Risk of stroke in male and female patients with atrial fibrillation in a nationwide cohort.

Female sex has been suggested as a risk modifier for stroke in patients with atrial fibrillation (AF) with comorbid prevalent stroke risk factors. Management has evolved over time towards a holistic approach that may have diminished any sex difference in AF-related stroke. In a nationwide cohort of AF patients free from oral anticoagulant treatment, we examine the time trends in stroke risk overall and in relation to risk differences between male and female patients. Here we show that among 158,982 patients with AF (median age 78 years (IQR: 71 to 85); 52% female) the 1-year thromboembolic risk was highest between 1997-2000 with a risk of 5.6% and lowest between 2013-2016 with a risk of 3.8%, declining over the last two decades. The excess stroke risk for female vs male patients has also been declining, with risk-score adjusted relative risk estimates suggesting limited sex-difference in recent years.

Positive predictive value and sensitivity of cancer-associated venous thromboembolism diagnoses in the Danish National Patient Register.

INTRODUCTION: Hospital discharge diagnoses from administrative registries are frequently used in studies of cancer-associated venous thromboembolism, but the validity of International Classification of Diseases (ICD) codes for identifying such events is unknown. MATERIALS AND METHODS: Using patient samples from the Danish National Patient Register, we calculated positive predictive values (PPV), i.e., the proportion of registered ICD codes, which could be confirmed after manual search of the electronic health record. Sensitivity was estimated in a sample of patients with imaging-verified venous thromboembolism but without prior knowledge about their ICD coding status. Sensitivity was calculated as the proportion of these patients, who were discharged with an ICD code for venous thromboembolism. RESULTS: The overall PPV of an ICD-10 diagnosis of cancer-associated venous thromboembolism was 75.9 % (95 % confidence interval 71.3-80.0). In subgroups, the PPV was particularly low for recurrent venous thromboembolism (44.2 %), diagnoses in a secondary position (55.7 %), outpatient diagnoses (65.3 %), and diagnoses given at surgical (66.7 %), emergency wards (48.4 %), or via hospices/palliative teams (0 %). The overall sensitivity was 68 %, meaning 32 % of patients with cancer diagnosed in hospital with venous thromboembolism were discharged without any registered ICD code for venous thromboembolism. CONCLUSIONS: The positive predictive value of an ICD diagnosis of cancer-associated venous thromboembolism in the Danish Patient Register was overall adequate for research purposes, but with notable variation across subgroups. Sensitivity was limited, as 1/3 of patients with venous thromboembolism were discharged without any relevant ICD code. Cautious interpretation of incidence of cancer-associated venous thromboembolism based on administrative register-based data is warranted.

Adherence and Persistence to Antiplatelet Therapy in Lower Extremity Peripheral Arterial Disease: A Danish Population Based Cohort Study.

OBJECTIVE: Adherence to antiplatelet therapy is recommended but unexplored in patients with symptomatic lower extremity peripheral arterial disease (PAD). Therefore, this study aimed to determine adherence and persistence to antiplatelet therapy in patients with PAD, defined as intermittent claudication and chronic limb threatening ischaemia. DESIGN: Population based nationwide cohort study. METHODS: This study included all Danish citizens aged ≥ 40 years with a first inpatient or outpatient diagnosis of symptomatic PAD between 2010 - 2017, and who had at least one prescription claim for aspirin and/or clopidogrel within 90 days after diagnosis. Adherence was determined by the proportion of days covered (PDC) during the first year after diagnosis. Persistence was defined as no treatment gap ≥ 30 days between prescription renewals over three year follow up. RESULTS: A total of 39 687 patients were eligible for inclusion, of whom 23 279 (58.7%) claimed a prescription for aspirin and/or clopidogrel within 90 days of diagnosis. Among these, 12 898 (55.4%) were prevalent users, while the remainder comprised new users who initiated the therapy after the index PAD diagnosis. The mean PDC was 74.5% (SD 35.0%) for prevalent users and 60.5% (SD 30.5%) for new users. Adherence increased with age and number of concomitant drugs. The overall one year cumulative incidence treatment discontinuation was 13.0% (95% CI 12.5 - 13.4%) overall, 17.2% (CI 16.6 - 17.9%) for prevalent users, and 7.9% (CI 7.4 - 8.4%) for new users. At three year follow up, the cumulative incidence of discontinuation was 31.5% (CI 30.9 - 32.2%) overall, 44.6% (CI 43.7 - 45.4%) for prevalent users, and 14.6% (CI 13.9 - 15.3) for new users. CONCLUSION: Less than 60% of patients with newly diagnosed symptomatic PAD claimed a prescription for antiplatelet therapy within 90 days of diagnosis, and both adherence and persistence were moderate during the first year after diagnosis. These findings underscore the importance of efforts to improve the initiation and continuation of antiplatelet therapy in patients with PAD.

