Elsevier

Medical Hypotheses

Volume 114, May 2018, Pages 65-68
Medical Hypotheses

Do the key prognostic factors for non-specific neck pain have moderation effects? – A study protocol

https://doi.org/10.1016/j.mehy.2018.03.004Get rights and content

Abstract

Neck pain is one of the common musculoskeletal conditions prevalent in the general population in Norway. Patients with neck pain, seek treatment from different health professionals such as general practitioners, physiotherapists, chiropractors and alternative medicine practitioners. The interventions for neck pain are typically provided in a primary care or specialised healthcare setting depending on the general practitioners’ referral patterns. Clinicians are interested to know the various prognostic factors that can explain the recovery from neck pain. In order to know this, studies have explored and reported on a range of prognostic factors that contribute to the outcomes in patients with neck pain. This information is currently available only for neck pain following whiplash injury that has a traumatic origin. There is limited information on the role of prognostic factors specifically for non-specific neck pain without a traumatic episode. Moreover, there is a lack of data on whether there are interactions (moderation effects) between the prognostic factors. Therefore, we propose a hypothesis to elucidate whether the same set of prognostic factors found in neck pain associated with whiplash injuries are also identified in patients with neck pain without trauma. Additionally, we hypothesize that the association between a prognostic factor and the outcome variable (s) would be dependent on the third variable, thereby confirming the moderation effects. Clinicians could make informed decisions in the clinical management of neck pain with the knowledge of prognostic factors that explain the outcomes. It could also be used for the development of new interventions or for modifying the existing ones.

Introduction

Neck pain (NP) is a musculoskeletal condition with the highest impact on disability-adjusted life-years [1]. In Norway, the 12-month prevalence of NP is estimated to be approximately 25% in the general population [2]. Patients with NP can present in different forms; however, in a majority of cases, there is no identifiable underlying disease or abnormal anatomical structure; thus, it is termed as non-specific neck pain [3]. Most often, either postural or mechanical factors, and in some instances, multifactorial reasons have been attributed to the cause of non-specific neck pain. Nevertheless, the aetiology of non-specific neck pain could also include whiplash injuries due to trauma, without any underlying structural damage. A number of studies have investigated the prognostic factors (PFs) that predict the recovery and/or delayed recovery from NP, which are synthesised in the systematic reviews [4], [5], [6], [7], [8], [9], [10]. It must be noted that the primary studies included in these systematic reviews have included patients with NP either due to whiplash-associated or work-related disorders.

An ‘overview of systematic reviews’ [11] concluded that there was strong evidence for increased risk of poor outcome in the presence of high pain intensity (PI), high neck-related disability (ND) or older age. The conclusions were less evident for factors such as catastrophizing, cold hypersensitivity/hyperalgesia, post-traumatic stress symptoms and history of other musculoskeletal disorders. A recent systematic review [12] showed that there was robust evidence for some of the same set of prognostic factors. However, this review included patients with arm and shoulder pain, in addition to neck pain. Furthermore, they found that the strength of evidence for some factors varied with the outcome(s) used. There were also differences in the impact of outcomes depending on whether there was a short-term or long-term follow-up. Thus, differences in research design and outcome measures utilised could play a role for explaining the influence of PFs in the recovery of neck pain.

The primary studies included in the earlier systematic reviews [4], [5], [6], [7], [8], [9], [10] have largely been exploratory prognostic factor research. In general, most of the prognostic factor studies in the field of health sciences have an exploratory aim rather than confirmatory [13]. Considering the wide range of factors identified as possible prognostic factor, it should be examined how their effects relate. This is necessary in order to obtain results with a minimal or devoid of any bias. Therefore, it is time to improve our research with a different approach, which includes incorporating appropriate study designs, and a thorough and more robust statistical analysis. The aims of the proposed study are 1) to conduct a confirmatory prognostic factor research for prognostic factors previously identified in trauma related-neck pain patients, and 2) to explore and identify a set of prognostic factors in a non-specific neck pain cohort.

Section snippets

Rationale

The current evidence from the ‘overview of systematic reviews’ [11] is compelling. Nevertheless, the evidence has been generated by including patients with NP due to whiplash-associated disorder (trauma). Hence, it is not clear whether the same set of key PFs could be identified in patients with NP of a non-traumatic origin. The methodological approaches different to that used in the earlier studies could be adopted in the future for obvious reasons. For instance, the primary studies included

The hypothesis

We propose the following hypotheses in accordance with the rationale detailed above.

  • 1)

    An association is likely to be demonstrated between each prognostic factor and the outcome measures of pain and neck disability individually – Unadjusted.

  • 2)

    Associations may be expected between a number of prognostic indicators and each of the outcome measures of pain and neck disability – Adjusted.

  • 3)

    Moderation effects are anticipated, possibly from one or more than one pair of prognostic factors in relation to the

Implications

The implications derived by conducting this type of research work are twofold. Firstly, this research project would contribute to the area of PFs for NP. Specifically, the findings generated from this study could provide plausible explanations related to recovery from neck pain. Furthermore, this would add new knowledge with a thorough understanding on whether moderation effects exist between the prognostic factors. More precisely, it would inform whether a particular prognostic factor predicts

Conflict of Interests

The authors state that there are no potential ‘conflicts of interest’ associated with this research work.

Source of funding

The research project leading to the studies has received funding from the European Union Seventh Framework Programme (FP7-PEOPLE-2013-COFUND) under Grant agreement n° 609020 – Scientia Fellows.

Acknowledgements

Arun Prasad Balasundaram is supported with a funding for the post-doctoral research fellowship programme from the “European Union Seventh Framework Programme (FP7-PEOPLE-2013-COFUND) under grant agreement n° 609020 – Scientia Fellows”.

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