Clinical pathology selected abstracts

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Editor: Deborah Sesok-Pizzini, MD, MBA, chief medical officer, Labcorp Diagnostics, Burlington, NC, and adjunct professor, Department of Clinical Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia.

Association between abnormal coagulation profile and risk of transfusion following major surgery

March 2023—Coagulation screening prior to surgery for patients without a history of a bleeding disorder is controversial. Studies have recommended routine screening of prothrombin time/International Normalized Ratio (PT/INR) and activated partial thromboplastin time (aPTT) to reduce the risk of perioperative and postoperative hemorrhage. Other studies have questioned the value of coagulation screening tests, such as INR, aPTT, and platelet count, because it is rare to detect an abnormal value in patients undergoing elective surgeries. Many professional society guidelines, such as those of the American Society of Anesthesiologists and British Committee for Standards in Hematology, advise against routine perioperative coagulation screening prior to surgery for patients who do not have a clinical history of abnormal bleeding, medical history of comorbidity, or bleeding disorders. The authors conducted a study in which they examined the association between abnormal coagulation profile and risk of transfusion following common elective surgery in patients who did not have bleeding disorders. They used the National Surgical Quality Improvement Program (NSQIP) database for their retrospective cohort study, which focused on adult patients across multiple disciplines who underwent common surgical procedures between 2004 and 2018. The authors employed the database to identify patients without a history of bleeding risks who were undergoing any of 23 common major elective procedures across 10 specialties. NSQIP is a validated surgical database for which 30-day preoperative and perioperative data are collected prospectively from more than 600 academic and community hospitals. The authors used these data in their study of adults undergoing elective surgeries and conducted multivariable logistic regression analyses to assess the association of coagulation profiles, including INR, aPTT, and platelet count, and the risk of intraoperative and postoperative transfusion. The results showed that 53.7 percent of 672,075 patients meeting the inclusion criteria had an abnormal coagulation profile preoperatively. Of these patients, 12.2 percent received a transfusion. In the setting of a normal aPTT/platelet count, both equivocal INR results of 1.1 to 1.5 (adjusted odds ratio [aOR], 1.41; 95 percent confidence interval [CI], 1.38–1.44) and abnormal INR of more than 1.5 (aOR, 1.81; 95 percent CI, 1.71–1.93) were significantly associated with an increased risk of transfusion. However, equivocal (60 to 70) and abnormal (more than 70) aPTT with a normal INR/platelet count did not show a comparable risk for transfusion. The data also demonstrated a synergistic effect for the risk of transfusion in the setting of an abnormal INR/aPTT and platelet count of less than 100,000 (aOR, 5.18; 95 percent CI, 3.04–8.84) compared with the effect of an abnormal INR/aPTT and normal/elevated platelet count (aOR, 1.90; 95 percent CI, 1.48–2.45). In summary, the authors found that transfusion risk was highest in patients with abnormalities in all three lab indices, resulting in a fivefold increased risk. There was a twofold increase in bleeding risk when patients had abnormal INRs and aPTT. The authors demonstrated a significant association between any abnormalities in INR, aPTT, and platelet count and bleeding complications requiring packed red blood cell transfusions within 72 hours of surgical incision. According to the authors, this is the first large analysis evaluating the association between bleeding risk and packed red blood cell transfusion in patients without a known history of bleeding disorders. The data from this study further support the need for prospective population-based registries to help investigators analyze the association between abnormal/equivocal preoperative coagulation profiles and transfusion risk.

Lim K, Satkunasivam R, Nipper C, et al. Association between isolated abnormal coagulation profile on transfusion following major surgery: A NSQIP analysis of individuals without bleeding disorders. Transfusion. 2022;62:2223–2234.

Correspondence: Dr. Christopher J. D. Wallis at wallis.cjd@gmail.com

Rates of follow-up colonoscopy after a positive stool screening test result for colorectal cancer

While colonoscopy is a common procedure for colorectal cancer screening in the United States, it is invasive and requires bowel preparation and sedation, and it must be performed at an outpatient clinic or day surgery center. An alternative to colonoscopy is stool-based screening tests (SBTs), which improve adherence to routine colorectal cancer (CRC) screening guidelines. These screening methods are noninvasive and include at-home–based stool tests, such as fecal immunochemical tests and multi-target stool DNA tests. Although SBTs are an alternative to colonoscopy for initial CRC screening, a positive SBT should be followed up with a colonoscopy. Failure to follow up and delayed follow-up are associated with a higher risk of CRC and related complications. At-home SBTs were used extensively during the COVID-19 pandemic. However, the medical community lacks updated information about follow-up colonoscopy (FU-CY) rates after a positive SBT. Therefore, the authors conducted a study to evaluate FU-CY rates after a positive SBT and to assess the impact of the pandemic on FU-CY rates. They conducted a mixed-methods cohort study of 32,769 U.S. primary care patients and retrospectively analyzed deidentified administrative claims and EHR data from the Optum Labs data warehouse between June 1, 2015 and June 30, 2021. They also conducted qualitative, semi-structured interviews with clinicians from five health care organizations. The study population included average-risk primary care patients between 50 and 75 years old who had a positive SBT result from any of 39 health care organizations. The primary outcome was the FU-CY rate within one year of a positive SBT result according to patient age, gender, race, ethnicity, insurance type, Charlson comorbidity index (CCI), and prior SBT use. The results showed that the study participants exhibited an FU-CY rate of 43.3 percent within 90 days of a positive SBT result, 51.4 percent within 180 days, and 56.1 percent within 360 days. The clinicians interviewed were surprised by the overall low FU-CY rates. When a Cox proportional hazards regression model was applied, the strongest positive association was with multi-target stool DNA tests (hazard ratio, 1.63 relative to fecal immunochemical tests), and the strongest significant negative association was with the presence of other comorbidities (hazard ratio, 0.64 for a CCI of more than four relative to zero). COVID-19 was also associated with lower FU-CY rates. The authors concluded that FU-CY rates after a positive SBT result for CRC screening were low among an average-risk population, with the median health care organization recording a 53.4 percent FU-CY rate within one year. Lower rates were significantly associated with race, ethnicity, insurance type, type of test, health care organization, and COVID-19. The authors recommend targeted interventions to improve overall FU-CY rates and to address the backlog of colonoscopies generated during the peak of COVID-19. Interventions are important because extensive delays in colonoscopy follow-up after an SBT may lead to poor CRC outcomes.

Mohl JT, Ciemins EL, Miller-Wilson LA, et al. Rates of follow-up colonoscopy after a positive stool-based screening test result for colorectal cancer among health care organizations in the US, 2017–2020. JAMA Network Open. 2023:6(1). doi:10.1001/jamanetworkopen.2022.52384