Predicting the onset of forearm pain

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Predicting the onset of forearm pain

• Martin Underwood
• Professor of General Practice
• Centre for Health Sciences
• Barts and The London
• Assurance Medical Society Conference
• May 2006

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Study Team

• Deborah Ashby
• Dawn Carnes
• Louise Letley
• Suzanne Parsons
• Martin Underwood

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Content of presentation

• Background
• Aims
• Method
• Results
• Conclusions

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Forearm pain

• Shortage of reliable information about forearm
  pain
• Diagnostic labelling of forearm pain problematic
• Ascribed as work related repetitive strain injury

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Prevalence

• Increase in the 80s, but bears little
  relationship to changes in working practices
• (Helliwell 2003)
• 8 of Dutch workers lose time from work due to
  RSI (Bongers et al 2002)

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Prevalence (cont)

• Seven day prevalence of forearm pain 4.3 (Kryger
  et al 2003)
• One year incidence of forearm pain in a cohort of
  computer operators, 1.3 (Kryger et al 2003)
• One month prevalence of forearm pain in a mixed
  work based cohort, 9 (Nahit et al 2001)

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Possible causes of chronic forearm pain

• Repetitive strain injury
• Work related overuse
• Referred pain
• Part of a pain complex, such as fibromyalgia
• Claudication of the radial artery

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Aim

• To examine the epidemiology of forearm pain in a
  representative community sample

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Objectives

• To explore the prevalence of chronic pain
• To examine the relationship between forearm pain
  and other musculoskeletal pain
• To investigate other factors associated with the
  presence of forearm pain
• To examine predictors for the development of, and
  recovery from chronic forearm pain

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Method

• Longitudinal community based postal questionnaire
  survey
• Baseline and follow-up survey, 2 years later

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A word from my (other) sponsors

• Baseline survey funded by arc
• Arthritis Research Campaign
• Study run through the Medical Research Council
  General Practice Research Framework
• Follow-up survey funded by Assurance Medical
  Society

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Sample

• Randomly selected people from GP registers in the
  south eastern quadrant of England
• 16 MRC-GPRF GP practices, 4,172 surveyed, 60
  response rate (2,493)
• Seven practices participated in the follow-up
  survey, 60 response rate (253)

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BEXS survey 4,000 patients, 16 practices
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The questionnaire

• Demographic details
• EQ5D
• Quality of life
• General Health Questionnaire
• Psychological distress
• Chronic Pain Grade
• Pain
• Disability

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Pain

• Persistent pain
• Present most days for the last year
• Pain drawing
• Asked to mark where they felt this pain
• Shading of drawing indicates important pain

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Pain drawing

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Scoring pain drawing
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Defining forearm pain
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Forearm and associated upper limb pain
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Statistical analysis

• Descriptive prevalence data
• Forearm pain and other pain
• Forearm pain and occupational group
• Risk of forearm pain and other variables
• Change in pain over 2 years
• Prognostic indicators

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Results

• Baseline Follow up
• ______________________________________
• Response rate 60 60
• Responses 2,942 253
• Males 43
  44
• Mean age 52 years 55
  years
• Chronic pain 45
  55
• Forearm pain 4
  5

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Age distribution of baseline and follow-up
samples in decades
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Upper body pain distribution
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Laterality

• Right only Left
  only Both___b
• Shoulder 123 (33) 94 (25) 158 (42)
• Upper arm 38 (35) 36 (33) 34 (31)
• Elbow 58 (35) 53 (32) 54 (33)
• Forearm 38 (40) 34 (36) 22 (23)
• Wrists 38 (28) 27 (20) 73 (53)
• Hands 62 (24) 44 (17) 151 (59)

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Upper axial body pain
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Proximal upper limb pain
28
Distal upper limb pain
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Forearm pain and pain in other areas
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Where else do they get pain?

• Head 12/94 (13)
• Neck 31/94 (33)
• Upper back 31/94 (33)
• Left shoulder 36/94 (38)
• Right shoulder 36/94 (38)

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Where else do they get pain?

• Left upper arm 32/94 (34)
• Right upper arm 23/94 (24)
• Left elbow 37/94 (39)
• Right elbow 31/94 (33)
• Left wrist 29/94 (31)
• Right wrist 31/94 (33)
• Left hand 33/94 (35)
• Right hand 34/94 (36)

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Prevalence of elbow and forearm pain by
occupation (working pop.1,367)

• Managers and senior officials 15/223 (7)
• Professional occupations 11/211 (5)
• Associate professional technical
• occupations 13/189 (7)
• Administrative and secretarial
• occupations 17/233 (7)
• Skilled trades occupations 10/141 (7)
• Personal services occupations 7/118 (6)
• Sales and customer service occupations
  7/84 (8)
• Process, plant and machine operatives 7/64
  (11)
• Elementary occupations 11/104 (11)

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Relationship between upper body pain locations
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Forearm pain presence and its relationship with
other variables
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Associated upper limb pain

• Forearm
• Wrist
• Elbow
• Upper arm

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Associated upper limb pain

• Forearm
• Wrist
• Elbow
• Upper arm

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Factors predicting recovery improvement
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Factors influencing recovery/improvement of
associated upper limb pain
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Predictors of new onset associated upper limb
pain
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Caveat

• Follow up analyses based on paired responses from
  251 people
• Less than expected because of changes within
  general practice in research bureaucracy

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Summary I

• Isolated forearm pain rare
• Strongly associated with elbow pain, then upper
  arm and wrist pain
• Forearm pain presence influenced most by pain in
  other areas

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Summary II

• Prognosis is good
• Three quarters of chronic forearm pain recovers
  over 2 years
• Half of distal upper limb pain recovers in 2
  years
• Only predictor of new onset forearm pain was high
  pain intensity elsewhere at baseline

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Summary III

• Little laterality in forearm pain
• Some for associated upper limb pain
• If occupational expect more problems R arm
• No data on dominant hand
• Occupation not associated with forearm pain
• Not obviously related to keyboards

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Implications

• Forearm pain prevalence is low and strongly
  associated with pain elsewhere
• Not very useful as an individual diagnostic
  category in epidemiological surveys

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Conclusions I

• In the community, forearm pain is not a big issue
• Attention to forearm pain in the workplace is
  disproportionate to its overall health impact

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Conclusions II

• Isolated long term forearm pain is a rare
• 0.8 of forearms affected in both surveys
• Mainly part of multi-site pain problem
• Strongly associated with other pain
• Strongest predictor of onset other pains
• Isolated treatment and management is unlikely to
  be satisfactory