Rhiannon J. Deierhoi

Timing of Surgical Antibiotic Prophylaxis and the Risk of Surgical Site Infection

IMPORTANCE Timing of prophylactic antibiotic administration for surgical procedures is a nationally mandated and publicly reported quality metric sponsored by the Centers for Medicare and Medicaid Services Surgical Care Improvement Project. Numerous studies have failed to demonstrate that adherence to the Surgical Care Improvement Project prophylactic antibiotic timely administration measure is associated with decreased surgical site infection (SSI). OBJECTIVE; To determine whether prophylactic antibiotic timing is associated with SSI occurrence. DESIGN Retrospective cohort study using national Veterans Affairs patient-level data on prophylactic antibiotic timing for orthopedic, colorectal, vascular, and gynecologic procedures from 2005 through 2009. SETTING National Veterans Affairs Surgical Care Improvement Project data from 112 Veterans Affairs hospitals and matched Veterans Affairs Surgical Quality Improvement Program data. PATIENTS Patients undergoing hip or knee arthroplasty, colorectal surgical procedures, arterial vascular surgical procedures, and hysterectomy. INTERVENTION Timing of prophylactic antibiotic administration with respect to surgical incision time. MAIN OUTCOMES AND MEASURES Data for prophylactic antibiotic agent, prophylactic antibiotic timing with respect to surgical incision, and patient and procedure risk variables were assessed for their relationship with the occurrence of a composite superficial or deep incisional SSI within 30 days after the procedure. Nonlinear generalized additive models were used to examine the association between antibiotic timing and SSI. RESULTS Of the 32,459 operations, prophylactic antibiotics were administered at a median of 28 minutes (interquartile range, 17-39 minutes) prior to surgical incision, and 1497 cases (4.6%) developed an SSI. Compared with procedures with antibiotic administration within 60 minutes prior to incision, higher SSI rates were observed for timing more than 60 minutes prior to incision (unadjusted odds ratio [OR] = 1.34; 95% CI, 1.08-1.66) but not after incision (unadjusted OR = 1.26; 95% CI, 0.92-1.72). In unadjusted generalized additive models, we observed a significant nonlinear relationship between prophylactic antibiotic timing and SSI when considering timing as a continuous variable (P = .01). In generalized additive models adjusted for patient, procedure, and antibiotic variables, no significant association between prophylactic antibiotic timing and SSI was observed. Vancomycin hydrochloride was associated with higher SSI occurrence for orthopedic procedures (adjusted OR = 1.75; 95% CI, 1.16-2.65). Cefazolin sodium and quinolone in combination with an anaerobic agent were associated with fewer SSI events (cefazolin: adjusted OR = 0.49; 95% CI, 0.34-0.71; quinolone: adjusted OR = 0.55; 95% CI, 0.35-0.87) for colorectal procedures. CONCLUSIONS AND RELEVANCE The SSI risk varies by patient and procedure factors as well as antibiotic properties but is not significantly associated with prophylactic antibiotic timing. While adherence to the timely prophylactic antibiotic measure is not bad care, there is little evidence to suggest that it is better care.

Preoperative oral antibiotics reduce surgical site infection following elective colorectal resections.

BACKGROUND: Surgical site infection is a major cause of morbidity after colorectal resections. Despite evidence that preoperative oral antibiotics with mechanical bowel preparation reduce surgical site infection rates, the use of oral antibiotics is decreasing. Currently, the administration of oral antibiotics is controversial and considered ineffective without mechanical bowel preparation. OBJECTIVE: The aim of this study is to examine the use of mechanical bowel preparation and oral antibiotics and their relationship to surgical site infection rates in a colorectal Surgical Care Improvement Project cohort. DESIGN: This retrospective study used Veterans Affairs Surgical Quality Improvement Program preoperative risk and surgical site infection outcome data linked to Veterans Affairs Surgical Care Improvement Project and Pharmacy Benefits Management data. Univariate and multivariable models were performed to identify factors associated with surgical site infection within 30 days of surgery. SETTINGS: This study was conducted in 112 Veterans Affairs hospitals. PATIENTS: Included were 9940 patients who underwent elective colorectal resections from 2005 to 2009. MAIN OUTCOME MEASURE: The primary outcome measured was the incidence of surgical site infection. RESULTS: Patients receiving oral antibiotics had significantly lower surgical site infection rates. Those receiving no bowel preparation had similar surgical site infection rates to those who had mechanical bowel preparation only (18.1% vs 20%). Those receiving oral antibiotics alone had an surgical site infection rate of 8.3%, and those receiving oral antibiotics plus mechanical bowel preparation had a rate of 9.2%. In adjusted analysis, the use of oral antibiotics alone was associated with a 67% decrease in surgical site infection occurrence (OR=0.33, 95% CI 0.21–0.50). Oral antibiotics plus mechanical bowel preparation was associated with a 57% decrease in surgical site infection occurrence (OR=0.43, 95% CI 0.34–0.55). Timely administration of parenteral antibiotics (Surgical Care Improvement Project-1) had a modest protective effect, with no effect observed for other Surgical Care Improvement Project measures. Hospitals with higher rates of oral antibiotics use had lower surgical site infection rates (R2 = 0.274, p < 0.0001). LIMITATIONS: Determination of the use of oral antibiotics and mechanical bowel preparation is based on retrospective prescription data, and timing of actual administration cannot be determined. CONCLUSIONS: Use and type of preoperative bowel preparation varied widely. These results strongly suggest that preoperative oral antibiotics should be administered for elective colorectal resections. The role of oral antibiotics independent of mechanical bowel preparation should be examined in a prospective randomized trial.

