Patient-important upper gastrointestinal bleeding in the ICU: A mixed-methods study of patient and family perspectives

INTRODUCTION

The objective of this study was to create a definition of patient-important upper gastrointestinal bleeding during critical illness as an outcome for a randomized trial.

DESIGN

This was a sequential mixed-methods qualitative-dominant multi-center study with an instrument-building aim. In semi-structured individual interviews or focus groups we elicited views from survivors of critical illness and family members of patients in the intensive care unit (ICU) regarding which features indicate important gastrointestinal bleeding. Quantitative demographic characteristics were collected. We analyzed qualitative data using inductive content analysis to develop a definition for patient-important upper gastrointestinal bleeding.

SETTING

Canada and the United States.

PARTICIPANTS

51 ICU survivors and family members of ICU patients.

RESULTS

Participants considered gastrointestinal bleeding to be important if it resulted in death, disability, or prolonged hospitalization. The following also signaled patient-important upper gastrointestinal bleeding: blood transfusion, vasopressors, endoscopy, CT-angiography, or surgery. Whether an intervention evinced concern depended on its effectiveness, side-effects, invasiveness and accessibility; contextual influences included participant familiarity and knowledge of interventions and trust in the clinical team.

CONCLUSIONS

Survivors of critical illness and family members described patient-important upper gastrointestinal bleeding differently than current definitions of clinically-important upper gastrointestinal bleeding.

What counts as patient-important upper gastrointestinal bleeding in the ICU? A mixed-methods study protocol of patient and family perspectives

INTRODUCTION

Clinically important upper gastrointestinal bleeding is conventionally defined as bleeding accompanied by haemodynamic changes, requiring red blood cell transfusions or other invasive interventions. However, it is unclear if this clinical definition reflects patient values and preferences. This protocol describes a study to elicit views from patients and families regarding features, tests, and treatments for upper gastrointestinal bleeding that are important to them.

METHODS AND ANALYSIS

This is a sequential mixed-methods qualitative-dominant multi-centre study with an instrument-building aim. We developed orientation tools and educational materials in partnership with patients and family members, including a slide deck and executive summary. We will invite intensive care unit (ICU) survivors and family members of former ICU patients to participate. Following a virtual interactive presentation, participants will share their perspectives in an interview or focus group. Qualitative data will be analysed using inductive qualitative content analysis, wherein codes will be derived directly from the data rather than using preconceived categories. Concurrent data collection and analysis will occur. Quantitative data will include self-reported demographic characteristics. This study will synthesise the values and perspectives of patients and family members to create a new trial outcome for a randomised trial of stress ulcer prophylaxis. This study is planned for May 2022 to August 2023. The pilot work was completed in Spring 2021.

ETHICS AND DISSEMINATION

This study has ethics approval from McMaster University and the University of Calgary. Findings will be disseminated via manuscript and through incorporation as a secondary trial outcome on stress ulcer prophylaxis.

TRIAL REGISTRATION NUMBER

NCT05506150.

Understanding pulse oximetry in hematology patients: Hemoglobinopathies, racial differences, and beyond

Pulse oximetry (SpO₂ ) is a widely used, non-invasive method of estimating arterial oxygen saturation. Measurement of SpO₂ relies on comparing the relative absorption of light in the red and infrared regions with the expected absorption pattern of oxygenated and deoxygenation adult hemoglobin. As this screening tool has entered common clinical use, test limitations have emerged, including concern about the risk of overestimation of oxygen saturation by pulse oximetry in a disproportionate number of people with dark skin pigment, leading to potential for underdiagnosis of true hypoxemia. In addition, a range of challenges may arise in patients with increased levels of methemoglobin - whether acquired or inherited - carboxyhemoglobin, or in patients with a subset of inherited variant hemoglobins. It is important for Hematologists, and indeed all clinicians who rely on pulse oximetry, to understand the principles and limitations of this ubiquitous test.

Mitapivat versus Placebo for Pyruvate Kinase Deficiency

BACKGROUND

Pyruvate kinase deficiency is a rare, hereditary, chronic condition that is associated with hemolytic anemia. In a phase 2 study, mitapivat, an oral, first-in-class activator of erythrocyte pyruvate kinase, increased the hemoglobin level in patients with pyruvate kinase deficiency.

