Preoperative Laboratory Investigations

Abstract

Background Increasing attention has been focused on low-value healthcare services. Through Choosing Wisely campaigns, routine laboratory testing before low-risk surgery has been discouraged in the absence of clinical indications. The authors investigated rates, determinants, and institutional variation in laboratory testing before low-risk procedures. Methods Patients who underwent ophthalmologic surgeries or predefined low-risk surgeries in Ontario, Canada, between April 1, 2008, and March 31, 2013, were identified from population-based administrative databases. Preoperative blood work was defined as a complete blood count, prothrombin time, partial thromboplastin, or basic metabolic panel within 60 days before an index procedure. Adjusted associations between patient and institutional factors and preoperative testing were assessed with hierarchical multivariable logistic regression. Institutional variation was characterized using the median odds ratio. Results The cohort included 906,902 patients who underwent 1,330,466 procedures (57.1% ophthalmologic and 42.9% low-risk surgery) at 119 institutions. Preoperative blood work preceded 400,058 (30.1%) procedures. The unadjusted institutional rate of preoperative blood work varied widely (0.0 to 98.1%). In regression modeling, significant predictors of preoperative testing included atrial fibrillation (adjusted odds ratio [AOR], 2.58; 95% CI, 2.51 to 2.66), preoperative medical consultation (AOR, 1.68; 95% CI, 1.65 to 1.71), previous mitral valve replacement (AOR, 2.33; 95% CI, 2.10 to 2.58), and liver disease (AOR, 1.69; 95% CI, 1.55 to 1.84). The median odds ratio for interinstitutional variation was 2.43. Conclusions Results of this study suggest that testing is associated with a range of clinical covariates. However, an association was similarly identified with preoperative consultation, and significant variation between institutions exists across the jurisdiction.

Influence of Institution-Based Factors on Preoperative Blood Testing Prior to Low-Risk Surgery: A Bayesian Generalized Linear Mixed Approach

“…The use of Bayesian approaches for the calculation of the CrI is advantageous in that the true parameter is contained within the interval [ 28 , 29 ]. Thus, our findings strongly suggest that institutional factors influence that rate of preoperative blood testing, consistent with the findings of previous Canadian studies [ 9 , 17 ]. Institutions with a large number of beds frequently performed preoperative blood tests, which may have been due to the following reasons: (1) institutions with a large number of beds have enough resources to perform routine laboratory tests regardless of patient status and (2) such testing may be routine at larger institutions.…”

“…We used a Bayesian generalized linear mixed approach to estimate the coefficients of each variable (patient variables and institutional factors) for preoperative blood tests. Preoperative tests were defined as those ordered within 60 days of the index procedure [ 17 ] and included the following: complete blood count (CBC), basic metabolic panel, coagulation tests, and liver function tests (LFTs). In Japan, health insurance coverage of these preoperative tests does not differ based on the patient's health insurance status.…”

Measuring the frequency and variation of unnecessary care across Canada

“…Receipt of any of the four tests was aggregated into a single outcome. For each province, two logistic models were regressed (both adjusting for procedure type) to independently investigate patient- and provider-level factors previously associated with use of low-value preoperative tests [9, 10]. Specifically, we captured patient characteristics (age, sex, and history of the same comorbidities listed in the lower back pain study), surgical procedure type, and whether the patient received a pre-operative consult (i.e., general medical or anesthetic) [10].…”

“…Initial estimates of the prevalence of unnecessary care are predominantly derived from U.S. data [5]; however, prior studies from the U.S. have largely been limited to Medicare beneficiaries or select commercial health plan members [6–8]. While some population-based studies have assessed overuse in Australia and Canada, these works have often been limited to a single region [9–13]. To our knowledge, there has not been a prior study that quantifies the use of unnecessary care across multiple services and Canadian jurisdictions.…”

Variability and Costs of Low-Value Preoperative Testing for Carpal Tunnel Release Surgery

“…Unfortunately, low value preoperative tests continue to be a common and major contributor to unnecessary health care spending in the US and Canada 6,7,12–14 , highlighting the need to better understand its drivers and what strategies might be effective to improve practice. Over 500,000 carpal tunnel releases (CTR) are performed each year in the US.…”