prevalence of chronic pain: systematic review introduction to medicine

Prevalence of Chronic Pain: Systematic review

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This systematic review is part of a research project for the

Introduction to Medicine subject, of Biostatistical Service in the

Medicine Faculty of Oporto University

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In this work we will focus:1. Title and keywords2. Introduction3. Participants 4. Methods5. Results6. Discussion7. Acknowledgements8. References9. Authors


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1. Title and keywords

Prevalence of Chronic Pain in the General Population

Keywords: Prevalence, Chronic pain, Systematic review, General population


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2. Introduction

Chronic pain: definition

Pain definition: “(...)an unpleasant sensory and emotional experience associated with actual and potential tissue damage, or described in terms of such damage (...)” ([15])

Chronic pain definition:“pain without apparent biological value that has persisted beyond the normal tissue healing time, usually taken to be 3 months” ([15])


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ePrevalence of Chronic Pain: Systematic

review

Definitions of Pain – Historical References

•16th century – Descartes developed the Specificity Theory

–Intensity of pain is directly related with the amount of tissue injury

•After Descartes – a lot of theories appeared

2. Introduction

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review

•Most accepted theory – “Gate Control”–Ronald Melzack and Patrick Wall;–Existance of “gates” that close or open depending on different variables;–The “Gates” open - pain messages run easily and the pain has a huge intensity;–The “Gates” close – pain is not experienced because the messages don’t cross the “gates”;

•However, no one has yet understood or explained the mechanisms that are behind the pain process and how it is controlled.

2. Introduction

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e Definition of pain and chronic pain – Associated Problems:

•Incapacity in quantifying pain;•Subjective nature; •Contextualization;•No agreement about the necessary time to consider chronic pain (1 month, 3 months or 6 months beyond a normal recovery period).


2. Introduction

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Systematic review: definition

•Planned review to answer a specific question and that uses systematic and explicit methods to identify, select and evaluate the studies;

•It consists in reviewing all the existent references in medicine databases: Scopus; Pubmed (for example).


2. Introduction

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Relevance of the question and comments

Chronic pain:

•Has an impact in patients’ quality of life, in family, health workers and institutions related to them and in society in general.1


2. Introduction

1- Pain Association’s International Network (P.A.I.N.)

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Objectives•Quantify the prevalence of chronic pain in general population;

•Relate chronic pain with variables such as geographical regions, anatomical areas, age, gender, ...;

•Determine the most common definition of chronicity.


2. Introduction

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3. Participants•Study design – systematic review•Selection criteria

–Inclusion criteria:•Articles should be published in an indexed scientific journal ;

•Focus chronic pain (or its synonyms such as “continuous pain”, “delayed pain” and “intolerable pain”);

•Cross-sectional studies (study of prevalence);

•Studies with participants 18 years old or above;


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e –Exclusion criteria:

•Studies focusing acute pain or other kind of pain;

•Studies related to children/teenagers (<18);

•Studies only comparing chronic pain with another type of pain;

•Studies with animals;

•Language not mastered.


3. Participants

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4. Methods•Search strategy in a systematic review:

–Query Formulation:•Pubmed

Pain – 308765

Pain AND prevalence – 27569

Pain AND prevalence AND chronic - 3966

“chronic pain” AND prevalence – 840•Scopus

“chronic pain” AND prevalence – 536

–Endnote (References management software)

–1137 (239 repeated articles)


Total: 1376

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e •Articles selection•1st phase or screenphase – reading the title and abstract of the obtained articles in the databases and exclusion of the ones that do not fit.

–5 random groups of 2 people;

•2nd phase or inclusion phase – according with the pre-established criteria of inclusion and exclusion, the fitting articles were chosen

– the groups were maintained.


4. Methods

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Bibliographic SearchQuery – “chronic pain” AND prevalence

ScreenphaseRevision through titles and abstracts

(5 groups of 2 revisers each)

123 articles selected

1014 articles not selected

· 65 articles not selected because the age of participants wasn t above 18

· 791 articles not selected because it didn t f ocus the chronic pain

· 151 articles not selected because it wasn’t a cross-sectional study

· 7 articles not selected because the participants weren’t humans

I nclusion PhaseRevision through the complete article

42 complete articles

Endnote

No

Exclusion Motives:· Unknown language· Didn’t f ocus the chronic pain· I t wasn’t a cross-sectional study· The participants weren’t above

18 years old· The participants weren’t only

humans

Data extraction and Quality Evaluation

17 articles included

25 articles excluded

Start

239 articles not selected (repeated)

End

81 articles not obtained

No

No

Yes

No

Articles selected?

