Cost-effectiveness of cerebrospinal biomarkers for the diagnosis of Alzheimer’s disease

Abstract

BackgroundAccurate and timely diagnosis of Alzheimer’s disease (AD) is important for prompt initiation of treatment in patients with AD and to avoid inappropriate treatment of patients with false-positive diagnoses.MethodsUsing a Markov model, we estimated the lifetime costs and quality-adjusted life-years (QALYs) of cerebrospinal fluid biomarker analysis in a cohort of patients referred to a neurologist or memory clinic with suspected AD who remained without a definitive diagnosis of AD or another condition after neuroimaging. Parametric values were estimated from previous health economic models and the medical literature. Extensive deterministic and probabilistic sensitivity analyses were performed to evaluate the robustness of the results.ResultsAt a 12.7% pretest probability of AD, biomarker analysis after normal neuroimaging findings has an incremental cost-effectiveness ratio (ICER) of $11,032 per QALY gained. Results were sensitive to the pretest prevalence of AD, and the ICER increased to over $50,000 per QALY when the prevalence of AD fell below 9%. Results were also sensitive to patient age (biomarkers are less cost-effective in older cohorts), treatment uptake and adherence, biomarker test characteristics, and the degree to which patients with suspected AD who do not have AD benefit from AD treatment when they are falsely diagnosed.ConclusionsThe cost-effectiveness of biomarker analysis depends critically on the prevalence of AD in the tested population. In general practice, where the prevalence of AD after clinical assessment and normal neuroimaging findings may be low, biomarker analysis is unlikely to be cost-effective at a willingness-to-pay threshold of $50,000 per QALY gained. However, when at least 1 in 11 patients has AD after normal neuroimaging findings, biomarker analysis is likely cost-effective. Specifically, for patients referred to memory clinics with memory impairment who do not present neuroimaging evidence of medial temporal lobe atrophy, pretest prevalence of AD may exceed 15%. Biomarker analysis is a potentially cost-saving diagnostic method and should be considered for adoption in high-prevalence centers.Electronic supplementary materialThe online version of this article (doi:10.1186/s13195-017-0243-0) contains supplementary material, which is available to authorized users.

Cortical Thinning Associated with Age and CSF Biomarkers in Early Parkinson’s Disease Is Modified by the SNCA rs356181 Polymorphism

“…As dementia in PD is characterized by cortical atrophy, finding biomarkers that can reliably predict and monitor cortical neurodegeneration is an urgent need. Cerebrospinal fluid (CSF) biomarkers of neural integrity have shown great potential at tracking early cortical damage in several neurological diseases [3].…”

Economic impacts of introducing diagnostics for mild cognitive impairment Alzheimer's disease patients

“…Lee et al. [20] found that the sensitivity and dependency of CSF biomarker analysis are affected by the prevalence of AD in the population tested. Where AD prevalence after clinical assessment and standard neuroimaging is low, analysis is unlikely to be cost‐effective, but when it is higher than 15%, it is likely to be cost‐saving.…”

“…Would greater scale improve accuracy through accumulation of experience or would it make it harder to assure quality if the number of centers carrying out tests multiplied? The finding by Lee et al [20] that the cost-effectiveness of diagnostic testing is linked to underlying prevalence of AD in the group tested suggests a need to consider offering tests only to people who screen positive on initial screening (e.g., mini-mental state examination). This would not be an issue if testing was offered only to people with MCI, as assumed here, since they have a high probability of having underlying AD.…”

Cost of diagnosing dementia in a German memory clinic

“…Thus, the cost of diagnosing dementia disease represents only a small proportion of 1% at the current rate of referral. However, a timely diagnosis allows prompt initiation of pharmacological and nonpharmacological interventions and prevents inappropriate treatment of patients with false-positive diagnoses [ 42 , 43 ]. These opportunities could lead to a reduction in healthcare costs, especially due to a delayed need for care and institutionalization [ 44 – 46 ].…”