Responsiveness and minimal clinically important difference for pain and disability instruments in low back pain patients

Table 4 Standardised response mean (SRM_raw) in relation to patients global important effect and according to patient entry point (primary and secondary sector patients) and pain location.

Instrument	Important improvement		No change		Difference	P
	n	SRM_raw (95% CI)	n	SRM_raw (95% CI)
Subpopulations
*Primary Sector Patients*
ODI	63	1.4 (1.2; 1.7)	23	0.8 (0.4; 1.2)	0.6	0.05
RMQ	63	1.7 (1.4; 2.0)	23	0.7 (0.3; 1.1)	1.0
LBPRS_disability	62	0.8 (0.4; 1.2)	22	0.5 (0.1; 0.9)	0.3
SF36 (pf)	64	1.1 (0.9; 1.3)	23	0.4 (0.0; 0.8)	0.7
LPBRS_pain	62	1.4 (1.1; 1.6)	23	0.6 (0.1; 1.1)	0.8	0.08
SF36 (bp)	64	2.1 (1.6; 2.5)	23	0.8 (0.4; 1.3)	1.2
NRS_pain	62	1.5 (1.2; 1.8)	23	0.8 (0.3; 1.3)	0.7
*Secondary Sector Patients*
ODI	19	1.0 (0.3; 1.7)	43	0.2 (-0.1; 0.5)	0.8	0.01
RMQ	18	1.3 (0.7; 1.9)	43	0.3 (0.0; 0.6)	1.0
LBPRS_disability	19	0.8 (0.4; 1.3)	43	0.3 (0.0; 0.7)	0.5
SF36 (pf)	19	0.7 (0.3; 1.1)	43	0.4 (0.1; 0.7)	0.3
LPBRS_pain	18	1.1 (0.3; 1.8)	42	0.2 (-0.1; 0.5)	0.9	0.06
SF36 (bp)	19	2.1 (1.1; 3.0)	43	0.7 (0.3; 1.0)	1.4
NRS_pain	18	0.9 (0.4; 1.3)	41	0.2 (-0.1; 0.5)	0.7
*LBP only patients*
ODI	58	1.4 (1.1; 1.6)	21	0.7 (0.3; 1.1)	0.7	0.03
RMQ	58	1.7 (1.4; 2.0)	21	0.7 (0.4; 1.0)	1.0
LBPRS_disability	57	0.8 (0.4; 1.3)	20	0.5 (0.2; 0.9)	0.3
SF36 (pf)	59	1.1 (0.9; 1.3)	21	0.7 (0.3; 1.0)	0.4
LPBRS_pain	57	1.3 (1.0; 1.6)	21	0.5 (0.0; 1.0)	0.8	0.07
SF36 (bp)	59	1.9 (1.5; 2.3)	21	0.9 (0.4; 1.4)	1.2
NRS_pain	58	1.4 (1.1; 1.7)	21	0.7 (0.3; 1.1)	0.7
*Leg pain (+/- LBP)*
ODI	24	1.2 (0.6; 1.7)	45	0.3 (0.0; 0.6)	0.9	0.05
RMQ	23	1.3 (0.8; 1.7)	45	0.3 (0.0; 0.6)	1.0
LBPRS_disability	24	0.8 (0.3; 1.2)	45	0.3 (0.0; 0.7)	0.5
SF36 (pf)	24	0.8 (0.4; 1.2)	45	0.3 (0.0; 0.6)	0.5
LPBRS_pain	23	1.3 (0.7; 1.9)	44	0.3 (0.0; 0.6)	1.0	0.46
SF36 (bp)	24	2.0 (1.3; 2.6)	45	0.6 (0.3; 1.0)	1.1
NRS_pain	22	1.3 (0.8; 1.8)	43	0.2 (-0.1; 0.5)	1.1

ODI = Oswestry Disability Index; RMQ = Roland Morris Disability Questionnaire; LBPRS_disability = Disability subscale of the Low Back Pain Rating Scale; SF36 (pf) = Physical function subscale of the SF36; LBPRS_pain = Pain subscale of the Low Back Pain Rating Scale; SF36 (bp) = Bodily pain subscale of the SF36; NRS_pain = Numeric 11-box pain rating scale; SRM_raw = standardised response mean of the raw change score.
Note: Results are shown according to where in the health care system the patients were seen and pain location. The 95% CIs for the SRM_raw were calculated using a bootstrap technique. The P values refer to a comparison of the difference in SRMs between patients with an "important improvement" and patients with "no change" for the disability and pain instruments within each subpopulation (linear regression model with a non-linear Wald-type test).

ISSN: 1471-2474