Comparison of Presentation, Treatment, and Outcomes of Venous Thromboembolism in Long-Term Immobile Patients Based on Age.

BACKGROUND: Chronic immobility is prevalent, especially as people age. However, little is known about venous thromboembolism (VTE) outcomes in this population. OBJECTIVE: To compare the presentation, treatment, and outcomes in chronically immobile (>8 weeks) patients older vs. younger than 75 who presented with VTE. DESIGN: An observational international registry of patients with VTE. PARTICIPANTS: Patients with acute VTE from the "Registro Informatizado Enfermedad TromboEmbolica" (RIETE) registry who were chronically immobile. MAIN MEASURES: Baseline characteristics, presenting signs and symptoms, treatment and outcomes including major bleeding, recurrent VTE, and mortality. KEY RESULTS: Among 4612 immobile patients (mean age 75.7 years, 34% male), 2127 (46%) presented with pulmonary embolism (PE). Patients >75 years presented more often with dyspnea (44% vs. 38%) or altered mental status (23% vs. 8.1%) and less often with chest pain (13% vs. 18%). The median duration of anticoagulation was shorter in older compared with younger patients [126 vs. 169 days]. During the first 90 days of anticoagulation, major bleeding (4.0% vs. 2.2%), PE-related death (2.5% vs. 1.1%), and bleeding-related death (0.78% vs. 0.26%) occurred more frequently among older patients. In 3550 patients who received anticoagulation beyond 90 days, older patients had more major bleeding [4.23 vs. 2.21 events per 100 patient years]. After anticoagulation discontinuation, recurrent VTE and major bleeding occurred in 11.8 and 9.25 and 1.49 and 0.69 events per 100 patient years, respectively, both in similar rates in both groups. In multivariable analysis, after stopping anticoagulation, VTE recurrence was inversely associated with long-term facility residence [OR 0.51 (0.28-0.92)], anemia [OR 0.63 (0.42-0.95)], and anticoagulation duration < 90 days [OR 0.38 (0.27-0.54)]. CONCLUSIONS: Chronically immobilized patients older than 75 years presenting with VTE experience a high rate of adverse events including major bleeding and recurrent VTE. When considering treatment beyond 90 days, we should account for bleeding, recurrence risk, and associated mortality.

A RIETE registry analysis of patients with upper extremity deep vein thrombosis and thoracic outlet syndrome.

BACKGROUND: Upper extremity deep vein thrombosis (UEDVT) related to thoracic outlet syndrome (TOS) is rare, and the literature is limited to institutional case series. METHODS: We used data from the RIETE Registry to compare outcomes (recurrences, major bleeding and signs and symptoms of post-thrombotic [PTS] syndrome) in patients with UEDVT and TOS undergoing first rib resection vs. those not undergoing surgery. RESULTS: From March 2001 to March 2021, there were 4214 patients with UEDVT, of whom 209 (4.96%) had TOS. Of these, 55 (26%) underwent first rib resection. Patients with TOS were younger and less likely to have comorbidities than those without TOS. There were no differences between patients with TOS undergoing surgery and those who did not. During anticoagulation, patients with TOS had a non-statistically significant lower rate of VTE recurrences than those without TOS (hazard ratio [HR]: 0.46; 95%CI: 0.14-1.12) and a lower bleeding rate (HR: 0.16; 95%CI: 0.01-0.83). No patient with TOS developed pulmonary embolism or died. Patients with TOS undergoing surgery had fewer PTS symptoms (odds ratio [OR]: 0.21; 95%CI: 0.06-0.68) or signs (OR: 0.11; 95%CI: 0.02-0.42) after one year than patients who did not have surgery. At two years, the differences in symptoms (OR: 0.25; 95%CI: 0.06-0.94) and signs (OR: 0.04; 95%CI: 0.002-0.33) persisted. CONCLUSIONS: Patients with UEDVT and TOS were younger and had less comorbidities than those without. Surgical resection of the first rib was associated with a lower proportion of patients developing PTS one and two years later.

