The Nordic back pain subpopulation program: predicting outcome among chiropractic patients in Finland
From: Chiropr Osteopat. 2008 Nov 7;16(1):13 [Epub ahead of print]
The causes of non specific low back pain are largely unknown. Obviously, this is a hindrance to a rational approach to both prevention and treatment. In general, both etiologic studies and randomized controlled clinical trials are based on the concept that non specific low back pain is one single entity. However, most clinicians with an interest in back pain probably consider it to consist of several specific conditions, which have not been properly recognized, understood and described.
Chiropractors in the Nordic countries use predominantly spinal manipulative therapy in their treatment of back problems, frequently in combination with soft tissue therapy, advice on exercise, ergonomic precautions, and lifestyle changes. Randomized controlled clinical trials have shown that spinal manipulative therapy has a positive effect on low back pain. However, overall, the magnitude of the effect seems to be relatively small. Those, who believe that back pain consists of several specific but (as yet) undefined subgroups, obviously think that the recognition of these would improve the quality of care and that the selection of homogeneous study populations in etiological studies and clinical trials would improve the quality of research.
Until recently it has not been documented which patients with low back pain are most likely to benefit from the chiropractic approach. However, the predictive value of a set of clinical observations has been previously studied in patients with low back pain receiving chiropractic care. This research, conducted in Norway and Sweden under the Nordic Back Pain Subpopulation Program, has been running over the past years, in which specific subgroups of patients with low back pain are systematically studied. For instance, it was shown that it is possible to predict which chiropractic patients with persistent low back pain will not report definite improvement early in the course of treatment, making it possible to exclude from treatment those who are unlikely to become low back pain free. Furthermore, early recovery at the 4th visit was noted to be a predictor for outcome 3 and 12 months later and the status already by the second visit predicted status at the fourth visit.
Specifically, in a Swedish study of patients with low back pain, it was shown that patients with low back pain for altogether at least 30 days in the past year, who had leg pain, and who did not report some improvement by the second treatment, were not good candidates for definite improvement by the 4th visit. Although the final model was excellent in predicting non-response at the 4th visit (96%), it could only predict 19% of patients who would be “definitely better”.
The results of the present study confirm that it is possible to predict short-term outcome in patients with low back pain who receive chiropractic care. This is a clinically relevant finding, as it has been previously shown that short-term outcome (i.e. recovery by the fourth visit) is a predictor for the outcome at both 3 and 12 months, at least in patients with relatively long-lasting or recurrent low back pain.
When the previously achieved best Swedish model was applied to patients from Finland, the associations between outcome and the three relevant variables (leg pain, duration of pain in the past year and leg pain) were again positive, although duration failed to reach significance and leg pain was only weakly associated, and in the final analysis, only improvement at the second visit remained significant.
Improvement at the second visit meant that patients reported that at least one of the five “disabilities” was better than at base-line, namely sleeping, turning in bed, putting on socks/shoes, getting up from a chair, or walking.
Even when adding the three new factors (BMI, other spinal pain and general health), improvement at the second visit was the only strongly associated variable that emerged from the multivariate analysis.
In the final analysis, taking into account also leg pain and BMI did not really improve the estimates in a clinically meaningful way. However, when the number of these predictor variables present in each person was tested against outcome, a doseresponse was revealed. In the whole study sample, the proportion of patients in the study who were “definitely better” at the fourth visit was 66%. In patients with none of these three predictors, 84% were better, whereas only 34% of those who had all three belonged to this category.
There are three important messages in this report. First, already at the first visit one should be vigilant with overweight/obese patients who have pain radiating into the leg. Second, at the return visit, for these patients if there is lack of improvement, the short-term prognosis is poor. Third, that any patient, who fails to improve at the 2nd visit has a poor short-term prognosis. Therefore, when treating patients with low back pain, the treatment strategy should be different for overweight/obese patients with leg pain as it should be for all patients who fail to improve by the 2nd and 4th visits.