The Relationship Between Timing of Surgical Complications and Hospital Readmission

IMPORTANCE Readmissions after surgery are costly and may reflect quality of care in the index hospitalization. OBJECTIVES To determine the timing of postoperative complications with respect to hospital discharge and the frequency of readmission stratified by predischarge and postdischarge occurrence of complications. DESIGN, SETTING, AND PARTICIPANTS This is a retrospective cohort study of national Veterans Affairs Surgical Quality Improvement Program preoperative risk and outcome data on the Surgical Care Improvement Project cohort for operations performed from January 2005 to August 2009, including colorectal, arthroplasty, vascular, and gynecologic procedures. The association between timing of complication with respect to index hospitalization and 30-day readmission was modeled using generalized estimating equations. MAIN OUTCOME AND MEASURE All-cause readmission within 30 days of the index surgical hospitalization discharge. RESULTS Our study of 59 273 surgical procedures performed at 112 Department of Veterans Affairs (VA) hospitals found an overall complication rate of 22.6% (predischarge complications, 71.9%; postdischarge complications, 28.1%). The proportion of postdischarge complications varied significantly, from 8.7% for respiratory complications to 55.7% for surgical site infection (P < .001). The overall 30-day readmission rate was 11.9%, of which only 56.0% of readmissions were associated with a currently assessed complication. Readmission was predicted by patient comorbid conditions, procedure factors, and the occurrence of postoperative complications. Multivariable generalized estimating equation models of readmission adjusting for patient and procedure characteristics, hospital, and index length of stay found that the occurrence of postdischarge complications had the highest odds of readmission (odds ratio, 7.4-20.8) compared with predischarge complications (odds ratio, 0.9-1.48). CONCLUSIONS AND RELEVANCE More than one-quarter of assessed complications are diagnosed after hospital discharge and strongly predict readmission. Hospital discharge is an insufficient end point for quality assessment. Although readmission is associated with complications, almost half of readmissions are not associated with a complication currently assessed by the Veterans Affairs Surgical Quality Improvement Program.

Oral antibiotic bowel preparation reduces length of stay and readmissions after colorectal surgery.

BACKGROUND Oral antibiotic bowel preparation (OABP) before colorectal resection has been shown to reduce surgical site infections. We examined whether OABP decreases length of stay (LOS) and readmissions for colorectal surgery. STUDY DESIGN This retrospective study used national Veterans Affairs Surgical Quality Improvement Program preoperative risk and outcomes data linked to Veterans Affairs Administrative and Pharmacy Benefits Management data on patients undergoing elective colorectal resections from 2005 to 2009. Exclusion criteria were preoperative LOS >2 days, American Society of Anesthesiologists class 5, or death before discharge. Patient and surgery characteristics, bowel preparation use, presence of an ostomy, indication for surgery, and indication for readmission using ICD-9 codes were determined. Negative binomial regression was used to model LOS. Logistic regression analyses modeled 30-day readmission. RESULTS Of the 8,180 patients, 1,161 (14.2%) were readmitted within 30 days. Length of stay and readmissions varied significantly by bowel preparation, procedure, presence of an ostomy, and American Society of Anesthesiologists class. Oral antibiotic bowel preparation was associated with a below-median postoperative LOS (negative binomial regression estimate = -0.1159; p < 0.0001) and fewer 30-day readmissions (adjusted odds ratio = 0.81; 95% CI, 0.68-0.97). Overall, 4.9% were readmitted for infections (ICD-9 codes) and this varied by bowel preparation (no preparation 6.1%, mechanical 5.4%, OABP 3.9%; p = 0.001). The readmission rate for noninfectious reasons was 9.3% and did not differ significantly by bowel preparation (no preparation 9.9%, mechanical 9.6%, OABP 8.8%; p = 0.38). CONCLUSIONS Oral antibiotic bowel preparation before elective colorectal surgery is associated with shorter postoperative LOS and lower 30-day readmission rates, primarily due to fewer readmissions for infections. Prospective studies are needed to verify these results.

