Socio-demographic and clinical profile of a cohort of patients referred to a Pain Clinic *

1. Orthopedist and Traumatologist, Pain Clinic, Department of Orthopedics and Traumatology, School of Medicine of São José do Rio Preto (FAMERP). São José do Rio Preto, SP, Brazil. 2. Occupational Therapist, Pain Clinic of Hospital de Base, Department of Neurological Sciences, School of Medicine of São José do Rio Preto (FAMERP). São José do Rio Preto, SP, Brazil. 3. Neurosurgeon, Pain Clinic of Hospital de Base, Department of Neurological Sciences, School of Medicine of São José do Rio Preto (FAMERP). São José do Rio Preto, SP, Brazil. 4. Physical Therapist, Pain Clinic of Hospital de Base, Department of Neurological Sciences, School of Medicine of São José do Rio Preto (FAMERP). São José do Rio Preto, SP, Brazil. 5. Social Worker, Pain Clinic of Hospital de Base, Department of Neurological Sciences, School of Medicine Foundation (FUNFARME). São José do Rio Preto, SP, Brazil. 6. Psychologist, Pain Clinic of Hospital de Base, Department of Neurological Sciences, School of Medicine Foundation (FUNFARME). São José do Rio Preto, SP, Brazil. 7. Nurse, Pain Clinic of Hospital de Base, Department of Neurological Sciences, School of Medicine Foundation (FUNFARME). São José do Rio Preto, SP, Brazil. 8. Anesthesiologist; Coordinator of the Pain Clinic of Hospital de Base. São José do Rio Preto, SP, Brazil. 9. Neurosurgeon; Coordinator of the Pain Clinic – Hospital de Base, Department of Neurological Sciences, School of Medicine of São José do Rio Preto (FAMERP). São José do Rio Preto, SP, Brazil.

This study aimed at identifying the profile of patients referred to a Pain Clinic using socio-demographic and clínical variables obtained by specific screening, correlating such variables to pain duration and intensity.METHOD: This is a cohort descriptive, transversal and exploratory study with 128 individuals seen by an outpatient setting specialized in pain management.Independent variables included age, gender, marital status, labor status, education, religiousness, ethnicity, clinic referring patients, original diagnosis, Pain Clinic diagnosis, pain duration and type.Evaluation tools were an electronic card and the physical evaluation performed by a pain specialist.Data were collected at first visit before the interaction with any health care provider.RESULTS: Pain was more prevalent among females (58.5%), married (66.4%), inactive (62.5%) and in those with mean school attendance of 6.8 ± 3.5 years.Most have religious beliefs (93.7%).Mean pain duration was 32.6 ± 21.9 months.There has been positive correlation between pain intensity and longer duration among females and educational level lower than 5 years.(p < 0.05).CONCLUSION: Chronic pain patients previously under the care of a different specialty and referred to a Pain Clinic supply data which may contribute to control pain with more effective therapeutic approaches, by the interaction of the knowledge of different professionals.Keywords: Chronic pain, Pain measurement, Pain treatment.

INTRODUCTION
In the last decade, multidisciplinary pain clinics have become a popular alternative for traditional management of persistent pain.There is however little information describing this health service users and the impact of this new demand on health services 1 .Chronic pain is very common and its management represents significant costs for the health care system 2 .Although being considered a frequent health problem bringing severe personal and economic losses to the population, very little is known about chronic pain epidemiology in Brazil and worldwide, especially in terms of studies to identify etiologic factors of persistent pain.These studies provide a broader view of the phenomenon and give subsidies for the planning of preventive actions and the organization of health services 3 .
Several epidemiological studies suggest that pain is more common during late midlife, between 55 and 65 years of age, and continues with the same prevalence during more advanced ages, regardless of anatomic location or its pathogenic cause 4 .Daily pain is a major risk factor for the development of deficiencies and older age cohorts are more vulnerable 4,5 .Similar relationships were documented for the risk of depression and mood disorders in persistent pain patients 5 .Studies report that the better understanding of the characteristics of pain patients looking for assistance, and of health professionals is critical for pain control services to better meet the needs of such patients 6,7 .Chronic and persistent pain affects patients with different diseases of different durations, however there is a common feature, the lack of understanding of factors triggering or maintaining its development and prevalence, in well conducted studies 7 .This study aimed at identifying the clínical profile of patients of a Pain Clinic, through the analysis of sociodemographic and clínical variables, correlating such variables to pain duration and intensity.

