Novel approaches to incorporating pharmacoeconomic studies into phase III clinical trials for Alzheimer's disease

Methodological challenges in assessing the impact of comorbidities on costs in Alzheimer's disease clinical trials

BACKGROUND

Alzheimer's disease (AD) is associated with considerable costs and has a significant impact on health and social care systems.

OBJECTIVE

This study assessed whether baseline comorbidities present in 2,594 patients with AD participating in two semagacestat randomized placebo-controlled trials (RCTs) would significantly impact overall costs.

METHODS

Resource utilization was captured using the Resource Utilization in Dementia Scale-Lite. Comorbidities and concomitant medications were tabulated via patient and caregiver reports. Only baseline data were analyzed. Direct and indirect costs per month were calculated per patient. The relationship between cost and explanatory variables was explored in a regression model.

RESULTS

The baseline monthly cost of care in this RCT population was £1,147 ± 2,483, with informal care costs accounting for 75% of costs. Gender, age, and functional status were significant predictors of costs (p ≤ 0.0001). The cost ratio was not impacted when the number of comorbidities was added to the model (cost ratio = 0.95; 95% CI 0.91-0.99) or when combined with the number of concomitant medications (cost ratio = 0.97; 95% CI 0.95-1.00). Inconsistent findings related to the impact of individual comorbidities on costs were noted in sensitivity analyses.

CONCLUSIONS

The number of comorbidities, alone or when combined with concomitant medications, did not impact baseline costs of care, perhaps because RCTs often enroll less severely ill and more medically stable patients. However, higher costs were consistently associated with greater functional impairment similar to non-RCT databases. Supplemental sources (e.g., claims databases) are likely needed to better estimate the effects of disease and treatment on costs of illness captured in RCTs for AD.

Patients' diagnosis decisions in Alzheimer's disease: the influence of family factors

It is surprising to observe that the number of patients receiving a late diagnosis for Alzheimer's disease (AD) remains high even in countries promoting early diagnosis campaigns. We explore the impact of family history and family support on the risks of receiving a delayed diagnosis. We use French data of 1131 patients diagnosed between 1991 and 2005. We find that the presence of AD history in the family increased the risks of receiving a delayed diagnosis. This was true especially when AD history involved brothers, sisters and other relatives (uncles or cousins). The presence of an informal caregiver at the time of the first warning signs reduced the risks of receiving a late diagnosis, regardless of the informal caregiver concerned (spouse, son, daughter etc.). We identify several opportunities for early detection campaigns. Families with history of disease should be targeted. Campaigns should also target isolated patients, who do not benefit from informal care. Our results underline the importance of improving the diagnosis access for old patients and for men.

Clinical trials in predementia stages of Alzheimer disease

Effective treatments of Alzheimer disease (AD) dementia are an urgent necessity. There is a growing consensus that effective disease-modifying treatment before the onset of clinical dementia and slowing the progression of mild symptoms are needed after recent setbacks in AD therapeutics. The identification of at-risk and preclinical AD populations is becoming important for targeting primary and secondary prevention clinical trials in AD. This article reviews the strategies and challenges in targeting at-risk and preclinical AD populations for a new generation of AD clinical trials. Design, outcome measures, and complexities in successfully completing a clinical trial targeting this population are reviewed.

Exploring the relationship between Alzheimer's disease severity and longitudinal costs

OBJECTIVE

The joint impact of cognitive, functional, and behavioral statuses must be measured when exploring the impact of new drugs on Alzheimer's disease (AD) costs. There are very few recent studies of AD costs by all dimensions of disease severity. Our objective was to improve estimation of the relationship between AD severity and costs of AD care by using more comprehensive AD data severity and a large sample size.

METHODS

Participants were community-dwelling AD patients recruited between 2003 and 2005 and followed annually during a 2-year period in 50 French memory clinics. We used the Resource Use in Dementia questionnaire to estimate costs from a societal perspective. We explored the presence of potential endogeneity bias by using instrumental variable regressions.

RESULTS

Cognitive declines impacted informal costs more than medical and nonmedical costs, while functional declines impacted nonmedical costs more than medical and informal costs. Both cognitive and function declines increased the total costs of care. We found that the endogeneity of these variables led to a large underestimation of their impact of AD severity on costs.

CONCLUSION

Potential endogeneity should be controlled for to prevent biased estimations of the impact of AD severity measures on costs.