Yes

Articles selected?

Yes

Searching articles

Articles obtained?

Articles selected?

Yes

Pubmed840 Articles Found

Scopus536 Articles Found

Total1376 Articles Found

1137 articles selected

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5. ResultsThe articles information was extracted with the help of the following table:

Authors

Research methods

DefinitionAspects taken in account

Prevalence

Demographic characteristics

•Author •Year of the study

•Research institute •Type of the questionaire•Age of the participants•Number•Response rate

•Time to be considered chronic pain•Intensity•Consequences•Pain localization

•Persistence of pain;•Settings•Gradation•Temporal characteristics•Social disability

•Prevalence

•Sexual distribution•Age•Association with social components, etc.


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e General Characteristics

•Articles since 1996 to 2005;

•Geographical distribution;

5. Results

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e General Characteristics

0

1

2

3

4

5

Country / Demographic Region

Nu

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Art

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s5. Results

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e •General/specific chronic pain

0123456789

1011121314

general chronic pain specific chronic pain

Nu

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of

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s

5. Results

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•Anatomical distribution

0

1

2

3

4

5

6

7

8

back

pain

neck

an

d/o

r h

ead

low

er

lim

b p

ain

up

per

lim

b p

ain

mu

scu

losk

ele

tal

join

t p

ain

ch

est

pain

ab

do

men

pain

head

ach

e

ost

eo

art

hri

tis

gast

roin

test

inal

ast

hm

a

psy

ch

iatr

ic

art

hri

tis

pelv

is p

ain

peri

nu

em

pain

sho

uld

er

pain

can

cer

pain

fyb

rio

mia

lgia

tem

pero

man

dib

ula

r

too

thach

e

wid

esp

read

pain

Type of chronic pain

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s5. Results

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e •Survey method

5. Results

0

1

2

3

4

5

6

7

8

9

non-specific telephone survey postal questionnaire

Survey Method

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e •Response rate

Minimum – 23,80%

Maximum – 95,50%

Median - 59,00%

5. Results

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e •Response rate

5. Results

67,00% 48,50% 54,00% 59,00%

0,00%

10,00%

20,00%

30,00%

40,00%

50,00%

60,00%

70,00%

80,00%

90,00%

100,00%

non-specificquestionnaire

postalquestionnaire

telephonesurvey

median

Survey Method

Re

sp

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se

Ra

te

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e •Number of participants•Minimum – 77

•Maximum – 131535

5. Results

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e •Number of participants5. Results

0

20000

40000

60000

80000

100000

120000

140000

[14] [11] [4] [3] [9] [21] [5] [24] [8] [19] [20] [12] [13] [2] [17] [7] [18]

Articles Number

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f Par

ticip

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e Definitions of Chronic Pain

•Chronicity (time needed so that acute pain becomes chronic pain)

0

1

2

3

4

5

6

7

8

9

10

11

12

3 months 6 months

Chronicity

Am

ou

nt

of

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e Definitions of Chronic Pain

•Intensity•Defined in six articles ([2], [4], [11], [13], [14], [17]).

•Two articles defined the same scale of intensity ([2], [13]):

•Grade I: low disability – low intensity;

•Grade II: low disability – high intensity;

•Grade III: high disability – moderately limiting;

•Grade IV: high disability – severely limiting.

•Two of the articles used numeric scales ([17] defined a 0-10 scale and [11] defined a 0-6 scale).

•The other two articles defined a nominal scale with two variables.

5. Results

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e •Consequences

•Consequences of chronic pain were defined in nine articles ([3], [4], [7], [8], [13], [14], [17], [18] and [24]).

•To define the grade of consequences of “chronic pain”, [17] defined a 0-10 scale.

•The remaining articles mentioned that the main consequences were interference in work, depression, anxiety, distress, sleep disturbances and great disability.