METHODS

In this global, phase 3, randomized, placebo-controlled trial, we evaluated the efficacy and safety of mitapivat in adults with pyruvate kinase deficiency who were not receiving regular red-cell transfusions. The patients were assigned to receive either mitapivat (5 mg twice daily, with potential escalation to 20 or 50 mg twice daily) or placebo for 24 weeks. The primary end point was a hemoglobin response (an increase from baseline of ≥1.5 g per deciliter in the hemoglobin level) that was sustained at two or more scheduled assessments at weeks 16, 20, and 24. Secondary efficacy end points were the average change from baseline in the hemoglobin level, markers of hemolysis and hematopoiesis, and the change from baseline at week 24 in two pyruvate kinase deficiency-specific patient-reported outcome measures.

RESULTS

Sixteen of the 40 patients (40%) in the mitapivat group had a hemoglobin response, as compared with none of the 40 patients in the placebo group (adjusted difference, 39.3 percentage points; 95% confidence interval, 24.1 to 54.6; two-sided P<0.001). Patients who received mitapivat had a greater response than those who received placebo with respect to each secondary end point, including the average change from baseline in the hemoglobin level. The most common adverse events were nausea (in 7 patients [18%] in the mitapivat group and 9 patients [23%] in the placebo group) and headache (in 6 patients [15%] and 13 patients [33%], respectively). Adverse events of grade 3 or higher occurred in 10 patients (25%) who received mitapivat and 5 patients (13%) who received placebo.

CONCLUSIONS

In patients with pyruvate kinase deficiency, mitapivat significantly increased the hemoglobin level, decreased hemolysis, and improved patient-reported outcomes. No new safety signals were identified in the patients who received mitapivat. (Funded by Agios Pharmaceuticals; ACTIVATE ClinicalTrials.gov number, NCT03548220.).

Race-based data collection among COVID-19 inpatients: A retrospective chart review

Public health data have demonstrated disproportionate COVID-19 morbidity and mortality among racialized populations. However, limited hospital data may prevent research into racial disproportionality among inpatients. We conducted a retrospective cross-sectional study of patients admitted with or without COVID-19 to an Ontario tertiary hospital between March and October 2020 to determine the percentage of inpatients with a formal race or ethnicity assessment in their medical record. The COVID-19 group included inpatients with concurrent COVID-19 positivity; the reference group included a random sample of General Medicine inpatients without COVID-19. We reviewed 80 patients with COVID-19 and 80 patients without COVID-19. Formal ethnicity assessments were recorded among 44% of the COVID-19 group and 49% of the reference group. Race and ethnicity data collection was less than 50% among inpatients with and without COVID-19 in one Ontario hospital. Adequate data collection is necessary to study racial health disparities in the hospital setting.

Ketamine administration for acute painful sickle cell crisis: A randomized controlled trial

OBJECTIVE

The objective was to evaluate the efficacy and safety of single-dose ketamine infusion in adults with sickle cell disease (SCD) who presented with acute sickle vasoocclusive crisis (VOC).

METHODS

This study was a parallel-group, prospective, randomized, double-blind, pragmatic trial. Participants were randomized to receive a single dose of either ketamine or morphine, infused over 30 min. Primary outcome was mean difference in the numerical pain rating scale (NPRS) score over 2 h. NPRS was recorded every 30 min for a maximum of 180 min and secondary outcomes were cumulative dose of opioids, emergency department (ED) length of stay, hospital admission, change in vital signs, and drug-related side effects. Authors performed the analysis using intention-to-treat principle.

RESULT

A total of 278 adults with SCD and who presented with acute sickle VOC participated in this trial. A total of 138 were allocated to the ketamine group. Mean (±standard deviation [SD]) NPRS scores over 2 h were 5.7 (±2.13) and 5.6 (±1.90) in the ketamine and morphine groups. The ketamine group received significantly lower cumulative doses of morphine during their ED stay (mean ± SD = 4.5 ± 4.6 mg) than of the morphine group (mean ± SD = 8.5 ± 7.55 mg). Both groups had similar rates of hospital admission: 6.3% in the ketamine group had drug-related side effects compared to 2.2% in the morphine group.

CONCLUSION

Early use of ketamine in adults with VOC resulted in a meaningful reduction in pain scores over a 2-h period and reduced the cumulative morphine dose in the ED with no significant drug-related side effects in the ketamine-treated group.

Comorbidities and complications in adults with pyruvate kinase deficiency

Objectives

Pyruvate kinase (PK) deficiency is caused by PKLR gene mutations, leading to defective red blood cell glycolysis and hemolytic anemia. Rates of comorbidities and complications by transfusion history and relative to the general population remain poorly quantified.

