefficients and 95% confidence intervals (95% CIs) between the change in ppFEV1 and change in CFRSD-CRISS items from index to day 7 and from index to the end of PEx treatment.

RESULTS

Lung function and symptom scores improved by the end of treatment; however, correlations between ppFEV1 and the specific CFRSD-CRISS measures were mostly weak to moderate. An exception was that among patients <18, we observed moderately strong correlations between changes in ppFEV1 and cough severity (r = -0.58 (95% CI: -0.80, -0.21)), mucus quantity (r = -0.51 (-0.77, -0.11)), and wheezing (r = -0.53 (-0.78, -0.14)) from index until end of treatment.

CONCLUSIONS

As novel treatments are developed for PEx, it is important to ensure that improvement is measured meaningfully. The generally weak associations between patient-reported symptoms and ppFEV1 that we found suggest that these measures capture different aspects of the disease and both metrics are important when evaluating new treatments.

Cystic fibrosis year in review 2018, part 2

Cystic fibrosis (CF) research and case reports were robust in the year 2018. This report summarizes publications related the multisystem effects of CF, pulmonary exacerbations, new and expanded therapies other than cystic fibrosis transmembrane conductance regulator modulator studies, and patient-reported priorities and outcomes.