Table 3.

Poisson regression models clustered by hospital to estimate changes in satisfaction between functional improvement levels at 12 months following surgery. IRR is Incidence relative risk ratio. CI is confidence interval. Poisson models adjusted for age, sex, smoking status, insurance, diagnosis, baseline function score, ASA status, and surgery invasiveness

	No Improvement in back pain n=159			Improvement in back pain n=265
Functional Improvement	% Satisfied	Unadjusted IRR (95%CI)	Adjusted IRR (95%CI)	% Satisfied	Unadjusted IRR (95%CI)	Adjusted IRR (95%CI)
None/worse ≤0)	55.55%	Ref	Ref	76.47%	Ref	Ref
Minimal (1 to 14)	63.79%	1.29** (1.17–1.42)	1.14 (0.95–1.36)	82.14%	1.15 (0.89–1.48)	1.16 (0.88 – 1.52)
Minor (15 to 29)	80.00%	1.71** (1.26–2.33)	1.66** (1.27–2.16)	94.74%	1.33* (1.02–1.74)	1.31 (1.00–1.71)
Major (≥30)	82.35%	1.98** (1.44–2.74)	2.30** (1.71–3.11)	95.96%	1.44* (1.14–1.84)	1.40* (1.08 – 1.81)

^**=<0.001;

^*<0.05