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Venous Thromboembolism Prophylaxis for Chronically Immobilized Long-Term Care Residents
Affiliation: Wingate University School of Pharmacy, Wingate, NC
Abstract: Venous thromboembolism (VTE) affects numerous patient populations, many of which are well defined in the literature. Subsequently, there are clear guidelines and recommendations to reduce the risk of VTE in these patients. Although chronic immobility is a known VTE risk factor, there are still many unanswered questions regarding the need for VTE prophylaxis in patients with this risk factor. This review summarizes the available literature regarding VTE prophylaxis for patients with chronic immobility and describes current practices in long-term care (LTC) facilities. Currently, the literature does not recommend prophylaxis for chronic immobility as a single risk factor for thromboembolism. Further studies are needed to clearly define the VTE risk and recommendations for these patients during their stay in an LTC facility.
Key words: Chronic immobility, long-term care, venous thromboembolism, VTE prophylaxis, deep vein thrombosis.
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Venous thromboembolism (VTE) affects many patient populations and is of concern to long-term care (LTC) providers. These providers must identify the patients at greatest risk of VTE and provide prophylaxis against this complication while balancing the risk of bleeding, which can be especially challenging in LTC residents due to their high prevalence of frailty, comorbidities, and polypharmacy. VTE has two subsets: deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT is a blood clot that forms in a vein deep in the body when the blood thickens and clumps together. These clots tend to form in the legs and pelvis and become life-threatening when they dislodge. PE is a blockage of the pulmonary artery or one of its branches by foreign matter, most commonly a blood clot that starts as a DVT.
In the US population, DVT has an incidence of approximately one in 1000 persons per year, and PE has an incidence of 20 in 1000 persons per year.1 The risk of both forms of VTE increases with age. The American College of Chest Physicians (ACCP) reports the incidence of symptomatic VTE in nursing home patients at 1%, and the incidence among post-acute care patients as ranging between 1% and 2.4%, but it acknowledges that the published data for these patient populations are limited.2
This article reviews the currently available literature on VTE prophylaxis in chronically immobilized LTC patients. It provides an overview of how chronic immobilization is defined in the literature, outlines the factors that place certain chronically immobilized patients at greater risk of VTE, and reviews the ACCP’s current guidelines regarding VTE prophylaxis for chronically immobilized patients. It also provides insights on how LTC providers can weigh the benefits and risks of VTE prophylaxis in their chronically immobilized patients.
Defining Immobility
According to the literature, a person is generally considered to be chronically immobilized when he or she is bedridden for 30 days or more, and considered to be acutely immobilized when bedridden for less than 15 days; however, there has been some overlap with these definitions, particularly when immobilization lasts between 15 and 30 days.3-8 The definition of immobility commonly extends to patients who are bedridden but have bathroom privileges, are confined to a chair, are unable to walk for at least 10 feet or have a history of this limitation for at least 72 hours, need assistance to ambulate, and have a lower limb cast.3-8 Per the ACCP’s evidence-based guidelines for the prevention of VTE in nonsurgical patients, these patients can include homebound patients, those who reside in nursing homes, and those being cared for in post-acute care facilities.2 As the literature shows, there are no universally agreed upon criteria that define chronic immobility, which adds to the challenge of determining VTE risk in these patients.
VTE Risk Factors and Risk Among LTC Residents
In addition to older age and immobility, a variety of factors increase a patient’s risk of developing a VTE (Table 1), many of which may be found in older adults.2,9-11 In 2008, a case-control study by Leibson and colleagues12 focused on identifying risk factors among Minnesota nursing home residents who developed a VTE over a 6-year period. The authors found that these residents were more likely to be newly admitted from a hospital than residents who did not develop a VTE (the control group). Those who developed a VTE also had a greater need for physical therapy and more activities of daily living (ADLs) that they could not independently perform, such as toileting, transferring, positioning in bed, and using a wheelchair, as compared with the control group. The authors did not directly evaluate these residents’ duration of immobility.12
In a series of studies from the Rochester Epidemiology Project, Heit and associates11,13,14 studied patients in Olmstead County, Minnesota, for risk factors related to VTE occurrence, predictors of survival after VTE, and the impact of VTE risk factors on VTE events. This series of studies was able to establish nursing home admission as an independent risk factor for VTE, with 13% of the VTE cases occurring in nursing home residents. They also ascertained that residence in a nursing home after a VTE event resulted in decreased survival rates.11,13,14
