Assessing specific secondary ICD-9-CM codes as potential predictors of surgical site infections

Rates of Infection After ACL Reconstruction in Pediatric and Adolescent Patients: A MarketScan Database Study of 44,501 Patients

BACKGROUND

Numerous studies have demonstrated an increase in the number of anterior cruciate ligament (ACL) reconstruction procedures performed in pediatric patients. Despite this, most knowledge of surgical site infection rates after these procedures are based on adult studies and data is currently limited in pediatric patients. The purpose of this study was to describe and analyze the rates of infection after ACL reconstruction among pediatric patients and adolescent patients (compared with young adult patients) utilizing the MarketScan Commercial Claims and Encounters Database.

METHODS

The Truven Health Analytics MarketScan Commercial Claims and Encounters database was assessed to access health care utilization data for privately insured individuals aged 5 to 30 years old. ACL reconstruction records performed between 2006 and 2018 were identified using Current Procedures Terminology (CPT) codes. International Classification of Diseases Ninth Revision (ICD-9), Tenth (ICD-10) codes and CPT codes were used to identify patients requiring treatment for infection. All patients had at least 180 days of insurance coverage after intervention.

RESULTS

A total of 44,501 individuals aged below 18 years old and 63,495 individuals aged 18 to 30 years old that underwent arthroscopic ACL reconstruction were identified. There were no differences in infection rates between those below 18 years old (0.52%) and those above 18 years old (0.46%, P=0.227). However, among patients below 18 years old, patients below 15 years old had a significantly lower rate of infection at 0.37% compared with adolescents (15 to 17 y old) at 0.55% (P=0.039). Among young adults, males had higher rates of infection than females (0.52% vs. 0.37%), while no difference was observed in the pediatric and adolescent population (0.58% vs. 0.47%, P=0.109).

CONCLUSION

Utilizing an insurance database, this study demonstrated that rates of infection after ACL Reconstruction in a pediatric/adolescent population are low (0.52%) and similar to rates in young adults. Infection rates after ACLR reconstruction appear to be slightly lower in patients under 15 years of age (0.37%).

LEVEL OF EVIDENCE

Level III-Retrospective comparative study.

Characteristics of Antibiotic Prophylaxis and Risk of Surgical Site Infections in Primary Total Hip and Knee Arthroplasty

BACKGROUND

Despite numerous antibiotic prophylaxis options for total hip arthroplasty (THA) and total knee arthroplasty (TKA), an assessment of practice patterns and comparative effectiveness is lacking. We aimed to characterize antibiotic utilization patterns and associations with infection risk and hypothesized differences in infection risk based on regimen.

METHODS

A retrospective cohort study was performed using data from 436,724 THA and 862,918 TKA (Premier Healthcare Database; 2006-2016). Main exposures were antibiotic type and duration: day of surgery only (day 0) or through postoperative day 1 (day 1). The primary outcome was surgical site infection (SSI) <30 days postoperation. Mixed-effect models measured associations between prophylaxis regimen and SSI as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

SSI prevalence was 0.21% (n = 914) for THA and 0.22% (n = 1914) for TKA. Among THA procedures, the most commonly used antibiotics were cefazolin (74.1%), vancomycin (8.4%), "other" antibiotic combinations (7.1%), vancomycin + cefazolin (5.1%), and clindamycin (3.3%). Here, 51.8% received prophylaxis on day 0 only, whereas 48.2% received prophylaxis through day 1. Similar patterns existed for TKA. Relative to cefazolin, higher SSI odds were seen with vancomycin (OR = 1.36; CI 1.09-1.71) in THA and with vancomycin (OR = 1.29; CI = 1.10-1.52), vancomycin + cefazolin (OR = 1.35; CI = 1.12-1.64), clindamycin (OR = 1.38; CI = 1.11-1.71), and "other" antibiotic combinations (OR = 1.28; CI = 1.07-1.53) in TKA. Prophylaxis duration did not alter SSI odds. Results were corroborated in sensitivity analyses.

CONCLUSION

Antibiotic prophylaxis regimens other than cefazolin were associated with increased SSI risk among THA/TKA patients. These findings emphasize a modifiable intervention to mitigate infection risk.

Symptomatic human immunodeficiency virus-infected patients have poorer outcomes following emergency general surgery: A study of the nationwide inpatient sample

BACKGROUND

The impact of human immunodeficiency virus (HIV) infection on outcomes following common emergency general surgery procedures has not been evaluated since the widespread introduction of highly active antiretroviral therapy.