Net Clinical Benefit of Oral Anticoagulation Among Frail Patients With Atrial Fibrillation: Nationwide Cohort Study.

BACKGROUND: Frail people with atrial fibrillation are often undertreated with oral anticoagulants (OACs), and evidence for the net clinical benefit (NCB) of OAC is sparse. We, therefore, examined the risk of thromboembolic events, major bleeding, and NCB of anticoagulation treatment. METHODS: This was a nationwide cohort study including frail patients aged with incident atrial fibrillation between 2013 and 2018. Patients were categorized according to OAC treatment exposure. One-year risks of thromboembolic events and major bleeding were ascertained where death was treated as a competing risk. The NCB of anticoagulation was assessed by a bivariate trade-off between thromboembolism and bleeding. RESULTS: We identified 36 223 frail patients with atrial fibrillation (median age, 79 years; 50.5% female), of whom 61.8% started OAC therapy, while 38.2% were untreated despite indication for stroke prevention. At 1 year, the risk of thromboembolic events was 2.1% (95% CI, 1.8%-2.3%) among patients not receiving OAC versus 1.5% (95% CI, 1.4%-1.7%) in patients with OAC. The bleeding risk was 3.2% (95% CI, 2.9%-3.5%) among patients without OAC versus 3.5% (95% CI, 3.2%-3.8%) among anticoagulated patients. The NCB was 0.70% (95% CI, 0.32%-1.08%), suggesting a benefit of OAC treatment; however, the NCB declined with age and increasing frailty and was lowest among patients >75 years of age or with high frailty level. CONCLUSIONS: Frail patients with atrial fibrillation are often untreated with OAC in routine clinical care despite an indication for stroke prevention. The NCB balancing thromboembolic events and major bleeding was in favor of anticoagulation but decreased with advancing age and increasing frailty.

Effectiveness and safety of direct oral anticoagulation vs. warfarin in frail patients with atrial fibrillation.

AIMS: Although frail patients with atrial fibrillation (AF) carry a high risk of stroke and treatment-related bleeding complications, evidence for the safety and effectiveness of anticoagulation remains sparse. This study investigated the effectiveness and safety of direct oral anticoagulant (DOAC) vs. warfarin in frail AF patients. METHODS AND RESULTS: Nationwide registry-based cohort study including 32 048 anticoagulation naïve frail patients (median age 80 years, 53% female) with incident AF during 2012-20. Frailty was assessed using the hospital frailty risk score. To address baseline confounding, we applied inverse probability of treatment weighting (IPTW) and marginal structural models with weighted pooled regression to compute weighted hazard ratios (wHRs) and risk differences for thromboembolism and major bleeding comparing specific DOAC doses with warfarin. After AF diagnosis, 6747 (21.1%) initiated warfarin, 17 076 (50.3%) initiated standard-dose DOAC, and 9179 (28.6%) initiated reduced-dose DOAC. Comparative effectiveness analyses in the IPTW pseudo-populations revealed similar thromboembolism risk between standard-dose DOAC and warfarin [wHR 0.95, 95% confidence interval (CI) 0.80-1.13] and between reduced-dose DOAC and warfarin (wHR 0.97, 95% CI 0.77-1.23). The 1-year thromboembolic event-free survival difference was -0.2% for DOAC, regardless of dosing, vs. warfarin. Major bleeding risk was significantly lower with standard-dose DOAC (wHR 0.69, 95% CI 0.59-0.87) and reduced-dose DOAC (wHR 0.67, 95% CI 0.55-0.81) vs. warfarin. The 1-year bleeding risk difference with DOAC ranged from -1.3% to -3.0%. CONCLUSION: Our findings indicate comparable thromboembolism risk and significantly lower bleeding risk with both standard and reduced DOAC regimens compared with warfarin in frail AF patients in routine care.

