Abstract
INTRODUCTION:
There is insufficient understanding of diagnosis of etiologic dementia subtypes and contact with specialized dementia care among older Americans.
METHODS:
We quantified dementia diagnoses and subsequent health care over five years by etiologic subtype and physician specialty among Medicare beneficiaries with incident dementia diagnosis in 2008/09 (226,604 persons/714,015 person-years).
RESULTS:
Eighty-five percent of persons were diagnosed by a non-dementia specialist physician. Use of dementia specialists within one-year (22%) and five-years (36%) of diagnosis was low. ‘Unspecified’ dementia diagnosis was common, higher among those diagnosed by non-dementia specialists (33.2%) than dementia specialists (21.6%). Half of diagnoses were Alzheimer’s disease.
DISCUSSION:
Ascertainment of etiologic dementia subtype may inform hereditary risk and facilitates financial and care planning. Use of dementia specialty care was low, particulary for Hispanics and Asians, and associated with more detection of etiological subtype. Dementia-related professional development for non-specialists is urgent given their central role in dementia diagnosis and care.
Keywords: diagnosis, dementia subtype, dementia specialist, disparities, Alzheimer’s disease, unspecified dementia
INTRODUCTION
The burden of Alzheimer’s disease (AD), vascular cognitive impairment and other neurodegenerative dementias is high and rapidly growing.1–4 Dementia affects approximately 7 million Americans and is projected to reach close to 12 million over the next 20 years, driven by population aging and increased life expectancy.5,6 While no current treatment can stop or reverse the neurodegenerative process of the most common types of dementias,5,7 outcomes may be improved by identifying the etiologic subtype of dementia followed by appropriate health care and psychosocial services. Early diagnosis and identification of dementia type may identify deficits sooner, provide symptomatic treatment, avoid medications that may worsen symptoms, inform disease progression over time, encourage advance care planning, and assist in developing and evaluating new drugs and gaining access to effective treatments when they become available. 8–12,9,11,13 Treatment with existing drugs may reduce cognitive symptoms and help maintain daily functioning in certain patients, improve quality of life, delay institutionalization, and reduce overall individual and societal costs.4,5,14–21 Timely diagnosis allows patients or their caregivers to communicate medical, legal, financial, living, and end-of-life desires, and access medical and other support services.
General practioners and other non-dementia specialists play an important role in screening because often they are the first point of contact yet, according to a recent Alzheimer’s association survey, only half of seniors are being assessed despite the fact that screenings are now reimbursable services.22 Several evidence-based guidelines have been developed to advise providers on how to detect cognitive impairment in primary care settings.23–25 AD or dementia diagnosis may be initiated in primary care settings following the clinician’s suspicion of memory deficits, based on patient symptoms and/or caregiver’s concerns, but can be difficult to detect without specific memory, cognitive, and behavioral assessments during follow-up visits.9,26 Assessment, typically made by neuropsychologist or other dementia specialists, may include one or more of the following: evaluation of the patient’s medical history; changes in cognitive function and daily activities; physical and laboratory exams (e.g., blood tests, brain imaging) to detect focal neurological signs, cardiovascular disease and rule out visual or auditory problems; vitamin B12 deficiency or thyroid disturbance; and most importantly, cognitive assessment using a mental state examination.
