Table 8.

Included Studies Evaluating Preoperative Hemoglobin A1c Levels and Postoperative Functional Outcomes, Length of Stay, and Cost.

First author, year	VAS	JOA	ODI	Fusion or nonunion rate	LOS	Cost
Cancienne, 2017 (ACDF)	NR	NR	NR	NR	NR	NR
Walid, 2010 (ACDF, LMD, LDF)	NR	NR	NR	NR	No DM: 1.42+/-1.984, HbA1c: 1.43 +/- 1.165, DM: 2.52 +/- 3.991	No DM: 28 363 +/- 7673*, HbA1c: 29 420 +/- 6130, DM: 36 748 +/- 31 970* p < 0.05 between DM and No DM groups*
					No DM: 2.75 +/- 4.318, HbA1c: 2.48 +/- 2.926, DM: 2.48 +/- 1.094	No DM: 23 115 +/- 14 608, HbA1c: 22 306 +/- 7702, DM: 23 644 +/- 7068
					No DM: 4.68 +/- 2.509*, HbA1c: 6.96 +/- 5.897*, DM: 5.55 +/- 3.615, p < 0.05 between no DM and HbA1c groups*	No DM: 54 914 +/- 14 034*, HbA1c: 65 974 +/- 18 341*, DM: 61 536 +/- 14 527 p < 0.05 between no DM and HbA1c groups*
Cancienne, 2017 (LD)	NR	NR	NR	NR	NR	NR
Takahashi, 2013 (PLF)	Low back pain: HbA1c >6.5: 29.3 vs HbA1c<6.5: 17.9, p = 0.013* Leg numbness: HbA1c >6.5: 37.9 vs HbA1c<6.5: 37.1 vs 27.9, p = 0.09	JOA Final FU: HbA1c>6.5, 24.4 vs HbA1c<6.5, 22.7, p = 0.137	NR	Nonunion rate: HbA1c>6.5: 20% HbA1c<6.5: 3%, p = 0.095*	NR	NR
Moazzeni, 2018 (PLF)	Preop: 7.8 vs 7.1, p < 0.001*	NR	Preop: 67.6 vs. 55.1, p < 0.001*	Fusion rate at 1 yr: HbA1c<6.5, 78% HbA1c>6.5, 53%, p = 0.002*	NR	NR
	2wk: 5.4 vs 4.4, p = 0.003*		2wk: 54.3 vs. 40.8, p < 0.001*
	6mo: 4.2 vs. 3.6, p = 0.08		6mo: 45.5 vs 34.7, p < 0.001*
	1yr: 3.5 vs. 2.9, p = 0.07		1yr: 40.7 vs 31.5, p = 0.002*
Hwang, 2019 (PLF)	NR	NR	NR	NR	NR	NR

Abbreviations: ACDF: Anterior Cervical Discectomy and Fusion, PLF: Posterior lumbar fusion, LMD: Lumbar Microdiscectomy, LDF: Lumbar Decompression and Fusion, LD: Lumbar Decompression, NR: Not reported, HbA1c: Hemoglobin A1c, VAS: Visual Analogue Scale, ODI: Oswestry Disability index, JOA: Japanese Orthopedic Association.

Bold*= Demonstrated statistical significance.