Abstract
This cohort study evaluates postoperative adherence to venous thromboembolism prophylaxis guidelines among US adults with pancreatic cancer using a national population sample drawn from Surveillance, Epidemiology, and End Results–Medicare data.
Venous thromboembolism (VTE) is the most common cause of preventable death after major cancer surgery. Consequently, clinical consensus guidelines from the National Comprehensive Cancer Network, the American College of Chest Physicians, and American Society of Clinical Oncology recommend up to 28 days of postoperative VTE prophylaxis after abdominal or pelvic cancer surgeries for high-risk patients.1,2,3 Despite the substantial risk of VTE among patients undergoing surgery for pancreatic cancer and consensus guidelines regarding postdischarge VTE prophylaxis, adherence to guidelines in the US remains unclear. We estimated adherence to VTE prophylaxis guidelines after pancreatic cancer surgery using a national population sample and hypothesized that postdischarge VTE prophylaxis is underused.
Methods
This retrospective cohort study used the Surveillance, Epidemiology, and End Results (SEER) database merged with Medicare data from January 1, 2009, to December 31, 2013, to compare receipt of postdischarge VTE prophylaxis among patients with stage I/II pancreatic adenocarcinoma who underwent resection. Patient characteristics were abstracted from the SEER database. Race and ethnicity were included to ascertain whether prescribing differences existed among all patients. Exclusion criteria included hospital length of stay 4 weeks or more, anticoagulation use within 6 months before surgery, new diagnosis requiring anticoagulation during hospitalization, or in-hospital death (eFigure in the Supplement). Adherence was assessed by examining the prevalence of filled outpatient prescriptions for low-molecular-weight heparin or unfractionated heparin and the number of days prescribed. Postdischarge VTE prophylaxis was considered prescribed if a prescription was filled within 5 days of discharge. Secondary outcomes included deep vein thrombosis or pulmonary embolism (DVT/PE), bleeding events, or any complication within 30 days of discharge; hospital length of stay; readmissions within 30 and 90 days; mortality within 30 days; and overall survival.
The research protocol was approved by the institutional review board of the University of California, Davis; a waiver of consent was granted owing to the use of deidentified data. The study followed the RECORD and STROBE reporting guidelines. Data were analyzed from September 1, 2019, to August 20, 2021; statistical analyses were performed using SAS, version 9.4 (SAS Institute).
Results
Among 888 patients, 34 (3.8%) filled a prescription for VTE prophylaxis within 5 days of hospital discharge. Of those patients, 24 (70.6%) were prescribed a duration to complete a 28-day total course and 33 (97.1%) received low-molecular-weight heparin. Overall, DVT/PE occurred in 28 (3.2%) patients within 30 days of discharge. There were no group differences regarding demographic, clinicopathologic, or treatment characteristics among patients who did and did not receive postdischarge VTE prophylaxis (Table 1). Postdischarge VTE prophylaxis (vs no VTE prophylaxis) did not influence overall complications (≤10 vs 189; P = .09), DVT/PE (0 vs 28; P = .62), or bleeding events (0 vs 25; P = .62) that occurred within 30 days of discharge (Table 2). Additionally, there were no group differences regarding median hospital length of stay (8 vs 9 weeks; P = .25), 30-day readmissions (≤10 vs 317; P = .07), 90-day readmissions (≤10 vs 400; P = .05), or 30-day mortality (0 vs ≤10; P > .99) (Table 2). Median overall survival was similar between patients who did and did not receive postdischarge VTE prophylaxis (20 vs 22 months; log-rank P = .77) (Table 2).
Table 1. Demographic and Clinicopathologic Differences by Treatment Group Among Patients With Early-Stage Pancreatic Cancer.
