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Obstetrics & Gynecology:
doi: 10.1097/AOG.0b013e3181ec448d
Original Research

Adherence to Evidence-Based Guidelines for Preoperative Testing in Women Undergoing Gynecologic Surgery

St. Clair, Caryn M. MD; Shah, Monjri MD; Diver, Elisabeth J. MD; Lewin, Sharyn N. MD; Burke, William M. MD; Sun, Xuming MS; Herzog, Thomas J. MD; Wright, Jason D. MD

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Author Information

From Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Columbia University College of Physicians and Surgeons, New York, New York.

Corresponding author: Jason D. Wright, MD, Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Columbia University College of Physicians and Surgeons, 161 Fort Washington Avenue, 8th Floor, New York, NY 10032; e-mail: jw2459@columbia.edu.

Financial Disclosure The authors did not report any potential conflicts of interest.

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Abstract

OBJECTIVE: To examine adherence to evidence-based recommendations for preoperative testing and health care costs associated with excessive testing.

METHODS: An institutional review of women who underwent gynecologic surgery between 2005 and 2007 was performed. Data on the type of surgery, age, comorbidities, and perioperative testing was extracted. We noted the preoperative performance of chest X-ray, electrocardiogram, metabolic panel, complete blood count, coagulation studies, liver function tests, and urinalysis. Each test was classified as being guideline-based (appropriate) or non–guideline-based (inappropriate) as described by the National Institute of Clinical Excellence perioperative guidelines.

RESULTS: A total of 1,402 patients were identified. Ninety-five percent of patients underwent all of the guideline-recommended preoperative testing. Ninety percent of women underwent at least one nonindicated preoperative test. None of the 749 urinalyses, 407 liver function tests, or 1,046 coagulation studies performed was appropriate. Ninety-nine percent of the 427 chest X-rays ordered were inappropriate. Only 17% of metabolic panels, 36% of electrocardiograms, and 29% of complete blood counts were in accordance with evidence-based guidelines. Inappropriate perioperative tests led to a direct cost of more than $418,000. Of the inappropriate tests ordered, abnormalities were noted frequently but rarely changed management.

CONCLUSION: Adherence to evidence-based recommendations for preoperative testing is poor. Inappropriate preoperative tests represent a major health care expenditure.

LEVEL OF EVIDENCE: III

All gynecologic surgery patients undergo some form of preoperative evaluation. The preoperative evaluation includes a history and physical examination, often accompanied by some combination of laboratory studies, imaging, electrocardiography, and potentially further cardiopulmonary evaluation. The purpose of the preoperative evaluation is threefold.1,2 First, the evaluation can be used to assess preexisting medical conditions and identify new, unsuspected conditions. Second, preoperative testing allows the surgeon to anticipate issues that may arise in the perioperative period and to plan accordingly. Finally, the preoperative evaluation establishes a baseline for later comparison.1,2

Despite the intuitive nature of the preoperative evaluation, an abundance of evidence suggests that the majority of preoperative testing is unnecessary.1–10 In the absence of a clear clinical indication, the chance of finding a meaningful abnormality is low, and such testing rarely affects surgical management.1–10 Unnecessary preoperative testing causes patient discomfort and anxiety and leads to additional testing that is often unnecessary and that is associated with substantial cost to the health care system. It is estimated that approximately $3 billion is spent annually on preoperative laboratory testing alone.11

In an attempt to standardize preoperative testing, a number of evidence-based guidelines have been formulated.12–16 These guidelines have been developed to promote clinically meaningful perioperative testing and to reduce the use of unneeded evaluations. Although these guidelines have been in place for a number of years, little is known about the uptake and adherence to these guidelines by clinicians.

The goal of our investigation was to examine adherence to evidence-based preoperative testing guidelines among gynecologic surgeons. We further examined factors associated with guideline-based perioperative testing and estimated the cost associated with inappropriate preoperative testing.

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MATERIALS AND METHODS

After obtaining approval from the Columbia University Institutional Review Board, an analysis of women who underwent gynecologic surgery from late 2005 to early 2007 was performed. Patients who underwent either outpatient or inpatient surgery were eligible for inclusion. Data were abstracted from inpatient and outpatient medical records.

Demographic data including age (less than 40, 40–65, greater than 65), race (white, African American, other, unknown), and year of procedure were collected. Each patient was classified based on the subspecialty of the attending physician of record into the following categories: general gynecology, urogynecology, gynecologic oncology, and reproductive endocrinology. The type of anesthesia utilized (general, regional, intravenous sedation) was noted for each patient. All procedures performed for each patient were recorded.

