Partitioned polygenic risk scores identify distinct types of metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses an excess of triglycerides in the liver, which can lead to cirrhosis and liver cancer. While there is solid epidemiological evidence of MASLD coexisting with cardiometabolic disease, several leading genetic risk factors for MASLD do not increase the risk of cardiovascular disease, suggesting no causal relationship between MASLD and cardiometabolic derangement. In this work, we leveraged measurements of visceral adiposity and identified 27 novel genetic loci associated with MASLD. Among these loci, we replicated 6 in several independent cohorts. Next, we generated two partitioned polygenic risk scores (PRS) based on the mechanism of genetic association with MASLD encompassing intra-hepatic lipoprotein retention. The two PRS suggest the presence of at least two distinct types of MASLD, one confined to the liver resulting in a more aggressive liver disease and one that is systemic and results in a higher risk of cardiometabolic disease.

Plasma levels of coagulation factors VIII and IX and risk of venous thromboembolism: Systematic review and meta-analysis

INTRODUCTION

The associations of plasma factor VIII (FVIII) and factor IX (FIX) levels with risk of venous thromboembolism (VTE) are not well defined. We performed a systematic review and meta-analysis of these associations.

METHODS

Random effects inverse-variance weighted meta-analysis was used to estimate pooled odds ratios for comparisons across equal quartiles of the distributions and 90 % thresholds (higher versus lower), and for testing linear trends.

RESULTS

Among 15 studies (5327 cases) the pooled odds ratio of VTE for the fourth versus first quarter was 3.92 (95 % confidence interval 1.61, 5.29) for FVIII level; and among 7 studies (3498 cases) 1.57 (1.32, 1.87) for FIX level. Comparing factor levels above, versus below, the 90th percentile, the estimated pooled odds ratios were 3.00 (2.10, 4.30) for FVIII; 1.77 (1.22, 2.56) for FIX; and 4.56 (2.73, 7.63) for both FVIII and FIX considered jointly.

CONCLUSIONS

We confirm increases in risk of VTE across population distributions of FVIII and FIX levels. Levels above the 90th percentile have almost twice the risk for FIX level compared to levels below; three-fold risk for FVIII level; and almost five-fold risk for both FVIII and FIX levels elevated.

Reference intervals of urinary kidney injury biomarkers for middle-aged men and women determined by quantitative protein mass spectrometry

BACKGROUND AND AIMS

There is an ongoing need to recognize early kidney injury and its progression in structural chronic pathologies. The proteins NGAL, IGFBP7, TIMP2, KIM-1, CXCL9, TGF-β1, SLC22A2, nephrin, cubilin and uromodulin have been proposed as early kidney injury biomarkers. To guide clinical interpretation, their urinary concentrations should be accompanied by reference intervals, which we here establish in a representative Dutch middle-aged population.

MATERIALS AND METHODS

The 24-h urine samples from 1443 Caucasian middle-aged men and women, were analyzed for the biomarkers by quantitative LC-MS/MS. Biomarker excretion per 24-h were calculated, and urine creatinine and osmolality were measured for dilution normalization. This population was characterized by demographic and anthropometric parameters, comorbid conditions, and conventional kidney function measures.

RESULTS

NGAL, IGFBP7, TIMP2, KIM-1 and uromodulin could be quantified in this population, whereas nephrin, SLC22A2 and CXCL9 were below their detection limits. Urine creatinine and osmolality ( r= -were correlated to urine volume (r = -0.71; -0.74) and to IGFBP7 (r = 0.73; 0.71) and TIMP2 (r = 0.71; 0.69). Crude and normalized biomarker concentrations were affected by sex, but not by age, BMI, smoking, kidney function or common comorbid conditions. The reference intervals (men; women) were 18-108; 21-131 pmol IGFBP7/mmol creatinine, 1- 63; 4-224 pmol NGAL/mmol creatinine, 7-48; 7- 59 pmol TIMP2/mmol creatinine, <1-9; <1-12 pmol KIM-1/mmol creatinine and 0.1-1.2; 0.1-1.7 mg uromodulin/mmol creatinine.

CONCLUSION

We present dilution-normalized and sex-stratified urinary reference intervals of kidney injury biomarkers in a middle-aged Caucasian population.

Hand osteoarthritis is associated with limitations in paid and unpaid work participation and related societal costs: the HOSTAS cohort

OBJECTIVES

Data on work participation impairment and related societal costs for patients with hand osteoarthritis (OA) are scarce. Therefore, we aimed to investigate the association of hand OA with work limitations and costs of productivity loss in paid and unpaid work.

