Progression analysis versus traditional methods to quantify slowing of disease progression in Alzheimer's disease.

BACKGROUND: The clinical meaningfulness of the effects of recently approved disease-modifying treatments (DMT) in Alzheimer's disease is under debate. Available evidence is limited to short-term effects on clinical rating scales which may be difficult to interpret and have limited intrinsic meaning to patients. The main value of DMTs accrues over the long term as they are expected to cause a delay or slowing of disease progression. While awaiting such evidence, the translation of short-term effects to time delays or slowing of progression could offer a powerful and readily interpretable representation of clinical outcomes. METHODS: We simulated disease progression trajectories representing two arms, active and placebo, of a hypothetical clinical trial of a DMT. The placebo arm was simulated based on estimated mean trajectories of clinical dementia rating scale-sum of boxes (CDR-SB) recordings from amyloid-positive subjects with mild cognitive impairment (MCI) from Alzheimer's Disease Neuroimaging Initiative (ADNI). The active arm was simulated to show an average slowing of disease progression versus placebo of 20% at each visit. The treatment effects in the simulated trials were estimated with a progression model for repeated measures (PMRM) and a mixed model for repeated measures (MMRM) for comparison. For PMRM, the treatment effect is expressed in units of time (e.g., days) and for MMRM in units of the outcome (e.g., CDR-SB points). PMRM results were implemented in a health economics Markov model extrapolating disease progression and death over 15 years. RESULTS: The PMRM model estimated a 19% delay in disease progression at 18 months and 20% (~ 7 months delay) at 36 months, while the MMRM model estimated a 25% reduction in CDR-SB (~ 0.5 points) at 36 months. The PMRM model had slightly greater power compared to MMRM. The health economic model based on the estimated time delay suggested an increase in life expectancy (10 months) without extending time in severe stages of disease. CONCLUSION: PMRM methods can be used to estimate treatment effects in terms of slowing of progression which translates to time metrics that can be readily interpreted and appreciated as meaningful outcomes for patients, care partners, and health care practitioners.

Survival and Quality of Life after Isolated Hepatic Perfusion with Melphalan as a Treatment for Uveal Melanoma Liver Metastases - Final Results from the Phase III Randomized Controlled Trial SCANDIUM.

OBJECTIVE: To investigate overall survival (OS) and health-related quality of life (HRQOL) of first-line isolated hepatic perfusion (IHP) compared to best alternative care (BAC) for patients with uveal melanoma liver metastases. SUMMARY BACKGROUND DATA: Approximately half of patients with uveal melanoma develop metastatic disease, most commonly in the liver and systemic treatment options are limited. Isolated hepatic perfusion (IHP) is a locoregional therapy with high response rates but with unclear effect on overall survival (OS). METHODS: In this phase III randomized controlled multicenter trial (the SCANDIUM trial) patients with previously untreated isolated uveal melanoma liver metastases were included between 2013-2021, with at least 24 months of follow-up. The planned accrual was 90 patients randomized 1:1 to receive a one-time treatment with IHP or BAC. Crossover to IHP was not allowed. The primary endpoint was the 24-month OS rate, with the hypothesis of a treatment effect leading to a 50% OS rate in the IHP group compared to 20% in the control group. HRQOL was measured by the EuroQol 5-domains 3-levels (EQ-5D-3L) questionnaire over 12 months. RESULTS: The intention-to-treat (ITT) population included 87 patients randomized to the IHP group (43 patients; 41 [89%] received IHP) or the control group (44 patients). The control group received chemotherapy (49%), immunotherapy (39%), or localized interventions (9%). In the ITT population, the median PFS was 7.4 months in the IHP group compared with 3.3 months in the control group, with a hazard ratio of 0.21 (95% CI, 0.12-0.36). The 24-month OS rate was 46.5% in the IHP group versus 29.5% in the control group (P=0.12). The median OS was 21.7 months versus 17.6 months, with a hazard ratio of 0.64 (95% CI, 0.37-1.10). EQ-5D-3L showed a sustained high health status for the IHP group over 12 months, compared to a deteriorating trend in the control group. CONCLUSIONS: For patients with liver metastases from uveal melanoma, IHP offers high response rates translating to a benefit in PFS including a trend of better HRQOL compared to the control group. However, the primary endpoint of OS at 24 months was not met.

