A Stratified Approach for Managing Patients With Low Back Pain in Primary Care (SPLIT Program): A Before-and-After Study

Article Figures & Data

Table 1.

Baseline Characteristics of Participants

	Total (n = 447)	UC (n = 115)	SPLIT (n = 332)	P Value
Sociodemographic
Age, y, mean (SD)	46.19 (11.65)	48.06 (11.41)	45.46 (11.75)	.035^{^a}
Female, No. (%)	268 (60.0)	65 (56.5)	203 (61.1)	.383^{^b}
BMI (kg/m²), No. (%)				.872^{^b}
Underweight or normal weight,	174 (39.4)	46 (40.0)	128 (39.1)
Overweight or obesity	268 (60.6)	69 (60.0)	199 (60.9)
Marital status, No. (%)				.937^{^b}
Lives alone	158 (35.3)	41 (35.7)	117 (35.2)
Lives with someone	289 (64.7)	74 (64.3)	215 (64.8)
Years of education, No. (%)				.365^{^b}
0-9	216 (48.5)	60 (52.2)	156 (47.3)
≥10	229 (51.5)	55 (47.8)	174 (52.7)
Work status, No. (%)				.068^{^b}
Active	314 (70.7)	89 (77.4)	225 (68.4)
Not working	130 (29.3)	26 (22.6)	104 (31.6)
Clinical
Duration of LBP episode, No. (%)				.618^{^b}
<12 weeks	231 (51.9)	62 (53.9)	169 (51.2)
≥12 weeks	214 (48.1)	53 (46.1)	161 (48.8)
Referred leg pain, No. (%)	206 (46.5)	76 (66.1)	130 (39.6)	≤.001^{^b}
LBP pain medication, No. (%)	225 (51.1)	66 (57.4)	159 (48.9)	.118^{^b}
Sickness certificate, No. (%)	95 (21.6)	31 (27.0)	64 (19.7)	.104^{^b}
SBST risk subgroup, No. (%)				≤.001^{^b}
Low	174 (38.9)	20 (17.4)	154 (46.4)
Medium	189 (42.3)	62 (53.9)	127 (38.3)
High	84 (18.8)	33 (28.7)	51 (15.4)
SBST psychosocial subscale (Q5-9, 0-5), mean (SD)	2.20 (1.45)	2.78 (1.28)	2.00 (1.45)	≤.001^{^a}
Back-related disability (RMDQ, 0-24), mean (SD)	9.46 (6.18)	12.63 (5.90)	8.37 (5.89)	≤.001^{^a}
Pain intensity (NPRS, 0-10), mean (SD)	4.23 (2.61)	5.41 (2.56)	3.83 (2.50)	≤.001^{^a}
HRQoL (EQ-5D-3L, 0-1), mean (SD)	0.56 (0.25)	0.44 (0.23)	0.61 (0.25)	≤.001^{^a}

BMI = body mass index; EQ-5D-3L = EuroQoL 5 dimensions 3 levels; HRQoL = health-related quality of life; LBP = low back pain; NPRS = Numeric Pain Rating Scale; Q5-9 = Questions 5-9; RMDQ = Roland-Morris Disability Questionnaire; SBST = STarT Back Screening Tool; SPLIT = stratified primary care for low back pain; UC = usual care.
Note: Sample size was not consistent, owing to missing data. Total: BMI (n = 442); years of education (n = 445); work status (n = 444); duration of LBP episode (n = 445); referred leg pain (n = 443); pain medication (n = 440); sickness certificate (n = 440). SPLIT: BMI (n = 327); years of education (n = 330); work status (n = 329); duration of LBP episode (n = 330); referred leg pain (n = 328); pain medication (n = 325); sickness certificate (n = 325).
↵a Mann-Whitney test.
↵b χ² test.

Table 2.

