Table 2

Baseline characteristics of participants in the treatment groups and for those with type I MCs

Amoxicillin (n=89)Placebo (n=91)Type I MCs amoxicillin
(n=60)
Type I MCs placebo
(n=58)
Age (mean (SD))44.7 (9.0)45.2 (9.0)46.0 (9.3)44.9 (9.3)
Women53 (60)52 (57)35 (58)35 (60)
Smoking, yes25 (28)21 (24)13 (22)18 (31)
Previous disc surgery18 (20)20 (22)12 (20)10 (17)
Educational level
 Primary school (9 years)10 (11)9 (10)4 (6.7)8 (14)
 High school (12 years)36 (41)42 (47)27 (45)21 (36)
 College or university (<4 years)27 (31)18 (20)11 (18)17 (29)
 University (≥4 years)15 (17)20 (22)16 (27)11 (19)
Employment status
 Working full time46 (52)43 (47)33 (57)32 (53)
 Partial sick leave14 (16)20 (22)7 (12)11 (19)
 Complete sick leave22 (25)16 (18)14 (24)11 (19)
 Disability pension3 (3)7 (8)3 (5)2 (3)
 Unemployed2 (2)3 (3)1 (2)2 (3)
 Student/other/unknown2 (2)2 (2)02 (3)
Physical workload
 Mostly sitting37 (48)26 (35)18 (30)28 (48)
 Job requires a lot of walking20 (26)20 (27)14 (23)12 (21)
 Job requires a lot of walking and lifting17 (22)24 (32)13 (22)9 (16)
 Job requires physically heavy work3 (4)4 (5)4 (6.7)2 (3.4)
Comorbidity*
 Score 1 (back pain only)62 (70)60 (66)40 (67)40 (69)
 Score 221 (24)27 (30)17 (28)13 (22)
 Score >26 (7)4 (4)3 (5.0)5 (8.6)
Use of healthcare in the month prior to inclusion24 (27)15 (17)17 (29)10 (17)
Use of medication the month prior to inclusion
 Non-opioid medication46 (52)52 (57)30 (52)34 (57)
 Opioid medication28 (32)26 (29)17 (29)10 (17)
Duration of back pain in years (median (IQR))3.0 (1.5–5.6)3.4 (1.7–7)4 (2–8)2.8 (1.5–5.2)
Back pain intensity (0–10)6.4 (1.2)6.3 (1.5)6.5 (1.1)6.3 (1.3)
Roland-Morris Disability Questionnaire (0–24)12.7 (4.7)12.8 (3.7)12.9 (4.3)12.3 (3.7)
EQ-5D-5L (-0.59–1)0.55 (0.19)0.54 (0.18)0.55 (0.18)0.56 (0.16)
  • N refers to the number of patients providing data.

  • Values are no/total no (%) unless stated otherwise.

  • *Functional Comorbidity Index33 – Score increased by 1 for each 18 diagnoses associated with decreased physical function.

  • MC, Modic changes.