A study by Sellier and associates6 that included 812 patients aged 65 years and older at 42 post-acute care facilities in France assessed DVT risk by evaluating 22 predefined characteristics, including medical and surgical risk factors, dependence in six basic ADLs rated using the Katz index, results on the Timed Up and Go Test, mobility, and the presence of pressure ulcers. All patients received lower limb ultrasonography upon initiation of the cross-sectional study, and the investigators found DVT in 113 patients (14%). When examining these patients’ risk factors, a positive trend in the odds of DVT were found for higher scores on the Timed Up and Go Test for patients who were not bedridden or confined to a chair (P=.007). Using a two-level multivariable analysis adjusted for prophylaxis against VTE, independent risk factors for DVT included older age (≥80 years), history of a VTE, presence of localized or metastatic cancer, dependence in more than three ADLs, and presence of pressure ulcers.6
A 2010 study by Zarowitz and associates4 sought to develop a risk stratification tool for VTE in LTC patients and define immobility in this population by extracting data from the medical literature focused on this patient population. The authors identified a total of 1165 relevant published reports related to VTE and 79 published reports related to immobility. Five of these reports were rated as high quality based on the Agency for Health Research and Quality criteria and therefore were used; four focused on VTE risk and one on immobility. Extracting data from these reports, the investigators found the following risk factors for VTE in the LTC population: age older than 60 years; comorbidities, including active cancer, acute infectious disease, chronic obstructive pulmonary disease, heart failure, hypercoagulable state, immobility, inflammatory bowel disease, obesity, and rheumatoid arthritis; catheter in a central vein; dehydration; history of VTE or a first-degree relative with a VTE; and use of several types of medications, including erythroid-stimulating agents to attain a hemoglobin value of 12 g/dL or higher, aromatase inhibitors, hormone replacement therapy, megestrol acetate, or selective estrogen receptor modulators. Although the authors comment on the lack of high-quality studies related to immobility, as they only located one such study, the study they included showed immobility to be an independent risk factor for VTE and a factor that augments other VTE risk factors in LTC patients.4
An article by Gatt and associates15 showed a nonsignificant difference in VTEs between chronically immobile bedridden patients and institutionalized mobile patients. In this study, nursing home patients in Israel were followed over a 10-year period to determine if chronic immobility (defined as >3 months of immobility) had a high risk of VTE occurrence. The study assessed change in mobility status over time, noting that some patients started as mobile but became immobile during the study period. The incidence of VTE reported for mobile patients was 15.8 cases per thousand patient-years versus 13.9 cases per thousand patient-years in immobile patients (P=.77) at the end of the study, further extending the uncertainty of the true incidence of VTE in the chronically immobilized patient population.15
Prophylaxis Recommendations for the Chronically Immobilized Patient
Based on the currently available literature, immobility is an important risk factor for VTE; however, there is still ambiguity regarding the level of risk that chronic immobility poses on VTE outcomes. Until the ninth edition of the ACCP’s evidence-based clinical practice guidelines were published, VTE prophylaxis for chronically immobilized patients was not addressed. Based on the currently available literature, the ACCP guidelines recommend against the routine use of thromboprophylaxis in chronically immobilized patients who reside at home or at a nursing home (level of evidence, Grade 2C).2 The rationale for advising against prophylaxis is based on several factors, including uncertainty regarding the incidence of symptomatic VTE, lack of randomized controlled trials to show a benefit of prophylaxis, and overall limited data for this patient population.2
The ACCP guidelines refer to a trial by Scannapieco and associates,16 which is a large prospective observational study of the incidence of symptomatic VTE in patients admitted to LTC units following hospitalization for a medical disease or surgery (eg, heart failure, ischemic stroke, orthopedic surgery); these patients were also identified by high Rankin scores that correlated with a high degree of immobility. The occurrence of symptomatic VTE during the 12-month period was 2.4% (72 of 3039 patients). Of the patients who developed a symptomatic VTE, 68.1% were on VTE prophylaxis upon LTC admission, with a median time to VTE occurrence of 13 days from admission. These patients were being treated with low-molecular-weight heparin (LMWH), unfractionated heparin, vitamin K, or nonpharmacologic prophylaxis strategies; however, the study did not report the methods of prophylaxis that may have been used prior to hospital admission and it failed to address any change in mobility status from before hospital admission to LTC admission.16
The ACCP guidelines also review a study by Labarère and associates,5 which combined data from two studies conducted in 50 hospital-based, post-acute care facilities in France, finding that immobilized patients receiving LMWH prophylaxis had a decrease in proximal DVT compared with those who did not receive prophylaxis (4% vs 5.7%, P=.16).5 Although these results did not reach statistical significance, they became significant once adjusted for confounding variables.5
Based on these studies and others, the ACCP guidelines note that the overall data provide some indirect support for routine prophylaxis of immobile patients in post-acute or subacute care settings, particularly because the literature shows that these patients may have a similar incidence of VTE as that of acutely ill hospitalized patients. However, in the absence of randomized clinical trials, the guidelines recommend against routine prophylaxis and note that such trials are needed to determine if the benefits of anticoagulant thromboprophylaxis outweigh the risks in chronically immobilized patients.