Epidemiological Trends and Projections of Incidence, Prevalence, and Disease Related Mortality Associated With Peripheral Arterial Disease: Observations Using Nationwide Danish Data.

OBJECTIVE: Peripheral arterial disease (PAD) trends remain unclear because contemporary data are sparse and conflicting. This nationwide cohort study quantified changes in PAD incidence, prevalence, and all cause mortality, and projected prevalence development through to 2040. METHODS: Population based registries covering the entire Danish population aged ≥ 40 years from 2000 to 2018 were linked to assess trends in PAD incidence, prevalence, and all cause mortality, overall and by sex and age groups. Based on observed trends in incidence and mortality, and estimated future annual age distribution and population mortality, the PAD prevalence through to 2040 was projected. RESULTS: The Danish population aged 40 - 99 years in 2000 - 2018 included 4 811 281 individuals, among whom 145 870 incident PAD diagnoses were identified. The age and sex standardised PAD incidence decreased from 2.26 per 1 000 person years in 2000 to 1.65 in 2018 (incidence RR 0.74, 95% CI 0.72 - 0.77). The incidence was approximately 20% higher in men than women but declined similarly over time. Concurrently, PAD prevalence in the Danish adult population increased from 1.3% to 1.6% (prevalence ratio 1.28, 95% CI 1.26 - 1.30). Among patients aged ≥ 80 years, the prevalence reached 5.7% in women and 7.9% in men. The age and sex standardised annual mortality among patients with PAD decreased from 9.8% in 2000 to 7.2% in 2018 (mortality ratio 0.75, 95% CI 0.72 - 0.78). Projections of PAD prevalence demonstrated that the rising PAD prevalence will continue until around 2030, followed by a decline towards 2040. Among individuals aged ≥ 80 years, the prevalence was projected to plateau at 8.9% for men and 6.2% for women before declining. CONCLUSION: Within an unselected nationwide population, the incidence and all cause mortality of PAD have declined over the last two decades. Concurrently, prevalence increased and is projected to increase further over the coming decade, emphasising the growing burden of this common atherosclerotic disease in ageing populations.

Risk of recurrent cancer-associated venous thromboembolism: A Danish nationwide cohort study.

BACKGROUND: Predictive factors for recurrent cancer-associated venous thromboembolism have been inconsistent across previous studies. To provide data for improved risk stratification, we described the risk of recurrent venous thromboembolism overall and across age, sex, calendar period, cancer type, Ottawa risk score, cancer stage, and cancer treatment in a nationwide cohort of patients with active cancer. METHODS: Using Danish administrative registries, we identified a cohort of all adult patients with active cancer and a first-time diagnosis of venous thromboembolism during 2003-2018. We accounted for the competing risk of death and calculated absolute risks of recurrent venous thromboembolism at six months. RESULTS: The population included 34,072 patients with active cancer and venous thromboembolism. Recurrence risks at six months were higher for patients with genitourinary cancer (6.5%), lung cancer (6.1%), gastrointestinal cancer (5.6%), brain cancer (5.2%), and hematological cancer (5.1%) than for patients with gynecological cancer (4.7%), breast cancer (4.1%), and other cancer types (4.8%). Recurrence risks were similar for men (5.2%) and women (4.9%), with and without chemotherapy (5.1%), across Ottawa risk score group (low: 5.0%; high: 5.1%) and across calendar periods but increased with increasing cancer stage. The overall six-month all-cause mortality risk was 26%, and highest for patients with lung cancer (49%) and lowest among breast cancer patients (4.1%). CONCLUSIONS: Six-month recurrence risk after first-time cancer-associated venous thromboembolism was high and varied by cancer type and patient characteristics. Refining risk stratification for recurrence may improve decision-making regarding treatment duration after cancer-associated thromboembolism.

