[Success of treatment in higher stages of pain chronification as well? An evaluation of the Mainz pain staging system based on the QUAST-analysis sample].

BACKGROUND

More than 10 years ago Gerbershagen gave a pessimistic prognosis for treatment success in patients with higher stages of pain chronification. To date only few studies concerning this statement exist and the results are inconsistent. The objective of this study was to evaluate the prognostic validity of the Mainz pain staging system (MPSS) in a large multicenter sample. It was assessed whether effects of treatment in patients with higher stages of pain chronification are less than those in other patients. Of further interest was whether treatment success is related to different outcome measures.

METHODS

A total of 1,461 patients with the pain syndromes headache, neuropathic pain, back pain or algiomuscular pain and arthralgia were enrolled in the analysis. They were selected from the QUAST analysis sample which includes patients from 19 cooperating pain clinics. All patients had completed the German pain questionnaire prior to pain treatment and these data were compared with the last available questionnaire during the course of treatment. Outcome measures were pain intensity, psychological disability scores and patient global impression of success (PGIS).

RESULTS

Analysis showed a significant improvement of all outcome measures in every MPSS stage. The greatest improvement was noted for pain intensity whereas outcome variables regarding mental health revealed the lowest improvement. Compared with patients with low pain chronification, changes in pain intensity were smaller for patients with the highest MPSS stage III but even in these patients the strength of effect was more than 0.80. About 50% of all patients showed a reduction of pain intensity of 2 or more points on an 11 point numerical rating scale and 46.6% of patients with a MPSS stage III showed this improvement. Importantly, PGIS was independent of the stage of chronification. Nearly 45% of all patients evaluated the treatment success as good or very good.

CONCLUSIONS

According to the view of the patients, treatment in specialized pain centres is successful even in the highest stage of pain chronification. This notwithstanding, success of treatment must not be confounded with the efficacy of an intervention. It has to be noted that the results of the current study do not allow conclusions regarding efficacy of treatment.