Dropouts and sub-groups--statistics can help but not cure

A systematic review and meta-synthesis of the impact of low back pain on people's lives

Background

Low back pain (LBP) is a common and costly problem that many interpret within a biopsychosocial model. There is renewed concern that core-sets of outcome measures do not capture what is important. To inform debate about the coverage of back pain outcome measure core-sets, and to suggest areas worthy of exploration within healthcare consultations, we have synthesised the qualitative literature on the impact of low back pain on people’s lives.

Methods

Two reviewers searched CINAHL, Embase, PsycINFO, PEDro, and Medline, identifying qualitative studies of people’s experiences of non-specific LBP. Abstracted data were thematic coded and synthesised using a meta-ethnographic, and a meta-narrative approach.

Results

We included 49 papers describing 42 studies. Patients are concerned with engagement in meaningful activities; but they also want to be believed and have their experiences and identity, as someone ‘doing battle’ with pain, validated. Patients seek diagnosis, treatment, and cure, but also reassurance of the absence of pathology. Some struggle to meet social expectations and obligations. When these are achieved, the credibility of their pain/disability claims can be jeopardised. Others withdraw, fearful of disapproval, or unable or unwilling to accommodate social demands. Patients generally seek to regain their pre-pain levels of health, and physical and emotional stability. After time, this can be perceived to become unrealistic and some adjust their expectations accordingly.

Conclusions

The social component of the biopsychosocial model is not well represented in current core-sets of outcome measures. Clinicians should appreciate that the broader impact of low back pain includes social factors; this may be crucial to improving patients’ experiences of health care. Researchers should consider social factors to help develop a portfolio of more relevant outcome measures.

Responder analyses in randomised controlled trials for chronic low back pain: an overview of currently used methods

PURPOSE

To provide an overview and a critical appraisal of the use of responder analyses in published randomised controlled trials (RCTs) of interventions for chronic low back pain (LBP). The methodology used for the analyses, including the justification, as well as the implications of responder analyses on the conclusions was explored.

METHODS

A convenience sample of four systematic reviews evaluating 162 RCTs of interventions for chronic LBP was used to identify individual trials. Randomised trials were screened by two reviewers and included if they performed and reported a responder analysis (i.e. the proportion of participants achieving a pre-defined level of improvement). The cutoff value for responders, the period of follow-up, and the outcome measure used were extracted. Information on how RCT authors justified the methodology of their responder analyses was also appraised.

RESULTS

Twenty-eight articles (17%) using 20 different definitions of responders were included in this appraisal. Justification for the definition of responders was absent in 80% of the articles. Pain was the most frequently used domain for the definition of response (50%), followed by back-specific function (30%) and a combination of pain and function (20%). A reduction in pain intensity ≥50% was the most common threshold used to define responders (IQR 33-60%).

CONCLUSIONS

Few RCTs of interventions for chronic LBP report responder analyses. Where responder analyses are used, the methods are inconsistent. When performing responder analyses authors are encouraged to follow the recommended guidelines, using empirically derived cutoffs, and present results alongside mean differences.