Current VTE Prophylaxis Practices in Nursing Homes
Despite the limited data on VTE prophylaxis in patients with chronic immobility, several studies describe the current practices of nursing homes and other post-acute care facilities with regard to preventing VTE. Zarowitz and associates4 used the risk stratification tool they developed to make VTE prophylaxis recommendations for LTC residents based on the residents’ VTE risk factors, which included immobility. The authors recommend mechanical prophylaxis for patients with at least two risk factors for a VTE, and they recommend prophylaxis for up to 10 days or until immobility resolves for patients with immobility and two other VTE risk factors.4
Dharmarajan and colleagues17 summarize the practice patterns for VTE prophylaxis in LTC facilities following acute care hospitalizations. The authors found that the patients most likely to receive prophylaxis were patients who had recent orthopedic surgery, trauma to their lower body, an acute medical illness, or a history of a DVT. They reported that most patients were given warfarin or LMWH as the pharmacologic means of VTE prophylaxis. Aside from the common contraindications for VTE prophylaxis (eg, history of bleeding and thrombocytopenia), the authors also state that patient or caregiver wishes against preventative measures, quality of life factors, and short life expectancy were reported as frequent contraindications to the use of prophylaxis.17 In an associated study by Dharmarajan and associates,18 the authors described an educational intervention given to LTC providers about VTE prophylaxis and how the intervention affected prescribing practices. The authors found an overall increase in VTE prophylaxis in LTC patients following this educational intervention, but that immobile patients continued to have nonsignificant odds in favor of not receiving VTE prophylaxis.18 However, the educational initiative focused on the ACCP’s 2008 guidelines (8th edition),9 the American College of Physicians and the American Academy of Family Physicians clinical practice guidelines for the management of VTE,19 and the American Society of Clinical Oncology guidelines for VTE prophylaxis in patients with cancer,20 with none of these guidelines directly addressing the care of chronically immobilized patients.
What We Can Learn From the Hospital Setting
According to the ACCP guidelines, once a chronically immobilized patient is admitted from an LTC facility to an acute care facility, the Padua Prediction Score risk assessment model21 is recommended as the tool to determine VTE risk for these patients.2 This validated risk assessment tool allocates patients to low- or high-risk categories based on various factors, with high-risk patients receiving a score of 4 or greater and low-risk patients receiving a score of less than 4 (Table 2).21 Of the items in this scoring system, immobility (defined as bed rest with bathroom privileges for at least 3 days) is given 3 points, as is active cancer, previous VTE, and known thrombophilic condition.2,21
Using this scoring system, many elderly patients with reduced mobility are considered to be at high-risk of developing a VTE, as they would receive 3 points for their immobility, 1 point if they are older than 70 years, and additional points if they have other risk factors. As a result, these patients would receive prophylaxis during their hospital admission. Although immobility ranks high on the Padua system as a VTE risk factor, it is up to the provider to weigh the patient’s risk assessment score against his or her bleeding risk. This is especially essential if the patient has known independent risk factors for bleeding, such as a low platelet count (<50 x109/L), is older than 85 years, or has hepatic failure among other risk factors.2
Although the current data do not support routine VTE prophylaxis for chronically immobilized patients as a single risk factor, many patients in LTC have risk factors beyond immobility, so prophylaxis should not automatically be ruled out for these patients. Like their already hospitalized counterparts, many of these patients would be candidates for prophylaxis if they were to be admitted to a hospital. Therefore, LTC providers need to carefully weigh the risks and benefits of prophylaxis on an individualized basis, using their best judgment and patient and/or caregiver collaboration until randomized clinical trials are undertaken that yield tailored tools to evaluate the risks and benefits of VTE prophylaxis in LTC residents with chronic immobility.
Conclusion
The data for the chronically immobilized LTC patient lack the clarity and strength in numbers that are available for other patient types, making it difficult to determine when VTE prophylaxis should be administered in this patient population. In addition, the studies that have examined this population have many limitations, including incomplete lists of VTE risk factors recorded for all patients, non-use of standard measurements to diagnose VTEs, lack of information supporting the true incidence of symptomatic VTEs, and lack of consideration of the length of immobility for the patients in each study. Further studies, but particularly randomized controlled trials, are needed in this area to clearly define the VTE risk for the chronically immobilized patient. These studies would benefit from having a universal definition of chronic immobility and from assessing mobility as it changes over time. Only once such studies are undertaken can meaningful recommendations for or against prophylaxis during a patient’s stay in an LTC facility be made.
References
1. Silverstein MD, Heit JA, Mohr DN, Petterson TM, O’Fallon WM, Melton LJ 3rd. Trends in the incidence of deep vein thrombosis and pulmonary embolism: a 25-year population-based study. Arch Intern Med. 1998;158(6):585-593.