METHODS

We used data from the Hand Osteoarthritis in Secondary Care cohort, including patients with hand OA diagnosed by their treating rheumatologist. Using the validated Health and Labour Questionnaire, we assessed experienced unpaid and paid work restrictions, unpaid work replacement by others and inefficiency and absence during paid work related to hand OA over the last 2 weeks. Societal costs (€) per hour of paid and unpaid work were estimated using Dutch salary data in 2019.

RESULTS

381 patients were included (mean age 61 years, 84% women, 26% high education level, 55% having any comorbidity). Replacement of unpaid work by others due to hand OA was necessary for 171 out of 381 patients (45%). Paid work was reported by 181/381 patients (47%), of whom 13/181 (7%) reported absenteeism, 28/181 (15%) unproductive hours at work and 120/181 (66%) paid work restrictions due to hand OA.Total estimated work-related societal costs per patient with hand OA (381 patients) were €94 (95% CI 59 to 130) per 2 weeks (€2452, 95% CI 1528 to 3377 per year).

CONCLUSIONS

Hand OA is associated with impairment in paid and unpaid work participation, which translates into substantial societal costs of lost productivity. These results highlight the importance of adequate hand OA treatment.

POS1121 HAND OSTEOARTHRITIS IS ASSOCIATED WITH LIMITATIONS IN PAID AN UNPAID WORK PARTICIPATION AND RELATED SOCIETAL COSTS: THE HOSTAS COHORT

Background

Rheumatic musculoskeletal diseases (RMDs) can cause impairment in paid and unpaid work which can contribute to societal burden and costs. However, data on this topic concerning hand osteoarthritis (OA) is scarce, while this is crucial for assessing the societal impact of this disease.

Objectives

To investigate the association of hand OA with paid and unpaid work limitations, productivity loss and costs of productivity loss.

Methods

We used data of the Dutch Hand OSTeoArthritis in Secondary care (HOSTAS) cohort, a primary hand OA cohort from a general rheumatology outpatient clinic. The treating rheumatologist defined hand OA presence. We assessed patient and OA characteristics using validated questionnaires and tests. We investigated work impairment due to hand OA with the Health and Labour Questionnaire (HLQ) which assesses the last two weeks on hand-OA related limitations, hours of sick leave and unproductiveness during paid work, and limitations and hours of the necessity of being replaced by others for unpaid work tasks.

We estimated societal costs of paid work by multiplying unproductive and sick leave hours due to hand OA by the average Dutch hourly societal costs of paid work for persons of the same age category and sex. We estimated societal costs of unpaid work by multiplying the hours of unpaid work replaced by others by the Dutch gross average hourly salary of a household help (€12.50).

Results

HLQ data was available for 382 patients (mean age 61 years, 86% women, 26% having a university degree, 41% having any comorbidity). Of these persons, 181 (47%) had paid work, 16 (4%) had full work disability due to hand OA and 117 (30%) were retired. Thirteen employed persons (7%) reported sick leave due to hand OA in the last two weeks, for whom a median of 42 working hours (interquartile range (IQR) 24 to 54) was lost. Unproductive paid work hours were present for 28 (15%) patients, with a median of 4 hours in the last two weeks (IQR 2 to 6). Hinder at work in the last two weeks was reported by 120 out of 181 working patients (66%), for whom median hinder score (score range 6-24) was 7 (IQR 6 to 8). Work production loss in the last two weeks due to hand OA (the sum of sick leave hours and unproductive hours) was present for 36 patients (19%). Patients with paid work productivity loss (n = 35, 19%) did not differ statically significantly in patient and disease characteristics from those without productivity loss (n = 146, 19%).

Unpaid work replacement in the last two weeks was reported by 171 patients (45%), with a median of three hours replaced (IQR 2 to 7). Any unpaid work hinder was reported by 297 (78%). Median unpaid work hinder score (score range: 4-16) was 8 (IQR 7 to 10) . Patients with unpaid work replacement by others due to hand OA (n=171, 45%) were statically significantly more often female and had a higher BMI than with those without any replacement (n=210, 55%).

We estimated total societal costs of hand OA related to paid work production loss at €61 (95% confidence interval (CI) 27 to 96) per two weeks, and societal costs for unpaid work at €33 (CI 27 to 40). Total estimated work-related societal costs per patient with hand OA were €94 (CI 59 to 130), translating to €2452 (CI 1528 to 3377) per year.

Conclusion

Hand OA is associated with impairment in paid and unpaid work, which translates into substantial societal costs. This highlights the social and economic importance of adequate hand OA treatment. It also highlights the importance of investigating work impairment experienced by hand OA patients visiting the outpatient clinic, for potentially more tailored treatment.

