Distressed, immobilized, or lacking employer support? A sub-classification of acute work-related low back pain.
BACKGROUND
One possibility for reducing the disabling effects of low back pain (LBP) is to identify subgroups of patients who might benefit from different disability prevention strategies. The aim of this study was to test the ability to discern meaningful patient clusters for early intervention based on self-reported concerns and expectations at the time of an initial medical evaluation.


METHODS
Workers seeking an initial evaluation for acute, work-related LBP (N = 496; 58 % male) completed self-report measures comprising of 11 possible risk factors for chronicity of pain and disability. Outcomes of pain, function, and return-to-work were assessed at 3-month follow-up. A K-means cluster analysis was used to derive patient subgroups based on risk factor patterns, and then these subgroups were compared with respect to 3-month outcomes.


RESULTS
Eight of the 11 measures showed significant associations with functional recovery and return-to-work, and these were entered into the cluster analysis. A 4-cluster solution met criteria for cluster separation and interpretability, and the four clusters were labeled: (a) minimal risk (29 %), (b) workplace concerns (26 %); (c) activity limitations (27 %); and (d) emotional distress (19 %). Functional outcomes were best in the minimal risk group, poorest in the emotional distress group, and intermediate in the other two groups. A global severity index at baseline also showed highest overall risk in the emotional distressed group.


CONCLUSIONS
Patterns of early disability risk factors from this study suggest patients have differential needs with respect to overcoming emotional distress, resuming normal activity, and obtaining workplace support. Classifying patients in this manner may improve the cost-benefit of early intervention strategies to prevent long-term sickness absence and disability due to LBP.
Department of Environmental Health, Harvard School of Public Health, Boston, MA 02215, USA. sreme@hsph.harvard.edu
Silje Endresen
SE
Reme
William S
WS
Shaw
Ivan A
IA
Steenstra
Mary Jane
MJ
Woiszwillo
Glenn
G
Pransky
Steven J
SJ
Linton
D000293:Adolescent; D000328:Adult; D000368:Aged; D016000:Cluster Analysis; D004185:Disability Evaluation; D006233:Persons with Disabilities; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000150:complications / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000145:classification* / Q000209:etiology; D010147:Pain Measurement / Q000379:methods / Q000523:psychology; D011788:Quality of Life; D062707:Return to Work; D012307:Risk Factors; D057566:Self Report; D012720:Severity of Illness Index; D012944:Social Support; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000150:complications*; D011795:Surveys and Questionnaires; D014481:United States; D055815:Young Adult