The study was approved by the Indiana University Purdue University-Indianapolis Institutional Review Board. All subjects or their caregivers provided written informed consent for participation.
Patients with AD were recruited from two large primary care practices from January 2002 to August 2004. The first practice included seven community-based health centers affiliated with Wishard Health Services, a university-affiliated urban health care system serving medically indigent patients in Indianapolis. This practice serves approximately 5,000 older adults. The second site included three primary care practices at the Roudebush Veterans Affairs Medical Center in Indianapolis. This practice provides primary care to approximately 6,000 veterans age 65 and older.
Patients were recruited through two methods: (1) physician referral following a written prompt that the patient may be eligible due to a medical record diagnosis consistent with a dementing illness; and (2) physician referral following a written prompt from the research team that the patient screened positive on cognitive testing. All patients aged 65 and older who were receiving primary care from one of the two sites were screened for dementia using a six-item screener instrument10
and an abbreviated version of the Community Screening Instrument for Dementia (CSI-D).11
All referred patients completed a formal diagnostic evaluation that included neuropsychological testing, comprehensive physical examination, a structured interview with the caregiver, brain imaging, and reversible work-up for dementia. All results were reviewed by a consensus diagnosis panel including a psychologist, neuropsychologist, geriatrician, and a geriatric psychiatrist. Subjects were eligible if they met criteria for possible or probable AD based on ICD-10 criteria. This diagnostic method is described in more detail elsewhere.12
Exclusion criteria included: residence in a nursing home, unable to understand English, no access to a telephone, or no caregiver willing to consent to participate in the study. The primary care physician could then refer the patient to be enrolled in a randomized trial to test the effectiveness of collaborative care management for older adults with AD compared with augmented usual care. In this study, caregivers were family members or friends who identified themselves as individuals who assisted the subjects with navigating daily life and who were willing to participate in the study.
Following enrollment into the clinical trial and as part of the baseline assessment, the caregivers completed an assessment by telephone and thus were the primary source of the patient’s data. The baseline interview included standardized instruments developed by the Consortium of Alzheimer Disease Center investigators13
and are considered the current gold standard for health outcome measures for patients with AD and their caregivers. These included the Neuropsychiatric Inventory (NPI),14
the Alzheimer’s Disease Cooperative Study-Activities of Daily Living Inventory (ADCS-ADL),15
and Resource Use Inventory (RUI).13,16
The NPI has been adopted by the Alzheimer’s Disease Cooperative Studies (ADCS) Group to obtain information on the presence of psychopathology in ten behavioral areas, including delusions, apathy, hallucinations, disinhibition, agitation, depression, aberrant motor behavior, anxiety, night-time behavior, and euphoria. Possible scores range from 0–120, with high numbers indicating more behavioral problems. The test has excellent reliability and validity.14,17,18
The ADCS-ADL is a 23-item inventory developed by the ADCS Group and is administered to the patient’s caregiver by a trained interviewer. The caregiver is asked to focus on the patient’s performance over the past month. Notably, the caregiver reports on what the patient actually did rather than an assessment of what the patient might be able to do. Thus, the inventory focuses on observed actions. The instrument assesses the traditional basic activities of daily living as well as variations on instrumental activities of daily living and a number of more complex and explicit self-care tasks.15
Patients’ scores range from 0–75, with higher scores indicating greater levels of function. The RUI is a 15-item questionnaire developed by the ADCS Group that is designed to measure the health care utilization and costs incurred by subjects with AD. Three categories of costs and use are assessed, including medical services, discretionary health care costs, and caregiver expenses. It inquires specifically about nursing home stays as well as home health visits, clinic visits, and hospitalizations. Even though studies have proven that the RUI provides data that are reliable and valid,16
in our previous studies we found that older adults have difficulty recalling use over the prior year.19
Thus, we completed the RUI for the previous six months to improve recall.
All patients themselves completed the Telephone Interview for Cognitive Status (TICS), a telephone version of the Mini-Mental State Examination20
that has the same score range from 0 to 30 with the higher number indicating less cognitive impairment.
Using each patient’s list of prescribed medications, we calculated the Chronic Disease Score (CDS) as a measure of medical comorbidity.21
The CDS excludes medications used for treatment of acute problems (such as antibiotics) or common symptoms (such as nasal congestion). Individual medications are assigned to pharmacy classes, which are then mapped to the chronic diseases that class of medication would treat. Each CDS class was assigned a weight by the original developers based on expert judgment. These weights are used to calculate the patient’s total CDS (range 0–24). The CDS has been validated as an indicator of comorbidity, and its scores are correlated with future resource utilization. Higher scores indicate greater chronic disease burden and risk of healthcare resource utilization.
In addition to providing information about the patient’s status, the caregiver provided information about their own demographics, their mood (PHQ-9), and their acute care utilization (RUI). The Patient Health Questionnaire-9 (PHQ-9)22
assesses incidence and severity of each of the nine DSM-IV criteria for depression, including anhedonia, appetite changes, low energy, and difficulty concentrating. Scores can range from 0–27, with higher scores indicating worsening depression. They also completed the RUI as a measure of their own acute healthcare utilization.