Risk factors which influence the evolution of acute pain into

chronic pain

Systematic ReviewClass 6

Faculty of Medicine – University of Porto

Department of Biostatistics and Medical Informatics

IntroductionPain • Unpleasant sensory and emotional experience

associated with actual or potential tissue damage [1].

Acute Pain & Chronic Pain• Chronic pain is a pain without apparent biological

value that has persisted beyond the normal tissue healing time (taken to be three months), whereas acute pain tends to have shorter duration, as well as it is connected with tissue lesions [2].

It is estimated that between 10 and 15 % of the population suffers from chronic pain [2].

[1] Iasp-pain.org [Homepage on the internet]. IASP – International Association for the Study of Pain; [updated 2005 Oct 10; cited 2005 Dec 13]. Available from: http://www.iasp-pain.org/[2] Smith BH, Hopton JL, Chambers WA. Chronic pain in primary care. Family Practice. 1999; 16: 475-482 .

Objective

• To review systematically the literature regarding risk factors which influence the evolution of acute pain into chronic pain

Methods

Inclusion criteria: Cohort studies that refer to the factors which

influence the evolution of acute pain into chronic pain.

Exclusion criteria: Language restriction: only studies in English or

Portuguese would be included. Studies that are not connected with the context

of our review. Studies that are not cohort studies. Studies that do not refer the evolution of acute

pain into chronic.

Methods

Query: • “Chronicity AND Pain”

Electronic databases used: • Medline [16] (Nov 2005)• Scopus [17] (Apr 2006)

Articles obtained in the research:• Medline – 376 articles• Scopus – 505 articles (361 are included in Medline’s

research)[16] Medline [database on the Internet]. National Library of Medicine (US); 2002 – [cited 2005 Nov]. Available from: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed[17] Scopus [database on the Internet]. New Jersey Institute of Technology (USA); [cited 2006 Mar]. Available from: http://www.scopus.com/scopus/home.url

Assessment Protocol (Medline)

Organization of reviewer groups:4 Reviewer Groups: three groups of 2 elements and one group of 3 elements

Revision by abstract:All groups reviewed a sample of 6 articlesTwo groups with 93 articles and two groups with 92 articles

Revision by full text:Three groups with 17 articles and one group with 18 articles

Assessment Protocol (Scopus)

Organization of reviewer groups:4 Reviewer Groups: three groups of 2 elements and

one group of 3 elements

Revision by abstract:Each reviewer group with 36 articles

Revision by full text:Each reviewer group with 2 articles

Fluxogram

Start

Bibliografic Research

Selected Articles 520 (361 in comum; 15 only in Medline;

144 only in Scopus)

Articles Revision by Title and/or Abstract

Excluded Articles 443

Remaining Articles Revision by Full

Text

Articles Included in the Sistematic Review

5

Definition of Query

End

Excluded Articles 72

Medline: 376 Articles

Scopus: 505 Articles

Included or Excluded (by applying exclusion criteria)?

Included or Excluded (by applying exclusion criteria)?

Excluded

Included

Excluded

Included

Articles Selection

Articles Revision by Title and/or Abstract

n=520

Remaining Articles Revision by Full Text

n=77

Selected Articles n=520

(361 in comum; 15 only in Medline; 144 only in Scopus)

Articles Included in the Sistematic Review

n=5

Excluded Articles n=443

Reason for exclusion:Articles nor in English nor in Portuguese n=75Articles not related with the context of the review n=245Not a cohort study n=54Article that do not refer the evolution of acute pain into chronic n=69

Excluded Articles n=72

Reason for exclusion:Articles not found in full text n=39Articles not related with the context of the review n=9Not a cohort study n=13Article that do not refer the evolution of acute pain into chronic n=11

Results

Table 1 - Main features of the studies used in the review

Reference PublicationPublication

yearCountry

SampleSize

Follow upPeriod

(months)

Follow uplosses

Kind ofpain

Francen, M. et al. Spine 2002 Australia 854 20 586Low back

pain

Williams, R. et al.Archivesof PMR

1998 USA 117 6 6Low back

pain

Andersson, H.European

JournalPain2003 Sweden 214 144 73

Neck-shoulder

pain

Gatchel, R. J. Health

Psychology1995 USA 324 6 14

Low back pain

Klimiuk, P.S. et al

Spine 1987 UK 11 12 -----Low back

pain

Table 2 - Inclusion and exclusion criteria of the sample’s subjects

Results

Reference Inclusion Criteria Exclusion Criteria

Fransen, M. et al [8]