Risk of recurrent venous thromboembolism in patients with autoimmune diseases: data from the Registro Informatizado de Enfermedad TromboEmbólica (RIETE) registry.

Autoimmune disease is a risk factor for first incident venous thromboembolism (VTE). However, data on the risk of recurrent VTE in people with autoimmune disease is sparse. We explored the risk of recurrent VTE using the RIETE registry, comparing people with autoimmune disease (n = 1305) to those without (n = 50608). Overall rates were 6.5 and 5.1 recurrent VTE/100 years for patients with autoimmune disease vs controls, respectively. After adjustment for sex and unprovoked/provoked VTE yielded an adjusted hazard ratio of 1.29 (95%CI 1.03-1.62). The analysis was limited by short median follow up time (161 days overall), precluding definitive conclusions on recurrent VTE risks.

Different Types of Statins and All-Cause Mortality during Anticoagulation for Venous Thromboembolism: Validation Study from RIETE Registry.

Introduction We previously reported that during the course of anticoagulation for venous thromboembolism (VTE) patients using statins were at a lower risk to die than nonusers. Methods We used the R egistro I nformatizado E nfermedad T rombo E mbólica (RIETE) registry to validate our previous findings in a subsequent cohort of patients and to compare the risk of death according to the use of different types of statins. Results From January 2018 to December 2019, 19,557 patients with VTE were recruited in RIETE. Of them, 4,065 (21%) were using statins (simvastatin, 1,406; atorvastatin, 1,328; rosuvastatin, 246; and others, 1,085). During anticoagulation (192 vs.182 days, for statin and no statin users respectively), 500 patients developed a VTE recurrence, 519 suffered major bleeding, and 1,632 died (fatal pulmonary embolism [PE], 88 and fatal bleeding, 78). On multivariable analysis, statin users were at a lower risk to die (hazard ratio [HR] = 0.68; 95% confidence interval [CI]: 0.59-0.79) than nonusers. When separately analyzing the drugs, on multivariable analysis, patients using simvastatin (HR = 0.64; 95% CI: 0.52-0.80), atorvastatin (HR 0.72; 95% CI: 0.58-0.89), or other statins (HR = 0.67; 95% CI: 0.52-0.87) were at a lower risk to die than nonusers. For those using rosuvastatin, difference was not statistically significant (HR = 0.77; 95% CI: 0.50-1.19), maybe due to the sample size. Conclusion Our data validate previous findings and confirm that VTE patients using statins at baseline are at a lower risk to die than nonusers. No statistically differences were found according to type of statins.

Outcome of patients with acute symptomatic pulmonary embolism and psychiatric disorders.

OBJECTIVE: To address the association between psychiatric disorders and short-term outcomes after acute symptomatic pulmonary embolism (PE). METHODS: We identified adults with PE enrolled in the RIETE registry between December 1, 2013, and January 31, 2019. Using multinomial regression, we assessed the association between a history of psychiatric disorders and the outcomes of all-cause mortality, PE-related mortality, and venous thromboembolism recurrence and bleeding rates through 30 days after initiation of treatment. We also examined the impact of depression on all-cause and PE-specific mortality. RESULTS: Among 13,120 patients diagnosed with acute PE, 16.1% (2115) had psychiatric disorders and 4.2% died within the first 30-days of follow-up. Patients with psychiatric disorders had increased odds for all-cause (adjusted odds ratio [OR] 1.50; 95% CI, 1.21 to 1.86; P < 0.001) and PE-related mortality (adjusted OR 1.64; 95% CI, 1.09 to 2.48; P = 0.02) compared to those without psychiatric disorders. Multinomial logistic regression showed a non-significant trend toward lower risk of recurrences for patients with psychiatric disorders (adjusted OR 0.49; 95% CI, 0.21 to 1.15; P = 0.10). Psychiatric disorders were not significantly associated with increased odds for major bleeds during follow-up (adjusted OR 1.09; 95% CI, 0.85 to 1.40; P = 0.49). Results were consistent in a sensitivity analysis that only considered patients with a diagnosis of depression. CONCLUSIONS: In patients with acute PE, history of psychiatric disorders might predict all-cause and PE-related death in the ensuing month after diagnosis.

