Long-term trajectories of back pain: cohort study with 7-year follow-up

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Published online 2013 Dec 11. doi: 10.1136/bmjopen-2013-003838

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Table 2

Cluster membership at 7 years stratified by the original study cluster (n=155)

Original study cluster	Number of people in the original study cluster	n (%)* in each cluster (trajectory) at 7 years
Original study cluster	Number of people in the original study cluster	No or occasional pain	Persistent mild pain	Fluctuating pain	Persistent severe pain
Recovering	57	34 (59)	18 (32)	3 (5)	2 (4)
Persistent mild	51	12 (23)	29 (56)	8 (15)	2 (5)
Fluctuating	16	1 (7)	6 (38)	2 (13)	7 (42)
Severe chronic	31	0 (0)	4 (12)	4 (14)	23 (74)

*Estimated following multiple imputation.

Weighted κ=0.54 (95% CI 0.42 to 0.65).