| Treatment groupa | P value | ||
|---|---|---|---|
| VTE prophylaxis | No VTE prophylaxis | ||
| Total | 34 (3.8) | 854 (96.2) | |
| Age, mean (SD), y | 74.4 (5.0) | 74.3 (5.6) | .89 |
| Sex | |||
| Male | 12 (35.3) | 353 (41.3) | .59 |
| Female | 22 (64.7) | 501 (58.7) | |
| Race or ethnicity | |||
| African American or Black | 0 | 33 (3.9) | .16 |
| Non-Hispanic White | 34 (100) | 763 (89.3) | |
| Other race or ethnicityb | 0 | 58 (6.8) | |
| Elixhauser Comorbidity Index score, mean (SD)c | 11.1 (8.7) | 12.5 (9.1) | .38 |
| Tumor grade | |||
| Well differentiated | ≤10d | 95 (11.1) | .24 |
| Moderately differentiated | 11 (32.4) | 375 (43.9) | |
| Poorly differentiated or undifferentiated | 18 (52.9) | 302 (35.4) | |
| Unknown | ≤10d | 82 (9.6) | |
| Tumor stage | |||
| T1 | ≤10d | 56 (6.6) | .72 |
| T2 | ≤10d | 123 (14.4) | |
| T3 | 26 (76.5) | 675 (79.0) | |
| Nodal stage | |||
| N0 | 15 (44.1) | 330e | .62 |
| N1 | 19 (55.9) | 522 (61.1) | |
| NX | 0 | ≤10d | |
| Composite stage | |||
| 1 | ≤10d | 117 (13.7) | .45 |
| 2 | >10d | 737 (86.3) | |
| Pancreatic resection | |||
| Pancreaticoduodenectomy | 28 (82.4) | 633 (74.1) | .64 |
| Distal pancreatectomy | ≤10d | 155 (18.1) | |
| Total pancreatectomy | ≤10d | 27 (3.2) | |
| Other | ≤10d | 39 (4.6) | |
| Chemotherapy | |||
| Neoadjuvant | ≤10d | 80 (9.4) | .13 |
| Adjuvant | >10d | 611 (71.5) | .70 |
Abbreviations: NX, unstageable nodal status; VTE, venous thromboembolism.
Data are presented as No. (%) of patients unless indicated otherwise.
Includes Asian, Hispanic/Latinx, and Native Hawaiian or Other Pacific Islander. These categories were combined given the low numbers of participants.
Ranges from −11 to 62; higher scores indicate more comorbidities.
Presented as ≤10 per Surveillance, Epidemiology, and End Results–Medicare guidelines regarding patient confidentiality.
Percentage masked per Surveillance, Epidemiology, and End Results–Medicare guidelines regarding patient confidentiality.
Table 2. Clinical Outcomes and Overall Survival by Treatment Group Among Patients With Early-Stage Pancreatic Cancer.
| Treatment groupa | P value | ||
|---|---|---|---|
| VTE prophylaxis | No VTE prophylaxis | ||
| Total | 34 (3.8) | 854 (96.2) | |
| Hospital length of stay, median (IQR), wk | 8 (7-12) | 9 (7-13) | .25 |
| Complication within 30 d of discharge | |||
| Any complication | ≤10b | 189 (22.1) | .09 |
| DVT/PE | 0 | 28 (3.3) | .62 |
| Bleeding | 0 | 25 (2.9) | .62 |
| 30-d Readmissions | ≤10b | 317 (37.1) | .07 |
| 90-d Readmissions | ≤10b | 400 (46.8) | .05 |
| 30-d Mortalityc | 0 | ≤10b | >.99 |
| Overall survival, median (IQR), mo | 20 (10-45) | 22 (11-36) | .77 |
Abbreviations: DVT/PE, deep vein thrombosis or pulmonary embolism; VTE, venous thromboembolism.
Data are presented as No. (%) of patients unless indicated otherwise.
Presented as ≤10 per Surveillance, Epidemiology, and End Results–Medicare guidelines regarding patient confidentiality.
Among 674 patients who died during the study period.
Discussion
The findings of this cohort study suggest that adherence to recommended guidelines for VTE prophylaxis is poor among patients who undergo pancreatic cancer surgery, because fewer than 5% of patients in this population were prescribed VTE prophylaxis after discharge. Potential explanations for these findings include physician knowledge, patient adherence, and/or concerns regarding bleeding complications.4 Despite potential clinical barriers, randomized clinical trials and clinical guidelines support the safe use of extended VTE prophylaxis after major abdominal surgery.5,6
Potential selection bias is a study limitation in that certain patients may have been prescribed VTE prophylaxis preferentially. The low adherence to the guidelines presented herein suggests a need for better understanding of this practice gap and consideration of interventions that may optimize postoperative VTE prophylaxis use among high-risk patients.
eFigure. Flow Diagram of Study Inclusion and Exclusion Criteria
References
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Associated Data
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Supplementary Materials
eFigure. Flow Diagram of Study Inclusion and Exclusion Criteria