METHODS

A retrospective cohort study was conducted using the Nationwide Inpatient Sample. Records of patients who underwent laparoscopic or open appendectomy, cholecystectomy, or colon resection after emergency admission from 2004 to 2011 were obtained. Outcomes analyzed included in-hospital mortality, length of stay, total charges, and selected postoperative complications. Patients were divided among three groups, HIV-negative controls, asymptomatic HIV-positive patients, and symptomatic HIV/acquired immune deficiency syndrome (AIDS) patients. Data were analyzed using χ and multivariable regression with propensity score matching among the three groups, with p value less than 0.05 significant.

RESULTS

There were 974,588 patients identified, of which 1,489 were HIV-positive and 1,633 were HIV/AIDS-positive. The HIV/AIDS patients were more likely to die during their hospital stay than HIV-negative patients (4.4% vs. 1.6%, adjusted odds ratio, 3.53; 95% confidence interval [CI], 2.67-4.07; p < 0.001). The HIV/AIDS patients had longer hospital stays (7 days vs. 3 days; adjusted difference, 3.66 days; 95% CI, 3.53-4.00; p < 0.001) and higher median total charges than HIV-negative patients (US $47,714 vs. US $28,405; adjusted difference, US $15,264; 95% CI, US $13,905-US $16,623; p < 0.001). The HIV/AIDS patients also had significantly increased odds of certain postoperative complications, including sepsis, septic shock, pneumonia, urinary tract infection, acute renal failure and need for transfusion (p < 0.05 for each). Differences persisted irrespective of case complexity and over the study period. Asymptomatic HIV-positive patients had outcomes similar to HIV-negative patients.

CONCLUSION

The HIV/AIDS patients have a greater risk of death, infectious, and noninfectious complications after emergency surgery regardless of operative complexity and despite advanced highly active antiretroviral therapy. Patients who have not developed advanced disease, however, have similar outcomes to HIV-negative patients.

LEVEL OF EVIDENCE

Prognostic and epidemiologic study, level III.

The Cost of Surgical Site Infections after Colorectal Surgery in the United States from 2001 to 2012: A Longitudinal Analysis

Surgical site infections (SSIs) are among the most common types of postoperative complications in the United States and are associated with significant prevalence of morbidity and mortality in patients undergoing surgical interventions, especially in colorectal surgery (CRS) where SSI rates are significantly higher than those of similar operative sites. SSIs were identified from the National Inpatient Sample-Healthcare Cost and Utilization Project database from 2001 to 2012 based on the specification of an ICD-9 code. Propensity score matching was used to compare costs associated with SSI cases with those of non-SSI controls among elective and nonelective admissions. Results were projected nationally using Healthcare Cost and Utilization Project sampling methodology to evaluate the incidence of SSIs and ascertain the national cost burden retrospectively. Among 4,851,359 sample-weighted hospitalizations, 4.2 per cent (203,597) experienced SSI. Elective admissions associated with SSI-stayed hospitalized for an average of 7.8 days longer and cost $18,410 more than their counterparts who did not experience an SSI. Nonelective admissions that experienced an SSI had an 8.5-day longer hospital stay and cost $20,890 more than counterparts without perioperative infections. This represents a 3 per cent annual growth in costs for SSIs and seems to be largely driven by cost increases in treatment of SSIs for elective surgeries. Current efforts of SSI management after CRS focused on compliance with guidelines and tracking of infection rates would benefit from some improvements. Considering the growing costs and increase in resource utilization associated with SSIs from 2001 to 2012, further research on costs associated with management of SSIs specific to CRS is necessary.

Validation of ICD-9-CM Diagnosis Codes for Surgical Site Infection and Noninfectious Wound Complications After Mastectomy

BACKGROUND Few studies have validated ICD-9-CM diagnosis codes for surgical site infection (SSI), and none have validated coding for noninfectious wound complications after mastectomy. OBJECTIVES To determine the accuracy of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes in health insurer claims data to identify SSI and noninfectious wound complications, including hematoma, seroma, fat and tissue necrosis, and dehiscence, after mastectomy. METHODS We reviewed medical records for 275 randomly selected women who were coded in the claims data for mastectomy with or without immediate breast reconstruction and had an ICD-9-CM diagnosis code for a wound complication within 180 days after surgery. We calculated the positive predictive value (PPV) to evaluate the accuracy of diagnosis codes in identifying specific wound complications and the PPV to determine the accuracy of coding for the breast surgical procedure. RESULTS The PPV for SSI was 57.5%, or 68.9% if cellulitis-alone was considered an SSI, while the PPV for cellulitis was 82.2%. The PPVs of individual noninfectious wound complications ranged from 47.8% for fat necrosis to 94.9% for seroma and 96.6% for hematoma. The PPVs for mastectomy, implant, and autologous flap reconstruction were uniformly high (97.5%-99.2%). CONCLUSIONS Our results suggest that claims data can be used to compare rates of infectious and noninfectious wound complications after mastectomy across facilities, even though PPVs vary by specific type of postoperative complication. The accuracy of coding was highest for cellulitis, hematoma, and seroma, and a composite group of noninfectious complications (fat necrosis, tissue necrosis, or dehiscence). Infect Control Hosp Epidemiol 2017;38:334-339.