Methods

Data for patients aged ≥ 18 years with two confirmed PKLR mutations were obtained from the PK deficiency Natural History Study (NCT02053480). Frequencies of select conditions were compared with an age‐ and sex‐matched cohort from a general insured US population without PK deficiency.

Results

Compared with the matched population (n = 1220), patients with PK deficiency (n = 122) had significantly higher lifetime rates of osteoporosis, liver cirrhosis, and pulmonary hypertension; splenectomy and cholecystectomy rates were also significantly higher in the 8 years before the index date. Sixty‐five (53.3%) patients with PK deficiency were classified as regularly transfused, 30 (24.6%) as occasionally transfused, and 27 (22.1%) as never transfused. Regularly transfused patients were significantly more likely than never transfused patients to have had splenectomy, cholecystectomy, and/or thrombosis. Liver iron overload was reported in 62% of patients and occurred regardless of transfusion cohort.

Conclusions

Even never transfused patients with PK deficiency had higher rates of select comorbidities and complications than individuals without PK deficiency.

Genotype-phenotype correlation and molecular heterogeneity in pyruvate kinase deficiency

Pyruvate kinase (PK) deficiency is a rare recessive congenital hemolytic anemia caused by mutations in the PKLR gene. This study reports the molecular features of 257 patients enrolled in the PKD Natural History Study. Of the 127 different pathogenic variants detected, 84 were missense and 43 non-missense, including 20 stop-gain, 11 affecting splicing, five large deletions, four in-frame indels, and three promoter variants. Within the 177 unrelated patients, 35 were homozygous and 142 compound heterozygous (77 for two missense, 48 for one missense and one non-missense, and 17 for two non-missense variants); the two most frequent mutations were p.R510Q in 23% and p.R486W in 9% of mutated alleles. Fifty-five (21%) patients were found to have at least one previously unreported variant with 45 newly described mutations. Patients with two non-missense mutations had lower hemoglobin levels, higher numbers of lifetime transfusions, and higher rates of complications including iron overload, extramedullary hematopoiesis, and pulmonary hypertension. Rare severe complications, including lower extremity ulcerations and hepatic failure, were seen more frequently in patients with non-missense mutations or with missense mutations characterized by severe protein instability. The PKLR genotype did not correlate with the frequency of complications in utero or in the newborn period. With ICCs ranging from 0.4 to 0.61, about the same degree of clinical similarity exists within siblings as it does between siblings, in terms of hemoglobin, total bilirubin, splenectomy status, and cholecystectomy status. Pregnancy outcomes were similar across genotypes in PK deficient women. This report confirms the wide genetic heterogeneity of PK deficiency.

Pharmacy hydroxyurea education materials for patients with sickle cell disease: An environmental scan and assessment of accuracy

BACKGROUND

Hydroxyurea (HU) remains a cornerstone of sickle cell disease (SCD) therapy; however, its use is limited by poor patient adherence owing to concerns about side effects. Pharmacies routinely provide patients with handouts about HU, which, we hypothesized, contain inaccuracies that may contribute to negative patient perceptions of HU.

METHODS

We used a systematic approach to collect and review patient information handouts (PIHs) on HU from pharmacies in Ontario, Canada. PIHs were evaluated according to: i. Number of inaccurate statements, ii. Percentage of essential statements based on comparison with a reference standard PIH developed by the Canadian Haemoglobinopathy Association (CanHaem), and iii. Reading level.

RESULTS

PIHs were collected from 98% of chain and community pharmacies registered in Ontario. All PIHs contained inaccurate statements, most frequently relating to the risk of developing cancer. Only 33% of PIHs identified SCD as an indication for HU use. Pharmacy PIHs contained 45% of the essential statements present within the CanHaem HU PIH, neglecting to mention use of HU for management of SCD and benefits of HU in preventing SCD complications. Moreover, the reading level across pharmacy PIHs was 1.8 grades higher than that advised for written patient education materials.

CONCLUSION

Patients who are prescribed HU are likely to be provided with PIHs that contain inaccuracies that are weighted toward the risks of HU therapy and run contrary to published literature. This study identifies a gap in the care of patients with SCD and an opportunity to improve the quality of HU PIHs to help patients make well-informed decisions about their health.