Primary and Secondary Outcomes Over the 6-Month Follow-Up

	UC	SPLIT
Back-related disability (RMDQ, 0 to 24)
2 months: UC, n = 110; SPLIT, n = 315
Mean (SD)	9.14 (6.77)	3.02 (3.81)
Achieved MIC, No. (%)^{^a}	54 (49.1)	240 (76.2)
Poor disability, No. (%)^{^b}	64 (58.2)	49 (15.6)
6 months: UC, n = 104; SPLIT, n = 281
Mean (SD)	8.37 (6.83)	3.06 (4.23)
Achieved MIC, No. (%)^{^a}	53 (51.0)	210 (74.7)
Poor disability, No. (%)^{^b}	56 (53.8)	47 (16.7)
Pain intensity (NPRS, 0 to 10)
2 months: UC, n = 110; SPLIT, n = 315
Mean (SD)	3.88 (2.90)	1.58 (2.17)
Achieved MIC, No. (%)^{^a}	55 (50.0)	239 (75.9)
6 months: UC, n = 104; SPLIT, n = 281
Mean (SD)	3.18 (3.24)	1.83 (2.55)
Achieved MIC, No. (%)^{^a}	60 (57.7)	195 (69.4)
Perceived effect of treatment (GPES, −5 to +5)
2 months: UC, n = 110; SPLIT, n = 315
Median (IQR)	3.0 (4.0)	4.0 (2.0)
Achieved MIC, No. (%)^{^a}	58 (52.7)	233 (74.0)
6 months: UC, n = 104; SPLIT, n = 281
Median (IQR)	3.0 (4.0)	4.0 (2.0)
Achieved MIC, No. (%)^{^a}	56 (53.8)	213 (75.8)
HRQoL (EQ-5D-3L, 0 to 1)
2 months: UC, n = 110; SPLIT, n = 314
Mean (SD)	0.61 (0.27)	0.81 (0.21)
6 months: UC, n = 104; SPLIT, n = 281
Mean (SD)	0.59 (0.25)	0.81 (0.23)

EQ-5D-3L = EuroQoL 5 dimensions 3 levels; GPES = Global Perceived Effect Scale; HRQoL = health-related quality of life; IQR = interquartile range; MIC = minimal important change; NPRS = Numeric Pain Rating Scale; RMDQ = Roland-Morris Disability Questionnaire; SPLIT = stratified primary care for low back pain; UC = usual care.
↵a Based on established MIC criteria: ≥30% decrease from baseline for RMDQ and NPRS and a GPES score ≥3.
↵b Based on a cutoff RMDQ score ≥7.

Table 3.

Effect Estimates for Comparison of Cohorts (SPLIT vs Usual Care) for Primary and Secondary Outcomes Over the 6-Month Follow-Up

	Crude ß/OR (95% CI)^{^a}	P Value	Adjusted ß/OR (95% CI)^{^a}	P Value
Back-related disability (RMDQ, 0 to 24)
Raw score	−5.19 (−6.09 to −4.29)	≤.001	−2.94 (− 3.63 to −2.24)	≤.001
Achieved MIC, yes vs no^{^b}	7.07 (3.31 to 15.08)	≤.001	8.67 (3.98 to 18.89)	≤.001
Poor disability, yes vs no^{^c}	0.07 (0.003 to 0.13)	≤.001	0.24 (0.15 to 0.38)	≤.001
Pain intensity (NPRS, 0 to 10)
Raw score	−1.76 (−2.18 to −1.35)	≤.001	−0.88 (−1.18 to −0.57)	≤.001
Achieved MIC, yes vs no^{^b}	3.55 (1.94 to 6.48)	≤.001	3.50 (1.88 to 6.49)	≤.001
Perceived effect of treatment (GPES, −5 to +5)
Raw score	1.50 (1.08 to 1.91)	≤.001	1.40 (0.97 to 1.82)	≤.001
Achieved MIC, yes vs no^{^b}	4.66 (2.39 to 9.12)	≤.001	4.40 (2.22 to 8.71)	≤.001
HRQoL (EQ-5D-3L, 0 to 1)
Raw score	0.19 (0.16 to 0.23)	≤.001	0.11 (0.08 to 0.14)	≤.001

EQ-5D-3L = EuroQoL 5 dimensions 3 levels; GPES = Global Perceived Effect Scale; HRQoL = health-related quality of life; MIC = minimal important change; NPRS = Numeric Pain Rating Scale; OR = odds ratio; RMDQ = Roland-Morris Disability Questionnaire; SPLIT = stratified primary care for low back pain; UC = usual care.
↵a For continuous outcomes (RMDQ, NPRS, GPES, and EQ-5D-3L raw scores over time), crude/adjusted ß values were derived via a linear mixed-effects model for the comparison of UC vs SPLIT. For categorical outcomes (achieved MIC of RMDQ, NPRS, and GPES, along with poor disability), crude/adjusted OR values were derived via a logistic mixed-effects model for the comparison of UC vs SPLIT. Adjusted ß/OR and 95% CI values were adjusted for age, duration of low back pain episode, referred leg pain, and baseline STarT Back Screening Tool psychosocial subscale, NPRS, RMDQ, and EQ-5D-3L values.
↵b Based on established MIC criteria: ≥30% decrease from baseline for RMDQ and NPRS and a GPES score ≥3.
↵c Based on a cutoff RMDQ score ≥7.