Faculdade de Medicina da Universidade do Porto Risk factors which influence the evolution of acute pain into chronic pain Systematic Review Turma 6

Introduction  Definitions  Context  Objective

Pain   Unpleasant sensory and emotional experience associated with actual or potential tissue damage [1].

Acute Pain   Pain connected with real tissue lesions [1];   Shorter duration;   Needs a treatment model

Chronic pain   Pain without biological value that has persisted beyond normal tissue healing time (3 months) [1].   “Current continuous or intermittent pain or discomfort which as persisted for more than three months, with recent or frequent seeking of treatment or use of analgesic medication” [3].

Chronic pain   Opposite to acute pain, needs a rehabilitative rather than a treatment model [2]. .  Among the most disabling and costing afflictions in North America, Europe and Australia [4].   Must be understood in a multi-dimensional way [2].   More women than man are affected   Prevalence increases with age   It is estimated that between 10 and 15 % of the population suffers from it [2].

Chronic pain  Chronic no-malignant pain is commonest at limbs and joints, at the back, as well as at neck and head [6][7].  Has a deep impact on suffers, as it prorogues a sense of loss of their lives, due to loss of confidence and self-esteem associated with psychological, social and economical implications [2].  To manage it, to issues must be take in count [2]: - treatment - drug therapy, invasive therapy, alternative therapies - rehabilitation - physiotherapy

Context  Acute and chronic pain are intimately correlated  Many factors are in the origin of such transition : - individual factors (obesity, severe radiating pain…) - psychological factors (anxiety, severe depression…) - workplace factors (heavy jobs, monetary compensation during inability…) - …

Context  Chronic pain may lead to loss of employment, loss of social and home roles, sleep disorders, having much psychological, social and economic implications [2] Importance and relevance of our work

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

Systematic Review The key steps are [9]:  Formulation of a focused review question  A comprehensive, exhaustive search and inclusion of primary studies  Quality assessment of included studies and data extraction  Synthesis of study results  Interpretation of the results and report-writing

Formulation of the Question It was verified that studies had already been made about the subject in interest Our target population is the published articles indexed on Medline Participants are articles that refer to the evolution of acute pain into chronic pain Cohort Studies were selected as the indicated Type of Study. No intervention will be applied The pretend result is the achievement of a relation between the existence of certain factors (risk factors) and the development of chronic pain in individuals previously suffering of acute pain

Formulation of the Question Systematic Review of pre-existing literature indexed on Medline, that refers and is based on cohort studies, in order to analyse and evaluate the relation between the presence of certain risk factors and the evolution of an acute pain into a chronic pain

Research and Study Selection Bibliographic Research Study Selection

Bibliographic Research  Bibliographic Database: Medline  Established Limits: Humans  Separated sensitive research Queries: “Chronic”, “Pain”, “Chronicity”  Application of Boolean operators:  “Chronicity AND Pain”, “Chronic AND Pain”, “Chronicity AND Pain AND Factors”, “Chronicity AND Pain AND Factors AND Cohort Studies”, “(“Chronicity AND Pain”) OR (“Chronic AND Pain”)”

Bibliographic Research  Selection of adequate Query: “Chronicity AND Pain”  Participants: 369 articles

Study Selection Definition of Selection Criteria:  Exclusion Criteria  Inclusion Criteria

Study Selection Exclusion Criteria:  Studies that do not consider that acute pain becomes chronic pain in a period of three months  Articles that do not include cohort studies

Study Selection Inclusion Criteria:  Cohort Studies that refer to factors wich influence the evolution of acute pain into chronic pain  Studies that include certain types of pain  Studies that refer to certain types of factors

Study Selection Organization of reviewer groups:  4 Reviewer Groups: three groups of 2 elements and one group of 3 elements  4 Article Groups: three of 92 articles and one of 93 articles

Study Selection Articles Revision by Titles and Abstracts  Application of Exclusion Criteria “Cohort Studies”: X articles excluded “Chronic Pain Definition”: Y articles excluded  Articles excluded by language different from English: Z Articles excluded

Study Selection Remaining Articles Revision by Full Text  Exclusion of articles which full text is not available: S articles excluded  Application of exclusion criteria: Q articles excluded  Application of inclusion criteria

Study Selection Reference Management software:  Register causes of exclusion  List of articles included in the systematic review: W articles

Quality Assessment  Organization of reviewer groups  Quality criteria

Quality Assessment Quality criteria:  The sample of patients is representative and homogeneous  Patients are homogeneous with respect to prognostic risk, exposure to factors  The follow up is sufficiently complete  Measurements of the outcomes are made in the same way on both groups (exposed and unexposed)

Quality Assessment Exclusion of articles that lack quality, not being compatible with the quality criteria established Stratification of studies by quality

Data Extraction Organization of reviewer groups for extraction of data Data extraction Processing the data on appropriate software

Data Extraction Data extraction on:  Information about existing influential factors: Which factors; How many factors was each individual exposed to; How long was each individual exposed to these factors before developing acute pain and after developing acute pain  Information on measurements taken after the development of acute pain  Information on type of pain  Information on period of pain existence

Study Results Analysis of Data Synthesis and Summary of study Results:  Tabulation of study characteristics

Results Publishing  Results published in a Scientific Article:  Introduction  Objective  Population studied and Methods  Results  Discussion/Conclusion

References [1] IASP – International Association for the Study of Pain [2] Smith BH; Hopton JL and Chambers WA; Chronic pain in primary care; Family Practice; 1999; 16; [3] Purves AM, Penny K, Munro C et al. Defining chronic pain for epidemiological research – acessing a subjective definition. The Pain Clinic 1998; 10; [4] IASP – Pain Clinical Updates; volume XI, No. 2; June 2003 [5] Von Korff M, Dworkin SF, Le Resche L. Graded chronic pain status: na epidemiologic evaluation. Pain 1990; 40: [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: [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: [8] Fransen M, Woodward M, Norton R et al, Risk Factors Associated with the Tansition From Acute to Chronic Occupational Back Pain, Spine, volume 27, number 1, pp 92-98, 2002 [9] Pai M, McCulloch M, Gorman JD et al, Systematic reviews and meta-analyses: An illustrated, step-by-step guide. The national medical journal of India, volume 17, No2, 2004