Can additional information be obtained from claims data to support surgical site infection diagnosis codes?

OBJECTIVE

International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes are increasingly used to identify healthcare-associated infections, often with insufficient evidence demonstrating validity of the codes used. Absent medical record verification, we sought to confirm a claims algorithm to identify surgical site infections (SSIs) by examining the presence of clinically expected SSI treatment.

METHODS

We performed a retrospective cohort study, using private insurer claims data from persons less than 65 years old with ICD-9-CM procedure or Current Procedure Terminology (CPT-4) codes for anterior cruciate ligament (ACL) reconstruction from January 2004 through December 2010. SSIs occurring within 90 days after ACL reconstruction were identified by ICD-9-CM diagnosis codes. Antibiotic utilization, surgical treatment, and microbiology culture claims within 14 days of SSI codes were used as evidence to support the SSI diagnosis.

RESULTS

Of 40,702 procedures, 401 (1.0%) were complicated by SSI, 172 (0.4%) of which were specifically identified as septic arthritis. Most SSIs were associated with an inpatient admission (232/401 [58%]), and/or surgical procedure(s) for treatment (250/401 [62%]). Temporally associated antibiotics, surgical treatment procedures, and cultures were present for 84% (338/401), 61% (246/401), and 59% (238/401), respectively. Only 5.7% (23/401) of procedures coded for SSI after the procedure had no antibiotics, surgical treatments, or cultures within 14 days of the SSI claims.

CONCLUSIONS

More than 94% of patients identified by our claims algorithm as having an SSI received clinically expected treatment for infection, including antibiotics, surgical treatment, and culture, suggesting that this algorithm has very good positive predictive value. This method may facilitate retrospective SSI surveillance and comparison of SSI rates across facilities and providers.

The effect of Surgical Care Improvement Project measures on national trends on surgical site infections in open vascular procedures

OBJECTIVE

The Surgical Care Improvement Project (SCIP) is a national initiative to reduce surgical complications, including postoperative surgical site infection (SSI), through protocol-driven antibiotic usage. This study aimed to determine the effect SCIP guidelines have had on in-hospital SSIs after open vascular procedures.

METHODS

The Nationwide Inpatient Sample (NIS) was retrospectively analyzed using International Classification of Diseases, Ninth Revision, diagnosis codes to capture SSIs in hospital patients who underwent elective carotid endarterectomy, elective open repair of an abdominal aortic aneurysm (AAA), and peripheral bypass. The pre-SCIP era was defined as 2000 to 2005 and post-SCIP was defined as 2007 to 2010. The year 2006 was excluded because this was the transition year in which the SCIP guidelines were implemented. Analysis of variance and χ(2) testing were used for statistical analysis.

RESULTS

The rate of SSI in the pre-SCIP era was 2.2% compared with 2.3% for carotid endarterectomy (P = .06). For peripheral bypass, both in the pre- and post-SCIP era, infection rates were 0.1% (P = .22). For open, elective AAA, the rate of infection in the post-SCIP era increased significantly to 1.4% from 1.0% in the pre-SCIP era (P < .001). Demographics and in-hospital mortality did not differ significantly between the groups.

CONCLUSIONS

Implementation of SCIP guidelines has made no significant effect on the incidence of in-hospital SSIs in open vascular operations; rather, an increase in SSI rates in open AAA repairs was observed. Patient-centered, bundled approaches to care, rather than current SCIP practices, may further decrease SSI rates in vascular patients undergoing open procedures.

Identifying colon and open reduction of fracture surgical site infections using a partially automated electronic algorithm

BACKGROUND

Algorithms leveraging electronic data may reduce manual review burden for surgical site infection (SSI) surveillance with little to no reduction in sensitivity. We developed an algorithm to identify colon and open reduction of fracture (FX) SSIs to reduce manual chart review.

METHODS

A retrospective cohort of colon and FX procedures and associated SSIs was constructed. Potential SSIs were identified by positive microbiologic cultures or administrative data for diagnosis or treatment of wound infection. Sensitivity and specificity of the algorithm were assessed. The number of charts needing review to identify 1 SSI, and the potential time-savings from the algorithm, were calculated.