METHOD
This is a descriptive and exploratory study of transversal cohort, carried out with 128 individuals seen by an outpatient setting specialized in pain management.Data for clínical profile analysis were obtained from history and physical evaluation during screening performed by a pain specialist.Studied variables were: age, gender, marital status, pain duration, labor status, education, religiousness, ethnicity, clinic referring patients, original diagnosis, Pain Clinic diagnosis, pain duration and type.Non-parametric Chi-square test was used for correlation among variables and a descriptive analysis has been made to characterize the sample.P < 0.05 was considered statistically significant.This study was approved by the Research Ethics Committee, School of Medicine of São José do Rio Preto (2384/2010).

RESULTS
Studied sample was made of 75 females (58.5%) and 53 males (41.5%), aged between 25 and 75 years, with mean age of 47.78 ± 12.49 years.Frequency distribution of the variables marital status, labor status, education, religiousness and ethnicity are shown in table 1.  Table 2 shows pain intensity and pain duration with regard to gender and educational level.Males have more moderate pain (48%), with higher incidence between 42 and 60 years of age.Females have more severe pain, with higher incidence between 35 and 55 years of age.

DISCUSSION
It is estimated that approximately 50 million people in Brazil suffer of some type of pain, being it the major reason for looking for health assistance, since pain is considered today a severe public health problem 8 .In our study, female gender, productive age, living with spouse, low educational level and inactivity were more prevalent for chronic pain, which is in line with other studies 9,10 .An American study to evaluate the impact of chronic pain in the community has analyzed 4611 individuals 11 and has observed that females were more affected.A different study with 2184 individuals with neck pain and incapacity has shown the same predominance 12 .A single paper has not shown differences between genders; however this population was made up of youngsters, which should be taken into consideration when analyzing such results 13 .Hormonal variations, lower pain threshold and tolerance and higher capacity to discriminate it may explain such differences.With regard to age and labor status, our study has shown mean age of 47.78 ± 12.49 years and that most patients were inactive (62.5%).Some studies believe that pain affecting middle-aged adults with 40 to 49 years of age may be associated to labor activities, since this is an economically active group 9,14 .Also with regard to inactivity, a recent study relating pain to opioids prescription has reported that the shorter the opioid prescription period, the shorter the time patients are absent from work 15 .With regard to pain and marital status, our study has shown that most patients were married, ratifying a study on chest pain where the authors have reported significantly early manifestation for care and shorter pain duration in married males with acute myocardial infarction associated to chest pain 16 .
An American study has shown that spiritual practices are a way for individuals to deal with cancer pain, and has described in patients of a cancer center contrast expressions and values about using spirituality to control pain in Afro-American and Caucasian individuals 17 .They have observed that groups were not different in demographics, pain status or integrative therapies, but the Afro-American group made more use of spirituality, mobilizing internal resources with more frequency and improving pain.In our study, 93% of patients reported having spiritual practices and 66.5% of individuals were Caucasian.Pain intensity was higher and duration was longer for females, with values similar to those found by other studies 18,19 .
Our study has shown a positive correlation between musculoskeletal pain and pain duration, in line with a study which shows that in addition to individual behavioral factors in face of chronic musculoskeletal pain, when pain tends to be more persistent or continuous, resolution prognosis becomes more limited or grim 15 .Specialties referring more patients to the Pain Clinic were oncology, neurosurgery, rheumatology and orthopedics.No similar data were found in the literature.These are the specialties dealing with a higher number of chronic pain patients, what explains their higher referral of patients to the Pain Clinic, which is a multiprofessional clinic, thus more qualified to treat such patients than specialists alone.Our study has observed that moderate pain prevails in males (48%), and was more frequent between 42 and 60 years of age; for females, pain was more severe and affected patients between 35 and 55 years of age.These results are in line with a study which has identified gender differences with regard to pain, with higher scores for females 20 .
The relationship between very severe pain and low educational level shown by this study is in line with other findings, where pain intensity was related to low educational level 21,22 .

CONCLUSION
Chronic pain patients, previously being cared by other specialties and referred to a Pain Clinic supply data which may contribute for pain control with more effective therapeutic alternatives by the interaction of knowledge of different professionals.

Table 1 -
Percentage distribution for variables marital status.labor status.education.religiousness and ethnicity.

Table 2 -
Distribution of variables: pain intensity and duration according to gender and educational level means.