Patients may also be referred to dementia specialists such as neurologists, psychiatrists, neuropsychiatrists, and geriatricians to confirm diagnosis of dementia or its cause(s), and to manage challenging affective and behavioral changes. Dementia specialists are generally more familiar with subtypes of dementia and hence may be less likely, for example, to misdiagnose Lewy bodies (LBD) as AD (early symptoms are similar), and wrongly prescribe antipsychotic medications to patients with LBD or acetylcholinesterase inhibitors to patients with fronto-temporal dementia.27–30 Although evidence on improved outcomes associated with dementia specialty care is scant, one study found that dementia patients seen by specialists were more likely than those seen by nonspecialists alone to be prescribed drug treatment for dementia symptoms31 and another found lower all-cause medical costs in the first year after diagnosis.32 A recent study found a comprehensive dementia care program, that included dementia specialist care, reduced admissions to long-term care facilities, hospital readmissions, emergency department visits and total Medicare costs.33
Despite the importance of identifying dementia and its subtype, and the potentially critical role of dementia specialists in diagnosis and care, there are no population based studies that describe the patterns of diagnosis and contact with specialized care for the large and growing population living with dementia in the U.S. Examining these relationships between dementia diagnosis, care and outcomes may shed light on how to improve population level health, and the critical first step is to improve our understanding of the scope of current practice in the US population. We do so by leveraging longitudinal data from a large sample of Medicare beneficiaries. We quantify the types of physicians that diagnosis dementia, what dementia subtype diagnoses are initially provided and how these change over time, the extent to which persons diagnosed with dementia access dementia specialty care, and how this varies by patient characteristics of gender and race/ethnicity. The study’s findings will aid in efforts to improve diagnosis, especially among patients and families not receiving timely post-diagnostic care and/or dementia specialist care. They will inform efforts to better target resources to physicians, and improve the planning and preparation necessary to link patients to appropriate new treatments as they become available.
METHODS
Data and Study Population
Participants are drawn from a random 20% sample of Medicare beneficiaries age 67 or older in 2008 or 2009. The sample is enrolled in fee-for-service (FFS) Medicare for at least two years, and had no dementia diagnosis prior to 2008 or 2009 and race/ethnicity was white, black, Hispanic, or Asian (n4,007,351).34,35 From this, we select a final sample (n226,604) with incident dementia diagnosis in 2008 or 2009 and examine health care claims for up to five years after diagnosis (to 2013 or 2014) or until death. Excluded from the final sample were beneficiaries who left FFS within 5-years of diagnosis (n14,244), or were diagnosed by a physician with an unknown specialty (n22,618). Sample selection is shown in eTable 1.
Dementia diagnoses were determined by the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes: 331.0, 331.11, 331.19, 331.2, 331.7, 290.0, 290.10, 290.11, 290.12, 290.13, 290.20, 290.21, 290.3, 290.40, 290.41, 290.42, 290.43, 294.0, 294.10, 294.11, 294.20, 294.21, 294.8, and 797.
Measures and Outcomes
Main outcomes were percent of population with incident diagnosed dementia; distribution of specialty of diagnosing physician; percent with a post-diagnostic visit with a dementia specialist by one and five years after diagnosis; distribution of dementia sub-type diagnosis and changes in diagnosis over time and by physician specialty.
Dementia Incidence.
We calculated the annual incidence rates of dementia diagnosis as the ratio of incident cases to the at-risk population in 2008 or at risk in 2009, separately by gender and race/ethnicity.
Distribution of Physician Specialty.
We quantified the percent of index diagnoses made by the various specialties of diagnosing physician, as determined by the claim’s provider specialty code and an algorithm linking each provider specialty code to a physician specialty, using the 10-character unique identifiers for health care providers (National Provider Identifier, NPI) on the claim, and the Medicare Provider/Supplier to Healthcare Provider Taxonomy Crosswalk file.36 All providers began using the NPI instead of legacy identifiers in 2007, consistent with the 1996 Health Insurance Portability and Accountability Act (HIPAA, Title II).37,38 Specialties classified as dementia specialties were neurology, psychiatry, neuropsychiatry, geriatrics, and geriatric psychiatry. All others were classified as non-dementia specialties (hereinafter non-specialists).
Post-diagnostic Dementia Health Services.
We calculated the percent of beneficiaries with incident dementia who had a post-diagnostic dementia care visit with a dementia specialist, percent with a non-dementia specialist and percent with no post dementia diagnosis health care visit. We calculated this percent at one-year, two-, three-, four- and five-years post-diagnosis for those who survived and those who died and separately for females, males and whites, blacks, Hispanics, and Asians. A post-diagnostic dementia visit was defined as health care service after initial dementia diagnosis with a dementia indicated as an either a first or additional code on the Part A or B claim.