RESULTS

Four hundred seventy-three colon (SSI rate = 7%) and 1081 FX (SSI rate = 3%) procedures were identified. The algorithm was 91% and 97% sensitive and 76% and 93% specific for colon and FX procedures, respectively. Overall, chart review would have been reduced by 24.3 hours per 100 procedures, decreasing the number of charts to review to identify 1 SSI from 23.9 for manual review to 3.9 with the algorithm.

CONCLUSIONS

The algorithm identified SSIs with excellent sensitivity and specificity, resulting in substantial reductions in manual chart review. This algorithm could be tailored and applied to other hospitals.

Matching bacteriological and medico-administrative databases is efficient for a computer-enhanced surveillance of surgical site infections: retrospective analysis of 4,400 surgical procedures in a French university hospital

OBJECTIVE

Our goal was to estimate the performance statistics of an electronic surveillance system for surgical site infections (SSIs), generally applicable in French hospitals.

METHODS

Three detection algorithms using 2 different data sources were tested retrospectively on 9 types of surgical procedures performed between January 2010 and December 2011 in the University Hospital of Nantes. The first algorithm was based on administrative codes, the second was based on bacteriological data, and the third used both data sources. For each algorithm, sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated. The reference method was the hospital's routine surveillance: a comprehensive review of the computerized medical charts of the patients who underwent one of the targeted procedures during the study period.

SETTING

A 3,000-bed teaching hospital in western France.

POPULATION

We analyzed 4,400 targeted surgical procedures.

RESULTS

Sensitivity results varied significantly between the three algorithms, from 25% (95% confidence interval, 17-33) when using only administrative codes to 87% (80%-93%) with the bacteriological data and 90% (85%-96%) with the combined algorithm. Fewer variations were observed for specificity (91%-98%), PPV (21%-25%), and NPV (98% to nearly 100%). Overall, performance statistics were higher for deep SSIs than for superficial infections.

CONCLUSIONS

A reliable computer-enhanced SSI surveillance can easily be implemented in French hospitals using common data sources. This should allow infection control professionals to spend more time on prevention and education duties. However, a multicenter study should be conducted to assess the generalizability of this method.

Has the rate of in-hospital infections after total joint arthroplasty decreased?

BACKGROUND

Although infections are a major cause of morbidity and mortality after total joint arthroplasty (TJA), little is known about nationwide epidemiology and trends of infections after TJA.

QUESTIONS/PURPOSES

We therefore determined (1) trends of postoperative pneumonia, urinary tract infection (UTI), surgical site infection (SSI), sepsis, and severe sepsis after TJA; (2) risk factors of these infections; (3) effect of these infections on length of stay (LOS) and hospital charges; and (4) the infection-related mortality rate and its predictors.

METHODS

The International Classification of Diseases, 9th Revision codes were used to identify patients who underwent TJA and were diagnosed with aforementioned infections during hospitalization in the Nationwide Inpatient Sample database from 2002 to 2010. Multivariate analysis was performed to identify risk factors of these infections.

RESULTS

Rates of pneumonia, UTI, SSI, sepsis, and severe sepsis were 0.74%, 3.26%, 0.31%, 0.25%, and 0.15%, respectively. Number of comorbidities and type of TJA were independent predictors of infection. Mortality decreased during the study period (odds ratio, 0.87; 95% confidence interval, 0.86-0.89). The median LOS was 3 days without complications but increased in the presence of SSI (median, 7 days), sepsis (median, 12 days), and severe sepsis (median, 15 days). Occurrence of pneumonia, sepsis, and severe sepsis increased risk of mortality 5.2, 8.5, and 66.2 times, respectively.

CONCLUSIONS

Rates of UTI, pneumonia, and SSI but not sepsis and severe sepsis are apparently decreasing. The likelihood of infection is increasing with number of comorbidities and revision surgeries. Rate of sepsis-related mortality is also decreasing.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Time-saving impact of an algorithm to identify potential surgical site infections

OBJECTIVE

To develop and validate a partially automated algorithm to identify surgical site infections (SSIs) using commonly available electronic data to reduce manual chart review.

DESIGN

Retrospective cohort study of patients undergoing specific surgical procedures over a 4-year period from 2007 through 2010 (algorithm development cohort) or over a 3-month period from January 2011 through March 2011 (algorithm validation cohort).

SETTING

A single academic safety-net hospital in a major metropolitan area.

