The classification of patients with chronic pain: age as a contributing factor

To explore the influence of age on the empirical classification of patients with chronic pain.

Cluster analyses of two cohorts defined by age.

Two outpatient pain management clinics for young and older people.

The sample consisted of 340 patients between the ages of 17 and 93 years, who were consecutively assessed on admission to the multidisciplinary pain clinics. The subjects were allocated to two groups according to age; either 17 to 65 years or 66 years and older.

Clustering was carried out using standardised scores from measures of pain (McGill Pain Questionnaire), depression (Zung or Geriatric Depression Scales), and impact of pain (Sickness Impact Profile adapted for pain).

Previous classifications of younger adults were replicated in the clusters of: "Good Pain Control," "Positive Adaption to Pain," and "Chronic Pain Syndrome." A fourth cluster, "High Impact," was identified in the older group and subsequently replicated in the combined sample. This group consisted of subjects with high levels of impact of pain and depression and low levels of pain.

Age differences are present in the clinical presentation of chronic pain patients. Some older patients with chronic pain present with a unique constellation of clinical symptoms, and the classic patient profile of high pain, high impact, and high mood disturbance (i.e., Chronic Pain Syndrome) identified in younger to middle-aged adults does not occur as frequently in older patients. A number of explanations are presented to account for these differences, including comorbidity as well as other medical, psychological, and social factors.