Positive Predictive Value of Non-Traumatic Bleeding Diagnoses in the Danish National Patient Register.

Purpose: The majority of bleeding diagnoses in the Danish National Patient Registry have not been validated despite extensive use in epidemiological research. Therefore, we examined the positive predictive value (PPV) of non-traumatic bleeding diagnoses in the Danish National Patient Registry. Study Design: Population-based validation study. Patients and Methods: Based on a manual review of electronic medical records, we estimated the PPV of diagnostic coding (International Classification of Diseases, Tenth Revision (ICD-10)) for non-traumatic bleeding for all patients ≥65 years of age with any hospital contact in the North Denmark Region during March-December 2019 as registered in the Danish National Patient Registry. We calculated PPVs and associated 95% confidence intervals (CI) for non-traumatic bleeding diagnoses overall and stratified according to primary or secondary diagnosis, and according to major anatomical sites. Results: A total of 907 electronic medical records were available for review. The population mean age was 79.33 years (standard deviation (SD)=7.73) and 57.6% were males. Primary bleeding diagnoses accounted for 766 of the records and 141 were secondary bleeding diagnoses. The overall PPV for bleeding diagnoses was 94.0% (95% CI: 92.3-95.4). The PPV was 98.7% (95% CI: 97.6-99.3) for the primary diagnoses and 68.8% (95% CI: 60.7-75.9) for the secondary diagnoses. When stratified according to subgroups of major anatomical sites, the PPVs ranged between 94.1% and 100% for the primary diagnoses, and between 53.8% and 100% for secondary diagnoses. Conclusion: The overall validity of non-traumatic bleeding diagnoses in the Danish National Patient Registry is high and considered acceptable for epidemiological research. However, PPVs were substantially higher for primary than for secondary diagnosis.

Risk of Recurrent Venous Thromboembolism in Selected Subgroups of Men: A Danish Nationwide Cohort Study.

Background Although men are considered at high risk for recurrent venous thromboembolism (VTE), sex-specific data on prognostic factors are lacking. We estimated the cumulative recurrence risks associated with clinical characteristics and comorbidities known or suspected to be associated with the development of VTE recurrence: major surgery, trauma, history of cancer, rheumatic disorder, ischemic heart disease, congestive heart failure, chronic obstructive pulmonary disease, diabetes, chronic renal disease, varicose veins, alcohol-related diseases, and arterial hypertension. Methods We linked nationwide Danish health registries to identify all incident VTE in- and outpatients in men from 2008 through 2018. Recurrent VTE risk 2 years after anticoagulant discontinuation was calculated using the Aalen-Johansen estimator, stratified by age above/below 50 years. Results The study included 13,932 men with VTE, of whom 21% ( n = 2,898) were aged <50 years. For men aged <50 years with at least one of the clinical characteristics, 2-year recurrence risk ranged from 6% (major surgery) to 16% (history of cancer). For men ≥50 years with at least one of the characteristics, recurrence risk ranged from 7% (major surgery) to 12% (ischemic heart disease, chronic obstructive pulmonary disease, and chronic renal disease). Men aged <50 and ≥50 years without the clinical characteristics all had a recurrence risk of 10%. Discussion We demonstrated a 2-year recurrence risk of at least 6%, regardless of age category and disease status, in this nationwide cohort of men with VTE. The recurrence risk must be balanced against bleeding risk. However, the high recurrence risk across all subgroups might ultimately lead to greater emphasis on male sex in future guidelines focusing on optimized secondary VTE prevention.

Risk of stroke or systemic embolism in patients with degenerative mitral stenosis with or without atrial fibrillation: A cohort study.