5. Results

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Prevalence of Chronic Pain

•Minimum – 0,79%

•Maximum – 83,90%

•Median – 19,00%

5. Results

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5. Results

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

[2]

[3]

[4]

[5]

[7]

[11]

[13]

[14]

(ca

nada

)

[14]

(sc

otla

nd)

[14]

(sw

eden

)

[16]

[18]

[19]

[23]

Med

ian

Articles Number

Pre

vale

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Neck and/or Head Pain – 23,80%; Chest Pain – 5,90%; Upper Limb Pain – 20,23%; Abdomen Pain – 7,45%; Lower Limb Pain – 25,88%; Back Pain – 41,63%; Musculoskeletal Pain – 35,95%; The differences between the different locations of chronic pain concerning its prevalence are not statistically significant (Kruskall-Wallis test).

•Prevalence concerning anatomical regions

5. Results

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e •Prevalence concerning geographical areasCountries / Region Number of

studiesArticles Prevalence

15 European countries + Israel

1 [4] 19,00% (1)

Finland 1 [20] (0)

Canada 1 [14] 19,00% (1)

Sweden 1 [14] 23,90% (1)

Holland 1 [11] 0,79% (1)

Spain 1 [5] 23,40% (1)

Denmark 1 [9] 19,00% (1)

Scotland 1 [14] 14,20% (1)

UK 2 [8] and [13] 30,40% (2)

Norway 2 [18] and [19] 24,40% (2)

Australia 3 [2], [3] and [14] 19,90% (3)

USA 4 [14], [16], [17] and [23] 51,45% (2)

Note: The number in brackets refers to the number of articles which mentioned the prevalence

5. Results

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e Patient characteristics

•Gender•Eleven studies ([2], [3], [5], [8], [9], [14], [18], [19], [20], [21], [24]) referred the prevalence in the different genders.

•[14] (the part about the USA) refers the prevalence only in the female gender; [18] refers the prevalence only in the male gender.

5. Results

Male gender: Median – 19,95%

Minimum – 14,80%Maximum – 75,00%

Female gender:Median – 22,55%

Minimum – 20,00%Maximum – 31,40%

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5. Results

0%

10%20%

30%

40%50%

60%

70%

80%90%

100%

Articles Number

Mal

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reva

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5. Results

0,00%

10,00%

20,00%

30,00%

40,00%

50,00%

60,00%

70,00%

80,00%

90,00%

100,00%

[2] [3] [5] [9] [18] [19] [20] [23] Median

Articles Number

Fem

ale

Pre

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•Age groups•Thirteen articles ([2], [3], [4], [5], [7], [8], [9], [11], [14], [19], [20], [21], [24]) referred the prevalence in different age groups.

•Social components•Eight articles ([3], [5], [7], [8], [9], [17], [20] and [24]) associate chronic pain with social components.

•No associations were made with the prevalence of chronic pain.

5. Results

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•Quality EvaluationThe quality evaluation of the data having into account the following criteria:

•Number of participants;•Definition of chronicity;•Specificity of pain;•Gradation;•Intensity;•Response rate;•Survey method;•Type of questionnaire;•Setting;•Socio-demographic characteristics.

5. Results

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6. Discussion


•The discussion was made taking into account the quality evaluation

•The main point focused were:

•Response Rate;

•Number of participants;

•Definition of chronic pain;

•Prevalence;

•Anatomical regions;

•Socio-demographic characteristics;

•Intensity;

•Consequences;

•Critical comparison with other studies;

•Limitations.

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•Response Rate

•The median response rate obtained was relatively high.

•The bigger the response rate, more quality was given to the study that was being analyzed.

•It seemed to be more correct to use standardized questionnaires such as telephone and postal questionnaires, but a larger response rate was obtained in the non-standardized ones. In order to evaluate this variable, the response rate was compared with each type of questionnaire.

6. Discussion

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•Number of participants

•A higher importance was given to the articles that mentioned a significative number of participants.

Note: This last variable is very close to the response rate and to the type of questionnaire so that this study tried to evaluate them as a whole.

6. Discussion

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e •Definition of Chronic Pain•The majority of articles used a 3 months definition;

• the criteria of this study further focusing the presence of a specific value such as 3 or 6 months, giving less importance to the articles that failed to mention the chronicity.

•More importance was given to the articles that focused general chronic pain and to those that referred the socio-demographic characteristics.

Chronicity

•Most of the articles, 64,71%, considered that the pain persistence was 3 months, similar to the definition of chronic pain that was initially established in this study (based on [15]), whilst 23,53% considered it to be 6 months; 11,76% did not mention.