Psychotropic Drugs and Outcome in Patients Receiving Anticoagulant Therapy for Venous Thromboembolism.

BACKGROUND: The influence (if any) of the use of psychotropic drugs on outcome in patients receiving anticoagulant therapy for venous thromboembolism (VTE) has not been consistently evaluated. METHODS: We used data from the RIETE (Registro Informatizado Enfermedad TromboEmbólica) database to compare the risk for VTE recurrences, major bleeding, or death during the course of anticoagulant therapy, according to the use of psychotropics at baseline. RESULTS: Among 49,007 patients with VTE enrolled from February 2009 to September 2019, total 5,230 (11%) were using psychotropics at baseline: antidepressants 3,273 (6.7%), antipsychotics 1,588 (3.2%), and anticholinesterases 369 (0.7%). During the course of anticoagulation, 1,259 patients developed VTE recurrences, 1,231 bled, and 3,988 died (fatal pulmonary embolism 269 and fatal bleeding 187). On multivariable analysis, patients using psychotropics at baseline had a similar risk for VTE recurrences (adjusted hazard ratio [HR]: 0.81; 95% confidence interval [CI]: 0.58-1.12), a nonsignificantly higher risk for major bleeding (adjusted HR: 1.15; 95% CI: 0.97-1.35), and a higher risk for intracranial bleeding (adjusted HR: 1.83; 95% CI: 1.32-2.53) or death (adjusted HR: 1.44; 95% CI: 1.32-1.57) compared with those not using psychotropics. When separately analyzed, the highest risk for intracranial bleeding was found in patients using antidepressants (adjusted HR: 1.60; 95% CI: 1.08-2.37) or antipsychotics (adjusted HR: 2.02; 95% CI: 1.17-3.49) but not in those on anticholinesterases (adjusted HR: 1.69; 95% CI: 0.62-4.60). CONCLUSION: During the course anticoagulation for VTE, patients using psychotropics at baseline were at increased risk for intracranial bleeding.

Inferior vena cava agenesis in patients with lower limb deep vein thrombosis in the RIETE registry. When and why to suspect.

BACKGROUND: Limited data exist about the clinical presentation and outcomes of patients with inferior vena cava agenesis (IVCA) who develop deep vein thrombosis (DVT). METHODS: We used the RIETE (Registro Informatizado Enfermedad Trombo Embólica) registry to compare clinical characteristics and outcomes of patients with lower limb DVT, according to the presence or absence of IVCA. Major outcomes included recurrent DVT, major bleeding and post-thrombotic syndrome (PTS). RESULTS: Among 50,744 patients with lower-limb DVT recruited in October 2018, 31 (0.06%) had IVCA. On multivariable analysis, patients aged < 30 years (odds ratio [OR]: 17.9; 95%CI: 7.05-45.3), with unprovoked DVT (OR: 2.49; 95%CI: 1.17-5.29), proximal (OR: 2.81; 95%CI: 1.05-7.53) or bilateral DVT (OR: 11.5; 95%CI: 4.75-27.8) were at increased risk to have IVCA. Patients with DVT and IVCA had lower odds to present with coexisting PE (OR: 0.22; 95%CI: 0.07-0.73). During the first year of follow-up, the rates of DVT recurrences (hazard ratio [HR]: 1.30; 95%CI: 0.07-6.43), pulmonary embolism (HR: 2.30; 95%CI: 0.11-11.4) or major bleeding (HR: 1.32; 95%CI: 0.07-6.50) were not significantly different with those with versus those without IVCA. One year after the index DVT, IVCA patients had a higher rate of skin induration (OR: 3.70; 95%CI: 1.30-9.52), collateral vein circulation (OR: 3.57; 95%CI: 1.42-8.79) or venous ulcer (OR: 5.87; 95%CI: 1.36-1.87) in the lower limb than those without IVCA. CONCLUSIONS: Certain clinical features such as unprovoked and bilateral proximal DVT in young patients should raise the suspicion for IVCA. Patients with IVCA had higher odds for symptoms of post-thrombotic syndrome.