The costs of chronic pain-Long-term estimates.

BACKGROUND: Chronic pain is a condition with severe impact on many aspects of life, including work, functional ability and quality of life, thereby reducing physical, mental and social well-being. Despite the high prevalence and burden of chronic pain, it has received disproportionally little attention in research and public policy and the societal costs of chronic pain remain largely unknown. This study aimed to describe the long-term healthcare and work absence costs of individuals with and without self-identified chronic pain. METHODS: The study population were participants in two Norwegian population health studies (HUNT3 and Tromsø6). Participants were defined as having chronic pain based on a self-reported answer to a question on chronic pain in the health studies in 2008. Individuals in the study population were linked to four national register databases on healthcare resource use and work absence. RESULTS: In our study, 36% (n = 63,782) self-reported to have chronic pain and the average years of age was 56.6. The accumulated difference in costs between those with and without chronic pain from 2010 to 2016 was €55,003 (CI: 54,414-55,592) per individual. Extrapolating this to the entire population suggests that chronic pain imposes a yearly burden of 4% of GDP. Eighty per cent of the costs were estimated to be productivity loss. CONCLUSION: Insights from this study can provide a greater understanding of the extent of healthcare use and productivity loss by those with chronic pain and serve as an important basis for improvements in rehabilitation and quality of care, and the education of the public on the burden of chronic pain. SIGNIFICANCE: This was the first study to estimate the economic burden associated with chronic pain in the general population using linked individual-level administrative data and self-reported survey answers. We provide calculations showing that annual costs of chronic pain may be as high as €12 billion or 4% of GDP. Findings from this study highlight the need for a greater understanding of the substantial healthcare use and productivity losses among individuals with chronic pain.

Disease severity and mortality in Alzheimer's disease: an analysis using the U.S. National Alzheimer's Coordinating Center Uniform Data Set.

BACKGROUND: Evidence on the relative risk of death across all stages of Alzheimer's disease (AD) is lacking but greatly needed for the evaluation of new interventions. We used data from the Uniform Data Set (UDS) of the National Alzheimer's Coordinating Center (NACC) to assess the expected survival of a person progressing to a particular stage of AD and the relative risk of death for a person in a particular stage of AD compared with cognitively normal (CN) people. METHODS: This was a retrospective observational cohort study of mortality and its determinants in participants with incident mild cognitive impairment (MCI) due to AD or AD dementia compared with CN participants. Overall survival and hazard ratios of all-cause mortality in participants ≥ 50 years of age with clinically assessed or diagnosed MCI due to AD, or mild, moderate, or severe AD dementia, confirmed by Clinical Dementia Rating scores, versus CN participants were estimated, using NACC UDS data. Participants were followed until death, censoring, or until information to determine disease stage was missing. RESULTS: Aged between 50 and 104 years, 12,414 participants met the eligibility criteria for the study. Participants progressing to MCI due to AD or AD dementia survived a median of 3-12 years, with higher mortality observed in more severe stages. Risk of death increased with the severity of AD dementia, with the increase significantly higher at younger ages. Participants with MCI due to AD and CN participants had a similar risk of death after controlling for confounding factors. CONCLUSIONS: Relative all-cause mortality risk increases with AD severity, more so at younger ages. Mortality does not seem to be higher for those remaining in MCI due to AD. Findings might imply potential benefit of lower mortality if preventing or delaying the progression of AD is successful, and importantly, this potential benefit might be greater in relatively younger people. Future research should replicate our study in other samples more representative of the general US population as well as other populations around the world.

Effect of mortality in cost-effectiveness modeling of disease-modifying treatment for Alzheimer's disease.