Disclosure of Interests

None declared

AB0976 Determination and characterization of patient subgroups with different pain progression in hand osteoarthritis

Background

Hand pain is common in hand osteoarthritis (OA). Previous cohort studies reported stable average pain levels on the short to midterm. Subgroups with different pain trajectories have been found in knee OA. Similar subgroups of hand OA patients may exist. Knowledge of such subgroups in hand OA patients may help inform decisions for pain treatment.

Objectives

To determine and characterize subgroups with different hand pain trajectories over four years in hand OA patients.

Methods

Data from the ongoing HOSTAS (Hand OSTeoArthritis in Secondary care) cohort were used, collected from consecutive patients at the LUMC Rheumatology outpatient clinic with primary hand OA followed for four years. Hand pain measurements were collected annually starting at baseline with the AUSCAN pain questionnaire (range 0-20).

Development of pain over time was modelled using latent class growth analysis (LCGA), dividing the cohort into subgroups based on differences in pain development. The optimal model was selected based on the AIC, BIC, entropy and likelihood ratio test for models with n vs n-1 classes. LCGA requires ≥2 measurements per case, so patients with less were excluded.

Associations of LCGA classes with baseline demographics and factors associated with hand pain were analyzed using multinomial logistic regression.

Results

Of 538 participants, 484 completed the AUSCAN at ≥2 timepoints. Data of excluded patients were missing at random. Included and excluded patients were comparable. Of included participants 86% were women, mean (SD) age was 60.8 (8.5), 29% had erosive disease, median (IQR) symptom duration was 5.2 (1.9-12.2), 91% fulfilled the ACR criteria for hand OA. Mean AUSCAN pain score was 9.3 (4.3).

LCGA yielded five classes (Figure 1). Classes were characterized by different pain levels at baseline; mean level of pain remained stable over time. Classes with more pain were associated with more erosive disease, higher tender joint count, longer symptom duration, more comorbidities, worse AUSCAN function scores and worse SF-36 and HADS scores (Table 1).

Figure 1.

LCGA trajectories.

Trajectories of AUSCAN pain identified by latent class growth analysis. Least pain to most pain, named class 1 (pink), class 2 (red), class 3 (brown), class 4 (blue) and class 5 (green).

Table 1.

Multinomial logistic regression for associations with 5 LCGA classes

OR (95% CI)Baseline1 (N=37)2 (N=104)3 (N=171)4 (N=131)5 (N=41)Erosive disease11.20 (0.45-3.18)1.48 (0.55-4.03)1.23 (0.41-3.70)1.21 (0.30-4.87)Symptom duration, years;11.05 (0.97-1.13)1.09 (1.01-1.18)1.13 (1.04-1.22)1.12 (1.03-1.23)KL sum score11.01 (0.98-1.05)1.01 (0.98-1.05)1.02 (0.99-1.06)1.03 (0.99-1.08)Tender joint count11.17 (0.98-1.39)1.20 (1.00-1.44)1.28 (1.07-1.54)1.29 (1.06-1.57)AUSCAN function10.98 (0.90-1.08)1.08 (0.99-1.18)1.17 (1.06-1.30)1.31 (1.13-1.51)SF-36-PCS10.95 (0.89-1.02)0.90 (0.84-0.97)0.84 (0.77-0.91)0.81 (0.73-0.89)-MCS10.98 (0.90-1.06)0.96 (0.89-1.04)0.95 (0.87-1.03)0.90 (0.82-0.99)HADS-Depression11.28 (0.91-1.82)1.46 (1.02-2.09)1.50 (1.04-2.16)1.54 (1.04-2.28)-Anxiety11.09 (0.85-1.38)1.19 (0.93-1.54)1.19 (0.91-1.54)1.24 (0.92-1.65)No. Comorbidities11.64 (0.77-3.47)1.84 (0.86-3.90)2.22 (1.01-4.88)2.12 (0.89-5.06)

Multinomial logistic regression of variables associated with LCGA classes adjusted for baseline AUSCAN pain, age, sex and BMI. Class 1 = least pain, class 5 = most pain. SF-36 = Short Form-36. MCS = Mental component scale. PCS = Physical component scale. HADS = Hospital anxiety and depression scale. SF-36 scores are standardized on age, sex and nationality with mean 50 and SD 10.

Conclusion

Latent class growth analysis showed five subgroups with different pain trajectories in hand OA patients, with differing baseline pain and stable pain over time. These subgroups were associated with disease characteristics, number of comorbidities, psychological distress and health-related quality of life. This knowledge can help develop treatment for hand OA patients and inform them about the disease course.