Correction to: Vena cava filters in patients presenting with major bleeding during anticoagulation for venous thromboembolism.

In the original publication, part of the conflict of statement was incorrectly published as "Dr. Bikdeli reports that he was approached by lawyers on behalf of plaintiffs in litigation related to IVC filters". The correct statement should read as "Dr. Bikdeli reports that he is a consulting expert (on behalf of the plaintiff) for litigation related to a specific type of IVC filters".

Correction to: Vena cava filters in patients presenting with major bleeding during anticoagulation for venous thromboembolism.

In the original publication, part of conflict of statement was incorrectly published.

Vena cava filters in patients presenting with major bleeding during anticoagulation for venous thromboembolism.

The association between inferior vena cava filter (IVC) use and outcome in patients presenting with major bleeding during anticoagulation for venous thromboembolism (VTE) has not been thoroughly investigated. We used the RIETE registry to compare the 30-day outcomes (death, major re-bleeding or VTE recurrences) in VTE patients who bled during the first 3 months of therapy, regarding the insertion of an IVC filter. A propensity score matched (PSM) analysis was performed to adjust for potential confounders. From January 2001 to September 2016, 1065 VTE patients had major bleeding during the first 3 months of anticoagulation (gastrointestinal 370; intracranial 124). Of these, 122 patients (11%) received an IVC filter. Patients receiving a filter restarted anticoagulation later (median, 4 vs. 2 days) and at lower doses (95 ± 52 IU/kg/day vs. 104 ± 55 of low-molecular-weight heparin) than those not receiving a filter. During the first 30 days after bleeding (after excluding 246 patients who died within the first 24 h), 283 patients (27%) died, 63 (5.9%) had non-fatal re-bleeding and 19 (1.8%) had recurrent pulmonary embolism (PE). In PSM analysis, patients receiving an IVC filter (n = 122) had a lower risk for all-cause death (HR 0.49; 95% CI 0.31-0.77) or fatal bleeding (HR 0.16; 95% CI 0.07-0.49) and a similar risk for re-bleeding (HR 0.55; 95% CI 0.23-1.40) or PE recurrences (HR 1.57; 95% CI 0.38-6.36) than those not receiving a filter (n = 429). In VTE patients experiencing major bleeding during the first 3 months, use of an IVC filter was associated with reduced mortality rates.Clinical Trial Registration NCT02832245.

Impact of sex, age, and risk factors for venous thromboembolism on the initial presentation of first isolated symptomatic acute deep vein thrombosis.

BACKGROUND AND AIMS: Sex-specific differences exist for the initial presentation of acute venous thromboembolism (VTE): men are more likely to present with proximal deep vein thrombosis (DVT) in the lower limbs (versus pulmonary embolism [PE] or isolated distal DVT [IDDVT]) than women. We studied in detail the influence of sex, age, and VTE risk factors on the initial presentation of IDDVT versus proximal DVT. METHODS: A total of 24,911 patients with a first episode of objectively diagnosed acute symptomatic lower-limb DVT (without symptomatic PE) were enrolled in RIETE (years 2000-2017) and included in the present analysis. RESULTS: A total of 4266 (17.1%) patients had IDDVT. No trend for more IDDVT diagnoses was observed over time. Women aged 40-69 had a higher proportion of IDDVT, especially between 40 and 49 years (+6.7%; 95CI +3.7%; +9.9%), whereas men had more often proximal DVT. The presenting location of first acute DVT depended on sex, age, and the prevalence and type of VTE risk factors. Recent surgery was independently associated with a diagnosis of IDDVT in both women and men, whereas active cancer and pregnancy were associated with proximal DVT. CONCLUSIONS: The interaction between age and VTE risk factors influences the presenting location (distal versus proximal) of the first acute lower-limb DVT observed in women and men. Our observations extend to IDDVT the concept that different clinical manifestations of acute VTE may not fully share the same pathophysiological mechanisms: this contributes to explain sex-specific prognostic differences.

