Spanish translation and preliminary validation of the Pain Treatment Satisfaction Scale

Satisfactory pain treatment could prevent adverse physical and psychological outcomes in patients. In this sense, adequate survey to measure patient satisfaction of pain management is important. In this study, we translated the Pain Treatment Satisfaction Scale to Spanish and analyzed the psychometric properties of its five dimensions. Reliability was determined with Chronbach ́s-α and convergent and divergent validity with a multitrait-multimethod analysis. The latter were reported as successful percentage. In the five dimensions, the reliability of the Spanish version showed Chronbach ́s-α values ≥ 0.75; successful percentage for convergent validity was ≥ 88, and successful percentage for divergent validity was ≥ 94. The Spanish version showed good psychometric properties and can be used to measure pain treatment satisfaction.

Through the activation of the pituitary-adrenal axis, inadequate pain treatment could produce postsurgical infection and poor wound healing.Pain also actives the sympathetic nervous system, which results in disruption of the cardiovascular, gastrointestinal and renal systems 1 .In addition, patients with pain may have a sense of helplessness or hopelessness.This may predispose them to anxiety and depression, and they may be reluctant to seek medical care for other health problems 2 .
Adequate pain control can improve the patient's attitudes and behaviors toward their treatment.They are more willing to comply with the advice of their health care provider, miss fewer medical appointments and are more likely to adhere to their medical treatment 3 .
In this sense, surveys to measure patient satisfaction and pain treatment are important for adequate health care.The aim of this study was to translate the Pain Treatment Satisfaction Scale (PTSS) 4 into Spanish and analyze some of its psychometric properties.

Survey.
The PTSS was developed by Evans et al. 4 and validated to assess satisfaction in patients with both acute and chronic pain.This survey includes 39 items grouped into five dimensions: information about your pain and treatment (5 items); medical care (8 items); impact of current pain medication (8 items); satisfaction with pain medication, which included the two subscales medication characteristics (3 items) and efficacy (3 items); and side effects (12 items).Each item is measured with a 5 point-Likert scale which ranges from 1 (major satisfaction) to 5 (worst satisfaction).Scales and items were transformed to a 0 to 100 score, where 100 represents highest satisfaction.
Translation.This process was carried out in 4 steps.In the first step, 2 authors, experts in pain medicine (TANO and SCG), performed the translation from English to Spanish.In the second step, all authors reviewed the translation and gave suggestions and recommendations to improve the clarity of the items.In the third step, external professional translators made the inverse translation from Spanish to English.In the final step, all authors reviewed both the inverse translation and the original survey.

Sample.
We applied the Spanish version to a random sample of 174 patients from the Dr José E. Gonzalez University Hospital with some type of pain.They were interviewed in the postoperative or ambulatory areas.The final Spanish version of the PTSS is available as supplementary material.Of the patients surveyed, 53.5% were men and 46.5% were women.Overall, mean age was 41.5 years, and according to gender, the mean age of women was 38.5 years and for men 44.6 years.The type of pain identified was acute in 60.8% (postoperative 15.2%) and chronic in 39.2% of patients.
Results of the PTSS are presented in Table 1.In general, patients with mild pain in the last 24 hours had a better score than patients with moderate or intense pain in almost all dimensions, except "side effects".Reliability and construct validity.The range of Chronbach´s alpha was 0.75 to 0.90, with medical care being the dimension with the lowest score and "impact of current pain medication" the dimension with the highest score.The %successful in convergent and divergent validity ranged from 88 to 100% and from 94 to 100%, respectively."Medical care" (88%) and "side effects" (92%) were the dimensions with the lowest %successful in convergent validity, while medical care (94%) was the dimension with the lowest %successful in discriminant validity.

Discussion
In this study, we translated and preliminarily evaluated the psychometric properties of PTSS in its Spanish version.In other studies, this survey has been translated and validated in Chinese 3 and French 4 where good psychometric properties have been shown.
In the case of reliability, values obtained are satisfactory since values of all dimensions were > 0.70 and similar to the original version.In general, the values of all dimensions were slightly lower than the original version.
With respect to convergent and discriminant validity, results are satisfactory and similar to the original version.The medical care dimension had lower values than the original in both convergent and discriminant validity.Side effects had a value slightly higher than the original.The rest of the dimensions had the same values as those of the original version.
The limitations of this study include lack of a rigorous diagnosis of the type of pain.The sample size was smaller than that used in other studies [3][4][5] and finally, a test-retest analysis was not performed.F1000Research been made, despite the fact that the authors had comparators against which they could perform this estimation.174 appears as a very low number for a population including both acute and chronic pain in a vast variety of patients.Indeed, if the translation is accurate, any difference in its validity will come mainly from socio-cultural factors in the population.The authors themselves are indeed conscious of this limitation, but they could have easily corrected it.
I have read this submission.I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.
No competing interests were disclosed.Competing Interests:

25Introduction
May 2016, :996 (doi:  )  Satisfactory pain management is important to prevent adverse physical and psychological results for patients and their families.

Raw data for 'Spanish translation and preliminary validation of the Pain Treatment Satisfaction Scale' http://dx.doi.org/10.5256/f1000research.8750.d122791
Patients older than 18 years who gave verbal consent were included in this study.The Ethical Committee of the Faculty of Medicine of the Autonomous University of Nuevo León approved this study, and exempted from written informed consent.The reference number is AN15-004.Correlations were obtained with the matrix multitrait-multimethod.The statistical software SPSS 21 and the package Psy for R 3.2.2 were used for the analyses.

Table 2 . Reliability of each dimension of the translated version and the original version.
*FromEvans 2004 3