The overall goal of this study is to use the National Health and Aging Trends Study (NHATS) data to gain an understanding of how multiple chronic conditions impact the health outcomes of older adults with back pain.

This study seeks to gain knowledge regarding how multiple chronic conditions affect the health and function of older adults with back pain. The investigators will perform a retrospective cohort study using secondary analysis of the National Health and Aging Trends Study (NHATS) data. NHATS collected longitudinal data on Medicare beneficiaries over 65 for six years, from 2011-2017. This set of data is comprehensive and includes self-reported survey data as well as physical performance data, both of which this study will utilize.

The specific aims include to 1) Estimate the longitudinal associations of the number of chronic conditions, using a standard classification scheme, with long-term physical performance, function, and recurrent falls, 2) Identify specific combinations of chronic conditions that are most strongly associated with long-term physical performance, function, and recurrent falls, 3) Determine the association of the number and type of chronic conditions with rehabilitation service use. The investigator will test a corresponding hypothesis for each aim: 1) Medicare beneficiaries reporting back pain with a greater number of chronic conditions will have worse physical performance, lower functional status, and be more likely to experience recurrent falls over 6 years, 2) Medicare beneficiaries reporting back pain with common and potentially modifiable conditions of anxiety, depression, and arthritis (individually and combined as dyads or a triad) will have worse physical performance, lower functional capacity, and be more likely to experience recurrent falls over 6 years, 3) Medicare beneficiaries with back pain and multiple chronic conditions will report lower use of rehabilitation services in the past one year compared to those with back pain alone or one additional chronic condition.

Inclusion Criteria:

• This study will include community-dwelling participants in the NHATS study who indicated that in the last month they had been bothered by pain in the last month and indicated that the site of pain was the lower back.

Exclusion Criteria:

• This study will exclude participants who are non-ambulatory (requires wheelchair or scooter).

NHATS is a cohort of older adults and is representative of Medicare beneficiaries age 65 and older. It is a "unique national resource for the scientific study of functioning in later life." The sample is drawn from the Medicare enrollment files, and the survey oversamples Blacks and those at older ages. Initial NHATS data collection began in 2011 (Round 1) with in-person interviews.