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Table 1

Return to:   What Have We Learned From Ten Years of Trajectory Research in Low Back Pain?

Overview of ten studies in which LBP trajectories have been identified by data-driven approaches

Author
Setting
Sample size
DesignTiming and duration of follow-upMeasurement toolOutcome measurea Clustering methodIdentified clusters
Label (% of cohort)
Dunn
Primary care
General practice
n = 342 (2001–03) [8]
n = 155 (2009–10) [10]
ObservationalMonthly for 6 monthsQuestionnairesLBP Intensity 3-cat.Latent Class Analysis2001-03 cohort
 Persistent mild 31 %
 Recovering 30 %
 Severe chronic 21 %
 Fluctuating 13 %
2009-10 cohort
 Persistent mild 37 %
 No or occasional 31 %
 Persistent severe 21 %
 Fluctuating 11 %



Axen
Primary care [12]
Chiropractic practice
n = 176
ObservationalWeekly for 6 monthsText messagingLBP Frequency 0–7Hierarchical Cluster informed by spline regression (intercept, slopes, knot)Typical [improve markedly during 4 weeks] 41 %
Stable [mild] 24 %
Slow improvement 15 %
Fast improvement 13 %
Not classified 6 %



Kongsted
Primary care [11]
General practice + Chiropractic practice
n = 1082
ObservationalWeekly for 12 monthsText messagingLBP Intensity 0–10
LBP Intensity 3-cat.
LBP Frequency 0–7
LBP Frequency 3-cat.
Latent Class Analysis
Latent Class Growth Analysis
bMild episodic 29 %
Recovery 26 %
Moderate/ severe 20 %
Improvement w/ relapse 13 %
Slow improvement 12 %



Macedo
Primary care + Secondary care [16]
General practice + outpatient clinic
(≥3 months duration)
n = 155
RCTMonthly for 12 monthsText messagingLBP Intensity 0–10Hierarchical Cluster
informed by linear regression (deviations from line)
Non-fluctuating 87 %
 recovering mild 54 %
 persistent moderate 58 %
 severe chronic 17 %
Fluctuating 13 %



Chen
Workers on sick leave [13]
n = 678
ObservationalWeek 4, 10, 16,52InterviewLBP Intensity 0–10Hierarchical Cluster informed by linear regression (slope)Continuous high 42 %
Fluctuating 33 %
Large reduction 12 %
Moderate reduction 12 %
Increasing 1 %



Tamcan
Population-based [14]
n = 305
ObservationalWeekly for 12 monthsDiaryLBP Intensity 3-cat.Latent Class AnalysisModerate 35 %
Fluctuating 34 %
Mild 20 %
Severe 10 %



Kent
Secondary care [15]
Outpatient clinic
n = 322
RCTFortnightly for 12 months
Monthly for 12 months
Test messagingLBP Frequency 0–7Two-step clusterFortnightly outcomesc
 Severe persistent 42 %
 Moderate 33 %
 Severe fluctuating 25 %
Monthly outcomes
 Severe 62 %
 Moderate 38 %



Deyo
Primary care + emergency care [17]
Age >65 years
n = 3929
ObservationalMonth 3, 6, 12Questionnaire or phoneLBP intensity 0–10
Activity limitation
Latent Class AnalysisPain intensity
 Moderate – High 36 %
 Low – Moderate 31 %
 High 13 %
 Moderate –Recovery 7 %
 Severe – Recovery 7 %
 Low 6 %
Activity limitation
 Moderate – High 32 %
 Low – Moderate 25 %
 Low 19 %
 High 19 %
 Recovery 6 %



Downie
Primary care [18]
General practice (<6 weeks duration of LBP)
N = 1585
RCTWeek 1, 2, 4, 12Recorded in a booklet - transcribed by phoneLBP intensityLatent Class Growth AnalysisRapid recovery 36 %
Recovery by week 12 34 %
Incomplete recovery 14 %
Fluctuating pain 11 %
Persistent high pain 5 %
aLBP Frequency = Number of days with LBP last week

bThe study presented 12 different models with from five to twelve trajectory patterns identified. The example was based on categorical LBP intensity

cTrajectories were named for the purpose of this paper. In the paper they were labeled with numbers