6. Discussion

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•Prevalence of chronic pain

•It was found great heterogeneity among the articles;

•The maximum prevalence: 83,90% [16] in a USA sample. Because of the fact that it is possible that the sample was rendered less than fully representative and the questionnaire was not validated;

•The minimum prevalence: 0,79% [11] in Holland

•Confined to unexplained pain, and not all chronic pain.

•Inclusion criteria focused the attention on very severe chronic pain patients, in contrast to other studies where patients are often troubled by pain.

•Defined chronicity as more than 6 months.

6. Discussion

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e •Anatomical Region

•The statistical data was not considered significant;

•It was concluded that the highest prevalence occurred in back pain and musculoskeletal pain;

•The lowest prevalence was related to abdominal pain and chest pain.

Age•It was concluded that there is a close relation between chronic pain and age;•Despite the insufficiency of data, the prevalence of chronic pain seems to increase with ageing.

6. Discussion

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•Geographical area

•The absence of information about developing countries limited the study conclusions.

•There were only discussed the countries that had more than one article;

6. Discussion

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•The upper value found was in USA: 51,45%

•From the data quality evaluation, it was concluded that the article [14] had to be given more importance than to the article [16] due to the fact that it contained a more significant sample.

•Norway : 24,40%

•It has two articles, [18] and [19], which had the same definition of chronic pain and obtained de same prevalence having also the same number of participants (4000). It is important to mention that both articles were made in 2004 by the same author.

6. Discussion

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•Australia: 19,90%

•It has three articles [2], [3] and [14], with the same chronic pain definition and similar response rates differing in prevalence.

•The article [2] focused the prevalence of chronic pain in adults over 18 years old and obtained 22,10%, while the article [3] included participants with 16 and 17 years old; the latter having a larger sample and a prevalence of 18,60%. The article [14], with a largest sample had a similar value of prevalence: 19,00%.

6. Discussion

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•United Kingdom: 30,40%

•There were two articles [8] and [13].

•The article [8] obtained a prevalence of 46,50% and the [13] 14,30%. These differences could be consequence of a different number of participants (higher in the [8] study) and because of the response rate of 82,30% of the article [8] and 17,00% of the article [13].

6. Discussion

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Consequences

•The consequences of chronic pain are closely associated with social components such as Education, Employment, Cohabitant Status, Residence Area and Race.

6. Discussion

Intensity

•No statistical treatment was done about this variable because of its high heterogeneity of scale, limiting the conclusions of this work.

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6. Discussion•Critical comparison with other studies• Compare the conclusions with another article [22] “Prevalence of chronic benign pain disorder among adults: a review of literature”.

•The articles have different first aims.

•Article [22] wanted to determine which methods were used to find the prevalence of chronic benign pain. Our article’s first aim is to determine the prevalence of chronic pain in the general population, this being a secondary objective of article [22].

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6. Discussion

•They concluded that the prevalence of chronic benign pain among adult people was 15% (CI: [2%;40%]), a lower value than the one found by this article.

•The differences between these two articles are mainly due to different definitions of chronic pain, the article [22] using a chronicity of only six months and only evaluating chronic benign pain.

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e Limitations of this systematic review

•The huge amount of articles found revealed how important and how interesting this area can be, however this made the Screen-phase and the Inclusion phase difficult.

•Some articles could not be included - non-mastered language.

•There were found great difficulties when trying to obtain all the included articles.

•The majority of articles were too long and not very accurate. Some articles from the same author and from the same year were found however published in different papers.

•Some of objectives could not be achieved, for instance the evaluation of the intensity and the gradation of chronic pain, since there were no related articles found.

6. Discussion

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7. Acknowledgements

•We thank the teacher Luis Azevedo for the guidance throughout this work, and teacher Ana Ferreira for helping us with the flowchart.

•We also thank the professor Altamiro da Costa Pereira, director of Introduction to Medicine subject, for the opportunity to complete this task, and for the constructive critic that helped us to improve our work.