INTRODUCTION: We examined (1) the magnitude of mortality attributed to Alzheimer's disease (AD), and (2) the effect of mortality in cost-effectiveness modeling of hypothetical disease-modifying treatment (DMT) in AD. METHOD: Data were derived from Swedish Dementia Registry (N = 39,308). Mortality was analyzed with survival analysis and multinomial logistic regression. A Markov microsimulation model was used to model the cost effectiveness of DMT using routine care as a comparator. Three scenarios were simulated: (1) indirect effect, (2) no effect on overall mortality, (3) indirect effect on AD-related mortality. RESULTS: Overall mortality increased with cognitive decline, age, male sex, number of medications used, and lower body mass index. Nearly all cause-specific mortality was associated with cognitive decline. DMT increased survival by 0.35 years in scenario 1 and 0.14 years in scenario 3. DMT with no mortality effect is the least cost effective. DISCUSSION: The results provide key mortality estimates and demonstrate influences on the cost effectiveness of DMT. Highlights: We describe cause-specific mortality in relation to disease severity in Alzheimer's disease (AD).We model different assumptions of disease-modifying treatment (DMT) on AD survival.DMT was the least cost effective when assuming no effect on AD survival.Cost effectiveness is mainly influenced by the relative cost of staying in each disease state.

Burden of disease and management of osteoarthritis and chronic low back pain: healthcare utilization and sick leave in Sweden, Norway, Finland and Denmark (BISCUITS): study design and patient characteristics of a real world data study.

OBJECTIVES: Osteoarthritis (OA) and chronic low back pain (CLBP) are common musculoskeletal disorders with substantial patient and societal burden. Nordic administrative registers offer a unique opportunity to study the impact of these conditions in the real-world setting. The Burden of Disease and Management of Osteoarthritis and Chronic Low Back Pain: Health Care Utilization and Sick Leave in Sweden, Norway, Finland and Denmark (BISCUITS) study was designed to study disease prevalence and the societal and economic burden in broad OA and CLBP populations. METHODS: Patients in Sweden, Norway, Finland and Denmark with diagnoses of OA or CLBP (low back pain record plus ≥2 pain relief prescriptions to indicate chronicity) were identified in specialty care, in primary care (Sweden and Finland) and in a quality-of-care register (Sweden). Matched controls were identified for the specialty care cohort. Longitudinal data were extracted on prevalence, treatment patterns, patient-reported outcomes, social and economic burden. RESULTS: Almost 1.4 million patients with OA and 0.4 million with CLBP were identified in specialty care, corresponding to a prevalence in the Nordic countries of 6.3 and 1.9%, respectively. The prevalence increased to 11-14% for OA and almost 6% for CLBP when adding patients identified in primary care. OA patients had a higher Elixhauser comorbidity index (0.66 vs. 0.46) and were using opioids (44.7 vs. 10.2%) or long-term nonsteroidal anti-inflammatory drug (NSAIDs) (20.9 vs. 4.5%) more than four times as often as compared to controls. The differences were even larger for CLBP patients compared to their controls (comorbidity index 0.89 vs. 0.39, opioid use 77.7 vs. 9.4%, and long-term NSAID use 37.2 vs. 4.8%). CONCLUSIONS: The BISCUITS study offers an unprecedented, longitudinal healthcare data source to quantify the real-world burden of more than 1.8 million patients with OA or CLBP across four countries. In subsequent papers we aim to explore among others additional outcomes and subgroups of patients, primarily those patients who may benefit most from better healthcare management.

Cost-effectiveness models for Alzheimer's disease and related dementias: IPECAD modeling workshop cross-comparison challenge.

