Analysis of a ten step protocol to decrease postoperative spinal wound infections

Table 1 Studies from orthopedic literature evaluating preoperative hemoglobin A1c and surgical site infections

Ref.	Study design(level of evidence)	Surgery performed	Groups	Main outcome	Significance
Hikata et al[23] (2013)	Retrospective cohort (IV)	Adult elective posterior instrumented thoracic and lumbar spinal arthrodesis	Non-diabetics (n = 309), Controlled diabetics (HbA1c < 7.0; n = 19), Uncontrolled diabetics (HbA1c ≥ 7.0; n = 17)	10 (3.2%) SSI in non-diabetic group, No SSI in controlled diabetic group, 6 (35.3%) SSIs in uncontrolled diabetic group	Diabetes was an independent risk factor for SSI (P = 0.0005), Significantly higher rate of infection in diabetics with HbA1c ≥ 7.0 (P = 0.006)
Adams et al[21] (2013)	Retrospective cohort (II)	Primary total knee arthroplasty	Non-diabetics (n = 32924), Controlled diabetics (HbA1c < 7.0; n = 5042), Uncontrolled diabetics (HbA1c ≥ 7.0; n = 2525)	216 (0.7%) deep infections in non-diabetics, 58 (1.2%) in controlled diabetics, and 13 (0.5%) in uncontrolled diabetics	No significant association between HbA1c level and deep infection
Harris et al[22] (2013)	Retrospective cohort (IV)	Total joint arthroplasty	Controlled diabetics (HbA1c < 7.0; n = 3961), Uncontrolled diabetics (HbA1c ≥ 7.0; n = 2127)	Identical percentage of patients in both groups developed superficial and deep infections	Significant increase in overall complications (P = 0.028), but not infections, for diabetics with HbA1c ≥ 7.0
Iorio et al[17] (2012)	Retrospective cohort (IV)	Primary or revision total hip or knee arthroplasty	Controlled diabetics (HbA1c < 7.0; n = 191), Uncontrolled diabetics (HbA1c ≥ 7.0; n = 85)	5 (2.6%) infections in controlled diabetics, 5 (5.9%) infections in uncontrolled diabetics	Increased rate of infections in uncontrolled diabetics without statistical significance (P = 0.293)
Myers et al[19] (2012)	Retrospective cohort (III)	Ankle and hindfoot fusions	Non-diabetics (n = 74), Controlled diabetics (HbA1c < 7.0; n = 30), Uncontrolled diabetics (HbA1c ≥ 7.0; n = 44)	1 (1.4%) SSI in non-diabetics, 2 (6.7%) SSI in controlled diabetics, 12 (27.3%) SSI in uncontrolled diabetics	Significantly higher rate of SSI in uncontrolled vs controlled diabetics (P < 0.05)
Jämsen et al[18] (2010)	Retrospective cohort (IV)	Primary total knee arthroplasty	Patients with HbA1c < 6.5 (n = 205), Patients with HbA1c ≥ 6.5 (n = 176)	No infections in patients with HbA1c < 6.5, 5 infections in patients with HbA1c ≥ 6.5 (2.84%)	Significant increase in infection rate in patients with HbA1c ≥ 6.5 (P = 0.015)
Lamloum et al[20] (2009)	Retrospective cohort (IV)	Any orthopaedic surgical procedure	Controlled diabetics (HbA1c < 7.0; n = 80), Uncontrolled diabetics (HbA1c ≥ 7.0; n = 238)	10 SSIs in controlled diabetics (12.5%), 33 SSIs in uncontrolled diabetics (13.9%)	No significant difference in SSI occurrence between the two groups (P > 0.05)
Marchant et al[16] (2009)	Retrospective cohort (III)	Total joint arthroplasty	Non-diabetics (n = 920555), Controlled diabetics (HbA1c < 7.0; n = 105485), Uncontrolled diabetics (HbA1c ≥ 7.0; n = 3973)	3807 (0.41%) non-diabetics with infection, 405 (0.38%) controlled diabetics with infection, 47 (1.18%) uncontrolled diabetics with infection	Uncontrolled diabetics had a statistically significant increased rate of infection compared to patients without or with controlled diabetes (P = 0.002)

HbA1c: Hemoglobin A1C; SSI: Surgical site infections.