The preoperative laboratory and radiograph evaluation of each patient was examined. Performance of the following tests was recorded: complete blood count, metabolic profile, coagulation studies (prothrombin time or activated partial thromboplastin time), liver function tests, urinalysis, chest radiograph, and electrocardiogram. For each test, patients were dichotomized as having undergone or not having undergone the test. Patients who underwent any study in the test groups (ie, prothrombin time but not partial thromboplastin time performed) were classified as having received the test. Institutional reference ranges were used to determine whether a given test yielded normal results (within the institutional reference range) or abnormal results (outside the institutional reference range). For each abnormal test, we determined if further follow-up was performed. We considered further follow-up as any additional testing (laboratory or radiographic), evaluation (consultation with an additional physician), or change in surgical management.

For each test, we determined whether the test was indicated based on the National Institute for Health and Clinical Excellence (NICE) guidelines (The Use of Routine Preoperative Tests for Elective Surgery; Table 1). The National Institute for Health and Clinical Excellence is an independent organization based in the United Kingdom that produces evidence-based guidelines for the promotion of good health and treatment of disease. Each NICE guideline is developed with the expertise of physicians and health advocates based on an extensive literature review. The NICE guidelines for preoperative testing were developed in 2003. The guidelines use age, type of surgery, comorbidities (cardiovascular, respiratory, and renal disease), and American Society of Anesthesiologists grade for anesthetic risk to determine if testing is indicated.12 Based on each patient's clinical scenario, we determined whether each test they received was recommended (guideline-based) or not recommended based on the 2003 NICE guidelines.

Table 1
Table 1
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To explore the economic impact of preoperative testing, two separate economic estimations were performed. The first was based on billed institutional charges; the second was based on New York Medicare reimbursement schedules. The primary endpoint of the study was to determine the proportion of women who underwent inappropriate testing. A priori we estimated that 50% of preoperative testing performed would be non–guideline-based. Collection of data for at least 1,200 women therefore would allow us to estimate the proportion of inappropriate tests with a 95% confidence interval of ±2.9%. Frequency distributions between categorical variables were compared using χ2 test. Logistic regression models were developed to identify possible predictors of adherence to evidence-based guidelines for individual tests (complete blood count, metabolic profile, electrocardiogram). In the logistic regression analysis, we modeled all the categories of each variable, controlling for all other variables in the model. All analyses were performed with SAS version 9.2 (SAS Institute, Cary, NC).

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RESULTS

The demographic and clinical characteristics of the 1,402 women are displayed in Table 2. The mean age of the cohort was 46 (range 11–90) years. The most frequent preoperative evaluations were complete blood count (87%), metabolic profile (81%), and coagulation studies (75%). Liver function tests (29%) and urinalysis (53%) were performed less frequently. Chest radiography was performed in 31% of women, whereas 54% underwent an electrocardiogram.

Table 2
Table 2
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None of the 1,046 coagulation studies, 407 liver function tests, or 749 urinalysis performed was indicated (Table 3). Only 0.9% (4) of the chest radiographs performed were guideline-based. Seventeen percent of the 197 metabolic profiles and 29% (357) of the complete blood counts were guideline-based. Thirty six percent (274) of the electrocardiograms were appropriate based on guidelines.

Table 3
Table 3
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Among women who underwent preoperative laboratory evaluation, abnormal testing was highest for the metabolic panel (75% abnormal) and lowest (11%) for chest radiography. Further evaluation or altered management occurred in 30% of patients based on urinalysis, 20% based on chest radiograph, 16% based on coagulation studies, 14% based on complete blood count, and 13% based on the electrocardiogram (Table 3).

Rarely were potentially indicated tests not performed. Fifty-six (4%) patients who met guideline criteria for an electrocardiogram did not receive it, whereas a complete blood count was not obtained in 22 (1.6%) patients and a metabolic panel was not requested in 16 (1.2%) patients who met guideline-based criteria to undergo testing. The direct attributable cost to non–guideline-based testing was $91,047 based on state Medicare reimbursement and $418,837 based on institutional charges. The highest expenditures for non–guideline-based testing were for chest radiography, electrocardiography, and coagulation studies. These cost estimates do not include pricing for follow-up evaluation for abnormal testing (Table 4).

Table 4
Table 4
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Table 5 displays a univariable analysis of factors associated with evidence-based performance of complete blood counts and electrocardiograms. Inappropriate testing was more commonly performed in younger women, white participants, and those who underwent operation performed by general gynecologists (P<.001 for all). These factors remained significant in multivariable logistic regression models (Table 6). For example, the odds ratio that a complete blood count was appropriate in a women older than 65 years compared with a patient younger than 40 years was 4.62 (95% confidence interval 2.88–7.40).

Table 5
Table 5
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Table 6
Table 6
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DISCUSSION

Our findings suggest that adherence to evidence-based guidelines for preoperative testing is poor. Although nearly all women underwent at least the minimum appropriate preoperative laboratory evaluation, more than 90% of patients underwent at least one nonindicated study. The overuse of preoperative testing among women undergoing gynecologic surgery led to significant health care expenditures.

