Latent class analysis derived subgroups of low back pain patients – do they have prognostic capacity?

Table 7 Prognostic capacity in addition to that of the baseline values of the outcomes measures and participants’ recovery beliefs

			Follow-up time points
Outcome measure	Description of prognostic variable	Prognostic variable	2 weeks	3 months	12 months
Outcome measure	Description of prognostic variable	Prognostic variable	Diff. of. adj. R²	Diff. of. adj. R²	Diff. of. adj. R²
Pain intensity (Numeric Rating Scale, 0–10)	LCA-derived subgroupings	Single-stage subgroups	0.028*	0.014*	0.026**
	LCA-derived subgroupings	Two-stage subgroups	0.022*	0.013*	0.019*
	Existing subgrouping tools	STarT Back Tool	0.014*	0.001	0.003
	Existing subgrouping tools	Quebec Task Force classification	0.006	0.010*	0.005
	Baseline characteristics	Baseline leg pain intensity (0–10 Numeric Rating Scale)	0.038**	0.007*	0.033**
	Baseline characteristics	Baseline disability (RMDQ-23) (0–100 = highest disability)	0.006	−0.001	0.000
	Results of first stage of two-stage LCA	All domain-specific patient categorisations	0.042**	0.049**	0.077**
Disability (23-item Roland Morris Disability Questionnaire, proportional score)	LCA-derived subgroupings	Single-stage subgroups	0.047**	0.041**	0.024*
	LCA-derived subgroupings	Two-stage subgroups	0.041**	0.035*	0.016
	Existing subgrouping tools	STarT Back Tool	0.020**	0.020**	0.003
	Existing subgrouping tools	Quebec Task Force classification	0.016**	0.027*	0.026*
	Baseline characteristics	Baseline back pain intensity (0–10 Numeric Rating Scale)	−0.009	−0.003	−0.007
	Baseline characteristics	Baseline leg pain intensity (0–10 Numeric Rating Scale)	0.032**	0.028**	0.042**
	Results of first stage of two-stage LCA	All domain-specific patient categorisations	0.054**	0.067**	0.064**

Diff. of. adj. R² = difference in adjusted R² obtained when the prognostic variable was added; LCA Latent Class Analysis
*P < .05
**P < .001

ISSN: 1471-2474