Background: Atrial fibrillation (AF) is associated with an increased risk of stroke and the combination of AF and mitral stenosis (MS) is associated with a higher risk. In developed nations, degenerative mitral stenosis (DMS) constitutes a sizeable proportion of patients with MS. Current international guidelines do not offer recommendations regarding anticoagulation in these patients. The objective of this study was to describe the incidence of stroke or systemic embolism in patients with DMS with or without prevalent AF. Methods: A cohort study of DMS patients from 1997 to 2018, using data from the Danish health registries. The cohort was stratified based on AF prevalence and prior ischemic stroke. The primary outcome was a diagnosis of ischemic stroke or systemic embolism after 1 year of follow-up from time of DMS diagnosis. Results: The study included 1162 patients with DMS, of which 421 had prevalent AF. The incidence rate of stroke or systemic embolism after 1 year of follow-up was highest in the DMS without AF group (7.58 vs. 6.63 per 100 person-years). In both groups, DMS without AF and DMS with AF, the incidence rate was highest in patients with prior thromboembolic events (29.61 vs. 5.15 and 19.53 vs. 5.15, respectively). Conclusions: The incidence rate of stroke or systemic embolism was highest in DMS patients without AF. Current Danish guidelines recommend DMS patients should be treated with anticoagulation only with concurrent AF, yet our results call for additional research to establish if DMS patients without AF could benefit from stroke prevention therapy.

Long-Term Management of Pulmonary Embolism: A Review of Consequences, Treatment, and Rehabilitation.

The concept of pulmonary embolism is evolving. Recent and emerging evidence on the treatment of specific patient populations, its secondary prevention, long-term complications, and the unmet need for rehabilitation has the potential to change clinical practice for the benefit of the patients. This review discusses the recent evidence from clinical trials, observational studies, and guidelines focusing on anticoagulation treatment, rehabilitation, emotional stress, quality of life, and the associated outcomes for patients with pulmonary embolism. Guidelines suggest that the type and duration of treatment with anticoagulation should be based on prevalent risk factors. Recent studies demonstrate that an anticoagulant treatment that is longer than two years may be effective and safe for some patients. The evidence for extended treatment in cancer patients is limited. Careful consideration is particularly necessary for pulmonary embolisms in pregnancy, cancer, and at the end of life. The rehabilitation and prevention of unnecessary deconditioning, emotional distress, and a reduced quality of life is an important, but currently they are unmet priorities for many patients with a pulmonary embolism. Future research could demonstrate optimal anticoagulant therapy durations, follow-ups, and rehabilitation, and effective patient-centered decision making at the end of life. A patient preferences and shared decision making should be incorporated in their routine care when weighing the benefits and risks with primary treatment and secondary prevention.

Risk of Cerebrovascular Events in Intracerebral Hemorrhage Survivors With Atrial Fibrillation: A Nationwide Cohort Study.

BACKGROUND: In patients with intracerebral hemorrhage (ICH) and prevalent atrial fibrillation (AF), the optimal stroke prevention strategy is unclear. We sought to estimate the risk of cerebrovascular events among ICH survivors with AF. METHODS: We used the Danish Stroke Registry to identify patients with incident ICH and prevalent AF between 2003 and 2018. Key inclusion/exclusion criteria of the PRESTIGE-AF (Prevention of Stroke in Intracerebral hemorrhage Survivors With Atrial Fibrillation) trial were applied. Cumulative incidence of recurrent ICH, cerebrovascular ischemic event, and all-cause death were investigated after one year. RESULTS: A total of 1885 patients (median age 80.0 years; 47.6% females) were included in the study. We observed 191 cerebrovascular events and 650 all-cause deaths, and more cerebrovascular ischemic events (N=63) than recurrent ICH events (N=40). Risks of recurrent ICH, cerebrovascular ischemic event, and all-cause death were 1.5%, 3.2%, and 30.3%, respectively, among patients not exposed to OAC during follow-up. The cumulative incidences were 2.8% for recurrent ICH, 3.2% for cerebrovascular ischemic events, and 22.0% for all-cause death among patients initiating/resuming OAC during follow-up. CONCLUSIONS: We observed a high risk of cerebrovascular ischemic events and a very high risk of all-cause death at one year after the incident ICH. The results of ongoing clinical trials are warranted to determine optimal stroke prevention treatment among ICH survivors with concomitant AF.

Disparities in oral anticoagulation initiation in patients with schizophrenia and atrial fibrillation: A nationwide cohort study.

