Table 5

 Determinants of the direct medical, direct non-medical, productivity, and total costs assessed by Cox proportional hazards analysis with costs as outcome

Direct medical costsDirect non-medical costsFriction costs*Total costs
Values are exp(B) (95% confidence interval).
*Cost of production losses during the time when the work of the sick person was not replaced.
AS, ankylosing spondylitis; CLBP, chronic low back pain; FM, fibromyalgia.
FM v AS0.93 (0.45 to 1.88)1.61 (1.36 to 2.27)1.64 (1.20 to 2.33)2.17 (1.59 to 2.94)
p = 0.8p = 0.007p = 0.007p<0.0001
CLBP v AS1.12 (0.58 to 2.13)1.92 (1.43 to 2.56)1.49 (1.23 to 2.00)2.27 (1.69 to 3.03)
p = 0.7p<0.0001p = 0.01p<0.0001
Intervention1.30 (0.74 to 2.33)0.84 (0.66 to 1.08)1.03 (0.80 to 1.31)0.88 (0.71 to 1.15)
p = 0.4p = 0.2p = 0.8p = 0.3
Female sex1.52 (1.15 to 1.96)0.69 (0.53 to 0.92)
p = 0.003p = 0.009