Table 2.

Frequency and severity of back pain, limitation of daily activities, and days in bed due to back pain in the last month

	Treatment point
	Baseline (n = 1,648)	3 months (n = 1,467)	6 months (n = 1,423)	12 months (n = 1,302)	18 months (n = 1,200)
Back pain experienced
Yes, n (%)	1,574 (95.5)	1,360 (92.7)	1,297 (91.1)	1,124 (86.3)	1,003 (83.6)
No, n (%)	70 (4.2)	97 (6.6)	112 (7.9)	166 (12.7)	184 (15.3)
Missing/unknown, n (%)	4 (0.2)	10 (0.7)	14 (1.0)	12 (0.9)	13 (1.1)
Frequency of back pain
n	1,574	1,360	1,297	1,124	1,003
Once or twice, n (%)	60 (3.8)	154 (11.3)	209 (16.1)	203 (18.1)	223 (22.2)
A few times, n (%)	156 (9.9)	391 (28.8)	366 (28.2)	315 (28.0)	251 (25.0)
Fairly often, n (%)	288 (18.3)	257 (18.9)	205 (15.8)	171 (15.2)	177 (17.6)
Every day or almost every day, n (%)	1,036 (65.8)	507 (37.3)	451 (34.8)	370 (32.9)	300 (29.9)
Missing/unknown, n (%)	34 (2.2)	51 (3.8)	66 (5.1)	65 (5.8)	52 (5.2)
Severity of back pain
n	1574	1360	1297	1124	1003
Minor, n (%)	139 (8.8)	315 (23.2)	381 (29.4)	370 (32.9)	375 (37.4)
Moderate/severe, n (%)	1,404 (89.2)	997 (73.3)	854 (65.8)	690 (61.4)	574 (57.2)
Missing/unknown, n (%)	31 (2.0)	48 (3.5)	62 (4.8)	64 (5.7)	54 (5.4)
Limitation of activities
n (%)	1,574	1,360	1,297	1,124	1,003
No limitation, n (%)	158 (10.0)	259 (19.0)	319 (24.6)	306 (27.2)	318 (31.7)
Minor, n (%)	237 (15.1)	355 (26.1)	356 (27.4)	304 (27.0)	244 (24.3)
Moderate/severe, n (%)	1,162 (73.8)	718 (52.8)	580 (44.7)	475 (42.3)	413 (41.2)
Missing/unknown, n (%)	17 (1.1)	28 (2.1)	42 (3.2)	39 (3.5)	28 (2.8)
Days in bed due to back pain
None, n (%)	1,237 (75.1)	1,247 (85.0)	1,213 (85.2)	1,055 (81.0%)	950 (79.2)
At least one, n (%)	324 (19.7)	108 (7.4)	78 (5.5)	62 (4.8%)	49 (4.1)
Median (Q1, Q3)a	7 (3, 15)	4 (2, 10)	3 (2, 6)	3.5 (2, 6)	3 (2, 10)
Missing/unknown, n (%)	87 (5.3)	112 (7.6)	132 (9.3)	185 (14.2%)	201 (16.8)

^aFor those patients with ≥1 day in bed due to back pain

All changes: P < 0.001 compared to baseline (sign test)