Economic and healthcare consulting firm Analysis Group found that approximately one in six patients with vascular dementia have been mistakenly misdiagnosed with Alzheimer's. For Parkinson's disease, approximately one in 12 patients had an earlier misdiagnosis of Alzheimer's.
"We estimated that the cost ranges up to $14,000 per year, per patient, in terms of the misdiagnosis," lead author Noam Kirson, PhD, Analysis Group manager, told AuntMinnie.com. "It is not that all patients incur $14,000 per year in perpetuity. Once the diagnosis is reconciled, we see a meaningful drop in the excess cost, which actually goes to zero."
Kirson said the findings could influence policy decisions regarding reimbursement of diagnostic imaging technologies, such as PET with agents that can detect potential causes of dementia, as the healthcare community and regulators gain a better understanding of the costs and benefits related to Alzheimer's.
As many as 6.8 million people in the U.S. suffer from dementia, according to the National Institute of Neurological Disorders and Stroke. Alzheimer's disease is the most prevalent form of dementia, followed by vascular dementia.
Because there is such similarity in the signs and symptoms of various forms of dementia and Parkinson's disease, it can be difficult for physicians to confirm a diagnosis -- which, if incorrect, could lead to unnecessary treatment and related costs.
"Patients are largely diagnosed on their clinical presentation, and there is much overlap in the early presentation of disease and other forms of dementia, as well as potentially other conditions that may drive dementia-like symptoms," Kirson said.
In the current study, the researchers sought to assess the potential economic benefits of the timely elimination of an Alzheimer's diagnosis among U.S. Medicare patients eventually diagnosed with vascular dementia or Parkinson's disease. To do this, they estimated excess medical costs among individuals previously misdiagnosed with Alzheimer's.
The retrospective study reviewed more than 3 million Medicare beneficiary claims from between 1999 and 2011. Vascular dementia and Parkinson's patients were evaluated separately based on prior Alzheimer's diagnosis within three years of their first confirmed vascular dementia or Parkinson's disease diagnosis.
Patients were included in the study if they had at least two distinct claims with a diagnosis for vascular dementia or Parkinson's disease without a claim for any other dementia type in between or after the two claims. The first claim was considered the first confirmed diagnosis of vascular dementia or Parkinson's disease. Prior Alzheimer's diagnosis was identified as two or more claims with the diagnosis code for Alzheimer's.
Kirson and colleagues took patients with a prior Alzheimer's diagnosis and matched them with control subjects with no prior indication of Alzheimer's. Total costs for medical services were compared between patients with and without a prior Alzheimer's diagnosis at one-year intervals during the follow-up period.
The study included 15,367 patients (mean age, 80.5 years) with vascular dementia, of which 2,544 (16.6%) had a prior Alzheimer's diagnosis. Among the 30,995 patients with Parkinson's disease (mean age, 78.6 years), 2,604 (8.4%) had a prior diagnosis of Alzheimer's.
Medical costs for the patients previously diagnosed with Alzheimer's were substantially higher ($14,101) in the time leading up to and including confirmation of vascular dementia or Parkinson's disease, compared with matched counterparts with no prior Alzheimer's diagnosis during the same time period, the researchers found.
In addition, excess cost declined and eventually disappeared following the accurate diagnosis of vascular dementia or Parkinson's.
The optimum solution is to accurately diagnose Alzheimer's earlier or rule out the disease by imaging patients who present with symptoms of cognitive impairment, Kirson said.
"Part of the issue is getting patients in the right treatment and level of attention relative to their condition," he added. "When given the wrong diagnoses, you will see patients and their caregivers going back to the doctor repeatedly to figure it out. We feel that is a large driver of the excess cost that we are seeing."
Kirson and colleagues plan to expand the research outside the U.S., perhaps to the U.K., to see if the cost-benefit results are similar.
"The natural extension of this research would be to go to a broader cost-benefit analysis of comparing these costs with the potential savings from using different diagnostic technologies," he said.