•Nurses•Nurses' aids•Heavy manual workers•Drivers

Williams, R. et al [10]

•Age between 15 and 18 years•Back pain (T6 or below) that had been present "on a daily bases" from the previous 8 weeks as the only pain problem

•Taking medications known to affect mood•Prior back surgery•Pain secondary to neoplastic disease osteomyelitis, or fracture since the clinical course of these conditions differs from the "usual" back disorder

Andersson, H. [11]

•Neck/shoulder pain with or without reflexion in arms•Pain in at least 3 regions of arms/legs

Gatchel, R. J. et al [12]

•Lumbar pain with duration inferior to 6 weeks •Unemployed people

Klimiuk, P.S. et al [13]

•Presence of a first episode of acute low back pain and sciatica•Patients had no other active disease, with no evidence of ankylosing spondylitis as demonstrated by normal sacroiliac joints on radiography and the absence of tissue type HLA B27•In all subjects the ESR blood count, serum calcium, phosphate, and alkaline phosphatase levels are normal

•No patients had been exposed to any invasive procedure other than venepuncture within the previous 3 months

ResultsTable 3 – Individual characteristics of subjects that influence the evolution into chronic pain

Reference Studied factors OR (95%CI)

Fransen et al [8]

Increasing age (>46) 1.61 (1.05-2.47)*

Severe radiating pain in legs 2.3 (1.44-3.76)*

Normal body mass index 1.0*

Higher than normal body mass index 1.85 (1.17-2.90)*

Oswestry Disability score indicating minimal disability 1.0*

Oswestry disability score indicating moderate disability 3.48 (1.65-7.35)*

Oswestry disability score indicating severe disability 5.89 (2.84-12.20)*

Oswestry disability score indicating extreme disability 5.69 (2.73-11.89)*

Andersson, H [11]

Chilliness 1.73 (0.44-6.83)**

Stiffness 1.09 (0.35-3.40)**

Number of painful areas 1-3 3.34 (1.43-7.79)**

Number of painful areas >3 15.8 (4.53-55.3)**

Gatchel, R. et al [12]

Race 0.207-1.152

Age 0.925-1.818

Pain and disability analogue 1.307-2.007

*Odds ratios (age- and gender-adjusted) for chronicity** Adjusted odds ratio (no data on adjusting factors

Table 4 – Psychosocial characteristics of subjects that influence the evolution into chronic pain

Reference Studied factors OR (95% CI)

Fransen et al [8]

Somatic symptoms 1.31 (0.95-1.81)*

Anxiety/insomnia 2.08 (1.50-2.89)*

Social dysfunction 2.79 (1.98-3.93)*

Severe depression 2.47 (1.66-3.67)*

Job insatisfaction 1.14 (0.80-1.64)*

New family member gained 0.60 (0.39-0.91)*

Andersson, H [11] Having a close friend outside the family 0.44 (0.21-0.92)**

Gatchel, R. et al [12]

Axis II personality disorder 0.874-4.415

*Odds ratios (age- and gender-adjusted) for chronicity** Adjusted odds ratio (no data on adjusting factors)

Table 5 –Workplace factors that influence the evolution into chronic pain

Reference Studied factors OR (95% CI)

Fransen et al [8]

Need to manoeuvre "extremely heavy" items regularly

1.48 (1.08-2.04)*

Need to spend, at least, 3/4 of the working day driving

1.82 (1.03-3.22)*

Unavailability of light duties on return to work 1.99 (1.39-2.86)*

Lifting time for about half a day 1.52 (1.01-2.24)*

Lifting time for about three fourths or more a day 2.04 (1.41-2.96)*

Andersson, H [11] Work in a bent position 5.31 (1.19-23.6)**

*Odds ratios (age- and gender-adjusted) for chronicity** Adjusted odds ratio (no data on adjusting factors)

Discussion

• Relevant Results• Physical, Psychological and Workplace factors

influence the evolution of acute pain into chronic pain

• Physical factors play the greatest influence• Number of painful areas >3 (OR 15.8)• Oswestry disability score indicating severe disability (OR 5.9)• Oswestry disability score indicating extreme disability (OR 5.7)

Discussion

• Relevant Results• Aggressive modifications on daily routine that

draw patients attention from pain reduce the risk of chronicity• New family member gained (OR 0.6)• Beginning of a different job (OR 0.7)

• Work conditions when returning to duties influence chronicity• Unavailability of light duties on return to work (OR 1.9)• Special tasks and psychological support for people recovering from acute pain

might reduce company’s expenses with monetary compensation during inability and increase job satisfaction

Discussion

• Connection with existent literature

The results presented agree with previous literature, supporting the evidence found for the influence of certain psychological factors in the progression to chronicity in Low Back Pain [15]

[15] Pincus T, Burton AK, Vogel S, Field AP. A Systematic Review of Psychological Factors as Predictors of Chronicity/Disability in Prospective Cohorts of Low Back Pain. Spine. 2002. Volume 27, number 5, pp E109-E120.

