CoaguChek® XS versus standard laboratory prothrombin time for anticoagulant monitoring in patients with antiphospholipid syndrome

INTRODUCTION

The standard of care for thrombotic antiphospholipid syndrome (APS) is anticoagulation with vitamin K antagonists (VKAs). Prothrombin time, and its corresponding international normalized ratio (INR), is the laboratory test routinely performed to assess anticoagulation. Self-management of VKA therapy using point-of-care (POC) devices seems to be an attractive option.

PURPOSE/OBJECTIVE

To evaluate the accuracy of a POC device (CoaguChek XS) in APS patients by comparing it with venous laboratory INR. Furthermore, we analyzed whether other clinical and laboratory features could interfere with the CoaguChek XS results.

PATIENTS AND METHODS

This is a single-center cross-sectional study with 94 APS patients from a tertiary rheumatology clinic performed from August 2014 to March 2015. The comparison between CoaguChek XS and venous laboratory INR results was evaluated using the coefficient of determination (r) followed by the Bland-Altman test. A paired t-test was also applied. A difference of up to ±0.5 INR unit between the two systems was considered clinically acceptable.

RESULTS

The mean CoaguChek-INR was 2.94 ± 1.41 and venous laboratory INR was 2.43±0.86, with a correlation coefficient (r) of 0.95. Categorizing INR values in ranges (INR <2, INR 2-3, INR 3-4, and INR >4), we found that the INR >4 group presented a lower correlation (r = 0.64) compared to the other ranges (p < 0.05). Although both methods were highly correlated, CoaguChek XS showed higher values than the venous laboratory INR, with an increased average of 0.42 ± 0.54. Therefore, we proposed a simple linear regression model to predict the venous laboratory INR values, using results obtained from CoaguChek XS. A difference ≤0.5 INR unit between the two systems was observed in 57.4% of patients, and the aPL profile did not influence the results.

CONCLUSION

Although CoaguChek XS and venous laboratory INR demonstrated a good linear correlation in the group of INR ≤4, extra caution should be taken in APS patients, since a reasonable proportion of patients can present differences in INR results that are not acceptable. We do not recommend routine POC in APS patients.

Understanding patient-provider discordance in adolescents with lupus: The role of pain and antidepressant medication use

The current study examines depression and pain as potential contributors to patient-provider discordance in the assessment of lupus disease activity. The study conducted a secondary analysis of data obtained from the Childhood Arthritis and Rheumatology Research Alliance registry, with N = 859 adolescent participants. Assessments of pain, disease activity, and antidepressant medication use were collected from the patient and provider. Results indicated that depression might be underdiagnosed in pediatric lupus patients. While psychotropic medication and pain scores were independently related to greater patient-provider discordance regarding health status, pain mediated this relationship. Implications for treatment outcomes are discussed.

Direct oral anticoagulants: an alternative treatment for thrombotic antiphospholipid syndrome?

Background

Direct oral anticoagulants (DOACs) demonstrate a lower risk–benefit ratio than vitamin K antagonists (VKAs) for secondary thromboprophylaxis of thrombotic events. But there are no data on the efficacy of DOACs for the prevention of thrombotic recurrence in patients with antiphospholipid syndrome (APS). In this study, we evaluated the efficacy of DOACs to prevent recurrences of thrombotic events in patients with APS.

Methods

This was a single-center pilot, using a multi-step Fleming design. If seven or fewer patients presented treatment failure with rivaroxaban, the study could conclude efficacy.

Results

A total of 23 patients were included. APS involved the veins only ( n = 19), arteries only ( n = 2) or both ( n = 1) and 1 patient exhibited catastrophic antiphospholipid syndrome (CAPS). Overall, two patients were positive for lupus anticoagulant, anti-beta-2 glycoprotein I antibodies and anticardiolipid antibodies (triple positivity). The mean duration of follow up was 35.6 (range, 29–40) months. A total of six treatment failures were reported: one patient, with triple positivity, developed bilateral distal pulmonary embolism (PE) after 20 months of treatment with rivaroxaban, two patients refused to take rivaroxaban, the treatment was stopped in three other patients: two with adverse effects and one with chronic iron-deficiency anemia.

Conclusions

Rivaroxaban may represent an alternative for secondary thromboprophylaxis for thrombo-embolism in patients with APS, in particular, those with poor international normalized ratio (INR) control and those who are not at the highest risk of recurrent thrombosis, such as those with triple positivity.

Antiphospholipid Syndrome On Cloud (APSOnCloud): web-based monitoring of oral anticoagulation

Antiphospholipid Syndrome (APS) is an autoimmune disease characterized by recurrent thromboses and fetal losses with the presence of antiphospholipid antibodies. The main treatment to prevent recurrent thrombotic events is oral anticoagulation with vitamin K antagonist (VKA), which requires frequent monitoring and dosage adjustments. Outpatient anticoagulation monitoring has its limitations, such as patients spending long hours between the testing procedure and waiting for the results to be adjusted. To optimize this adjustment and to improve APS patients-doctors relationship, we developed a website to help monitor APS patients, called Antiphospholipid Syndrome On Cloud or APSOnCloud. To test it, since March 2014 to March 2016, we registered 20 patients with APS that have inserted 132 international normalized ratio (INR) values. Sixty two percent were out of range and it took on average 7 hours for the doctor in charge to adjust these values. The mean time in therapeutic range was 58.1%. Our preliminary experience in monitoring VKA oral anticoagulation on APSOnCloud suggests that patients with APS might benefit from this web-based monitoring.

Thrombotic events in patients with antiphospholipid syndrome treated with rivaroxaban: a series of eight cases

The current treatment for antiphospholipid syndrome (APS) with thrombotic manifestation is long-term anticoagulation. Vitamin K antagonists (VKA) are usually the agents of choice. However, VKA limitations, such as unpredictable anticoagulation effects due to interaction with diet and other drugs, require regular monitoring. This may impact on patients' quality of life. Since the approval of new oral anticoagulants (NOAC) for non-valvular atrial fibrillation and deep vein thrombosis prevention, much has been speculated about its use in APS patients. We report here a series of eight APS patients with failure of thrombotic prevention during rivaroxaban use. All patients had venous thrombosis as the initial manifestation of APS, and two of them also had arterial manifestations. Three patients had triple antibody positivity. Five patients developed arterial events during the treatment with rivaroxaban. Until the results of ongoing trials of rivaroxaban for APS are presented, NOAC should not be recommended to APS patients. Our preliminary experience as well cases previously reported in the literature suggest that there is a high-risk group that is less protected with rivaroxaban, namely those with previous arterial thrombosis or triple positivity. VKA remains to be the mainstay treatment for thrombotic APS.