Disclosure of Interests:

None declared

POS0123 NEUROPATHIC PAIN SYMPTOMS IN INFLAMMATORY HAND OSTEOARTHRITIS(OA) LOWERS HEALTH RELATED PHYSICAL QUALITY OF LIFE AND MAY REQUIRE ANOTHER APPROACH THAN ANTI-INFLAMMATORY TREATMENT

Background:

Pain is a common, difficult to manage symptom in hand osteoarthritis (OA). Multiple pain mechanisms may play a role in hand OA.

Objectives:

To investigate presence of neuropathic pain symptoms in patients with inflammatory hand OA, characteristics of those patients, their impact on health related quality of life (HR-QoL), and the influence of anti-inflammatory treatment on neuropathic pain symptoms.

Methods:

Data from a randomised, double-blind, placebo-controlled trial of prednisolone including 92 patients with hand OA fulfilling ACR criteria were used. At baseline patients had signs of synovial inflammation, a VAS finger pain of ≥30 mm and who flared ≥20 mm upon NSAID washout. The primary endpoint was VAS finger pain (0-100) at week 6.

Neuropathic pain symptoms were measured at baseline and week 6 using the validated painDETECT questionnaire, consisting of questions on pain quality, pain intensity over time and radiating pain. Scores range -1 to 38 and patients are classified as having unlikely (<13), indeterminate (13-18) and likely (>18) neuropathic pain. HR-QoL was measured with physical component scale (PCS) of Short-Form 36 (SF36; 0-100), comorbidities with the Self-administered Comorbidities Questionnaire (SCQ; 0-45), radiographic severity with Kellgren-Lawrence (KL) sum score (0-120), and treatment response with OMERACT-OARSI responder criteria.

Association of patient characteristics with neuropathic pain symptoms was analysed with univariate and multivariate ordinal logistic regression, with painDETECT as dependent variable. Association of neuropathic pain symptoms with HR-QoL was analysed with multivariate linear regression, adjusted for age, sex, BMI, VAS finger pain, SCQ score and KL sum score, with PCS as dependent variable. Response of neuropathic pain symptoms and VAS pain to prednisolone was analysed with generalised estimating equations. Association of neuropathic pain symptoms at baseline with response to treatment was analysed using χ2-tests and GEE.

Results:

91 patients had complete painDETECT data at baseline (mean painDETECT score 12.8 [SD 5.9]). Scores were <13 in 53%, 13-18 in 31% and >18 in 16%. Higher painDETECT score categories were associated with less radiographic damage, more comorbidities, female sex and higher VAS finger pain in multivariate analysis. (table 1)

Table 1.

Ordinal logistic regression with painDETECT categories as dependent variable

VariablesMean (SD) N=91 (100%)Odds ratio (95% CI)Age64 (9)0.96 (0.90 to 1.02)Female sex; N (%)72 (79%)3.84 (1.19 to 12.39)*BMI; median (SD)27 (24 to 29)0.97 (0.89 to 1.06)SCQ score; median (SD)2 (1 to 5)1.04 (1.04 to 1.36)*VAS finger pain53.8 (2.1)1.02 (1.00 to 1.04)*KL sum score37 (16)0.96 (0.93 to 1.00)*

*p<0.05. BMI = body mass index. SCQ = Self-administered comorbidities questionnaire. VAS = visual analog scale. KL= Kellgren-Lawrence.

Patients with painDETECT scores >18 had a lower HR-QoL (PCS -6.5 [95%CI -10.4 to -2.6]) than those with painDETECT scores <13.

PainDETECT scores remained unchanged throughout the trial in both prednisolone-treated and placebo-treated patients, and there was no between-group difference at week 6. VAS pain improved more in the prednisolone group than in the placebo group (mean between-group difference -16.5 [95%CI -26.1 to -6.9]) (figure 1). No association between the presence of neuropathic pain symptoms at baseline and OMERACT-OARSI response to treatment was found.

Conclusion:

Patients with inflammatory hand OA and additional neuropathic pain symptoms are more often female and have more comorbidities, and report a lower QoL, than those without. Neuropathic pain symptoms seem unresponsive to anti-inflammatory therapy. Clinicians should be aware of neuropathic pain symptoms in their patients as they might benefit from additional, specific treatment.

Acknowledgements:

The authors thank all patients for their participation in the HOPE study, and participating rheumatologists for inclusion of patients in the HOPE study. We also thank research nurses B.A.M.J. van Schie-Geyer and S. Wongsodihardjo, and technicians J.C. Kwekkeboom and E.I.H. van der Voort, for their contributions.

