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Body mass index is not a clinically meaningful predictor of patient reported outcomes of primary hip replacement surgery: prospective cohort study

Body mass index is not a clinically meaningful predictor of patient reported outcomes of primary hip replacement surgery: prospective cohort study
Body mass index is not a clinically meaningful predictor of patient reported outcomes of primary hip replacement surgery: prospective cohort study
Objectives

To describe whether body mass index (BMI) is a clinically meaningful predictor of patient reported outcomes following primary total hip replacement (THR) surgery.

Design

Combined data from prospective cohort studies. We obtained information from four cohorts of patients receiving primary THR for osteoarthritis: Exeter Primary Outcomes Study (EPOS) (n = 1431); EUROHIP (n = 1327); Elective Orthopaedic Centre (n = 2832); and St. Helier (n = 787). The exposure of interest was pre-operative BMI. Confounding variables included: age, sex, SF-36 mental health, comorbidities, fixed flexion, analgesic use, college education, OA in other joints, expectation of less pain, radiographic K&L grade, ASA grade, years of hip pain. The primary outcome was the Oxford Hip Score (OHS). Regression models describe the association of BMI on outcome adjusting for all confounders.

Results

For a 5-unit increase in BMI, the attained 12-month OHS decreases by 0.78 points 95%CI (0.27–1.28), P-value 0.001. Compared to people of normal BMI (20–25), those in the obese class II (BMI 35–40) would have a 12-month OHS that is 2.34 points lower. Although statistically significant this effect is small and not clinically meaningful in contrast to the substantial change in OHS seen across all BMI groupings. In obese class II patients achieved a 22.2 point change in OHS following surgery.

Conclusions

Patients achieved substantial change in OHS after THR across all BMI categories, which greatly outweighs the small difference in attained post-operative score. The findings suggest BMI should not present a barrier to access THR in terms of PROMs.
epidemiology, osteoarthritis, hip replacement, patient reported outcome, body mass index, decision making
1063-4584
431-439
Judge, A.
c6a83964-1d7c-4aa8-b2bf-9c264d1e487d
Batra, R.N.
1dcf5c66-3a03-4e58-8f59-c07b48044257
Thomas, G.E.
af927412-354d-4400-a6af-ca9743e8639f
Beard, D.
109d8a7c-8747-4ee6-91c3-f8584c889104
Javaid, M.K.
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Murray, D.W.
f581b8f8-3f6d-46c4-8c90-0642ae6048b9
Dieppe, P.A.
74be978d-206a-4ed7-8da9-6d0cb5fa8a9e
Dreinhoefer, K.E.
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Peter-Guenther, K.
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Field, R.
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Cooper, C.
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Arden, N.K.
23af958d-835c-4d79-be54-4bbe4c68077f
Judge, A.
c6a83964-1d7c-4aa8-b2bf-9c264d1e487d
Batra, R.N.
1dcf5c66-3a03-4e58-8f59-c07b48044257
Thomas, G.E.
af927412-354d-4400-a6af-ca9743e8639f
Beard, D.
109d8a7c-8747-4ee6-91c3-f8584c889104
Javaid, M.K.
51d3310b-032e-4c15-83ac-b878bce090f3
Murray, D.W.
f581b8f8-3f6d-46c4-8c90-0642ae6048b9
Dieppe, P.A.
74be978d-206a-4ed7-8da9-6d0cb5fa8a9e
Dreinhoefer, K.E.
4f731f0b-6ada-4ed9-88a0-2531f98a79ba
Peter-Guenther, K.
64168c2e-8470-4b92-a14c-2c1458c82824
Field, R.
60203309-4504-429e-a836-b4ef92064a83
Cooper, C.
e05f5612-b493-4273-9b71-9e0ce32bdad6
Arden, N.K.
23af958d-835c-4d79-be54-4bbe4c68077f

Judge, A., Batra, R.N., Thomas, G.E., Beard, D., Javaid, M.K., Murray, D.W., Dieppe, P.A., Dreinhoefer, K.E., Peter-Guenther, K., Field, R., Cooper, C. and Arden, N.K. (2014) Body mass index is not a clinically meaningful predictor of patient reported outcomes of primary hip replacement surgery: prospective cohort study. Osteoarthritis and Cartilage, 22 (3), 431-439. (doi:10.1016/j.joca.2013.12.018). (PMID: 24418679 )

Record type: Article

Abstract

Objectives

To describe whether body mass index (BMI) is a clinically meaningful predictor of patient reported outcomes following primary total hip replacement (THR) surgery.

Design

Combined data from prospective cohort studies. We obtained information from four cohorts of patients receiving primary THR for osteoarthritis: Exeter Primary Outcomes Study (EPOS) (n = 1431); EUROHIP (n = 1327); Elective Orthopaedic Centre (n = 2832); and St. Helier (n = 787). The exposure of interest was pre-operative BMI. Confounding variables included: age, sex, SF-36 mental health, comorbidities, fixed flexion, analgesic use, college education, OA in other joints, expectation of less pain, radiographic K&L grade, ASA grade, years of hip pain. The primary outcome was the Oxford Hip Score (OHS). Regression models describe the association of BMI on outcome adjusting for all confounders.

Results

For a 5-unit increase in BMI, the attained 12-month OHS decreases by 0.78 points 95%CI (0.27–1.28), P-value 0.001. Compared to people of normal BMI (20–25), those in the obese class II (BMI 35–40) would have a 12-month OHS that is 2.34 points lower. Although statistically significant this effect is small and not clinically meaningful in contrast to the substantial change in OHS seen across all BMI groupings. In obese class II patients achieved a 22.2 point change in OHS following surgery.

Conclusions

Patients achieved substantial change in OHS after THR across all BMI categories, which greatly outweighs the small difference in attained post-operative score. The findings suggest BMI should not present a barrier to access THR in terms of PROMs.

Full text not available from this repository.

More information

e-pub ahead of print date: 11 January 2014
Published date: March 2014
Keywords: epidemiology, osteoarthritis, hip replacement, patient reported outcome, body mass index, decision making
Organisations: Faculty of Medicine

Identifiers

Local EPrints ID: 365850
URI: http://eprints.soton.ac.uk/id/eprint/365850
ISSN: 1063-4584
PURE UUID: 6f230e59-d07b-4e92-8fd0-ecc7a9c45358
ORCID for C. Cooper: ORCID iD orcid.org/0000-0003-3510-0709

Catalogue record

Date deposited: 17 Jun 2014 11:01
Last modified: 03 Dec 2019 01:58

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Contributors

Author: A. Judge
Author: R.N. Batra
Author: G.E. Thomas
Author: D. Beard
Author: M.K. Javaid
Author: D.W. Murray
Author: P.A. Dieppe
Author: K.E. Dreinhoefer
Author: K. Peter-Guenther
Author: R. Field
Author: C. Cooper ORCID iD
Author: N.K. Arden

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