Distribution of Dementia Subtype Diagnosis.
We calculated the percentage of initial diagnoses that were Alzheimer’s disease (ICD-9-CM code 331.0), unspecified dementia (ICD-9-CM codes 294.0, 294.10, 294.11, 294.8, 331.7,294.20, 294.21) or other non-AD dementia (331.11, 331.19, 331.2, 290.0, 290.10, 290.11, 290.12, 290.13, 290.20, 290.21, 290.3, 290.40, 290.41, 290.42, 290.43, 290.8, 290.9, 294.0, 294.9, 797). Distribution of dementia subtype was quantified separately by whether diagnosing physician was a dementia specialist or non-dementia specialist.
Change in Dementia Subtype Diagnosis over Time.
Among those initially diagnosed with unspecified dementia by a non-dementia specialist, we quantified the percent of beneficiaries who had a subsequent change in dementia subtype to AD or non-AD dementia. We quantified this separately for beneficiaries who had a subsequent health care visit with a dementia specialist over the next five years and those who did not.
This study was approved by the University of Southern California Institutional Review Board. All analyses were conducted using the SAS programming language available on the National Bureau of Economic Research servers.39,40 The study was supported by the National Institute on Aging of the National Institutes of Health, P30AG043073, USC Resource Center for Minority Aging Research (USC-RCMAR), and R01AG055401.
RESULTS
Characteristics of sample
Among beneficiaries without a dementia diagnosis prior to 2008 (or 2009), the annual incidence of diagnosed dementia was 3.73% [95CI (3.71-3.74)] (Table 1). Annual incidence of diagnosed dementia was higher for females [4.10%; 95CI (4.08-4.12)] than males [3.23%; 95CI (3.21-3.25)] and higher for blacks [4.55%; 95CI (4.49-4.61)] and Hispanics [3.77%; 95CI (3.70-3.84)] than whites [3.68%; 95CI (3.66-3.69)] and Asians [3.19%; 95CI (3.10-3.28)] (eTable 2). Mean age of beneficiaries with a dementia diagnosis was 82.91 years. Those diagnosed by a non-dementia specialist were older (83.13 years) and less likely to be male (36.77%) than those diagnosed by a dementia specialist (81.71 years; 39.00%, respectively).
Table 1.
Characteristics of the Medicare Beneficiaries with Initial Dementia Diagnosis in 2008 or 2009
| Diagnosing Physician | |||
|---|---|---|---|
| All | Non-Dementia Specialist | Dementia Specialist | |
| Total | 226,604 | 191,684 | 34,920 |
| Annual incidence of dementia diagnosis in 08 or 09(%) | 3.73 | ||
| Age Mean (sd) | 82.91 (7.24) | 83.13 (7.23) | 81.71 (7.22) |
| Sex | |||
| Male(%) | 84,105 (37.12) | 70,485 (36.77) | 13,620 (39.00) |
| Female(%) | 142,499 (62.88) | 121,199 (63.23) | 21,300 (61.00) |
| Race | |||
| White(%) | 196,180 (86.57) | 166,095 (86.65) | 30,085 (86.15) |
| Black(%) | 17,261 (7.62) | 14,504 (7.57) | 2,757 (7.90) |
| Hispanic(%) | 9,540 (4.21) | 8,031 (4.19) | 1,509 (4.32) |
| Asian(%) | 3,623 (1.60) | 3,054 (1.59) | 569 (1.63) |
| Physician Specialty | |||
| Neurologist(%) | 15,367 (6.78) | NA | 15,367 (44.01) |
| Psychiatrist(%) | 9,629 (4.25) | NA | 9,629 (27.57) |
| Geriatric Psychiatrist(%) | 4,588 (2.02) | NA | 4,588 (13.14) |
| Geriatrician(%) | 2,986 (1.32) | NA | 2,986 (8.55) |
| Neuropsychiatrist(%) | 2,350 (1.04) | NA | 2,350 (6.73) |
| TOTAL (dementia specialist) | 34,920(15.41) | ||
| Internal Medicine(%) | 75,292 (33.23) | 75,292 (39.28) | NA |
| Family Practice(%) | 48,215 (21.28) | 48,215 (25.15) | NA |
| Emergency Medicine(%) | 12,171 (5.37) | 12,171 (6.35) | NA |
| Diagnostic Radiology(%) | 7,768 (3.43) | 7,768 (4.05) | NA |
| Psychologist, Clinical(%) | 5,608 (2.47) | 5,608 (2.93) | NA |
