Reasons why osteoarthritis predicts mortality:  Path analysis within a Cox proportional hazards model

Ross Wilkie; Simran Singh Parmar; Milica Blagojevic-Bucknall; Diane Smith; Martin J. Thomas; Bethany Jane Seale; Gemma Mansell; George Peat

doi:10.1136/rmdopen-2019-001048

Reasons why osteoarthritis predicts mortality: Path analysis within a Cox proportional hazards model

Ross Wilkie^*
, Simran Singh Parmar
, Milica Blagojevic-Bucknall
, Diane Smith
, Martin J. Thomas
, Bethany Jane Seale
, Gemma Mansell
, George Peat

^*Corresponding author for this work

Keele University
Keele University, School of Medicine
Manchester Metropolitan University

Research output: Contribution to journal › Article › peer-review

31 Citations (SciVal)

49 Downloads (Pure)

Abstract

Objectives To identify potentially modifiable factors that mediate the association between symptomatic osteoarthritis (OA) and premature mortality. Methods A population-based prospective cohort study; primary care medical record data were linked to self-report information collected by questionnaire in adults aged 50 years and over (n=10 415). OA was defined by primary care consultation and moderate-to-severe pain interference in daily life. A Cox proportional hazards analysis determined the total effect (TE) of OA on mortality after adjustment for potential confounders. Within the Cox model, path analysis was used to decompose the TE to assess the indirect and direct effects for selected potential mediators (anxiety, depression, unrefreshed sleep and walking frequency). Results are expressed as HRs with 95% CIs derived from bootstrap resampling. Results OA was significantly associated with mortality (TE-adjusted HR 1.14; 95% CI 1.00 to 1.29). The indirect effects for walking frequency were 1.05 (95% CI 1.04 to 1.06), depression 1.02 (95% CI 1.02 to 1.03), anxiety 1.01 (95% CI 1.00 to 1.02) and unrefreshed sleep 1.01 (95% CI 1.00 to 1.01). Conclusions The analysis indicates that encouraging people to walk and get out and about' in addition to targeting OA could be protective against excessive mortality. The findings also suggest that depression, anxiety and unrefreshed sleep have a role in premature mortality for people with OA; however, this has low clinical significance.

Original language	English
Article number	e001048
Journal	RMD Open
Volume	5
Issue number	2
DOIs	https://doi.org/10.1136/rmdopen-2019-001048
Publication status	Published - 1 Nov 2019

Bibliographical note

© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

Funding

Funding this study is supported financially by a programme grant awarded by the Medical research council, UK (grant code: g9900220), and by funding secured from the north Staffordshire Primary care r&D consortium for nHS service support costs. MJt is supported by an integrated clinical academic Programme clinical lectureship from the national institute for Health research (niHr) and the Health education england (Hee) (ica-cl-2016-02-014).

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Keywords

epidemiology
health services research
osteoarthritis
outcomes research

Access to Document

10.1136/rmdopen-2019-001048Licence: CC BY-NC 3.0

Reasons why osteoarthritis predicts mortality
© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
Final published version, 772 KBLicence: CC BY-NC 3.0

Cite this

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title = "Reasons why osteoarthritis predicts mortality: Path analysis within a Cox proportional hazards model",

abstract = "Objectives To identify potentially modifiable factors that mediate the association between symptomatic osteoarthritis (OA) and premature mortality. Methods A population-based prospective cohort study; primary care medical record data were linked to self-report information collected by questionnaire in adults aged 50 years and over (n=10 415). OA was defined by primary care consultation and moderate-to-severe pain interference in daily life. A Cox proportional hazards analysis determined the total effect (TE) of OA on mortality after adjustment for potential confounders. Within the Cox model, path analysis was used to decompose the TE to assess the indirect and direct effects for selected potential mediators (anxiety, depression, unrefreshed sleep and walking frequency). Results are expressed as HRs with 95\% CIs derived from bootstrap resampling. Results OA was significantly associated with mortality (TE-adjusted HR 1.14; 95\% CI 1.00 to 1.29). The indirect effects for walking frequency were 1.05 (95\% CI 1.04 to 1.06), depression 1.02 (95\% CI 1.02 to 1.03), anxiety 1.01 (95\% CI 1.00 to 1.02) and unrefreshed sleep 1.01 (95\% CI 1.00 to 1.01). Conclusions The analysis indicates that encouraging people to walk and get out and about' in addition to targeting OA could be protective against excessive mortality. The findings also suggest that depression, anxiety and unrefreshed sleep have a role in premature mortality for people with OA; however, this has low clinical significance.",