Novel High Oxygen Affinity Hemoglobin Variant in a Patient with Polycythemia: Hb Kennisis [β85(F1)Phe→Leu (TTT>TTG); HBB: c.258T>G]

We report the case of a 61-year-old Canadian male of Maltese descent investigated for unexplained polycythemia. Decreased p50 suggested the presence of a high oxygen affinity hemoglobin (Hb) variant. Molecular genetic testing demonstrated that he carries a novel missense mutation (HBB: c.258T>G), resulting in a Phe→Leu substitution at position 85 of the β chain. The novel Hb variant has been designated Hb Kennisis in recognition of where the proband resides. Two other missense mutations have been reported at this position [Hb Bryn Mawr or Hb Buenos Aires, β85(F1)Phe→Ser (HBB: c.257T>C); Hb Grantham, β85(F1)Phe→Cys; (HBB: c.257T>G)], both of which have increased oxygen affinity.

American Society of Hematology 2019 guidelines for sickle cell disease: cardiopulmonary and kidney disease

BACKGROUND

Prevention and management of end-organ disease represent major challenges facing providers of children and adults with sickle cell disease (SCD). Uncertainty and variability in the screening, diagnosis, and management of cardiopulmonary and renal complications in SCD lead to varying outcomes for affected individuals.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about screening, diagnosis, and management of cardiopulmonary and renal complications of SCD.

METHODS

ASH formed a multidisciplinary guideline panel that included 2 patient representatives and was balanced to minimize potential bias from conflicts of interest. The Mayo Evidence-Based Practice Research Program supported the guideline development process, including performing systematic evidence reviews up to September 2017. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 10 recommendations for screening, diagnosis, and management of cardiopulmonary and renal complications of SCD. Recommendations related to anticoagulation duration for adults with SCD and venous thromboembolism were also developed.

CONCLUSIONS

Most recommendations were conditional due to a paucity of direct, high-quality evidence for outcomes of interest. Future research was identified, including the need for prospective studies to better understand the natural history of cardiopulmonary and renal disease, their relationship to patient-important outcomes, and optimal management.

How we diagnose and manage altered oxygen affinity hemoglobin variants

Altered oxygen affinity variant hemoglobins (Hbs) are caused by mutations of the globin genes. Changes in Hb oxygen affinity shift the oxygen dissociation curve, and can be identified by abnormal p50 measurements of patient red blood cells. Variants are categorized as either low oxygen affinity (high p50) or high oxygen affinity (low p50). Accurate diagnosis requires recognition of typical clinical and laboratory findings. In this case-based review, we present two patients with altered oxygen affinity variants, illustrating barriers to prompt and accurate diagnosis, and issues in management. We then review pathophysiology, diagnostic tests, clinical features, and management strategies.

Strategies for eliciting and synthesizing evidence for guidelines in rare diseases

Background

Rare diseases are a global public health priority. Though each disease is rare, when taken together the thousands of known rare diseases cause significant morbidity and mortality, impact quality of life, and confer a social and economic burden on families and communities. These conditions are, by their nature, encountered very infrequently by individual clinicians, who may feel unprepared to address their diagnosis and treatment. Clinical practice guidelines are necessary to support clinical and policy decisions. However, creating guidelines for rare diseases presents specific challenges, including a paucity of high certainty evidence to inform panel recommendations.

Methods

This paper draws from the authors’ experience in the development of clinical practice guidelines for three rare diseases: hemophilia, sickle cell disease, and catastrophic antiphospholipid syndrome.

Results

We have summarized a number of strategies for eliciting and synthesizing evidence that are compatible with the rigorous, internationally accepted standards for guideline development set out by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. These strategies include: use of pre-existing and ad hoc qualitative research, use of systematic observation forms, use of registry data, and thoughtful use of indirect evidence. Their use in three real guideline development efforts, as well as their theoretical underpinnings, are discussed. Avenues for future research to improve clinical practice guideline creation for rare diseases – and any disease affected by a relative lack of evidence - are also identified.

Conclusions

Rigorous clinical practice guidelines are needed to improve the care of the millions of people worldwide who suffer from rare diseases. Innovative evidence elicitation and synthesis methods will benefit not only the rare disease community, but also individuals with common diseases who have rare presentations, suffer rare complications, or require nascent therapies. Further refinement and improved uptake of these innovative methods should lead to higher quality clinical practice guidelines in rare diseases.

Hemoglobin H identification by high-performance liquid chromatography in confirmed hemoglobin H disease

INTRODUCTION

Among hemoglobin (Hb) H disease cases diagnosed by DNA testing in our hemoglobinopathy laboratory, we have noted instances of unreported Hb H from high-performance liquid chromatography (HPLC) results of referring laboratories.

METHODS

To characterize these issues, we identified all cases of genotypic Hb H disease diagnosed in our laboratory. HPLC chromatograms were reviewed to determine the presence and retention time of the Hb H peak.