Choice of Intravenous Antibiotic Prophylaxis for Colorectal Surgery Does Matter

BACKGROUND The Surgical Care Improvement Program endorses mandatory compliance with approved intravenous prophylactic antibiotics; however, oral antibiotics are optional. We hypothesized that surgical site infection (SSI) rates may vary depending on the choice of antibiotic prophylaxis. STUDY DESIGN A retrospective cohort study of elective colorectal procedures using Veterans Affairs Surgical Quality Improvement Program (VASQIP) and SSI outcomes data was linked to the Office of Informatics and Analytics (OIA) and Pharmacy Benefits Management (PBM) antibiotic data from 2005 to 2009. Surgical site infection rates by type of IV antibiotic agent alone (IV) or in combination with oral antibiotic (IV + OA) were determined. Generalized estimating equations were used to examine the association between type of antibiotic prophylaxis and SSI for the entire cohort and stratified by use of oral antibiotics. RESULTS After 5,750 elective colorectal procedures, 709 SSIs (12.3%) developed within 30 days. Oral antibiotic + IV (n = 2,426) had a lower SSI rate than IV alone (n = 3,324) (6.3% vs 16.7%, p < 0.0001). There was a significant difference in the SSI rate based on type of preoperative IV antibiotic given (p ≤ 0.0001). Generalized estimating equations adjusting for significant covariates of age, body mass index, procedure work relative value units, and operation duration demonstrated an independent protective effect of oral antibiotics (odds ratio [OR] 0.37, 95% CI 0.29 to 0.46), as well as increased rates of SSI associated with ampicillin/sulbactam (OR 2.21, 95% CI 1.37 to 3.56) and second generation cephalosporins (cefoxitin, OR 2.50, 95% CI 1.83 to 3.42; cefotetan, OR 2.70, 95% CI 1.72 to 4.22) when compared with first generation cephalosporin/metronidazole. CONCLUSIONS The choice of IV antibiotic was related to the SSI rate; however, oral antibiotics were associated with reduced SSI rate for every antibiotic class.

Association between Surgical Care Improvement Program venous thromboembolism measures and postoperative events

BACKGROUND In 2006, the Surgical Care Improvement Program (SCIP) implemented measures to reduce venous thromboembolism (VTE). There are little data on whether these measures reduce VTE rates. This study proposed to examine associations between SCIP-VTE adherence and VTE rates. METHODS SCIP-VTE adherence for 30,531 surgeries from 2006 to 2009 was linked with VA Surgical Quality Improvement Program data. Patient demographics, comorbidities, and surgical characteristics associated with VTE were summarized. VTE rates were compared by SCIP-VTE adherence. Multivariable logistic regression was used to model VTE by adherence, adjusting for multiple associated factors. RESULTS Of 30,531 surgeries, 89.9% adhered to SCIP-VTE; 1.4% experienced VTE. Logistic regression identified obesity, smoking, functional status, weight loss, emergent status, age older than 64 years, and surgical time as associated with VTE. SCIP-VTE was not associated with VTE (1.4% vs 1.33%; P = .3), even after adjustment. CONCLUSIONS This study identified several important risk factors for VTE but found no association with SCIP-VTE adherence.

Adverse cardiac events in patients with coronary stents undergoing noncardiac surgery: a systematic review

BACKGROUND When patients with drug-eluting stents (DES) present for surgery, current guidelines recommend delaying elective surgeries until 1 year of dual antiplatelet therapy has been completed. METHODS We performed a systematic literature review of the major adverse cardiac events (MACE) associated with noncardiac surgery in patients with DES. RESULTS Twenty-eight of 358 studies met inclusion criteria. Overall, MACE rates decreased as time to surgery increased and varied from 0% to 18% for surgeries within 1 year as compared with 0% to 12% for surgery more than 1 year after a stent. In addition, the current literature showed limited evidence for a protective effect of continuing perioperative dual antiplatelet therapy on MACE rates. CONCLUSIONS The current literature supports a significant decrease in MACE when surgery is performed 1 year after DES placement; however, the level of evidence is weak. Larger studies are needed to determine the safe interval for surgery after stent placement.