Preoperative testing provides baseline laboratory data, allows for the assessment of preexisting medical conditions, and provides a screen for undiagnosed comorbidities. Despite the rationale for preoperative testing, an abundance of data suggest that in the absence of clinical indications, routine testing rarely detects abnormalities; when abnormal findings are detected, they rarely alter surgical or anesthetic management.2–10 In an analysis of 2,000 patients undergoing elective surgery, 60% of the tests that were ordered would not have been performed if performed only for a recognizable indication. Further, only 0.22% of these tests revealed an abnormality that may have affected surgical management.4 In an analysis of more than 18,000 patients with cataracts in whom approximately half underwent preoperative laboratory testing and half did not, there was no difference in the overall complication rate.8 Our findings are in accord with previous studies; although mild test abnormalities were common, they seldom altered management.

To facilitate effective preoperative testing strategies by physicians, a number of groups have developed evidence-based consensus recommendations to guide preoperative testing.12–16 Despite the availability of these guidelines, limited data suggest that uptake by physicians is relatively poor. In an analysis of 534 preoperative tests, 31% of the tests ordered were not compliant with the Canadian Anesthesiologists' Societies preoperative guidelines. Abnormal test results were rare and surgery proceeded as scheduled in all cases.17 We noted similar trends. None of the coagulation studies or liver function tests ordered was indicated, whereas less than 1% of chest radiographs and less than one-third of the complete blood counts were indicated.

Why do physicians fail to adhere to evidence-based guidelines? Studies conducted in Spain and Italy that have queried surgeons and anesthesiologists regarding preoperative evaluation have concluded that patterns of testing vary widely, that protocols for selective testing are rarely applied, and that use of routine preoperative testing is driven more by personal experience than by up-to-date scientific principles.18–20 Surgeons often cite fear of anesthesia delays and cancellations when questioned regarding the overuse of preoperative studies, whereas 70% of anesthesiologists reported that legal protection was a major factor in the widespread ordering of presurgical tests.18,21 Further, the complexity of many published guidelines may also contribute to providers' slow adoption. Although the NICE guidelines are thought by many to be the most comprehensive, with 74 tables in total delineating various patient variables and subsequent testing recommendations, ease of use is debatable.1,12,22 Critics point out that while these guidelines are a good start, they are not devoid of pitfalls.22

Although our study benefits from the inclusion of a relatively large number of patients, we recognize several limitations. A priori we chose to use the NICE guidelines for analysis. We recognize that a number of guidelines are available and adherence would differ based on the guidelines chosen. The NICE guidelines are the most comprehensive guidelines available and there are no widely accepted published guidelines from the United States. The goal of our study was to provide a descriptive analysis of patterns of preoperative testing. As such, the study was not powered to detect all of the factors that predicted inappropriate testing. Our data represent findings from a single institution and may not be generalizeable to other hospitals and health care systems. The cost analysis performed relied on institutional billing rates and New York state Medicare reimbursement schedules. We acknowledge that cost will vary widely across the country and that our estimates are not comprehensive, because we did not include the cost of follow-up for abnormal tests. The economic analysis is purely descriptive and meant to show that testing leads to significant expenditures. A more detailed economic modeling study is clearly warranted. Finally, evidence-based recommendations are meant to merely serve as a guide. Guidelines do not take into account individual patient characteristics that may warrant testing. Our findings should be interpreted within the context that some of the testing performed may have had clinical merit despite the fact that it was not guideline-based.

A number of strategies have been developed to improve the comparative effectiveness of the preoperative evaluation. Hospital-level implementation of guidelines appears to be highly effective in reducing unnecessary testing.23–25 Barazzoni et al23 demonstrated a 57% reduction in the number of chest radiographs ordered and a 43% reduction in electrocardiograms after the implementation of institutional-based practice guidelines. A second strategy is the implementation of preoperative evaluation clinics. Preoperative evaluation clinics, typically overseen by anesthesiologists, have been shown to be cost-effective and to increase quality of care.26–28

In conclusion, our findings suggest that inappropriate preoperative testing results in significant health care expenditures. We have demonstrated that among women undergoing gynecologic surgery, unnecessary preoperative laboratory and radiologic testing is common. Physicians and institutions should develop strategies to reduce unneeded preoperative testing and to improve the quality and effectiveness of the preoperative evaluation for women undergoing gynecologic surgery.

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REFERENCES

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12. National Institue for Clinical Excellence (NICE). The use of routine preoperative tests for elective surgery: NICE Clinical Guidance No 3. London (UK): National Institute for Clinical Excellence; 2003.

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16. Institute for Clinical Systems Improvement (ICSI) Health Care Guideline: Preoperative Evaluation. Available at http://www.icsi.org/preoperative_evaluation/preoperative_evaluation_2328.html. Retrieved February 1, 2010.

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18. Ricciardi G, Angelillo IF, Del Prete U, D'Errico MM, Groass GM, Gregorio P, et al. Routine preoperative investigation. Results of a multicenter survey in Italy. Collaborator Group. Int J Technol Assess Health Care 1998;14:526–34.

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© 2010 by The American College of Obstetricians and Gynecologists.

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