Our study has used SBT as a stratifying tool and showed that there is an association between high score on BQ and SBT - the higher the BQ, the higher the SBT score. We also see that patients who score higher than 40 on the BQ are most often also categorized as “distressed by condition” (>4) on SBT. Furthermore, those who score more than 4 on the depression item in BQ, also score high on the corresponding question on SBT in the “distressed by condition” group.
Close association between BQ and SBT for depression scores
This study has provided a comparative analysis of the measuring properties of the SBT and the BQ for patients presenting to a chiropractic clinic. The BQ is only validated as an outcome measure. It is, as opposed to SBT, also validated to measure outcome of treatment for neck pain . It has been developed to be a simple yet thorough tool to measure outcome of treatment. The psychosocial variables measuring anxiety and depression have shown poor responsiveness to change using BQ. Most likely because populations of patients presenting to chiropractic care have a low BQ baseline score (4 or below) for these items and consequently have too little change from baseline to follow-up when used as an outcome measure, i.e. a floor effect . Here we have shown that these items may be of interest for the clinician if the patient present with a high score, especially for depression. This is apparent for all area of complaints included in this study. There is a low association between question 2 of the SBT and question 4 of the BQ addressing anxiety. The reason for this is unclear, but it is questionable if this SBT question actually represents the original anxiety component of the Hospital Anxiety and Depression Scale (HADS-Anx).
The study population are patients with a painful complaint and all groups had a fairly high pain score that was only slightly higher for patients with SBT score >4. There was a moderate to high association between the BQ pain question and the SBT bothersomeness question indicating that these items are related. Pain was less associated with the other SBT items and particularly not associated with the fear and anxiety items.
A Danish study indicate a tenfold risk of psychosocial risk factors such as depression, catastrophizing and fear avoidance being present in the patients SBT identified as “high risk” . Eleven percent was found to be in the high-risk group in this study of Danish LBP patients. This is comparable to what we found in our Norwegian population indicating a similar profile of chiropractic patients in Scandinavia. In contrast, the high risk group has been reported as high as 28% in an UK LBP population . Our study shows a significant difference in the patient profile at baseline between chiropractic patients in Norway and England. Norwegian patients are somewhat younger, are less distressed by condition in general, have significantly lower catastrophization and depression scores, but are mildly more anxious than English patients. It therefore appears to be important that validation of diagnostic tools is restricted to the country it is being utilized within, as significant variations between countries are present.
In both countries there were more women than men seeking care. This concurs with findings from a Canadian chiropractic teaching clinic . In the Canadian study they also reported that a majority of patients seeking care had spinal pain (81.4%) similar to the Norwegian population in our study where 66% presented with back pain and 21% with neck pain. One in five in the Canadian study had an extremity complaint and 10% cervical pain while in our study one in five had a cervical complaint and 10% extremity complaint. In a Belgian study of chiropractic clinics 91.5% of patients presented with spinal pain complaints . In contrast, the prevalence of the different musculoskeletal areas of complaint to those presenting to general practitioners (UK) is quite different to that presenting to chiropractors, the most common area of complaint is low back (16%), and neck pain is fifth (9%) after knee, chest and shoulder complaint . In a Norwegian epidemiological study , 34% of the population reported low back pain and 36% neck pain within the last week.
In our study we have shown that the neck pain, LBP and extremity pain patients score differently on BQ total, SBT total, “distressed by condition” and on the different sub-questions for both the BQ and the SBT. The group categorized as “other” in our study however, is small and therefore any statistical significance should be treated with caution. However, these patients show a tendency towards a more distressed psychosocial profile that should be explored in a larger study. There is a need to develop good stratification tools and outcome measures for generic use since as many as one in three seeking care has a complaint other than LBP as well as more than one area of complaint.
Using questionnaires on different populations
The purpose of the SBT is to serve as a tool in deciding a treatment plan for patients presenting to primary care with low back pain, providing a more individualized treatment not based purely on the clinicians’ experience and expertise. Our study has found that the SBT psychological profile for LBP patients is similar to that found by other authors. The treatment package provided for the patient by different health care providers may differ in regards to addressing psychosocial issues depending on the clinician’s interest and formal training in treating musculoskeletal pain patients. This will influence the need to use stratification tools for referral but may give the qualified therapist a way to objectively target treatment for high risk patients.