Low discriminating power of the modified Ottawa VTE risk score in a cohort of patients with cancer from the RIETE registry.

Treatment of patients with cancer-associated venous thromboembolism (VTE) remains a major challenge. The modified Ottawa score is a clinical prediction rule evaluating the risk of VTE recurrences during the first six months of anticoagulant treatment in patients with cancer-related VTE. We aimed to validate the Ottawa score using data from the RIETE registry. A total of 11,123 cancer patients with VTE were included in the analysis. According to modified Ottawa score, 2,343 (21 %) were categorised at low risk for VTE recurrences, 4,525 (41 %) at intermediate risk, and 4,255 (38 %) at high risk. Overall, 477 episodes of VTE recurrences were recorded during the course of anticoagulant therapy, with an incidence rate for low, intermediate, and high risk groups of 6.88 % (95 % CI 5.31-8.77), 11.8 % (95 % CI 10.1-13.6), and 21.3 % (95 % CI 18.8-24.1) patient-years, respectively. Overall mortality had an incidence rate of 21.1 % (95 % CI 18.2-24.3), 79.4 % (95 % CI: 74.9-84.1), and 134.7 % (95 % CI: 128.3-141.4) patient-years, respectively. The accuracy and discriminating power of the modified Ottawa score for VTE recurrence was modest, with low sensitivity, specificity and positive predictive value, and a C-statistics of 0.58 (95 % CI: 0.56-0.61). In our analysis, the modified Ottawa score did not accurately predict VTE recurrence among patients with cancer-associated thrombosis, thus hindering its use in clinical practice. It is time to define a new score including other clinical predictors.

Uterine bleeding during anticoagulation in women with venous thromboembolism.

BACKGROUND: Women presenting with uterine bleeding during the course of anticoagulant therapy for venous thromboembolism (VTE) present a difficult therapeutic dilemma due to the absence of evidence-based recommendations. METHODS: We used the RIETE (Registro Informatizado Enfermedad TromboEmbólica) database to assess the clinical characteristics of women presenting with uterine bleeding during anticoagulation for VTE, its frequency, time course, management and 30-day outcomes. RESULTS: As of October 2016, 31,951 women with VTE were recruited in RIETE. During the course of anticoagulant therapy, 53 (0.17%) developed major uterine bleeding, 118 (0.37%) non-major uterine bleeding and 948 (2.97%) had major bleeding in other sites. Median time elapsed from VTE to bleeding was: 32, 71 and 22 days, respectively. Mean age was: 56±17, 52±20 and 75±14 years, respectively. Women with major uterine bleeding more likely had cancer (51%), anemia (72%), raised platelet count (19%) or recent major bleeding (11%) at VTE presentation than those in the other subgroups. During the first 30 days after bleeding, 17%, 1.7% and 31% of women died, respectively. Of 11 women with uterine bleeding who died, 9 (82%) had cancer, two (18%) died of bleeding and one (9.1%) died of pulmonary embolism after discontinuing anticoagulation. CONCLUSIONS: Uterine bleeding during the course of anticoagulation for VTE is not uncommon and mostly affects young women. Those with cancer, anaemia, raised platelet count or recent bleeding at baseline are at an increased risk for uterine bleeding during anticoagulation.