AIMS: Schizophrenia is associated with poor anticoagulation control and clinical prognosis in patients with atrial fibrillation (AF). Little is known about initiation of oral anticoagulation therapy (OAC) in this patient population. METHODS: In the nationwide Danish health registries, we identified all patients with incident AF and schizophrenia with indication for OAC treatment. Patients with schizophrenia (n = 673) were matched 1:5 on sex, age, stroke risk score, and calendar-period to incident AF patients without schizophrenia. We calculated absolute risk and risk difference (RD) of OAC initiation, adjusting for stroke and bleeding risk factors. Analyses were stratified by calendar period (2000-2011 and 2012-2018) to account for changes after the introduction of non-vitamin K OACs (NOAC). RESULTS: Among patients with schizophrenia (mean age 69.5 years, 50.3% females), 33.7% initiated OAC within the first year after AF diagnosis, compared with 54.4% of patients without schizophrenia, corresponding to an adjusted RD of -20.7 (95% confidence interval [CI]: -24.7 to -16.7). OAC initiation increased over time regardless of schizophrenia status. During 2000-2011, 18.3% of patients with schizophrenia and 42.9% without schizophrenia initiated OAC (adjusted RD -23.6%, 95% CI -28.8 to -18.6). During 2012-2018, this was 48.5% and 65.7%, respectively (adjusted RD -14.4%, 95% CI -20.4 to -8.4). CONCLUSION: Initiation of OAC was substantially lower among patients with AF and schizophrenia compared with matched AF peers. These findings accentuate the importance of close attention to disparities in initiation of OAC treatment, and potential missed opportunities for prevention of disabling strokes in AF patients with schizophrenia.

Oral anti-coagulant treatment patterns in atrial fibrillation patients diagnosed with cancer: A Danish nationwide cohort study.

Data on the use of oral anti-coagulants (OAC) for stroke prevention in cancer patients with atrial fibrillation (AF) are sparse. Nationwide cohort study of patients with AF (2012-2018) and an indication for OAC who were diagnosed with cancer at least one year later (N = 12 756). We identified treatment with OAC at cancer diagnosis and the following year and described the incidence of discontinuing or switching between warfarin and direct oral anti-coagulants (DOACs). We also described baseline characteristics associated with OAC non-persistence. One third of the cancer patients received no OAC therapy, whereas 42% received warfarin and 24% received DOAC treatment. Switching incidence between OACs was higher for those receiving warfarin treatment (8.6%) than DOAC treatment (1.7%) within one year. Treatment discontinuation was 61% for warfarin and 26% for DOAC. Females were less likely to discontinue DOAC than males (ratio 0.77, 95% confidence interval: 0.66, 0.90). Increasing cancer stage was associated with discontinuation of DOAC, but not warfarin. OAC for stroke prevention in AF was used by two thirds of patients with newly diagnosed cancer. Switching between OACs and discontinuation was more common for warfarin than DOAC, and females had higher persistence with DOACs.

Hematuria in anticoagulated patients with atrial fibrillation and urologic cancer.

BACKGROUND: Based on their renal excretion, direct oral anticoagulants (DOACs) may increase the risk of hematuria in patients with atrial fibrillation (AF) and urologic cancer compared with vitamin K antagonists. OBJECTIVES: To examine the risk of bleeding associated with DOAC versus warfarin in patients with AF and urologic cancer. METHODS: We conducted a Danish nationwide cohort study with individually linked registry data on patients with AF and active or a history of urologic cancer. We calculated crude rates per 100 person-years of hospital episodes of major bleeding and hematuria. We then compared rates of hematuria during the year after initial oral anticoagulation filled prescription by treatment regimen using inverse probability of treatment weighting and Cox regression. RESULTS: The study population included 2615 patients with AF and urologic cancer (6.1% women; median age, 76 years) initiating a DOAC or warfarin. One-year risk of hematuria was 4.8% in the DOAC group and 4.7% in the warfarin group with a corresponding weighted hazard ratio (HR) of 1.21 (95% confidence interval [CI], 0.81-1.81). HRs for hematuria were generally similar in analyses restricted to patients treated with standard-dose DOAC and patients with active cancer. For those with cancer of the kidney, renal pelvis, ureter, and bladder, the HR was 0.82 (95% CI, 0.44-1.54). Results were mirrored for other bleeding events, whereas the risk for intracranial bleeding was lower with DOACs. CONCLUSION: In patients with AF and urologic cancer, there was a similar risk of hematuria associated with DOAC and warfarin treatment.