INTRODUCTION: The credibility of model-based economic evaluations of Alzheimer's disease (AD) interventions is central to appropriate decision-making in a policy context. We report on the International PharmacoEconomic Collaboration on Alzheimer's Disease (IPECAD) Modeling Workshop Challenge. METHODS: Two common benchmark scenarios, for the hypothetical treatment of AD mild cognitive impairment (MCI) and mild dementia, were developed jointly by 29 participants. Model outcomes were summarized, and cross-comparisons were discussed during a structured workshop. RESULTS: A broad concordance was established among participants. Mean 10-year restricted survival and time in MCI in the control group ranged across 10 MCI models from 6.7 to 9.5 years and 3.4 to 5.6 years, respectively; and across 4 mild dementia models from 5.4 to 7.9 years (survival) and 1.5 to 4.2 years (mild dementia). DISCUSSION: The model comparison increased our understanding of methods, data used, and disease progression. We established a collaboration framework to assess cost-effectiveness outcomes, an important step toward transparent and credible AD models.

Global estimates on the number of persons across the Alzheimer's disease continuum.

INTRODUCTION: Global estimates on numbers of persons in early stages of Alzheimer's disease (AD), including prodromal and preclinical, are lacking, yet are needed to inform policy decisions on preventive measures and planning for future therapies targeting AD pathology. METHODS: We synthesized the literature on prevalence across the AD continuum and derived a model estimating the number of persons, stratified by 5-year age groups, sex, and disease stage (AD dementia, prodromal AD, and preclinical AD). RESULTS: The global number of persons with AD dementia, prodromal AD, and preclinical AD were estimated at 32, 69, and 315 million, respectively. Together they constituted 416 million across the AD continuum, or 22% of all persons aged 50 and above. DISCUSSION: Considering predementia stages, the number of persons with AD is much larger than conveyed in available literature. Our estimates are uncertain, especially for predementia stages in low- and middle-income regions where biomarker studies are missing.

Health economic modeling for Alzheimer's disease: Expert perspectives.

The successful development of an economic model for the evaluation of future Alzheimer's disease (AD) interventions is critical to accurately inform policy makers and payers. As our understanding of AD expands, this becomes an increasingly complex and challenging goal. Advances in diagnostic techniques for AD and the prospect of disease-modifying treatments raise an urgent need to define specifications for future economic models and to ensure that the necessary data to populate them are available. This Perspective article provides expert opinions from health economists and governmental agency representatives on how future economic models for AD might be structured, validated, and reported. We aim to stimulate much-needed discussion about the detailed specification of future health economic models for AD.

Swedish Normative Data for Mindmore: A Comprehensive Cognitive Screening Battery, Both Digital and Self-Administrated.

OBJECTIVE: Cognitive impairment is a key element in most mental disorders. Its objective assessment at initial patient contact in primary care can lead to better adjusted and timely care with personalised treatment and recovery. To enable this, we designed the Mindmore self-administrative cognitive screening battery. What is presented here is normative data for the Mindmore battery for the Swedish population. METHOD: A total of 720 healthy adults (17 to 93 years) completed the Mindmore screening battery, which consists of 14 individual tests across five cognitive domains: attention and processing speed, memory, language, visuospatial functions and executive functions. Regression-based normative data were established for 42 test result measures, investigating linear, non-linear and interaction effects between age, education and sex. RESULTS: The test results were most affected by age and to a lesser extent by education and sex. All but one test displayed either linear or accelerated age-related decline, or a U-shaped association with age. All but two tests showed beneficial effects of education, either linear or subsiding after 12 years of educational attainment. Sex affected tests in the memory and executive domains. In three tests, an interaction between age and education revealed an increased benefit of education later in life. CONCLUSION: This study provides normative models for 14 traditional cognitive tests adapted for self-administration through a digital platform. The models will enable more accurate interpretation of test results, hopefully leading to improved clinical decision making and better care for patients with cognitive impairment.

Predictors of drug survival: A cohort study comparing anti-tumour necrosis factor agents using the Swedish inflammatory bowel disease quality register.