Discussion

• Methodological and Data limitations• Query Definition

• Cohort Studies • Longitudinal prospective studies give reliable data, as they follow the

participants while the causes play their role• However they lose a significant percentage of the initial sample,

reducing the statistical significance of conclusions

Heterogeneity The heterogeneity verified among the studies reduced the possibility

of aggregating the results

Discussion

• Methodological and Data limitations Articles

There are several studies concerning chronic pain and how it should be handled, but few about factors that promote chronicity

When factors are studied, they are usually acessed whithin chronicity

Further studies should be carried out, as this is an important issue with psychological, social and economic implications

Discussion

• Conclusions• Physical, Psychological and Workplace factors

influence the evolution of acute pain into chronic pain

• Physical factors play the greatest influence

• Further studies should be carried out

References[1] Iasp-pain.org [Homepage on the internet]. IASP – International Association for the Study of Pain; [updated 2005 Oct 10; cited 2005 Dec 13]. Available

from: http://www.iasp-pain.org/[2] Smith BH, Hopton JL, Chambers WA. Chronic pain in primary care. Family Practice. 1999; 16: 475-482 .[3] Purves AM, Penny K, Munro C. Defining chronic pain for epidemiological research – acessing a subjective definition. The Pain Clinic. 1998; 10: 139-

147.[4] IASP – Pain Clinical Updates; volume XI, No. 2; June 2003[5] Von Korff M, Dworkin SF, Le Resche L. Graded chronic pain status: an epidemiologic evaluation. Pain. 1990; 40: 279-291.[6] Bowsher D, Rigge M, Sopp L. Prevalence of chronic pain in the British population: a telephone survey of 1037 households. The Pain Clinic. 1991; 4:

223-230.[7] Brattberg G, Thorslund M, Wilkman A. The prevalence of pain in the general population. The results of a postal survey in a county in Sweden. Pain.

1989; 37: 215-222.[8] Fransen M, Woodward M, Norton R, Coggan C, Dawe M, Sheridan N. Risk Factors Associated with the Transition From Acute to Chronic Occupational

Back Pain. Spine. 2002; 27(1): 92-98. [9] Pai M, McCulloch M, Gorman JD, Pai N, Enanoria W, Kennedy G et al. Systematic reviews and meta-analyses: An illustrated, step-by-step guide. The

National Medical Journal of India. 2004; 17(2): 86-95. [10] Williams RA, Pruitt SD, Doctor JN, Epping-Jordan JE, Wahlgren DR, Grant I, et al. The contribution of job satisfaction to the transition from acute to

chronic low back pain. Archives of physical medicine and rehabilitation. 1998 April; 79: 366-374.[11] Andersson H. The course of a non-malignant chronic pain: a 12-year follow-up of a cohort from the general population. European Journal of Pain. 2004;

8: 47-53.[12] Gatchel RJ, Polatin PB, Kinney RK. Predicting outcome of chronic back pain using clinical predictors of psychopathology: a prospective analysis.

Health Psychol. 1995 Sep; 14(5): 415-20.[13] Klimiuk PS, Pountain GD, Keegan AL, Jayson MI. Serial measurements of fibrinolytic activity in acute low back pain and sciatica. Spine. 1987

Nov;12(9): 925-8. [14] Fairbanks JC, Coouper J, Davies JB, et al. The Oswetry Low Back Pain Disability Questionnaire. Physioteherapy 1980; 66:271-3[15] Pincus T, Burton AK, Vogel S, Field AP. A Systematic Review of Psychological Factors as Predictors of Chronicity/Disability in Prospective Cohorts

of Low Back Pain. Spine. 2002; Volume 27, number 5, pp E109-E120.[16] Medline [database on the Internet]. National Library of Medicine (US); 2002 – [cited 2005 Nov]. Available from: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed[17] Scopus [database on the Internet]. New Jersey Institute of Technology (USA); [cited 2006 Mar]. Available from:

http://www.scopus.com/scopus/home.url