PATIENTS

Patients undergoing at least 1 included surgical procedure during the study period.

METHODS

Procedures were identified in the National Healthcare Safety Network; SSIs were identified by manual chart review. Commonly available electronic data, including microbiologic, laboratory, and administrative data, were identified via a clinical data warehouse. Algorithms using combinations of these electronic variables were constructed and assessed for their ability to identify SSIs and reduce chart review.

RESULTS

The most efficient algorithm identified in the development cohort combined microbiologic data with postoperative procedure and diagnosis codes. This algorithm resulted in 100% sensitivity and 85% specificity. Time savings from the algorithm was almost 600 person-hours of chart review. The algorithm demonstrated similar sensitivity on application to the validation cohort.

CONCLUSIONS

A partially automated algorithm to identify potential SSIs was highly sensitive and dramatically reduced the amount of manual chart review required of infection control personnel during SSI surveillance.

Comparison of two computer algorithms to identify surgical site infections

BACKGROUND

Surgical site infections (SSIs), the second most common healthcare-associated infections, increase hospital stay and healthcare costs significantly. Traditional surveillance of SSIs is labor-intensive. Mandatory reporting and new non-payment policies for some SSIs increase the need for efficient and standardized surveillance methods. Computer algorithms using administrative, clinical, and laboratory data collected routinely have shown promise for complementing traditional surveillance.

METHODS

Two computer algorithms were created to identify SSIs in inpatient admissions to an urban, academic tertiary-care hospital in 2007 using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes (Rule A) and laboratory culture data (Rule B). We calculated the number of SSIs identified by each rule and both rules combined and the percent agreement between the rules. In a subset analysis, the results of the rules were compared with those of traditional surveillance in patients who had undergone coronary artery bypass graft surgery (CABG).

RESULTS

Of the 28,956 index hospital admissions, 5,918 patients (20.4%) had at least one major surgical procedure. Among those and readmissions within 30 days, the ICD-9-CM-only rule identified 235 SSIs, the culture-only rule identified 287 SSIs; combined, the rules identified 426 SSIs, of which 96 were identified by both rules. Positive and negative agreement between the rules was 36.8% and 97.1%, respectively, with a kappa of 0.34 (95% confidence interval [CI] 0.27-0.41). In the subset analysis of patients who underwent CABG, of the 22 SSIs identified by traditional surveillance, Rule A identified 19 (86.4%) and Rule B identified 13 (59.1%) cases. Positive and negative agreement between Rules A and B within these "positive controls" was 81.3% and 50.0% with a kappa of 0.37 (95% CI 0.04-0.70).

CONCLUSION

Differences in the rates of SSI identified by computer algorithms depend on sources and inherent biases in electronic data. Different algorithms may be appropriate, depending on the purpose of case identification. Further research on the reliability and validity of these algorithms and the impact of changes in reimbursement on clinician practices and electronic reporting is suggested.

Use of Medicare diagnosis and procedure codes to improve detection of surgical site infections following hip arthroplasty, knee arthroplasty, and vascular surgery

OBJECTIVE

To evaluate the use of routinely collected electronic health data in Medicare claims to identify surgical site infections (SSIs) following hip arthroplasty, knee arthroplasty, and vascular surgery.

DESIGN

Retrospective cohort study.

SETTING

Four academic hospitals that perform prospective SSI surveillance.

METHODS

We developed lists of International Classification of Diseases, Ninth Revision, and Current Procedural Terminology diagnosis and procedure codes to identify potential SSIs. We then screened for these codes in Medicare claims submitted by each hospital on patients older than 65 years of age who had undergone 1 of the study procedures during 2007. Each site reviewed medical records of patients identified by either claims codes or traditional infection control surveillance to confirm SSI using Centers for Disease Control and Prevention/National Healthcare Safety Network criteria. We assessed the performance of both methods against all chart-confirmed SSIs identified by either method.

RESULTS

Claims-based surveillance detected 1.8-4.7-fold more SSIs than traditional surveillance, including detection of all previously identified cases. For hip and vascular surgery, there was a 5-fold and 1.6-fold increase in detection of deep and organ/space infections, respectively, with no increased detection of deep and organ/space infections following knee surgery. Use of claims to trigger chart review led to confirmation of SSI in 1 out of 3 charts for hip arthroplasty, 1 out of 5 charts for knee arthroplasty, and 1 out of 2 charts for vascular surgery.

CONCLUSION

Claims-based SSI surveillance markedly increased the number of SSIs detected following hip arthroplasty, knee arthroplasty, and vascular surgery. It deserves consideration as a more effective approach to target chart reviews for identifying SSIs.