BACKGROUND: Whether long-term effectiveness differs between anti-tumour necrosis factor (anti-TNF) agents is unknown. AIMS: To examine drug survival of first-line anti-TNF agents and identify predictors of discontinuation. To reduce channelling bias, we also compared drug survival of the second anti-TNF. METHODS: Biologic-naïve patients (N = 955) recorded in the Swedish IBD Quality Register (SWIBREG) were examined. We used propensity score matching, comparing drug survival over up to three years of follow-up. Cox regression estimated adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs). RESULTS: In Crohn's disease, discontinuation because of lack/loss of response was 32% [95%CI = 26%-38%] for infliximab versus 16% [95%CI = 11%-21%] for adalimumab. Infliximab [vs adalimumab; aHR = 1.96; 95%CI = 1.20-3.21] and colonic disease (L2) [vs no L2; aHR = 2.17; 95% CI = 1.26-3.75] were associated with higher discontinuation rates, whereas normalised CRP at three months [aHR = 0.40; 95% CI = 0.19-0.81] with a lower rate. Consistently, patients who switched from adalimumab to infliximab (vs infliximab to adalimumab) had earlier discontinuation (P = 0.04). Concomitant use of immunomodulators was associated with a lower adverse drug reaction-mediated discontinuation rate [aHR = 0.46; 95% CI = 0.28-0.77], in part explained by fewer infusion reactions [aHR = 0.27; 95% CI = 0.08-0.89]. In ulcerative colitis, the probability of discontinuation because of lack/loss of response was 40% [95% CI = 33%-47%] for infliximab versus 37% [95% CI = 21%-53%] for adalimumab. Disease duration ≥10 years [aHR = 0.25; 95% CI = 0.10-0.58] and normalised CRP after three months [aHR = 0.39; 95% CI = 0.18-0.84] were associated with lower discontinuation rates. CONCLUSIONS: Clinical characterisation of patients may aid decision-making on anti-TNF treatment. The consistently shorter drug survival for infliximab (vs adalimumab) in Crohn's disease, suggests a potential difference between the two drugs.

Health utility in preclinical and prodromal Alzheimer's disease for establishing the value of new disease-modifying treatments-EQ-5D data from the Swedish BioFINDER study.

Quality of life and health utility are important outcomes for patients with Alzheimer's disease (AD) and central for demonstrating the value of new treatments. Estimates in biomarker-confirmed AD populations are missing, potentially delaying payer approval of treatment. We examined whether health utility, assessed with the EuroQoL-5 3-level version (EQ-5D-3L), differed between individuals with a positive or negative amyloid beta (Aß) biomarker in patients with mild cognitive impairment (MCI) and cognitively unimpaired (CU) participants from the Swedish BioFINDER study (n = 578). Participants with prodromal AD (Aß-positive MCI) reported better health utility (n = 79, mean = 0.81, 95% confidence interval [CI] 0.77-0.85) than Aß-negative MCI (mean = 0.71, 95% CI 0.64-0.78), but worse than controls (Aß-negative CU, mean = 0.87, 95% CI 0.86-0.89). Health utility in preclinical AD (Aß-positive CU; mean = 0.86, 95% CI 0.83-0.89) was similar to controls. This relatively good health utility in prodromal AD suggests a larger value of delaying progression to dementia than previously anticipated and a great value of delaying clinical progression in preclinical AD.

Conducting public involvement in dementia research: The contribution of the European Working Group of People with Dementia to the ROADMAP project.

BACKGROUND: Dementia outcomes include memory loss, language impairment, reduced quality of life and personality changes. Research suggests that outcomes selected for dementia clinical trials might not be the most important to people affected. OBJECTIVE: One of the goals of the 'Real world Outcomes across the Alzheimer's Disease spectrum for better care: Multi-modal data Access Platform' (ROADMAP) project was to identify important outcomes from the perspective of people with dementia and their caregivers. We review how ROADMAP's Public Involvement shaped the programme, impacted the research process and gave voice to people affected by dementia. DESIGN: The European Working Group of People with Dementia (EWGPWD) were invited to participate. In-person consultations were held with people with dementia and caregivers, with advance information provided on ROADMAP activities. Constructive criticism of survey content, layout and accessibility was sought, as were views and perspectives on terminology and key concepts around disease progression. RESULTS: The working group provided significant improvements to survey accessibility and acceptability. They promoted better understanding of concepts around disease progression and how researchers might approach measuring and interpreting findings. They effectively expressed difficult concepts through real-world examples. CONCLUSIONS: The role of the EWGPWD in ROADMAP was crucial, and its impact was highly influential. Involvement from the design stage helped shape the ethos of the programme and ultimately its meaningfulness. PUBLIC CONTRIBUTION: People with dementia and their carers were involved through structured consultations and invited to provide feedback on project materials, methods and insight into terminology and relevant concepts.