RESULTS

Hemoglobin H was not reported in 24.2% of patients (23 of 95) with genotypic Hb H disease. The characteristic prerun peak of Hb H was present on review of all eight Variant or Variant II β-thalassemia short-program chromatograms. Elevated Hb F (≥3%) was reported in 14 cases. The Hb H peak was found in the Hb F window in 11 dual program cases. The incorrect identification of Hb H as elevated Hb F resulted in two testing referrals for 'δβ-thalassemia'.

CONCLUSIONS

Hemoglobin H may go unreported due to failure to examine for or recognize its peak on Variant or Variant II β-thalassemia short-program chromatograms. Elution of Hb H in the Hb F window resulted in misidentification of Hb H for Hb F and may indicate a Variant II HbA2 /HbA1C program software error. Our findings highlight the need for careful chromatogram inspection and clinical correlation in the diagnosis of Hb H disease.

Splanchnic venous thrombosis driven by a constitutively activated JAK2 V617F philadelphia-negative myeloproliferative neoplasm: a case report

INTRODUCTION

Splanchnic venous thrombosis (SVT) has varied etiology with Philadelphia-negative myeloproliferative neoplasms (MPNs) being the most frequent underlying prothrombotic factor. Hematological indices often remain within normal range because of portal hypertension and its sequelae, causing diagnostic challenges. The high frequency of JAK2 mutation among patients with SVT reinforces the diagnostic utility of JAK2V617F testing.

CASE REPORT

We report a case of a 62-year-old black man with progressive abdominal swelling and features of decompensated chronic liver disease found to have SVT-portal vein thrombosis and how JAK2 V617F was useful in unmasking an underlying myeloproliferative neoplasm.

CONCLUSION

A high index of suspicion for an underlying prothrombotic factor is critical for patients presenting with thrombosis in unusual sites. This is useful in prognostic stratification and patient outcomes. JAK2 mutation screening is now part of the standard diagnostic workup in SVT.

Haptoglobin testing in hemolysis: measurement and interpretation

Haptoglobin is primarily produced in the liver and is functionally important for binding free hemoglobin from lysed red cells in vivo, preventing its toxic effects. Because haptoglobin levels become depleted in the presence of large amounts of free hemoglobin, decreased haptoglobin is a marker of hemolysis. Despite its ubiquity and importance, a paucity of literature makes testing difficult to interpret. This review highlights the many physiological roles that have been recently elucidated in the literature. Different methodologies have been developed for testing, including spectrophotometry, immunoreactive methods, and gel electrophoresis. These are covered along with their respective advantages and disadvantages. As there is no single gold standard for hemolysis, validation studies must rely on a combination of factors, which are reviewed in this article. Pitfalls and limitations of testing are also addressed. False positives can occur in improper specimen preparations, cirrhosis, elevated estrogen states, and hemodilution. False negatives can occur in hypersplenism and medications such as androgens and corticosteroids. Haptoglobin testing in the setting of inflammation is additionally discussed as interpretation can be difficult in this setting. Given the widespread use of haptoglobin testing, it is vital that clinicians and laboratory staff understand the principles and correct interpretation of this test.

Severe fetal and neonatal hemolytic anemia due to a 198 kb deletion removing the complete β-globin gene cluster

Fetal and neonatal hemolytic anemia can be caused by (γδβ)(0)-thalassemia deletions of the β-globin gene cluster. Many of these deletions have not been well characterized, and diagnostic tests are not readily available, thus hampering carrier detection, family counseling, and antenatal diagnosis. We report and define a 198 kb deletion removing the entire β-globin gene cluster, which was found in members of a multigeneration family of Irish/Scottish descent. The proband had life-threatening fetal and neonatal hemolytic anemia which subsided by 1 year of age.

Hb A2 Hong Kong - A novel δ-globin variant in a Chinese family masks the diagnosis of β-thalassemia trait

A 42-year-old Chinese woman (FP) was the mother of a patient with β-thalassemia major (β-TM) due to a compound heterozygosity for β(0)-thalassemia (β(0)-thal) mutations. She was also found to have a low Hb A(2) level of 1.6% by high performance liquid chromatography (HPLC) despite being a heterozygous carrier of the codons 41/42 (-TCTT) (HBB:c.126_129delCTTT) β(0)-thal mutation. Doubling the amount of hemolysate loaded for chromatography revealed a widened Hb A(2) peak and raised the level to 4.1%, consistent with β-thal trait. Direct nucleotide sequencing detected a novel δ-globin gene mutation at codon 29 (HBD:c.89G>A), which leads to a glycine to aspartic acid substitution. A homologous mutation at codon 29 in the β-globin gene [Hb Lufkin or β29(B11)Gly→Asp] has been reported in Black families. This report highlights the importance of genotype-phenotype correlation and the potential pitfall of relying on Hb A(2) level for phenotypic diagnosis of β(0)-thal trait.

