Low back pain (LBP) is one of the most common causes of patient visits to general physicians [1]. This complaint is not well approached and diagnosed in a great number of cases, resulting in inaccurate management [2]. In most cases, the pain resolves on its own in <4 weeks; however, some patients experience pain again later in life [3]. Although LBP is generally considered as a self-limiting complaint, it causes enormous expense, resulting from unnecessary diagnostic tests, inappropriate therapy, and long-term absence from work [4,5].

An essential part of a good clinical management is a thorough and systematic evaluation of the complaint. For this, the physician should rely on both subjective and objective data. The objective data are mandatory because the physician assesses the progress and response to treatment using parameters such as range of motion and tenderness [6]. However, subjective information plays an equally important role. No one is more aware of the pain and its associated factors than the patient himself. Standard questionnaires assessing the patient’s perception of their condition are useful in these situations [7], as they give the doctor and patient data which can be transformed into standard quantified variables. These data can then be shared worldwide with other clinicians and researchers [8].

The Million Visual Analogue Scale Questionnaire (MVAS) is a 15-item self-administered questionnaire [9], aimed to measure the impact of LBP on an individual’s different aspects of life. It is considered to be one the most useful instruments for assessing LBP in recent years owing to the ease of administration and the short time required for completing and scoring this questionnaire [10]. MVAS uses the Visual Analog Scale (VAS) and assesses the essential domains of daily living in its assessment. Therefore, we aimed to validate the Persian version of this questionnaire for clinicians and researchers with Persian patients, as a standard international instrument.

In total, 150 participants enrolled in the study (122 males and 28 females). Respondents were aged 46±9.8 years. Completion of each questionnaire took approximately 5 minutes and the scoring was completed in <3 minutes. To assess the factorial structure of the MVAS questionnaire, the CFA was also conducted (Fig. 1) and the results are summarized in Table 1. We used the hypothesized model and compared it with the covariance matrix based on our empirical data. According to our findings, the CFA indicated excellent goodness of fit results. The standard beta CFA and reliability indexes are reported in Table 2. Reliability values were acceptable for all the domains assessed in MVAS. The ICCs for all domains of MVAS were in the range of excellent reliability. The number of patients who achieved minimum or maximum scores in the test was not greater than the 15% threshold, therefore there was no need to consider the ceiling and floor effect. For content validity, the committee of researchers assigned to evaluate the questions considered almost all of the questions essential with CVI and CVR values greater than 0.78.

To confirm the Persian version of MVAS as a robust instrument, we evaluated the two major domains of validity and reliability. Validity was divided into three subgroups, including translation validity, construct validity, and content validity. We used the forward-backward translation method in accordance with specific guidelines [15]. The pre-final version of the questionnaire was derived through comparison of the translated and original version. Next, after administering a small pilot study, the final version was agreed upon. There were some minor changes in the content of the questions due to the linguistic properties of the Persian language, but the intention of questions and the overall structure were preserved. In questions 7 and 15, we added “Because of your LBP…” to the questions for clarity. There was no need for alterations owing to cultural differences. A hundred millimeter line was placed as an answering medium for each question. Both ends of these lines were marked with dots, the numbers ‘0’ and ‘100,’ with expressions added to clarify of the process of answering. We provided a brief guide at the beginning of the questionnaire to ensure that all patients could completely understand how to complete the questionnaire. To make the questions look more distinct and much easier to answer, the background color of questions was changed from white to grey, and alternated between questions. Our results indicated that almost all participants understood and answered the questions without difficulty. The questionnaires were completed in an average time of 5 minutes and scored in about 2 minutes, similar to that observed in the original version [9].

Construct validity was measured using the CFA, resulting in excellent chi-square, GFI, RMSEA, and CFI parameters listed in Table 1. The CFA indicates an excellent fitness of results for the Persian MVAS.

The reliability of our instrument was evaluated by measuring the ICC and Cronbach’s alpha. The ICC values, indicating the homogeneity of the questionnaire, as shown in Table 2, were all greater than 0.7. Our study also showed excellent scores of Cronbach’s alpha ranging from 0.670 to 0.799. The ICC values plus the Cronbach’s alpha measurements both are indicators of the excellent reliability of the Persian MVAS.

Musculoskeletal problems such as LBP can become chronic and influence physical activities. This chronic pain has an undeniable socioeconomic consequence in the patient’s life and the society, particularly in handworkers [16,17]. LBP not only harms the patient’s body, but can also limit their personal and social life. Occupational and psychosocial stresses are also considered risk factors for LBP [18,19]. Workload, shift work, workplace violence, and job stress all affect musculoskeletal injuries, particularly LBP [20,21]. Clinicians and researchers aim to measure and quantify this effect, and now have the ability to compare and share these parameters with other colleagues. We have selected MVAS because it is easy to use and supports different aspects of daily and social life. The MVAS questionnaire is one of the most-used instruments to assess LBP by clinicians and researchers alongside Roland-Morris Disability Questionnaire (RDQ) [22], Oswestry Disability Index (ODI) [23], and Quebec Back Pain Disability Scale [10,24].

Similar to the RDQ, the MVAS questions ask the patient about their own capabilities. In other words, MVAS is a performance-based questionnaire and not capacity-based. This is important because capacity-based questionnaires tend to overestimate or underestimate their condition and ability [25]. Unlike ODI and RDQ, which measure the effect of pain on patient’s activities, MVAS concerns itself with the effect of activities on pain, which makes it a unique instrument.

One of the limitations of our study was not assessing responsiveness, which reflects how good an instrument is in detecting small changes in answers after an event such as therapeutic intervention [26]. As MVAS uses a visual scale, it can potentially be one of the most powerful tools to assess responsiveness. Therefore, future studies are warranted in this domain for the Persian MVAS. There are also some limitations to the use of both original and Persian MVAS. Due to the use of VAS, it is difficult to complete the questionnaire over telephone. The other downside of MVAS compared to RDQ is that there is no specific time course assigned to the answers. With the RDQ, the questions must be answered based on the experience of the patient over the last 24 hours.

The Persian Version of MVAS is recommended for the evaluation of patient activities on pain, owing to its ease of administration, assessment of social and daily life, and excellent validity and reliability. Clinicians can benefit from administration of MVAS in combination with a physical examination.

This study shows that the Persian version of MVAS has a great level of validity and reliability. Therefore, it is recommended as a valid and reliable scale to assess the effect of LBP on a patient’s life.