| General Surgery(%) | 4,621 (2.04) | 4,621 (2.41) | NA |
| Nurse Practitioner(%) | 4,248 (1.87) | 4,248 (2.22) | NA |
| Clinical Laboratory(%) | 3,688 (1.63) | 3,688 (1.92) | NA |
| Ambulance Service Provider(%) | 2,658 (1.17) | 2,658 (1.39) | NA |
| General Practice(%) | 2,519 (1.11) | 2,519 (1.31) | NA |
| Other (%) | 24,896 (10.99) | 24,896 (12.99) | NA |
| TOTAL (non-dementia specialist) | 116,392 (84.59) | ||
Sample is 20% random sample of Medicare beneficiaries in fee for service from 2008/09 to 2014. Dementia specialists are physicians with the following specialties: neurologist, psychiatrist, neuropsychiatrist, geriatrician, or geriatric psychiatrist. Incidence is calculated as 263,466 (134,201+129,265 in 2008 and 2009 respectively) diagnosed out of 7,067,421 person-years at-risk in 2008/2009.
Distribution of Physician Specialty
Among diagnosed beneficiaries, 84.6% were initially diagnosed by a non-dementia specialist physician (Table 1). Of those diagnosed by non-specialists, 64.4% were by internal medicine/family practice physicians. Among those diagnosed by a dementia specialist, 47.4% were psychiatrists/geriatric psychiatrists/neuropsychiatrists, 44.0% neurologists, 8.6% geriatricians.
Post-diagnostic Dementia Health Services
Figure 1 (eTable 3 with confidence intervals) shows the distribution of follow-up visit, if any, by physician type and mortality across time. Within one year of a dementia diagnosis, 22.31% had a specialist visit. This includes the 19.83% who survived and 2.48% who died. An additional 44.17% had a non-specialist visit within one year of diagnosis including those who survived (37.57%) and those who died (6.60%). Percent with a specialist doctor visit increased over time to 36.15% (within five-years), while the percent with non-specialist visit remained unchanged over time. One-year post-diagnosis, 33.52% had no subsequent health care visit with dementia coded as the primary purpose and declining to 19.86% over 5-years’ time.
Figure 1.
Distribution of health care follow-up visit for Medicare beneficiaries with a dementia diagnosis by physician specialty and mortality over time
Sample is 226,604 Medicare beneficiaries with incident dementia diagnosis in 2008 or 2009.
Figure 2 (eTables 4a, b with confidence intervals) shows the distribution of post-diagnosis dementia health care visits with specialists, non-specialists or no follow-up at one-year and five-years and by race and sex. Hispanics (20.77%, 95CI (19.95-21.58)) and Asians (18.91%, 95CI (17.63-20.18)) were less likely than whites (22.40%, 95CI (22.21-22.58)) and blacks (22.94%, 95CI (22.31-23.56)) to have a post-diagnosis dementia health care visit with a dementia specialist and the differences were statistically significant. Hispanics and Asians more likely than whites and blacks to have no follow up: Hispanics (36.99%, 95CI (36.02-37.96)), Asians 40.22%, 95CI (38.62-41.81), whites (33.28%, 95CI (33.07-33.48)), blacks 32.95%, 95CI (32.25-33.65). The one-year differences and 5-years post-diagnosis differences between Hispanics and Asians compared to whites and blacks were statistically significant. There was no statistically significant difference between females and males in likelihood of post-diagnosis health care visit with a specialist. Males (35.25%, 95CI (34.92-35.57)) were more likely than females (32.50%, 95CI (32.26-32.74) to have no post-diagnosis health care visit for dementia within the first year and also five-years post-diagnosis and the differences were statistically significant.
