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 .

Inflammatory bowel disease (IBD) patients with impaired quality of life on biologic therapy benefit from the support of an IBD nurse specialist: Results of a randomised controlled trial in Germany (IBDBIO-ASSIST study).

BACKGROUND: IBDBIO-ASSIST was a randomised controlled trial assessing the efficacy of care provided by IBD nurse specialists in Germany in improving health-related quality of life (QoL) in IBD patients on biologic therapy. AIM: To evaluate patient-related outcomes and economic consequences associated with integrating IBD nurses into usual care. METHODS: We randomly assigned 1086 patients with IBD on biologic therapy to a control group (CG) receiving usual care or an intervention group (IG) receiving additional care from an IBD nurse specialist. The primary outcome was disease-specific QoL (sIBDQ) assessed at 6, 12 and 18 months. RESULTS: At baseline, patients in both groups were highly satisfied with their treatment situation and had relatively high sIBDQ values (range: 1-7; CG: 5.12; IG: 4.92). In the intention-to-treat (ITT) analysis of the overall sample, there was no significant difference in sIBDQ between groups at the assessment time points. However, a per-protocol analysis of patients with impaired QoL at baseline (EQ-VAS < 75 [median]), showed improvement in sIBDQ over 6 months that became significant at month 12 and remained significant through month 18 (baseline: IG 4.24; CG 4.31; 18 months: IG 5.02; CG 4.76; p = 0.017). CONCLUSION: High baseline satisfaction of IBD patients with treatment and the relatively high baseline sIBDQ values may have contributed to the lack of significant difference in sIBDQ scores for the overall sample. However, patients with impaired QoL derived significant benefit from additional care provided by an IBD nurse specialist, leading to meaningful improvements in sIBDQ over the long term.

Market diffusion of biosimilars in off-patent biologic drug markets across Europe.

Biologics are among the most expensive pharmaceuticals but have begun to lose their exclusivity rights over the past 15 years, offering the possibility for biosimilar competition. Therefore, we examine the market diffusion of biosimilars across Europe. Using revenues and sales data from IQVIA, we identified 12 biologic substances facing first biosimilar competition between 2014 and 2020 in 25 European countries. We investigated biosimilar market share depending on product and market characteristics with beta regression. Moreover, we compared market diffusion across countries using multilevel modelling. The average market share of biosimilars at first biosimilar entry was about seven percent in the retail and hospital market and grew to 34.69% and 38.29% after 16 quarters, respectively. Quarters since first biosimilar entry had a positive but decreasing effect on biosimilar market share (p<.001 for both markets). Quarterly growth ranged from 0.006 (Netherlands) to 0.026 (Slovakia) in the retail market and from 0.007 (Hungary) to 0.040 (United Kingdom) in the hospital market. The diffusion increased over time across all European markets, although at different rates. Biosimilar market share was higher in the hospital market. Compared to generics, diffusion of biosimilars is much slower. If policymakers desire to increase biosimilar diffusion, they should aim at policies that increase competition and use countries with the highest diffusion rates as benchmarks.