Risk of recurrent venous thromboembolism in patients with HIV infection:A nationwide cohort study

Background Multiple studies have described a higher incidence of venous thromboembolism (VTE) in people living with an HIV infection (PWH). However, data on the risk of recurrent VTE in this population are lacking, although this question is more important for clinical practice. This study aims to estimate the risk of recurrent VTE in PWH compared to controls and to identify risk factors for recurrence within this population. Methods and findings PWH with a first VTE were derived from the AIDS Therapy Evaluation in the Netherlands (ATHENA) cohort (2003-2015), a nationwide ongoing cohort following up PWH in care in the Netherlands. Uninfected controls were derived from the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA) follow-up study (19992003), a cohort of patients with a first VTE who initially participated in a case-control study in the Netherlands who were followed up for recurrent VTE. Selection was limited to persons with an index VTE suffering from deep vein thrombosis in the lower limbs and/or pulmonary embolism (PE). Participants were followed from withdrawal of anticoagulation to VTE recurrence, loss to follow-up, death, or end of study. We estimated incidence rates, cumulative incidence (accounting for competing risk of death) and hazard ratios (HRs) using Cox proportional hazards regression, adjusting for age, sex, and whether the index event was provoked or unprovoked. When analyzing risk factors among PWH, the main focus of analysis was the role of immune markers (cluster of differentiation 4 [CD4]+ T-cell count). There were 153 PWH (82% men, median 48 years) and 4,005 uninfected controls (45% men, median 49 years) with a first VTE (71% unprovoked in PWH, 34% unprovoked in controls) available for analysis. With 40 VTE recurrences during 774 person-years of follow-up (PYFU) in PWH and 635 VTE recurrences during 20,215 PYFU in controls, the incidence rates were 5.2 and 3.1 per 100 PYFU (HR: 1.70, 95% CI 1.23-2.36, p = 0.003). VTE consistently recurred more frequently per 100 PYFU in PWH in all predefined subgroups of men (5.6 versus 4.8), women (3.6 versus 1.9), and unprovoked (6.0 versus 5.2) or provoked (3.1 versus 2.1) first VTE. After adjustment, the VTE recurrence risk was higher in PWH compared to controls in the first year after anticoagulant discontinuation (HR: 1.67, 95% CI 1.04-2.70, p = 0.03) with higher cumulative incidences in PWH at 1 year (12.5% versus 5.6%) and 5 years (23.4% versus 15.3%) of follow-up. VTE recurred less frequently in PWH who were more immunodeficient at the first VTE, marked by a better CD4+ T-cell recovery on antiretroviral therapy and during anticoagulant therapy for the first VTE (adjusted HR: 0.81 per 100 cells/mm3 increase, 95% CI 0.67-0.97, p = 0.02). Sensitivity analyses addressing potential sources of bias confirmed our principal analyses. The main study limitations are that VTEs were adjudicated differently in the cohorts and that diagnostic practices changed during the 20-year study period. Conclusions Overall, the risk of recurrent VTE was elevated in PWH compared to controls. Among PWH, recurrence risk appeared to decrease with greater CD4+ T-cell recovery after a first VTE. This is relevant when deciding to (dis)continue anticoagulant therapy in PWH with otherwise unprovoked first VTE. Author summary Why was this study done? The HIV pandemic affects approximately 40 million people and causes significant morbidity, including a markedly increased risk of a venous thromboembolism (VTE). The recurrence risk of VTE in people living with HIV (PWH) is unknown, although this risk drives the anticoagulant therapy duration after a first VTE. Our study determined the recurrent VTE risk in PWH compared to uninfected controls. What did the researchers do and find? We performed an observational cohort study using data from the national ATHENA PWH cohort (2003-2015) in the Netherlands and the Dutch Multiple Environmenta

Risk of recurrent venous thromboembolism in patients with HIV infection: A nationwide cohort study

Background Multiple studies have described a higher incidence of venous thromboembolism (VTE) in people living with an HIV infection (PWH). However, data on the risk of recurrent VTE in this population are lacking, although this question is more important for clinical practice. This study aims to estimate the risk of recurrent VTE in PWH compared to controls and to identify risk factors for recurrence within this population. Methods and findings PWH with a first VTE were derived from the AIDS Therapy Evaluation in the Netherlands (ATHENA) cohort (2003-2015), a nationwide ongoing cohort following up PWH in care in the Netherlands. Uninfected controls were derived from the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA) follow-up study (1999-2003), a cohort of patients with a first VTE who initially participated in a case-control study in the Netherlands who were followed up for recurrent VTE. Selection was limited to persons with an index VTE suffering from deep vein thrombosis in the lower limbs and/or pulmonary embolism (PE). Participants were followed from withdrawal of anticoagulation to VTE recurrence, loss to follow-up, death, or end of study. We estimated incidence rates, cumulative incidence (accounting for competing risk of death) and hazard ratios (HRs) using Cox proportional hazards regression, adjusting for age, sex, and whether the index event was

Risk of Venous Thrombosis in Antithrombin Deficiency:A Systematic Review and Bayesian Meta-analysis

Antithrombin deficiency is a strong risk factor for venous thromboembolism (VTE), but the absolute risk of the first and recurrent VTE is unclear. The objective of this paper is to establish the absolute risks of the first and recurrent VTE and mortality in individuals with antithrombin deficiency. The databases Embase, Medline Ovid, Web of Science, the Cochrane Library, and Google Scholar were systematically searched for case-control and cohort studies. Bayesian random-effects meta-analysis was used to calculate odds ratios (ORs), absolute risks, and probabilities of ORs being above thresholds. Thirty-five publications were included in the systematic review and meta-analysis. Based on 19 studies, OR estimates for the first VTE showed a strongly increased risk for antithrombin deficient individuals, OR 14.0; 95% credible interval (CrI), 5.5 to 29.0. Based on 10 studies, meta-analysis showed that the annual VTE risk was significantly higher in antithrombin-deficient than in non-antithrombin-deficient individuals: 1.2% (95% CrI, 0.8-1.7) versus 0.07% (95% CrI, 0.01-0.14). In prospective studies, the annual VTE risk in antithrombin deficient individuals was as high as 2.3%; 95% CrI, 0.2-6.5%. Data on antithrombin deficiency subtypes are very limited for reliable risk-differentiation. The OR for recurrent VTE based on 10 studies was 2.1; 95% CrI, 0.2 to 4.0. The annual recurrence risk without long-term anticoagulant therapy based on 4 studies was 8.8% (95% CrI, 4.6-14.1) for antithrombin-deficient and 4.3% (95% CrI, 1.5-7.9) for non-antithrombin-deficient VTE patients. The probability of the recurrence risk being higher in antithrombin-deficient patients was 95%. The authors conclude that antithrombin deficient individuals have a high annual VTE risk, and a high annual recurrence risk. Antithrombin deficient patients with VTE require long-term anticoagulant therapy