Editor's Note: Commentary based on Lee H, Shi SM, Kim DH. Home time as a patient-centered outcome in administrative claims data. J Am Geriatr Soc 2019;67:347-51.

Rationale for Study: Cardiovascular clinical trials have predominantly focused on "hard" outcomes such as all-cause mortality, myocardial infarction, stroke, etc., but there has been recent increased interest in and reporting of patient-centered outcomes. However, there remains a gap in the ability of observational studies, using administrative claims data, to obtain patient-centered outcomes. Home time, i.e., the number of days spent at home during a specified time interval, is usually available in administrative claims data and may provide insight into patient-centered outcomes, including quality of life, in observational studies.

Funding: Federal funding via NIA K-Grant (K08AG051187), the American Federation for Aging Research, the John Hartford Foundation, and Atlantic Philanthropies

Methods

Study Design: Observational study

Cohort: Nationally representative sample of Medicare beneficiaries who took part in the Medicare Current Beneficiary Survey (MCBS) between 2010-2011. Participants had 12 rounds of survey over 4 years, and survey data were linked to Medicare claims data.

Exposure: Home time = Total number of follow-up days in the 2011 claims data. Total number days spent in hospitals and skilled nursing facilities (including rehabilitation)
(0 days = no days in 2011 at home; 365 = all days in 2011 at home).

Patient-Centered Outcome(s): (Yes/No)
Poor self-rated health
Mobility impairment
Depression
Limited social activity
Difficulty in self-care

Total Functional Limitation Score (continuous variable): Includes above outcomes and telephone use, light house work, heavy house work, meal preparation, shopping, managing money, stooping/crouching/kneeling, lifting 10 pounds, extending arms above shoulder, writing, and walking 1/4 mile.

Statistical Analysis: Standard descriptive statistics.
Investigators created a measure called Minimum Clinically Important Difference (MCID) in home time. This was developed in order to gain understanding of how the number of days at home could be associated with functional changes. They defined MCID as the average difference in home time between those classified "otherwise healthy" and those with functional limitations.

Results:

1. Mean home time was 355.8 days (SD 42.1) with distribution left skewed with a large majority (84.1%) having 365 days of home time. Older participants, those with poor self-rated health, mobility impairment, depression, limited social activity, difficulty in self-care and functional limitations at baseline had shorter home time or died within the year.
2. An inverse relationship was demonstrated between home time and patient-centered outcomes. More home time correlated with less poor self-rated health, less mobility impairment, less depression, less limited social activity and less difficulty in self-care.
3. Minimum clinically important difference of home time between those who experienced worsening functional limitations or death (345.3 ± 62.0 days) and those who did not (363.9 ± 6.3 days, p < 0.001) was 18.6 days (i.e., in comparing two groups, a difference in home time of 18.6 days or greater implies increased risk for worsening functional limitation or death within the year)

Limitations of study:

1. A lack of further details of the actual quality of life at home
2. MCID is hypothesis generating concept that will need to be further studied.

Take Home Message: The cardiovascular clinical team should acknowledge home time as an important patient-centered outcome, particularly in older adults with multimorbidity and concomitant cardiovascular diseases.

Keywords: Geriatrics, Skilled Nursing Facilities, Research Personnel, Self Care, Follow-Up Studies, Quality of Life, Myocardial Infarction, Medicare, Stroke, Depression

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