Table 3. Adjusted Analyses According to Treatment Received for the Baseline Workers' Compensation and Nonworkers' Compensation Groups*.
| Treatment Effect (95% CI)† | ||||||
|---|---|---|---|---|---|---|
| Outcome Scale | WC Status | At 6 wk | At 3 mo | At 6 mo | At 1 yr | At 2 yr |
| SF-36 bodily pain‡ | Non-WC | 10.8 (8.0–13.5) | 17.8 (14.7–21) | 15.7 (12.4–19) | 12.2 (8.9–15.5) | 11 (7.7–14.4) |
| WC | 10.8 (3.1–18.5) | 11.8 (3.5–20.1) | 7.3 (−1.7–16.3) | 2.2 (−7.7–12.2) | −5.9 (−16.7–4.9) | |
| P | 0.99 | 0.18 | 0.086 | 0.06 | 0.003 | |
| SF-36 physical function‡ | Non-WC | 13.8 (11.2–16.4) | 18.1 (15.1–21.1) | 19. (16–22.3) | 16.4 (13.3–19.5) | 13.4 (10.3–16.5) |
| WC | 10.9 (3.8–18) | 12.4 (4.7–20.1) | 5.3 (−3–13.6) | 5 (−4.2–14.2) | 5 (−4.9–15) | |
| P | 0.45 | 0.17 | 0.002 | 0.02 | 0.11 | |
| Oswestry disability index§ | Non-WC | −15.5 (−17.6 to −13.3) | −16.1 (−18.5 to −13.6) | − 15.6 (−18.2 to −13) | −14.4 (−17 to −11.8) | −12.5 (− 15.2 to −9.9) |
| WC | −11.3 (−17.3 to −5.4) | −9.4(−15.8 to −2.9) | −4.8 (−11.8–2.2) | −2.2 (−9.9–5.5) | −2(−10.3–6.3) | |
| P | 0.20 | 0.054 | 0.004 | 0.003 | 0.018 | |
| Sciatica bothersomeness index¶ | Non-WC | NA | −4.6(−5.5 to −3.8) | NA | −3 (−3.8 to −2.1) | −2.6 (−3.5 to −1.8) |
| WC | NA | −2.6 (−4.8 to −0.4) | NA | −0.5 (−3–2) | 0.2 (−2.5–3) | |
| P | 0.084 | 0.067 | 0.049 | |||
| Satisfaction with symptoms (very/somewhat satisfied) | Non-WC | 48.3 (42.5–54.2) | 41.6 (34.5–48.7) | 35.8 (28.2–43.4) | 30.2 (22.4–38) | 22.5 (14.6–30.4) |
| WC | 42.6 (25.4–59.7) | 20.1 (−0.6–40.7) | 30.3 (8.7–51.9) | −6.5 (−32–19.1) | −3.6 (−31.7–24.5) | |
| P | 0.89 | 0.13 | 0.75 | 0.01 | 0.13 | |
| Self-rated improvement (major improvement) | Non-WC | 52 (46.2–57.7) | 39.7 (32.7–46.7) | 32.4 (25.1–39.7) | 24.5 (17.1–31.9) | 11 (3.5–18.5) |
| WC | 43.7 (26.9–60.5) | 31.8 (11.5–52) | 15.8 (−7.3–38.9) | 28.4 (3.9–52.9) | 17.4 (−9.9–44.8) | |
| P | 0.24 | 0.17 | 0.041 | 0.85 | 0.82 | |
| Working (full or part-time) | Non-WC | −20.8 (−26.8 to −14.9) | −3.4 (−8.4–1.6) | −0.5 (−4.3–3.3) | 1.9 (−2.2–6) | 0.8 (−3.4–5) |
| WC | −35.1 (−59.6 to −10.7) | −17.4 (−39.1–4.3) | −2.4 (−21.4–16.6) | 13.3 (−9–35.6) | 7.7 (−14.6–30.1) | |
| P | 0.67 | 0.47 | 0.93 | 0.41 | 0.63 | |
| Disability compensation (receiving, pending appeal) | Non-WC | 1.5 (0.4–2.7) | 0.2 (−1–1.3) | 0.2 (−1.1–1.6) | 0 (−1.3–1.4) | |
| WC | NA | 11 (−3.1–25.1) | 15.4 (−0.9–31.7) | −17 (−47.7–13.7) | −14.7 (−43–13.6) | |
| P | 0.44 | 0.19 | 0.25 | 0.29 | ||
Values have been adjusted for WC propensity score, age, gender, ethnicity, marriage status, work status, insurance coverage, compensation status, BMI, smoking status, presence or absence of joint disorders or migraine, any neurologic deficit, herniation results (type, location, level), baseline sciatica bothersomeness score, baseline outcome score, baseline satisfaction score, self-rated health trend, and center. Variables included in the WC propensity score include: cohort (randomized/observational), gender, physical importance of lifting weight, preferred to work fewer hours, occupation, expectations of returning to work with nonoperative treatment, depleted financial resources, duration of spine problems, SF-36 social function subscale score. NA denotes not available and WC denotes workers compensation.
The treatment effect is the difference in the mean change from baseline between the surgical group and the non-operative group.
The SF-36 scores range from 0 to 100, with higher scores indicating less severe symptoms.
The Oswestry Disability Index ranges from 0 to 100, with lower scores indicating less severe symptoms.
The Sciatica Bothersomeness Index ranges from 0 to 24, with lower scores indicating less severe symptoms.