Improved outcomes associated with a revised quality measure for continuing perioperative β-blockade.

IMPORTANCE The Surgical Care Improvement Project perioperative β-blocker (BB) (SCIP-BB) continuation measure was revised in 2012 to incorporate inpatient BB continuation after discharge from the postanesthesia care unit. OBJECTIVE To determine whether adherence to the original or revised SCIP-BB measure is associated with decreased adverse events. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study using national Veterans Affairs patient-level data on adherence to the original SCIP-BB measure and inpatient BB continuation for operations between July 2006 and August 2009. METHODS Data for SCIP-BB measure adherence, inpatient BB continuation, and patient and procedure risk variables were used to estimate the associations between adherence to the original and revised SCIP-BB measures and outcomes of major adverse cardiovascular or cerebrovascular events (MACCEs) and their components of cardiovascular events, cerebrovascular events, and 30-day mortality. In addition to unadjusted estimates, propensity score matching and bootstrapping were used to estimate the associations and generate 95% CIs. MAIN OUTCOMES AND MEASURES Major adverse cardiovascular or cerebrovascular events. RESULTS Of 14,420 nonemergent operations with at least 2 postoperative inpatient days, 13,170 (91.3%) adhered to the original SCIP-BB measure, and 480 (3.3%) experienced a MACCE. Propensity score-matched analyses showed that adherence to the original SCIP-BB measure was not associated with MACCEs (odds ratio [OR], 1.00; 95% CI, 0.66-1.54) but was associated with increased cerebrovascular events (OR, 3.01; 95% CI, 1.00-10.07). Adherence to the revised SCIP-BB measure occurred in 11,597 (80.4%), and in matched analysis adherence was associated with decreased MACCEs (OR, 0.75; 95% CI, 0.57-0.95), cardiovascular events (OR, 0.66; 95% CI, 0.46-0.93), and 30-day mortality (OR, 0.74; 95% CI, 0.53-0.98). Adherence to the revised SCIP-BB measure was not associated with increased cerebrovascular events (OR, 1.22; 95% CI, 0.62-2.38). CONCLUSIONS AND RELEVANCE Adherence to the original SCIP-BB measure was associated with increased cerebrovascular events but not improved cardiovascular event outcomes. β-Blocker continuation consistent with the revised SCIP-BB measure is associated with reduced MACCEs, cardiovascular events, and 30-day mortality. These data provide a cautionary tale of implementing performance measures before they have been rigorously tested. Although the observed associations between adherence to the revised SCIP-BB measure and outcomes are promising, they should be evaluated in the postimplementation period.

Agreement between patient survey and medical chart: Pitfalls in measurement strategies for hernia recurrence

BACKGROUND Little information is available on agreement between patient-reported outcomes and data collected from medical chart abstraction (MCA) for recurring events. Recurring conditions pose a risk of misclassification, especially when events occur relatively close together in time. We examined agreement, predictors of agreement, and relative accuracy of patient survey and MCA for assessment of outcomes of incisional hernia repair (IHR). METHODS Surveys to assess hernia outcomes were mailed to 1,124 living patients who underwent ≥ 1 IHR during 1998-2002 at 16 Veterans Affairs Medical Center study sites. Patients were asked if they developed a recurrence or an infection at their hernia site. Physician-abstracted data from the medical chart were compared with patient response. Chi-square tests were used to assess significance. RESULTS Of 487 (43.3%) individuals responding to the survey, 33 (6.8%) with >1 re-repair during 1998-2002 and 98 (20.5%) with a repair before the 1998-2002 period were excluded from the analysis. Although recurrence rates derived from self-reported data and data abstracted from the medical chart were similar (29.3% and 26.1%, respectively), overall concordance was low. Only 49% (n = 54) of self-reported recurrences were confirmed by data abstracted from the medical chart. In addition, 16 (8.3%) recurrences abstracted from the medical chart were not reported by the patient. Factors associated with discordance were high reported pain intensity (P = .02), poorer general health (P = .03), and poorer perceived repair results (P < .0001). CONCLUSION Multiple recurrences and subsequent operations across the study period complicate the interpretation of both patient response and data abstracted from the medical chart when referring to a hernia repair. Further study on how best to assess treatment outcomes for recurring conditions is warranted.