Comparison of severity of chronic pain in patients differing in pain diagnosis: an analysis by means of the Mainz Pain Staging System

Introduction. Testing the validity of the Mainz Pain Staging System (MPSS) is often carried out by pain classification according to chronic stage. It is assumed that pain syndromes distribute equally over the chronic stages. This analysis was carried out to answer three questions: Do different pain syndroms vary in chronicity, do the four axes of the MPSS differ between pa in syndromes, and are there any specific item responses with respect to a p ain syndrome? Methods. 406 patients with different pain diagnoses were included in this a nalysis. Patients were chosen from the PAIN-Documentation-System of the pai n outpatients' department of the Medical University of Luebeck. The pain sc ore according to MPSS had been assessed, and a diagnosis attributed accordi ng to the Multidimensional Classification of Pain (MASK). Results. Pain diagnoses do differ in pain chronification. Patients with hea dache showing the lowest chronification,and patients with back pain describ ing the most severe chronification, formed the extreme patient groups. Furt her analysis using the axes of the MPSS demonstrate different sensitivity w ith respect to pain syndromes, i.e. intake of drugs being the least sensiti ve and aspects of time being the most sensitive axes. Statistical analysis using configural frequency analysis indicated a relation between pain syndr omes and specific item responses. Conclusion. Using pain stages of the MPSS as an experimetal factor in studi es of pain, it is imperative either to control pain syndromes or to confine to a single pain syndrome, to avoid confoundations between pain syndromes and severity of pain chronification.