The 2007 NHHCS used a stratified, two-stage probability sample design. In the first stage, providers were stratified by type of agency (home health, hospice, or mixed) and geographic location, and randomly selected within strata. In the second stage, up to ten current home healthcare patients or hospice discharges were randomly selected within each agency. Current home healthcare patients were patients who were on the rolls of the agency as of midnight of the day immediately before the agency interview. Data were collected through in-person interviews with agency directors or their designated staffs and medical records; the patient health module had an overall unweighted response rate of 66% (weighted: 55%) [5
We focused on current home healthcare patients 65 years or older at the time of the interview and had Medicare fee-for-service (under the episode-based prospective payment system) as the primary payment source (accounting for 93% of all elderly Medicare patients in home healthcare). This represents a population of relatively homogeneous clinical need (i.e., patients receiving post-acute care for medical and surgical reasons) and payment and financial incentives for the agencies.
For each patient selected, current home healthcare diagnoses (one primary and up to fifteen secondary) were reported. While the NHHCS did not provide explicit information on the source of these diagnoses, they most commonly come from diagnoses listed by the referring physician at the patient's admission into home healthcare, and can be modified based on assessment by the home health agency/nurse. Among our patient sample, 24% had a current primary diagnosis that was different from the primary diagnosis at admission, indicating some, albeit limited, update and revision by agencies/nurses when documenting current diagnoses. Current depression diagnosis either by the referring physician or the agency (“diagnosed depression” hereafter) was defined as the occurrence of at least one of the following International Classification of Disease, 9th Revision (ICD-9-CM) codes in any of the current primary and secondary diagnosis fields: 296.2× (major depression single episode), 296.3× (major depression recurrent episode), 311× (depression not elsewhere classified) and 300.4× (dysthymia, anxiety depression, or prolonged depressive reaction).
We examined key demographics (age, gender, race/ethnicity, marital status/living arrangements, and presence of caregiver other than home health agency), function (number of activities of daily living the patient needed help with), and healthcare utilization (whether institutionalized before admission, skilled nursing and home health aide visits / any therapy visits / any medical social service provided by the agency in the past 60 days or since admission, number of current medications, and the use of antidepressants).
Descriptive statistics were weighted to reflect probabilities of sample selection, and to adjust for non-response [5
]. Pearson and Wald tests corrected for the complex sampling design were used to test differences in categorical and continuous characteristics, respectively, between the diagnosed and non-diagnosed groups.
This research was exempted from Institutional Review Board review at the Weill Cornell Medical College.