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8. References


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2. Blyth FM, Counsins MJ, March LM. Chronic pain-related disability and use of analgesia and health services in a Sydney community. Medical Journal of Australia 2003; 179 (2):84-7

3. Blyth FM, March LM, Brnabic AJ et al. Chronic Pain in Australia: a prevalence study, Pain 2001; 89 (2-3):127-34

4. Breivik H, Collett B., Ventafridda, V et al. Survey of chronic pain in Europe: Prevalence, impact on daily life, and treatment. Eur J Pain 2005

5. Catala E, Reig E, Artes M et al. Prevalence of pain in the Spanish population: Telephone survey in 5000 homes. Eur J of Pain 2002; 6(2):133-40

6. Chrubasik S, Junck H, Zappe H et al. A survey on pain complaints and heath care utilization in a German population sample, European Journal of Anaesthesiology 1998; 15(4):397-408

7. Chung JW, Kim JH, Kho HS et al. Chronic orofacial pain among Korean elders: Prevalence and impact using the graded chronic pain scale. Pain 2004; 112 (1-2):164-70

8. Elliott AM, Smith BH, Penny KI et al. The epidemiology of chronic pain in the community. Lancet 1999; 354 (9186):1248-52.

9. Eriksen J, Jensen MK, Sjøgren P et al. Epidemiology of chronic non-malignant pain in Denmark. Pain 2003; 106 (3):221-8.

10. Jahnsen R, Stanghelle J, Villien L et al., Muscoskeletal pain in adults with cerebral palsy compared with the general population, Journal of Rehabilitation Medicine 2004; 36(2):78-84

11. Kerssens JJ, Verhaak PF, Bartelds AI et al. Unexplained severe chronic pain in general practice. Eur J Pain 2002; 6 (3):203-12.

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12. Lindell L, Bergman S, Petersson IF et al. Prevalence of fibromyalgia and chronic widespread pain. Scandinavian Journal of Primary Health Care 2000; 18 (3):149-53.

13. Mallen C, Peat G, Thomas E et al. Severely disabling chronic pain in young adults: prevalence from a population-based postal survey in North Staffordshire. BMC Musculoskelet Disord 2005; 6:42.

14. Meana M, Cho R, DesMeules M. Chronic Pain: The Extra Burden on Canadian Women. BMC Womens Health 2004; 4 Suppl 1:S17.

15. Merskey H, Bogduk N. Classification of Chronic Pain. 2nd ed. Seattle: IASP Press 1994, p. 209-214

16. 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 2004; 17.

17. Portenoy RK, Ugarte C, Fuller I et al. Population-based survey of pain in the United States: differences among white, African American, and Hispanic subjects. J Pain 2004; 5 (6):317-28.

18. Rintala DH, Hart KA, Loubser PG et al. Chronic pain in a community-based sample of men with spinal cord injury: Prevalence, severity, and relationship with impairment, disability, handicap, and subjective well-being. Archives of Physical Medicine and Rehabilitation 1998; 79 (6):604-14.

19. Rustoen T, Wahl AK, Hanestad BR et al. Gender differences in chronic pain--findings from a population-based study of Norwegian adults. Pain Manag Nurs 2004; 5 (3):105-17.

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20. Rustøen T, Wahl AK, Hanestad BR et al. Prevalence and characteristics of chronic pain in the general Norwegian population. European Journal of Pain 2004; 8 (6):555-65.

21. Saastamoinen P, Leino-Arjas P, Laaksonen M et al. Socio-economic differences in the prevalence of acute, chronic and disabling chronic pain among ageing employees. Pain 2005; 114 (3):364-71.

22. Smith B, Elliot A, Chambers W et al. The impact of chronic pain in the community. Fam Pract 2001;18(3):292-9.

23. Verhakk P, Kerssens J, Dekker J et al. Prevalence of chronic benign pain disorder among adults: a review of literature. Pain 1998; 77:231-239.

24. Von Korff M, Miglioretti DL, Simon G et al. Chronic spinal pain and physical-mental comorbidity in the United States: Results from the national comorbidity survey replication. Pain 2005; 113 (3):331-9.

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9. Authors• Ana Catarina Fareleira• Ana Sofia Sampaio• Ana Teresa Sousa• André da Silva Pinto• André de Castro Pinho• André Filipe Silva• Andreia Gomes da Costa• António Manuel Oliveira• Daniela Ladeiras Pina• Rita Bettencourt Silva• Rita Joana Matos

Class 4

First YearMedicine Faculty of Oporto University


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prevalence of chronic pain: systematic review introduction to medicine

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