Clinical features and short-term outcomes of cancer patients with suspected and unsuspected pulmonary embolism: the EPIPHANY study.

The study aimed to identify predictors of overall 30-day mortality in cancer patients with pulmonary embolism including suspected pulmonary embolism (SPE) and unsuspected pulmonary embolism (UPE) events. Secondary outcomes included 30- and 90-day major bleeding and venous thromboembolism (VTE) recurrence.The study cohort included 1033 consecutive patients with pulmonary embolism from the multicentre observational ambispective EPIPHANY study (March 2006-October 2014). A subgroup of 497 patients prospectively assessed for the study were subclassified into three work-up scenarios (SPE, truly asymptomatic UPE and UPE with symptoms) to assess outcomes.The overall 30-day mortality rate was 14%. The following variables were associated with the overall 30-day mortality on multivariate analysis: VTE history, upper gastrointestinal cancers, metastatic disease, cancer progression, performance status, arterial hypotension <100 mmHg, heart rate >110 beats·min-1, basal oxygen saturation <90% and SPE (versus overall UPE).The overall 30-day mortality was significantly lower in patients with truly asymptomatic UPE events (3%) compared with those with UPE-S (20%) and SPE (21%) (p<0.0001). Thirty- and 90-day VTE recurrence and major bleeding rates were similar in all the groups.In conclusion, variables associated with the severity of cancer and pulmonary embolism were associated with short-term mortality. Our findings may help to develop pulmonary embolism risk-assessment models in this setting.

Prognostic value of computed tomography pulmonary angiography indices in patients with cancer-related pulmonary embolism: Data from a multicenter cohort study.

OBJECTIVE: To analyze the prognostic value of pulmonary artery obstruction versus right-ventricle (RV) dysfunction radiologic indices in cancer-related pulmonary embolism (PE). METHODS: We enrolled 303 consecutive patients with paraneoplastic PE, evaluated by computed tomography pulmonary angiography (CTPA) between 2013 and 2014. The primary outcome measure was serious complications at 15days. Multivariate analyses were conducted by using binary logistic and robust regressions. Radiological features such as the Qanadli index (QI) and RV dysfunction signs were analyzed with Spearman's partial rank correlations. RESULTS: RV diameter was the only radiological variable associated with an adverse outcome. Subjects with enlarged RV (diameter>45mm) had more 15-day complications (58% versus 40%, p=0.001). The QI correlated with the RV diameter (r=0.28, p<0.001), left ventricle diameter (r=-0.19, p<0.001), right ventricular-to-left ventricular diameter ratio (r=0.39, p<0.001), pulmonary artery diameter (r=0.22, p<0.001), and pulmonary artery/ascending aorta ratio (r=0.27, p<0.001). A QI≥50% was only associated with 15-day complications in subjects with enlarged RV, inverted intraventricular septum, or chronic cardiopulmonary diseases. The central or peripheral PE location did not affect the correlations among radiological variables and was not associated with clinical outcomes. CONCLUSIONS: Right ventricular dysfunction signs in CTPA are more useful than QI in predicting cancer-related PE outcome.

Long-Term Anticoagulant Therapy of Patients with Venous Thromboembolism. What Are the Practices?

