Table 1.
Baseline characteristics of patients in the trials included in the meta‐analysis
| Study | Country | Publication year | Study design | BMI (kg/m2) | No. of patients | type of surgical procedure | Male/female | Age (mean ± SD, year) | NOS score |
|---|---|---|---|---|---|---|---|---|---|
| Kalanithi et al.5 | USA | 2012 | Retrospective cross‐sectional study | <25.0 | 83,152 | ACDF/posterior cervical fusion | NA | NA | 7 |
| ≥40 | 1455 | ACDF/posterior cervical fusion | NA | NA | |||||
| Sielatycki et al.14 | USA | 2016 | Prospective cohort | <35 | 219 | ACDF | 124/95 | 52.8 ± 10.3 | 7 |
| ≥35 | 80 | ACDF | 36/44 | 51.3 ± 9.2 | |||||
| Buerba et al.22 | USA | 2014 | Retrospective cohort | 18.5–29.9 | 2072 | ACDF | 1024/1003 | NA | 7 |
| 30–34.9 | 915 | ACDF | 508/407 | NA | |||||
| 35–39.9 | 419 | ACDF | 180/239 | NA | |||||
| ≥40 | 265 | ACDF | 97/168 | NA | |||||
| Narain et al.23 | USA | 2018 | Retrospective cohort | <25.0 | 58 | ACDF | 29/29 | 49.5 ± 11.3 | 7 |
| 25.0–29.9 | 104 | ACDF | 60/44 | 48.8 ± 9.2 | |||||
| 30.0–34.9 | 69 | ACDF | 44/25 | 51.8 ± 11.2 | |||||
| ≥35.0 | 46 | ACDF | 22/24 | 53.4 ± 11.2 | |||||
| Phan et al.24 | USA | 2017 | Retrospective cohort | ≤30 | 322 | Posterior cervical fusion | 184/138 | NA | 7 |
| >30 | 202 | Posterior cervical fusion | 103/99 | NA | |||||
| Wilson et al.25 | USA | 2017 | Retrospective cohort | <18.5 | 17 | ACDF | NA | NA | 6 |
| 18.5–24.99 | 271 | ACDF | NA | NA | |||||
| 25–29.99 | 275 | ACDF | NA | NA | |||||
| >30 | 194 | ACDF | NA | NA | |||||
| Sami Walid et al.26 | USA | 2010 | Retrospective cohort | <30 | 318 | ACDF | NA | NA | 6 |
| ≥30 | 287 | ACDF | NA | NA |
ACDF, anterior cervical discectomy and fusion; BMI, body mass index; NA, not available; SD, standard deviation.