2. Kahn SR, Lim W, Dunn AS, et al. Prevention of VTE in nonsurgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2012;141(suppl 2):195S-226S.
3. Bosson JL, Labarere J, Sevestre MA, et al. Deep vein thrombosis in elderly patients hospitalized in subacute care facilities: a multicenter cross-sectional study of risk factors, prophylaxis, and prevalence. Arch Intern Med. 2003;163(21):2613-2618.
4. Zarowitz BJ, Tangalos E, Lefkovitz A, et al. Thrombotic risk and immobility in residents of long-term care facilities. J Am Med Dir Assoc. 2010;11(3):211-221.
5. Labarère J, Sevestre MA, Belmin J, et al. Low-molecular-weight heparin prophylaxis of deep vein thrombosis for older patients with restricted mobility: propensity analyses of data from two multicentre, cross-sectional studies. Drugs Aging. 2009;26(3):263-271.
6. Sellier E, Labarère J, Sevestre MA, et al. Risk factors for deep vein thrombosis in older patients: a multicenter study with systematic compression ultrasonography in postacute care facilities in France. J Am Geriatr Soc. 2008;56(2):
224-230.
7. Weill-Engerer S, Meaume S, Lahlou A, et al. Risk factors for deep vein thrombosis in inpatients aged 65 and older: a case-control multicenter study. J Am Geriatr Soc. 2004;52(8):1299-1304.
8. Arpaia G, Ambrogi F, Penza M, et al. Risk of venous thromboembolism in patients nursed at home or in long-term care residental facilities. Int J Vasc Med. 2011;2011:305027.
9. Geerts WH, Bergqvist D, Pineo GF, et al. Prevention of venous thromboembolism: American College of Chest Physicians evidence-based clinical practice guidelines (8th edition). Chest. 2008;133(suppl 6):381S-453S.
10. Geerts WH, Pineo GF, Heit JA, et al. Prevention of venous thromboembolism: the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004;126(suppl 3):338S-400S.
11. Heit JA, O’Fallon M, Petterson TM, et al. Relative impact of risk factors for deep vein thrombosis and pulmonary embolism: a population-based study. Arch Intern Med. 2002;162(11):1245-1248.
12. Leibson CL, Petterson TM, Bailey KR, Melton LJ 3rd, Heit JA. Risk factors for venous thromboembolism in nursing home residents. Mayo Clin Proc. 2008;83(2):151-157.
13. Heit JA, Silverstein MD, Mohr DN, Petterson TM, O’Fallon WM, Melton LJ 3rd. Predictors of survival after deep vein thrombosis and pulmonary embolism. Arch Intern Med. 1999;159(5):445-453.
14. Heit JA, Silverstein MD, Mohr DN, Petterson TM, O’Fallon WM, Melton LJ 3rd. Risk factors for deep vein thrombosis and pulmonary embolism: a population-based case-control study. Arch Intern Med. 2000;160(6):809-815.
15. Gatt ME, Paltiel O, Bursztyn M. Is prolonged immobilization a risk factor for symptomatic venous thromboembolism in elderly bedridden patients? Results of a historical-cohort study. Thromb Haemost. 2004;91(3):538-543.
16. Scannapieco G, Ageno W, Airoldi A, et al. Incidence and predictors of venous thromboembolism in post-acute care patients. A prospective cohort study.Thromb Haemost. 2010;104(4):734-740.
17. Dharmarajan TS, Nanda A, Agarwal B, et al. Prevention of venous thromboembolism: Practice patterns in 17 geographically diverse long-term care facilities in the United States: Part 1 of 2 (an AMDA Foundation project). J Am Med Dir Assoc. 2012;13(3):298-302.
18. Dharmarajan TS, Nanda A, Agarwal B, et al. Prevention of venous thromboembolism: Practice patterns in 17 geographically diverse long-term care facilities in the United States: Part 2 of 2 (an AMDA Foundation project). J Am Med Dir Assoc. 2012;13(3):303-307.
19. Snow V, Qaseem A, Barry P, et al. Management of venous thromboembolism:a clinical practice guideline from the American College of Physicians and American Academy of Family Physicians. Ann Intern Med. 2007;146(3):204-210.
20. Lyman GH, Khorana AA, Falanga A, et al. American Society of Clinical Oncology guideline: recommendations for venous thromboembolism prophylaxis and treatment in patients with cancer. J Clin Oncol. 2007;25(34):5490-5505.
21. Barbar S, Noventa F, Rosetta V, et al. A risk assessment model for the identification of hospitalized medical patients at risk for venous thromboembolism:the Padua Prediction Score. J Thromb Haemost. 2010;8(11):2450-2457.
Disclosures: The author reports no relevant financial relationships.
Address correspondence to: April Robinson, PharmD, 515 N. Main Street, Wingate University School of Pharmacy, Wingate, NC 28174; a.robinson@wingate.edu