Figure 2.
Distribution of health care follow-up visit for Medicare beneficiaries with a dementia diagnosis by physician specialty, sex and by race at one-year and five-years post diagnosis
Sample is 226,604 beneficiaries with incident dementia diagnosis in 2008 or 2009. Includes both beneficiaries who survive and those who die.
Distribution of Subtype Diagnosis
Among beneficiaries who do not have a dementia specialist visit within one year of diagnosis, 33.23%, (95CI (33.02-33.44)) had a diagnosis of ‘unspecified dementia,’ 37.38% (95CI (37.16-37.59)) had a non-AD diagnosis and 29.39% (95CI (29.19-29.60)) had an AD diagnosis (Figure 3, eTable 5 with confidence intervals). Among beneficiaries who have a dementia specialist health care visit within one year of diagnosis, percent with an unspecified dementia was lower (21.58%; 95CI (21.15-22.02)) and diagnoses of AD were higher (41.75%, 95CI (41.23-42.26)) compared to those without specialist care.
Figure 3:
Percent of Medicare beneficiaries with Alzheimer’s disease diagnosis, non-Alzheimer’s disease diagnosis and unspecified dementia diagnosis one to five-years after diagnosis, by physician specialty
Sample is 226,604 (34,920 + 191,684 diagnosed by specialist, non-specialist respectively) beneficiaries with incident dementia diagnosis in 2008 or 2009. Includes both beneficiaries who survive and those who die.
Five-years post initial diagnosis, percent with unspecified dementia diagnosis had declined to 23.46% (95CI (23.27-23.65)) among those who did not have a dementia specialist visit and to 16.24% (95CI (15.85-16.62)) among those who did. Diagnoses of AD increased by five years of initial diagnosis: 40.73% (95CI (40.51-40.95)) of diagnoses among those with no dementia specialist visit and 49.58% (95CI (49.06-50.11)) of diagnoses among those with dementia specialist care.
Diagnosis Change Over Time
Figure 4 shows the percent of beneficiaries with diagnoses of unspecified dementia, non-AD, and AD diagnoses after an initial diagnosis of unspecified dementia by a non-dementia specialist. Results are shown separately for those who, subsequent to initial diagnosis, received dementia specialty care and those who did not within five years. Table 2 shows all changes in diagnosis subtype after initial diagnosis by non-specialists. Among beneficiaries with an initial unspecified dementia diagnosis and subsequent dementia specialty care, 24.08% (95CI (23.59-24.57)) remain with an unspecified dementia diagnosis while 46.13% (95CI (45.56-46.70)) have a change to AD. The percent that remain with an unspecified dementia diagnosis is higher, 38.32% (95CI (37.88-38.75)), and the percent that are identified with an AD diagnosis is lower (33.65% (95CI (33.23-34.08)) among beneficiaries without dementia specialist care compared to persons with a dementia specialist health care visit.
Figure 4.
Follow-up diagnosis of dementia subtype after initial diagnosis of unspecified dementia by non-specialist, by physician specialty at post-diagnostic health care visit
Sample is 77,502 beneficiaries with incident unspecified dementia diagnosis in 2008 or 2009, initially diagnosed by a non-dementia specialist physician who had a follow-up health care visit for dementia.
Table 2.