Obtaining EQ-5D-5L utilities from the disease specific quality of life Alzheimer's disease scale: development and results from a mapping study.

PURPOSE: The Quality of Life Alzheimer's Disease Scale (QoL-AD) is commonly used to assess disease specific health-related quality of life (HRQoL) as rated by patients and their carers. For cost-effectiveness analyses, utilities based on the EQ-5D are often required. We report a new mapping algorithm to obtain EQ-5D indices when only QoL-AD data are available. METHODS: Different statistical models to estimate utility directly, or responses to individual EQ-5D questions (response mapping) from QoL-AD, were trialled for patient-rated and proxy-rated questionnaires. Model performance was assessed by root mean square error and mean absolute error. RESULTS: The response model using multinomial regression including age and sex, performed best in both the estimation dataset and an independent dataset. CONCLUSIONS: The recommended mapping algorithm allows researchers for the first time to estimate EQ-5D values from QoL-AD data, enabling cost-utility analyses using datasets where the QoL-AD but no utility measures were collected.

Health-related quality of life in people with predementia Alzheimer's disease, mild cognitive impairment or dementia measured with preference-based instruments: a systematic literature review.

BACKGROUND: Obtaining reliable estimates of the health-related quality of life (HR-QoL) of people with predementia Alzheimer's disease [AD] (preclinical or prodromal AD), mild cognitive impairment (MCI) and dementia is essential for economic evaluations of related health interventions. AIMS: To provide an overview of which quality of life instruments are being used to assess HR-QoL in people with predementia AD, MCI or dementia; and, to summarise their reported HR-QoL levels at each stage of the disease and by type of respondent. METHODS: We systematically searched for and reviewed eligible studies published between January 1990 and the end of April 2017 which reported HR-QoL for people with predementia AD, MCI or dementia. We only included instruments which are preference-based, allowing index scores/utility values to be attached to each health state they describe based on preferences obtained from population surveys. Summary results were presented by respondent type (self or proxy), type of instrument, geographical location and, where possible, stage of disease. Health state utility values derived using the EuroQoL 5-Dimensions (EQ-5D) were meta-analysed by pooling reported results across all studies by disease severity (MCI, mild, mild to moderate, moderate, severe dementia, not specified) and by respondent (person with dementia, carer, general public, not specified), using a fixed-effects approach. RESULTS: We identified 61 studies which reported HR-QoL for people with MCI or dementia using preference-based instruments, of which 48 used the EQ-5D. Thirty-six studies reported HR-QoL for mild and/or moderate disease severities, and 12 studies reported utility values for MCI. We found systematic differences between self-rated and proxy-rated HR-QoL, with proxy-rated utility valued being significantly lower in more severe disease states. CONCLUSIONS: A substantial literature now exists quantifying the impact of dementia on HR-QoL using preference-based measures, giving researchers and modellers a firmer basis on which to select appropriate utility values when estimating the effectiveness and cost-effectiveness of interventions in this area. Further research is required on HR-QoL of people with preclinical and prodromal AD and MCI, possible differences by type of dementia, the effects of comorbidities, study setting and the informal caregiver's own HR-QoL, including any effect of that on their proxy-ratings.

Challenges in demonstrating the value of disease-modifying therapies for Alzheimer's disease.

