This study aims at translating, cross culturally adapting and establishing the psychometric properties of the The Core Outcome Measure Index (COMI) for patients with low back pain (LBP) in Egypt. This study will be conducted at the outpatient clinic of public hospitals in Egypt.

This study will be divided into two main stages: (1) Translation and cross culture adaptation, and (2) Validation.

In the translation and cross culture adaptation stage, the original English version will be translated into modern Arabic following the guidelines described by Beaton et al. (2000). Then, the translated final version will be tested on a sample of 30-40 participants in a small pilot study to ensure linguistic clarity.

For the validation stage, 100 male and female adults with LBP will be recruited from public physiotherapy outpatient clinics. Eligible patients will be asked to complete a questionnaire booklet containing The Arabic versions of Oswestry Disability index (ODI), Ronald Morris Disability Questionnaire (RMDQ), Short-form 36 (SF-36) and the Visual analogy scale (VAS).

Further, disability and function will be assessed by Timed Up and Go test (TUG), 50 feet walking and loaded reach test.

Outcome measures will include:

1. Face validity which will be evaluated subjectively based on judgment of expert committee and patients' feedback.
2. Concurrent validity is assessed by testing correlation between the COMI and VAS, ODI, RMDQ and SF-36
3. Construct validity will be assessed by testing the correlation between the scores for each item of the COMI and its corresponding valid back specific full-length questionnaire including the ODI, RMDQ, SF-36 and VAS.

All testing procedure will be repeated after seven days for testing reliability.

PROCEDURE:

(1) Translation and cross culture adaptation:

The cross-cultural adaptation process for the COMI will be done as described by (Beaton et al., 2000). This will include the following phases:

1. Initial translation that includes forward translation to translate the questionnaire from the English language to Arabic by two independent bilingual translators one of them is familiar with the concepts of the COMI and the other translator doesn't have medical background. Both translators will be arabic native speakers.
2. Synthesis of the translations by comparing the two Arabic translations and combine them into one version.
3. Back translation to translate the Arabic version to the English language by two independent native english translators. It is preferred that both translator do not have any information regarding the concept being tested nor have a medical background. The two translations will be compared and a Consensus will be developed.
4. Expert committee that at least consists of a research methodologists, a health professionals, language professionals, and the translators (forward and back translators). The committee will compare between versions of the translated and original COMI and consolidate the pre-final version. The role of the expert committee to detect and correct any conceptual errors or inconsistencies, grammatical or other errors.
5. Test of the pre-final version of the instrument in a small sample (30-40 individual) to assess its content and face validity according to patients' feedback and collect comments about wording and clarity of the translated version via semi-structured interview. The sample will fulfill the study inclusion and exclusion criteria of the proposed LBP sample that will be recruited for the validation and reliability testing. Patients will be asked to complete the pre-final Arabic version of COMI and will be asked to comment on any linguistic ambiguity. Finally, researcher will discuss received comments and a consensus will be done to adapt any necessary changes.
6. Submission of documentation to the developers or coordinating committee for appraisal of the adaptation process, IN this stage all reports will be submitted at the end of the translation process to explain details of the development of each.

(2) Validation and reliability testing:

One hundred male and female adults will be recruited from public physiotherapy outpatient clinics. This sample size has been recommended as an appropriate size for reliability and validity analyses (Terwee et al., 2007). Patients will be eligible to participate in this study based on study inclusion and exclusion criteria.

Testing procedure:

First, eligible patients will have the purpose of the study and the procedures fully explained. Then, patients will be asked to participate in the study. If they accepted, an informed consent form will be signed.

Validation:

1. Concurrent validity:

   Eligible patients will be asked to complete a questionnaire booklet containing The Arabic versions of ODI, RMDQ, SF-36 and VAS.

2. Content validity:

Disability and function will be assessed by TUG, 50 feet walking and loaded reach test (Bennell, et al., 2011). All tests will be demonstrated to the patient in details before asking them to take the test as follow:

Timed Up and Go test (TUG):

First, a 3-meter distance will be marked on the floor. An armchair will be placed at one end of this distance. This test will be performed by measuring the time (in seconds) required by the patients to stand from sitting position and walk at his/her normal pace then turn back to the starting position(Bohannon, 2006; Herman and Hausdorff, 2011).

50-feet walk test: The patient will walk 25 foot forward then return back to the starting position as fast as s/he could. The time spent in this task will be measured in seconds using a stopwatch (Simmonds et al., 1998)

Inclusion Criteria:

1. Adults male and females with age ranging from 21 to 50 years.
2. Referred with a diagnosis of low back pain described as pain and discomfort, localized below the costal margin and above the inferior gluteal folds, with or without referred leg pain (Airaksinen et al., 2006).
3. Arabic speaking in the Egyptian dialect.

Exclusion Criteria:

1. Back pain secondary to known specific pathology (e.g. infection, tumor, Osteoporosis, fracture, structural deformity, inflammatory disorder (e.g. ankylosing spondylitis), radicular syndrome or cauda equine syndrome) (Mannion et al., 2012).
2. Pregnant women
3. Post-operative patients
4. Patients who had traumatic injury in the lower quadrant within the past 6 months.

This study will be delimited to:

1-140 Egyptian patients diagnosed clinically with LBP with or without leg pain. 2- Patients' age ranging from 21 years to 50