Percent of beneficiaries with diagnoses of unspecified, non-Alzheimer’s dementia, Alzheimer’s disease within 5-years of initial diagnosis by a non-dementia specialist
| Initial Dx by Non-Specialist – Follow-Up Specialist Visit (n=58,403) | Initial DX by Non-Specialist – No Subsequent Specialist Visit (n=93,598) | |||||||
|---|---|---|---|---|---|---|---|---|
| Diagnosis within 5-years | Diagnosis within 5-years | |||||||
| Initial Dx | Row Totals (N) | Unspecified | Non-AD | AD | Row Totals (N) | Unspecified | Non-AD | AD |
| Unspecified | 29,526 | 24.08 (23.59-24.57) | 29.79 (29.27-30.31) | 46.13 (45.56-46.70) | 47,976 | 38.32 (37.88-38.75) | 28.03 (27.63-28.43) | 33.65 (33.23-34.08) |
| Non-AD | 17,879 | 19.00 (18.42-19.58) | 35.79 (35.09-36.49) | 45.21 (44.48-45.94) | 30,336 | 13.04 (12.66-13.42) | 55.95 (55.39-56.51) | 31.01 (30.49-31.53) |
| AD | 10,998 | 15.90 (15.22-16.59) | 21.92 (21.15-22.70) | 62.17 (61.27-63.08) | 15,286 | 9.77 (9.30-10.24) | 10.87 (10.38-11.37) | 79.35 (78.71-80.00) |
Sample is 152,001 beneficiaries with incident dementia diagnosis in 2008 or 2009, initially diagnosed by a non-dementia specialist physician and had a follow-up health care visit for dementia.
DISCUSSION
In this study, we leveraged the strengths of longitudinal Medicare claims data to investigate dementia diagnoses and dementia specialist use in the US population. We identified approximately four million Medicare beneficiaries age 67 and older with no prior dementia diagnosis, and analyzed their health care claims for up to five years following an initial dementia diagnosis in either 2008 or 2009. This study quantified by whom dementia was diagnosed and how diagnoses changed over time in a diverse populations of older Americans yielding several new insights. First, non-specialists overwhelmingly provided the initial dementia diagnosis: 85% of persons first diagnosed with dementia were diagnosed by a non-dementia specialist physician. Second, follow-up care by dementia specialists was not common within the first year after receiving a diagnosis (22%), rising to just over one-third (36.2%) within five years of diagnosis with Hispanics and Asians less likely than whites and blacks to have a health care visit with a dementia specialist. Third, diagnosis of dementia subtype as ‘unspecified dementia’ was common: even after five-years about one quarter (23.5%) of beneficiaries diagnosed by a non-specialist had a diagnosis of unspecified dementia but this rate was lower among beneficiaries with dementia specialist health care (16%). Fourth, over 5 years less than half of all persons with dementia received an AD diagnosis, higher among those who had a dementia specialist health care visit (49.6%) than non-specialist (41.0%).
The estimated annual diagnosed dementia incidence of 3.7% is a level within recent estimated ranges and does not suggest significant under-diagnosis of dementia.41–43 Although studies reported AD pathology in 60-80 percent of dementia cases,3 estimates of 50% are in line with rates of autopsy-diagnosed AD in community-based samples44 Pathological diagnosis of cerebral infarcts is higher in community compared to clinic based autopsy samples.44 About 41% (40.7%) of persons with a dementia diagnosis by a non-dementia specialist in this study was identified with Alzheimer’s disease and may indicate under-identification of Alzheimer’s disease.
Low rates of dementia specialist care are consistent with recent findings about regional US neurologist shortages.45 We examined the supply of neurologists per 100,000 population by beneficiaries’ zip code using the Area Health Resources File from the US Department of Health and Human Services. We found 3.9 neurologists per 100k population in residential zip codes of beneficiaries who never saw a dementia specialist in the first year after diagnosis compared to 5.0 per 100k population among beneficiaries who had a specialist visit. Demand factors may also drive dementia specialist health care use. In addition, low rates of disclosure of a dementia diagnosis by healthcare providers to their patients have been previously reported and may contribute to low dementia specialist care use.46
Symptoms of AD include memory and cognitive impairment, but also may include depression, and behavioral disturbances and the variation in their sequence and timing may impede identification of AD.47 Non-dementia specialists may be less confident about making distinctions between neurodegenerative types of dementia (e.g. AD, DLB, FTD) or mixed dementia (AD plus vascular dementia). Current dementia evaluation guidelines for primary care physicians do not include biomarkers for β-amyloid and p-tau, which were incorporated into research diagnosis of mild-cognitive impairment and dementia due to AD in 2011.48 Non-dementia specialists may be less confident about identifying memory impairment or atrophy associated specifically with neurofibrillary degeneration of the hippocampus. Dementia specialists are trained to identify AD and can therefore facilitate participation in clinical trials aimed at preventing or slowing the progression of AD. Accurate identification will be increasingly important over time as new treatments become available that target the pathology of AD. More generally, with differences in management, disease course and outcomes across various dementia types, identification of dementia type aids in a family’s financial and care planning and improves knowledge of inheritable dementia risk. There may be benefits gained by investments in resources to train the primary care workforce in dementia, such as those being made by the Health Resources and Services Administration, or investments in health care delivery models that emphasize coordinated dementia care or the integration of behavioral health in primary care.
