Identifying subgroups of paediatric chronic pain patients: a cluster-analytic approach.
BACKGROUND
Paediatric chronic pain patients are a heterogeneous group. Individuals respond differently to standardized treatment.


OBJECTIVE
This study aimed to identify subgroups of adolescent chronic pain patients.


METHODS
Subgroups were identified by means of a cluster analysis (Sample A, nA  = 266). The stability of clusters was tested in a cross-validation with a second sample (Sample B, nB  = 108). In a third sample (Sample C, nC  = 83), differences in change scores of the outcome parameters were tested between cluster subgroups 12 months after a standardized treatment.


RESULTS
Five distinct cluster subgroups with pain problems differing by pain intensity, school absence, pain-related disability, passive pain coping and affective pain perception were identified. Two groups reported overall moderate pain problems and differed with regard to passive pain coping, which was low in Cluster 1 and moderate in Cluster 2. The patients in Cluster 3 reported severe pain problems, including high pain-related disability and frequent school absences. The patients in Clusters 4 and 5 reported very severe pain problems, with those in Cluster 5 reporting very frequent school absences. Cross-validation was performed to assess the accuracy of our subgrouping and indicated a stable cluster solution (κ = 0.64). The five subgroups displayed distinct patterns in treatment outcome after a standardized multidisciplinary treatment program. The mean change scores were significantly different between subgroups [F(4,78) = 5.88; p = 0.017].


CONCLUSIONS
The patient subgroups that were established proved stable across samples. Depending on the subgroup classification, patients differed in changes of core outcomes. These results offer initial hints for the need for subgroup-specific treatment planning.
German Paediatric Pain Centre, Children's and Adolescents' Hospital, Datteln, Germany; Department of Children's Pain Therapy and Paediatric Palliative Care, Faculty of Health, School of Medicine, Witten/Herdecke University, Germany.
J
J
Wager
B
B
Zernikow
A
A
Darlington
S
S
Vocks
T
T
Hechler
D000293:Adolescent; D002648:Child; D059350:Chronic Pain / Q000145:classification* / Q000503:physiopathology / Q000523:psychology; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008297:Male