Validation of the Khorana score for predicting venous thromboembolism in 40 218 patients with cancer initiating chemotherapy.

The Khorana score is recommended for guiding primary venous thromboembolism (VTE) prophylaxis in cancer patients, but its clinical utility overall and across cancer types remains debatable. Also, some previous validation studies have ignored the competing risk of death, hereby potentially overestimating VTE risk. We identified ambulatory cancer patients initiating chemotherapy without other indications for anticoagulation using Danish health registries and estimated 6-month cumulative incidence of VTE stratified by Khorana levels. Analyses were conducted with and without considering death as a competing risk using the Kaplan-Meier method vs the cumulative incidence function. Analyses were performed overall and stratified by cancer types. Of 40 218 patients, 35.4% were categorized by Khorana as low risk (score 0), 53.6% as intermediate risk (score 1 to 2), and 10.9% as high risk (score ≥3). Considering competing risk of death, the corresponding 6-month risks of VTE were 1.5% (95% confidence interval [CI], 1.3-1.7), 2.8% (95% CI, 2.6-3.1), and 4.1% (95% CI, 3.5-4.7), respectively. Among patients recommended anticoagulation by guidelines (Khorana score ≥2), the 6-month risk was 3.6% (95% CI, 3.3-3.9). Kaplan-Meier analysis overestimated incidence up to 23% compared with competing risk analyses. Using the guideline-recommended threshold of ≥2, the Khorana score did not risk-stratify patients with hepatobiliary or pancreatic cancer, lung cancer, and gynecologic cancer. In conclusion, the Khorana score was able to stratify ambulatory cancer patients according to the risk of VTE, but not for all cancer types. Absolute risks varied by methodology but were lower than in key randomized trials. Thus, although certain limitations with outcome identification using administrative registries apply, the absolute benefit of implementing routine primary thromboprophylaxis in an unselected cancer population may be smaller than seen in randomized trials.

First Trimester Anticoagulant Exposure and Adverse Pregnancy Outcomes in Women with Preconception Venous Thromboembolism: A Nationwide Cohort Study.

OBJECTIVE: The purpose of this study was to investigate first trimester anticoagulant exposure and risks of adverse pregnancy-related and fetal outcomes. METHODS: Using Danish nationwide registries, we identified all pregnant women with preconception venous thromboembolism, 2000-2017, and linked data on exposure to low-molecular-weight heparin (LMWH), vitamin K antagonist (VKA), or non-VKA oral anticoagulant (NOAC) during pregnancy. We assessed pregnancy-related and fetal outcomes associated with first trimester anticoagulant exposure. RESULTS: Among 4490 pregnancies in women with preconception venous thromboembolism (mean age 31 years, 40% nulliparous) during the first trimester, 63.1% were unexposed, 25.9% were exposed to LMWH, 10.4% VKA, and 0.6% NOAC. Adverse outcomes were lowest in unexposed and LMWH exposed. Compared with unexposed, VKA was associated with higher risks of preterm (adjusted odds ratio [OR] 2.26; 95% confidence interval [CI], 1.70-2.99) and very preterm birth (adjusted OR 3.78; 95% CI, 1.91-7.49), shorter mean gestational age was associated with VKA (-7.5 days; 95% CI, -9.1 to -5.9 days) or NOAC (-2.3 days; 95% CI, -8.4-3.8), and lower mean birthweight with VKA (-55 g; 95% CI, -103.1 to -8.5) or NOAC (-190 g; 95% CI, -364.1 to -16.4). Adjusted ORs for small-for-gestational-age infants were 1.07 (95% CI, 0.77-1.50) with VKA, and 3.29 (95% CI, 1.26-7.95) with NOAC. Mean 5-minute Apgar score (9.8) and congenital defect prevalence (8.4%-10%) varied little across exposure groups. CONCLUSIONS: Fetal risk was lowest in unexposed and LMWH-exposed pregnancies, supporting the recommendation of LMWH during pregnancy. NOAC safety during pregnancy is unclear due to the rarity of NOAC exposure.