There are limitations to our study. The estimated population not receiving dementia care will be underestimated by the number who have dementia but are not diagnosed. We found that 34% of persons with a dementia diagnosis had no subsequent health care visit for dementia within the first year following dementia diagnosis declining over time to 20% five-years following diagnosis. The first-listed diagnosis on a health care claim may be indicative of a symptom when a diagnosis has not been confirmed, thus beneficiaries with no follow up health care visit for dementia will include those with an initial dementia diagnosis that were later determined not to have dementia, as well as those who did not receive follow-up care for dementia. In robustness analyses we examined the diagnoses codes for the 45,009 beneficiaries with no follow-up within five-years (or death) and while there are more than 5,000 diagnosis codes, among the 10 most common diagnoses were several conditions with symptoms that may mimic dementia including anemia, urinary tract infection, and hypertension.
We found Hispanics and Asians were less likely than whites and blacks to have post-diagnosis dementia specialist care. More study is needed to identify factors driving these differences such as differences by race/ethnicity in severity at diagnosis, complexity of case, in disease progression rates and/or differences in care seeking or access. We examined diagnosis change from initial diagnosis to diagnoses at subsequent health care visits but do not know if the physician was the same person. However, we do find that among those with dementia specialist visits, 86% have both visits with same type of specialist taxonomy. The lower rates of AD diagnoses among beneficiaries without dementia specialist care compared to those with dementia specialist care will reflect differences in physicians’ training in AD detection but also differences in the population of beneficiaries utilizing specialists or non-specialists. This study cannot differentiate between these factors.
Whether increasing use of dementia specialist health care should be a policy goal is uncertain. Use of specialist services may increase health care costs and may or may not lead to better outcomes and thus may not be a cost-effective approach to dementia care.49,12 Non-specialists and specialists may be complementary in dementia diagnosis and care with the former, as often the first point of contact, key to evaluating and excluding treatable illness or reversible causes of dementia symptoms and the latter, key to making finer distinction across neurodegenerative dementia subtype.12 Quantifying by whom dementia was diagnosed, etiologic subtype, and changes in dementia diagnosis over time in the US population aids in efforts to improve diagnosis, to identify characteristics of patients and their families not receiving timely post-diagnostic care and/or dementia specialist care. This study also informs methodology. Given the frequency of diagnosis changes, this study demonstrates that for researchers using claims data in studies of dementia, it is critical to conduct longitudinal study of persons’ health care claims to identify dementia and subtype.
CONCLUSION
Less than half of persons with a dementia diagnosis were identified with AD which may indicate under-identification of AD in the population. ‘Unspecified dementia’ diagnosis was common. With differences in management, disease course and outcomes, identification of dementia subtype is important for a family’s financial and care planning and procurement of information about their hereditary dementia risk. Dementia specialty care was associated with less ‘unspecified dementia’ diagnoses and more identification of dementia subtype including AD, yet use of dementia specialists was low. The centrality of non-dementia specialists in diagnosing and treating dementia adds importance to their education and training for these health care services. It is unknown whether low rate of dementia specialty care lead to worse outcomes. A critical next step is to investigate the links between these patterns of diagnosis, health care use and outcomes in the US populations.