INTRODUCTION: Alzheimer's disease (AD) is a complex neurodegenerative disease, affecting millions of people worldwide and imposing heavy economic burdens to societies. Currently, only symptomatic treatments are available for patients, but there is ongoing research on potential therapies that can modify the course of disease. The main objective of this work is to identify and explore the challenges surrounding decision modeling for economic evaluation of interventions for AD. AREAS COVERED: This article discusses the challenges in modeling the natural history of disease, particularly regarding the selection of disease progression and outcome measures, the inclusion of biomarker status in models, and the approach to model mortality. Challenges stemming from the use of long-term assumptions regarding treatment effects and the need for real-world evidence to fill data gaps are discussed. Lastly, the overwhelming economic impact of disease and the challenges in estimating these costs for modeling are addressed. EXPERT OPINION: Value assessment frameworks need to be reconsidered in order to demonstrate the full benefit of new disease-modifying therapies spanning beyond the scope of health systems. Data collection efforts that expand the evidence base, upon which economic models are based, will reduce the uncertainties surrounding the long-term outcomes of interventions in AD.

Valuing Alzheimer's disease drugs: a health technology assessment perspective on outcomes.

OBJECTIVES: Due to the nature of Alzheimer's disease (AD), health technology assessment (HTA) agencies might face considerable challenges in choosing appropriate outcomes and outcome measures for drugs that treat the condition. This study sought to understand which outcomes informed previous HTAs, to explore possible reasons for prioritizations, and derive potential implications for future assessments of AD drugs. METHOD: We conducted a literature review of studies that analyzed decisions made in HTAs (across disease areas) in three European countries: England, Germany, and The Netherlands. We then conducted case studies of technology assessments conducted for AD drugs in these countries. RESULTS: Overall, outcomes measured using clinical scales dominated decisions or recommendations about whether to fund AD drugs, or price negotiations. HTA processes did not always allow the inclusion of outcomes relevant to people with AD, their carers, and families. Processes did not include early discussion and agreement on what would constitute appropriate outcome measures and cut-off points for effects. CONCLUSIONS: We conclude that in order to ensure that future AD drugs are valued appropriately and timely, early agreement with various stakeholders about outcomes, outcome measures, and cut-offs is important.

The use of ICD codes to identify IBD subtypes and phenotypes of the Montreal classification in the Swedish National Patient Register.

Introduction: Whether data on International Classification of Diseases (ICD)-codes from the Swedish National Patient Register (NPR) correctly correspond to subtypes of inflammatory bowel disease (IBD) and phenotypes of the Montreal classification scheme among patients with prevalent disease is unknown.Materials and methods: We obtained information on IBD subtypes and phenotypes from the medical records of 1403 patients with known IBD who underwent biological treatment at ten Swedish hospitals and retrieved information on their IBD-associated diagnostic codes from the NPR. We used previously described algorithms to define IBD subtypes and phenotypes. Finally, we compared these register-generated subtypes and phenotypes with the corresponding information from the medical records and calculated positive predictive values (PPV) with 95% confidence intervals.Results: Among patients with clinically confirmed disease and diagnostic listings of IBD in the NPR (N = 1401), the PPV was 97 (96-99)% for Crohn's disease, 98 (97-100)% for ulcerative colitis, and 8 (4-11)% for IBD-unclassified. The overall accuracy for age at diagnosis was 95% (when defined as A1, A2, or A3). Examining the validity of codes representing disease phenotype, the PPV was 36 (32-40)% for colonic Crohn's disease (L2), 61 (56-65)% for non-stricturing/non-penetrating Crohn's disease behaviour (B1) and 83 (78-87)% for perianal disease. Correspondingly, the PPV was 80 (71-89)% for proctitis (E1)/left-sided colitis (E2) in ulcerative colitis.Conclusions: Among people with known IBD, the NPR is a reliable source of data to classify most subtypes of prevalent IBD, even though misclassification commonly occurred in Crohn's disease location and behaviour and also among IBD-unclassified patients.