USING BIOMARKER TESTING TO TARGET TREATMENT TO PATIENTS WITH MILD COGNITIVE IMPAIRMENT AT INCREASED RISK OF ALZHEIMER'S DISEASE

Using Biomarker Testing to Target Treatment to Patients with Mild Cognitive Impairment at Increased Risk of Alzheimer's Disease

Purpose:

To quantify the potential value of biomarker testing for patients with mild cognitive impairment (MCI). Biomarkers provide information about a patient's risk of developing Alzheimer's disease (AD) and can allow for early targeted interventions for those patients found to be at higher risk of AD than others.

 

Method:

We developed a Markov cohort model to project 10-year quality-adjusted life years (QALYs), costs, and cost-effectiveness in terms of varying treatment thresholds defined by MCI patients' biomarker levels. We considered strategies of no treatment, biomarker testing and treatment, and treatment. For the biomarker testing and treatment strategies (figure), we considered treating different levels of risk (in quintiles, R_j) classified from baseline biomarker information varying from treating only the highest risk group to treating all but the lowest risk group. The target population was a cohort of 65-year-old MCI patients in which biomarker level-based transition probabilities were incorporated using data from Alzheimer's Disease Neuroimaging Initiative. We performed deterministic and probabilistic sensitivity analyses and conducted expected value of perfect information (EVPI) analyses to estimate the values of eliminating uncertainty around the all parameters and parameters of interest.

Figure. Simplified schematic diagram of biomarker testing + treatment strategy on MCI patients. R_j: risk ranking defined by biomarker level, j=[1, 5].

 

 

Result:  

The base-case results show that treating all but not the lowest risk group (four out of five groups) among MCI patients resulted in 0.05 QALYs gained at an incremental cost of $2012, producing a 10-year incremental cost-effectiveness ratio (ICER) of $38,736 per QALY compared with treating the first three highest risk groups among the five. The ICER was sensitive to the treatment effectiveness, the transition probability from MCI to AD in each risk group, treatment costs, and utility in MCI patients. The overall EVPI was $113 (or 0.0294 QALYs) per patient at a willingness to pay threshold of $50,000 per QALY.

 

Conclusion:  

This study illustrates the potential for early targeted interventions for MCI patients who are at increased risk of developing AD. Treating MCI patients by their risk ranking derived from baseline biomarker information to postpone the progression to AD may be economically attractive.