Supplementary Material
eTable 1. Sample Selection
eTable 2. Dementia incidence in 2008 and 2009 by sex and race
eTable 3. Distribution of Medicare beneficiaries with dementia diagnosis over time by survival and follow-up with dementia specialist (with 95% CI)
eTable 4a. Distribution of Medicare beneficiaries with dementia diagnosis and follow-up with dementia specialist by sex and race (with 95% CI)
eTable 4b. Distribution of Medicare beneficiaries with dementia diagnosis and follow-up with dementia specialist by sex and race (with survival or not)
eTable 5. Percent of Medicare beneficiaries with Alzheimer’s Disease diagnosis, non-Alzheimer’s Disease diagnosis, and unspecified dementia diagnosis years 1-5 after diagnosis, by physician specialty
eTable 6. Percent of beneficiaries with changes in initial diagnosis by subtype at initial diagnosis (unspecified non-AD, or AD) and subsequent diagnosis and by whether initial and subsequent was made by a specialist or not.
Research in Context.
Systematic review: Despite the importance of identifying dementia and its subtype, and the potentially critical role of dementia specialists in diagnosis and care, there are no population based studies that describe the patterns of diagnosis and contact with specialized care for the large and growing population living with dementia in the U.S.
Interpretation: Quantifying by whom dementia was diagnosed, etiologic subtype, and changes in dementia diagnosis over time in the US population aids in efforts to improve diagnosis, to identify characteristics of patients and their families not receiving timely post-diagnostic care and/or dementia specialist care.
Future directions: It is unknown whether low rate of dementia specialty care lead to worse outcomes. A critical next step is to investigate the links between these patterns of diagnosis, health care use, and outcomes in the US populations.
ACKNOWLEDGEMENTS
Research reported in this publication was supported by National Institutes of Health awards R01AG055401, P30AG043073. Additional support was received from NIH/NHLBI grants R01HL126804 and R01HL130462, grant 1R34AG049652 from the University of Southern California Zumberge Research Fund, and the Schaeffer-Amgen Fellowship Program. We thank Patricia St. Clair, Bryan Tysinger for programming assistance on earlier versions. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Footnotes
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CONFLICT OF INTEREST DISCLOSURES
None to declare.
Contributor Information
Emmanuel Fulgence Drabo, Department of Health Policy and Management, Bloomberg School of Public Health, Johns Hopkins, Baltimore, MD.
Douglas Barthold, Comparative Health Outcomes, Policy, and Economics (CHOICE) Institute, Department of Pharmacy, University of Washington, Seattle, WA.
Geoffrey Joyce, Pharmaceutical Economics and Policy, School of Pharmacy Leonard D. Schaeffer Center for Health Policy and Economics University of Southern California, Los Angeles, CA.
Patricia Ferido, Leonard D. Schaeffer Center for Health Policy & Economics University of Southern California, Los Angeles, CA.
Helena Chang Chui, Keck School of Medicine, University of Southern California, Los Angeles, CA.
Julie Zissimopoulos, USC Price School of Public Policy, Leonard D. Schaeffer Center for Health Policy and Economics, University of Southern California, Los Angeles, CA 635 Downey Way, VPD Suite 210, Los Angeles, CA 90089-3333, USA.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
eTable 1. Sample Selection
eTable 2. Dementia incidence in 2008 and 2009 by sex and race
eTable 3. Distribution of Medicare beneficiaries with dementia diagnosis over time by survival and follow-up with dementia specialist (with 95% CI)
eTable 4a. Distribution of Medicare beneficiaries with dementia diagnosis and follow-up with dementia specialist by sex and race (with 95% CI)
eTable 4b. Distribution of Medicare beneficiaries with dementia diagnosis and follow-up with dementia specialist by sex and race (with survival or not)
eTable 5. Percent of Medicare beneficiaries with Alzheimer’s Disease diagnosis, non-Alzheimer’s Disease diagnosis, and unspecified dementia diagnosis years 1-5 after diagnosis, by physician specialty
eTable 6. Percent of beneficiaries with changes in initial diagnosis by subtype at initial diagnosis (unspecified non-AD, or AD) and subsequent diagnosis and by whether initial and subsequent was made by a specialist or not.