As the BQ has never been used to stratify patients to “targeted treatment”, it is not possible to determine from our study whether the association between a high BQ score and high SBT score is clinically relevant. In a study assessing the SBT on chiropractic LBP patients showed that the high risk group had greater improvement and were equal to the median and low risk groups by the 30 day assessment . Despite the high-risk group having greater pain and disability at baseline, they experienced greater improvement with regular chiropractic care. The chiropractic treatment paradigm may have aspects that address the psychosocial issues of the high-risk patient as measured by SBT, or the chiropractic patient population may differ from that of the general practitioners’. It is likely that the patients in both Field and Newell  and our studies were largely self-selecting and sought chiropractic care directly. In the UK population 41% of the patients had previously seen the chiropractor, and although this was not recorded for the Norwegian population or tested for, there is the possibility that an established therapeutic alliance may affect the patient’s psychological profile at different testing points.
The developers of SBT emphasize that an advantage of the tool is that it is validated for use in primary care, whilst other tools like the Oswestry Disability Index (ODI) and the Roland-Morris Disability Questionnaire are developed for use in secondary care. In the study by Hill and co-workers  the patients were referred to a physiotherapist, who then stratified the patient to “targeted treatment” through the use of SBT. Already at this stage in the stratification process the patient is once removed from the first point of contact in primary care. Evaluation of the implementation of diagnostic stratification tools in different areas of health care service may be of importance. This must be considered when using diagnostic and outcome instruments developed for use in a different health care settings than where it has been tested through RCTs.
Patients in primary care and secondary care may have different expectation to treatment success and thereby choice of treatment and this may also affect the baseline psychosocial profile of a patient population. In a study looking at minimal clinical important change in the ODI in a Danish population of LBP patients, one group treated by chiropractors in primary care and another group treated in the secondary sector of the Danish health care system, the investigators found a large difference in the reduction in ODI score needed for the patient to acknowledge a change. The percentage change scores from baseline were substantially higher in chiropractic patients in primary care (71%) compared to patients in secondary Care (27%) for a similar change in minimal important clinical change . Although patients in primary care tend to be more acute and a rapid change in clinical presentation is expected, there may be an expectation of treatment outcome that are different for patients seeking chiropractic care.
BQ has never been validated as a stratifying tool, nor validated to identify predictors for chronicity. A study regarding BQ’s predictive and monitoring properties questioned its accuracy . However, they did find that certain individual items were useful in predicting specific outcomes, making it still a useful predictive tool. They found that patients with a low score for BQ Work had a lower risk of being on sick-leave the following year. Patients scoring high on BQ Control had a higher risk of having LBP during the following year while a low score on this item or on BQ ADL predicted absence of debilitating LBP. They also found that a high score on BQ ADL, BQ Social and BQ Control predicted persistent LBP the following year. Although the use of BQ as a predictive instrument has been criticized  it is in use and has been found useful as part of a diagnostic package in clinical practice . The generic use of BQ and SBT in general chiropractic practice is promising but should be used with caution until validated.
A validated Norwegian translation of the SBT was not available at the time of our study and may differ from the latest validated version. The SBT has received much attention and is of interest for health care decision makers. The informal translations available on the Keele University website are in clinical use. If the tool is applied on a population where it has not been properly validated it may have unforeseen consequences. We have here addressed the necessity of proper validation for both the generic versions of the SBT and the BQ. The public may assume that the translation process is of the same scientifically quality as the rest of the published work of the research group since the developers have approved translations through written permissions and posted them on their website.
The diagnostic grouping in the Norwegian population is crude, with the “other” group being small and heterogenic. There may also be a bias in which patient the participating chiropractor entered in the database as there was a large difference in number of patients provided from the Norwegian chiropractors. In future studies the distribution of diagnosis should be compared with the reimbursement registry for chiropractors to ensure that the data is representative for regular practice. In this study we did not analyze the influence of age and duration on the psychosocial profile in the different diagnostic groups.
For stratification tools and outcome tools to be of value in routine practice, they need to be easy to collect and evaluate for the clinician. The effort of manually collecting and logging the patient forms from paper may have been the reason why not all Norwegian clinics were able to submit data to the study, this in spite of the fact that it took less than one minute to enter a patient’ data set into the online survey database. Using an online data collection tool with automated data collection from the patient at baseline and follow up, such as the one used for data collection in the UK study population, could improve the utilization of questionnaires for clinical use as well as for research.
Clinical relevance and further research
Clinicians using BQ routinely should be aware that patients with a high total score or with a high score on the depression question may have a psychosocial profile that should be taken into consideration when developing a treatment plan.
This study is the first to give a diagnostic and psychosocial profile of chiropractic patients in Norway. The results show that there is a significant difference in demographics and psychological profile between the Norwegian and UK chiropractic patients, showing that study results cannot necessarily be extrapolated between countries, prompting the need for research across borders, and caution when pooling data from different countries.
This study shows that both SBT and BQ generic versions for use in all musculoskeletal complaints may give valuable insight into the patient psychosocial profile and that there is a need for validation of the generic versions of these questionnaires.