keywords = "epidemiology, health services research, osteoarthritis, outcomes research",

author = "Ross Wilkie and Parmar, \{Simran Singh\} and Milica Blagojevic-Bucknall and Diane Smith and Thomas, \{Martin J.\} and Seale, \{Bethany Jane\} and Gemma Mansell and George Peat",

note = "{\textcopyright} Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/. ",

year = "2019",

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doi = "10.1136/rmdopen-2019-001048",

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T2 - Path analysis within a Cox proportional hazards model

AU - Wilkie, Ross

AU - Parmar, Simran Singh

AU - Blagojevic-Bucknall, Milica

AU - Smith, Diane

AU - Thomas, Martin J.

AU - Seale, Bethany Jane

AU - Mansell, Gemma

AU - Peat, George

N1 - © Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

PY - 2019/11/1

Y1 - 2019/11/1

N2 - Objectives To identify potentially modifiable factors that mediate the association between symptomatic osteoarthritis (OA) and premature mortality. Methods A population-based prospective cohort study; primary care medical record data were linked to self-report information collected by questionnaire in adults aged 50 years and over (n=10 415). OA was defined by primary care consultation and moderate-to-severe pain interference in daily life. A Cox proportional hazards analysis determined the total effect (TE) of OA on mortality after adjustment for potential confounders. Within the Cox model, path analysis was used to decompose the TE to assess the indirect and direct effects for selected potential mediators (anxiety, depression, unrefreshed sleep and walking frequency). Results are expressed as HRs with 95% CIs derived from bootstrap resampling. Results OA was significantly associated with mortality (TE-adjusted HR 1.14; 95% CI 1.00 to 1.29). The indirect effects for walking frequency were 1.05 (95% CI 1.04 to 1.06), depression 1.02 (95% CI 1.02 to 1.03), anxiety 1.01 (95% CI 1.00 to 1.02) and unrefreshed sleep 1.01 (95% CI 1.00 to 1.01). Conclusions The analysis indicates that encouraging people to walk and get out and about' in addition to targeting OA could be protective against excessive mortality. The findings also suggest that depression, anxiety and unrefreshed sleep have a role in premature mortality for people with OA; however, this has low clinical significance.

AB - Objectives To identify potentially modifiable factors that mediate the association between symptomatic osteoarthritis (OA) and premature mortality. Methods A population-based prospective cohort study; primary care medical record data were linked to self-report information collected by questionnaire in adults aged 50 years and over (n=10 415). OA was defined by primary care consultation and moderate-to-severe pain interference in daily life. A Cox proportional hazards analysis determined the total effect (TE) of OA on mortality after adjustment for potential confounders. Within the Cox model, path analysis was used to decompose the TE to assess the indirect and direct effects for selected potential mediators (anxiety, depression, unrefreshed sleep and walking frequency). Results are expressed as HRs with 95% CIs derived from bootstrap resampling. Results OA was significantly associated with mortality (TE-adjusted HR 1.14; 95% CI 1.00 to 1.29). The indirect effects for walking frequency were 1.05 (95% CI 1.04 to 1.06), depression 1.02 (95% CI 1.02 to 1.03), anxiety 1.01 (95% CI 1.00 to 1.02) and unrefreshed sleep 1.01 (95% CI 1.00 to 1.01). Conclusions The analysis indicates that encouraging people to walk and get out and about' in addition to targeting OA could be protective against excessive mortality. The findings also suggest that depression, anxiety and unrefreshed sleep have a role in premature mortality for people with OA; however, this has low clinical significance.

KW - epidemiology

KW - health services research

KW - osteoarthritis

KW - outcomes research

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DO - 10.1136/rmdopen-2019-001048

M3 - Article

AN - SCOPUS:85075046301

SN - 2044-6055

VL - 5

JO - RMD Open

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