Unexpectedly low pulse oximetry measurements associated with variant hemoglobins: a systematic review

Pulse oximetry estimates arterial blood oxygen saturation based on light absorbance of oxy- and deoxy-hemoglobin at 660 and 940 nm wavelengths. Patients with unexpectedly low SpO₂ often undergo cardio-pulmonary testing to ascertain the cause of their hypoxemia. However, in a subset of patients, a variant hemoglobin is responsible for low SpO₂ measurements. The extent of this problem is unclear. We performed a systematic literature review for reports of low SpO₂ associated with variant hemoglobins. We also reviewed unpublished cases from an academic hemoglobin diagnostic reference laboratory. Twenty-five publications and four unpublished cases were identified, representing 45 patients with low SpO₂ and confirmed variant hemoglobin. Fifty-seven family members of patients had confirmed or suspected variant hemoglobin. Three low oxygen affinity variant hemoglobins had concordantly low SpO₂ and SaO₂. Eleven variant hemoglobins were associated with unexpectedly low SpO₂ measurements but normal SaO₂. Hemoglobin light absorbance testing was reported in three cases, all of which showed abnormal absorption spectra between 600 and 900 nm. Seven other variant hemoglobins had decreased SpO₂, with unreported or uncertain SaO₂. Twenty-one variant hemoglobins were found to be associated with low SpO₂. Most variant hemoglobins were associated with spuriously low SpO₂. Abnormal absorption spectra explain the discrepancy between SpO₂ and SaO(2) for some variants. The differential diagnosis of possible variant hemoglobin ought to be considered in asymptomatic patients found to have unexpectedly low SpO₂. The correct diagnosis will help to spare patients from unnecessary investigations and anxiety.

Laboratory testing for fibrinogen abnormalities

Fibrinogen is essential for the formation of a fibrin clot. Acquired and congenital disorders of fibrinogen may result in decreased concentration or altered function of fibrinogen, often leading to an increased risk of bleeding. Routine coagulation testing and specialized laboratory investigations can guide diagnosis in patients suspected of having a fibrinogen abnormality. This article summarizes the types of laboratory assays that are used to assess fibrinogen disorders, and key abnormalities found in different types of fibrinogen disorders.

Systematic review: D-dimer to predict recurrent disease after stopping anticoagulant therapy for unprovoked venous thromboembolism

BACKGROUND

The optimal duration of anticoagulation for a first episode of unprovoked venous thromboembolism (VTE) is uncertain. Methods for predicting risk for recurrence may identify low-risk patients who are less likely to benefit from prolonged anticoagulation.

PURPOSE

To synthesize evidence evaluating the value of D-dimer as a predictor of recurrent disease in patients who have stopped anticoagulant therapy after a first unprovoked VTE.

DATA SOURCES

The MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched until March 2008 without language restrictions. The strategy was supplemented with manual review of reference lists and contact with content experts.

STUDY SELECTION

Randomized, controlled trials or prospective cohort studies that measured D-dimer after anticoagulant therapy in patients who received at least 3 months of anticoagulant treatment of unprovoked VTE.

DATA EXTRACTION

Two authors independently reviewed articles and extracted data.

DATA SYNTHESIS

Seven studies, totaling 1888 patients with a first unprovoked VTE, were eligible for analysis. During 4500 person-years of follow up, annual rates of recurrent VTE differed statistically significantly: 8.9% (95% CI, 5.8% to 11.9%) in patients with positive D-dimer results and 3.5% (CI, 2.7% to 4.3%) in patients with negative D-dimer results.

LIMITATION

The duration of anticoagulation, timing of D-dimer testing, and D-dimer assay varied across studies.

CONCLUSION

In patients who have completed at least 3 months of anticoagulation for a first episode of unprovoked VTE and after approximately 2 years of follow-up, a negative D-dimer result was associated with a 3.5% annual risk for recurrent disease, whereas a positive D-dimer result was associated with an 8.9% annual risk for recurrence. These rates should inform decisions about the balance of risks and benefits of prolonging anticoagulation.