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Characteristics of patients with chronic low back pain selected for surgery: a comparison with the general population reported from the Swedish lumbar spine study.

STUDY DESIGN
A group of surgical candidates with chronic low back pain was compared with a random sample of the general population.


OBJECTIVES
To compare the sociodemographic, physical, and psychological characteristics of patients enrolled in a randomized trial of fusion surgery for chronic low back pain with those of an age- and gender-matched general population, and to assess whether the results of the current study can be generalized to other groups of subjects with chronic low back pain.


SUMMARY OF BACKGROUND DATA
The patients with low back pain in industry, primary care, and rehabilitation clinics are well described, with evidence of increased psychological distress, social disturbance, and occupational dissatisfaction. The characteristics of surgical candidates with chronic low back pain are less well described and not compared with the general population.


METHODS
Social, occupational, psychological, and physical data from self-administered questionnaires completed by 294 consecutive surgical candidates with chronic low back pain were compared with the same data from 278 subjects in an age- and gender-matched random sample of the Swedish general population. Data were analyzed with the general population sample divided in two subgroups: subjects with and those without back pain.


RESULTS
The surgical candidates with chronic low back pain differed significantly from the control subjects free of back pain by demonstrating more smoking, general morbidity, and depressive symptoms as well as heavier occupation and self-assessed workload. However, they did not differ from the control subjects with back pain in these respects. In a multiple logistic regression analysis, physical disability was the only variable that independently discriminated between all three groups. The groups did not differ in terms of depressive symptoms. Differences were more obvious between the two general population groups than between the two groups with back pain. The rate of major depression was lower (9%) among the surgical candidates than in other reported groups with chronic low back pain.


CONCLUSIONS
The surgical candidates in the current study resembled the average Swedish citizen with back pain. Although selected for treatment because of symptom severity, they did not otherwise differ substantially from the general population with back pain. On the contrary they unexpectedly were affected only a little by depressive symptoms, distinguishing them from patients with chronic low back pain in pain clinics and rehabilitation centers. Therefore, the results of the this outcome study are not generally applicable to every patient with chronic low back pain.