Current guidelines of antithrombotic therapy suggest early initiation of vitamin K antagonists (VKA) in non-cancer patients with venous thromboembolism (VTE), and long-term therapy with low-molecular weight heparin (LMWH) for those with cancer. We used data from RIETE (international registry of patients with VTE) to report the use of long-term anticoagulant therapy over time and to identify predictors of anticoagulant choice (regarding international guidelines) in patients with- and without cancer. Among 35,280 patients without cancer, 82% received long-term VKA (but 17% started after the first week). Among 4,378 patients with cancer, 66% received long term LMWH as monotherapy. In patients without cancer, recent bleeding (odds ratio [OR] 2.70, 95% CI 2.26-3.23), age >70 years (OR 1.15, 95% CI 1.06-1.24), immobility (OR 2.06, 95% CI 1.93-2.19), renal insufficiency (OR 2.42, 95% CI 2.15-2.71) and anemia (OR 1.75, 95% CI 1.65-1.87) predicted poor adherence to guidelines. In those with cancer, anemia (OR 1.83, 95% CI 1.64-2.06), immobility (OR 1.51, 95% CI 1.30-1.76) and metastases (OR 3.22, 95% CI 2.87-3.61) predicted long-term LMWH therapy. In conclusion, we report practices of VTE therapy in real life and found that a significant proportion of patients did not receive the recommended treatment. The perceived increased risk for bleeding has an impact on anticoagulant treatment decision.

Gender differences in cancer patients with acute venous thromboembolism.

BACKGROUND: The outcome of cancer patients with acute venous thromboembolism (VTE) may differ according to gender. METHODS: We used the RIETE database to compare the rate of VTE (pulmonary embolism [PE] or deep vein thrombosis [DVT]) recurrences), major bleeding and mortality during the course of anticoagulation, according to gender. RESULTS: As of August 2014, 11,055 patients with active cancer were enrolled in RIETE, of whom 5,104 (46%) were women. During the course of anticoagulation (mean: 142 days), 505 patients developed recurrent VTE, 429 bled and 2730 died. Compared with men, women had a significantly lower rate of fatal bleeding (risk ratio [RR]: 0.69; 95% CI: 0.47-0.99) and death (RR: 0.90; 95% CI: 0.83-0.97), and a non-significantly lower rate of PE recurrences (RR 0.83; 95% CI: 0.65-1.06) and major bleeding (RR: 0.89; 95% CI: 0.74-1.08). CONCLUSIONS: During the course of anticoagulation, cancer women with VTE had a better outcome than men.

Incógnitas del tratamiento de la enfermedad tromboembólica venosa en los pacientes con cáncer / Unsolved issues in the treament of venous thromboembolic disease in patients with cancer

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Long-term therapy with low-molecular-weight heparin in cancer patients with venous thromboembolism.

Long-term therapy with low-molecular-weight heparin (LMWH) is the treatment of choice for cancer patients with venous thromboembolism (VTE). However, the ideal doses of LMWH have not been thoroughly studied. We used the RIETE Registry data to assess the influence of the daily LMWH dosage on outcome during the first three months after VTE. We used propensity score-matching to compare patients who received <150 vs. those receiving ≥150 UI/kg/day LMWH. Up to July 2010, 3,222 cancer patients with VTE received long-term therapy with fixed doses of LMWH. Of these, 1,472 (46%) received <150 IU/kg/day (mean, 112 ± 28), and 1,750 received ≥150 IU/kg/day (mean, 184 ± 32). Results of the propensity score matching involved 1269 matched pairs. During follow-up, the incidence of pulmonary embolism (PE) recurrences was similar (1.2% vs. 1.9%), but patients receiving <150 IU/kg/day LMWH had a lower incidence of fatal PE than those treated with ≥150 IU/kg/day (0.2% vs. 1.0%; p=0.004). Multivariate analysis confirmed that patients receiving <150 IU/kg/day LMWH had a lower risk for fatal PE (odds ratio [OR]: 0.2; 95% confidence interval [CI]: 0.06-0.8) and for major bleeding (OR: 0.6; 95% CI: 0.3-1.0) than those treated with ≥150 IU/kg/day. In real life, one in every two cancer patients with VTE received lower doses of LMWH than those used in randomised trials, with large variations from patient to patient. Unexpectedly, patients treated with <150 IU/kg/day LMWH had fewer fatal PE cases and fewer major bleeding events than those receiving ≥150 IU/kg/day LMWH. This finding, however, should be validated in prospective clinical trials.