Disclosure of Interests:

Coen van der Meulen: None declared, Lotte van de Stadt: None declared, Féline Kroon: None declared, Marion Kortekaas: None declared, Annelies Boonen Speakers bureau: Lecture for UCB; paid to department., Consultant of: Yes. Advisory board meetings at Galapagos, Eli Lilly and Abvvie; paid to department., Grant/research support from: Yes. Grants by Celgene and Abbvie; paid to department., Stefan Böhringer: None declared, Marieke Niesters: None declared, Monique Reijnierse: None declared, Frits Rosendaal: None declared, Naghmeh Riyazi: None declared, M. Starmans: None declared, Franktien Turkstra: None declared, Jende van Zeben: None declared, Cornelia Allaart: None declared, Margreet Kloppenburg Consultant of: For Abbvie, Pfizer, Levicept, GlaxoSmithKline, Merck-Serono, Kiniksa, Flexìon, Galapagos, Jansen, CHDR and local investigator of industry-driven trial (Abbvie). All fees were paid to the institution., Grant/research support from: Grant by the Dutch Arthritis Society

POS1431 THE ASSOCIATION OF CLINICAL AND STRUCTURAL KNEE OSTEOARTHRITIS WITH PHYSICAL ACTIVITY IN THE MIDDLE-AGED POPULATION: THE NEO STUDY

Background:

Lack of physical activity in individuals with knee OA has shown to be associated with increased cardiovascular risk and mortality. Consequently, physical activity is a potential target for interventions in knee OA. However, most of the available studies concerning physical activity in individuals with knee OA were performed in relatively old populations with an inactive lifestyle. It is unclear how previous results can be generalized to other populations with different lifestyle and physical activity habits.

Objectives:

To investigate if knee OA is associated with lower physical activity in a general middle-aged Dutch population. Furthermore, to investigate the association of physical activity with patient reported outcomes such as knee pain and function, and health-related quality of life in individuals with knee OA.

Methods:

We used cross-sectional data from the Netherlands Epidemiology of Obesity (NEO) study, in which participants aged 45-65 years were included. Clinical knee OA was defined using the ACR criteria. Structural knee OA was defined on MRI using the modified criteria by Hunter et al. in a random subset of 1,285 individuals of our study population.

We assessed knee pain and function with the Knee injury and Osteoarthritis Score (KOOS), and health-related quality of life (HRQoL) with the Short Form (SF)-36. Physical activity (in Metabolic Equivalent of Task (MET) hours per week) was assessed using the Short Questionnaire to Assess Health-enhancing physical activity (SQUASH).

We used linear regression analyses to investigate 1) the association of knee OA with physical activity, and 2) of physical activity with knee pain, function, and HRQoL in participants with clinical knee OA. All analyses were adjusted for age, sex, body mass index (BMI), ethnicity, educational level and comorbidities. To account for possible information bias, we performed a sensitivity analysis to assess the association between clinical knee OA and physical activity measured by an accelerometer in a random subset of 15% of the study population.

Results:

Of 6,212 participants, we observed clinical knee OA in 14%, and structural knee OA in 12%. The general population characteristics and median physical activity of our study population are presented in Table 1. In comparison to participants without knee OA, participants with clinical knee OA had on average 9.60 (95% CI 3.70;15.50) MET hours per week more total physical activity (Figure 1). Structural knee OA was associated with 3.97 (-7.82; 15.76) MET hours per week more physical activity, compared with no structural knee OA.

Sensitivity analysis showed a weak positive association of clinical knee OA with physical activity measured by an accelerometer: 2.37 (-6.05; 10.80) MET hours per week more physical activity in participants with clinical knee OA, compared with participants without clinical knee OA.

In the subpopulation of participants with clinical knee OA, physical activity was not associated with knee pain, function or HRQoL.

Conclusion:

Knee OA was not associated with lower physical activity in this middle-aged Dutch population. This contrasts previous findings and warrants caution when generalizing physical activity outcomes to other populations. Furthermore, it stresses the need of more insight in the barriers and facilitators of physical activity in the middle-aged population.

Table 1.

Characteristics of the NEO study population

Alln = 6,214No clinical knee OA86%Clinical knee OA14%General population characteristics Age (year)55.7 (6.0)55.4 (6.1)57.5 (5.0) Sex (% women)555467 BMI (kg/m2)26.3 (4.4)26.1 (4.3)27.6 (5.1) Comorbidities (% present)242332Physical activity Total^ (MET-hours per week)118.8 (76.8;155.0)118.4 (76.6;154.4)123.5 (77.8;157.2)

Numbers represent mean (SD) or percentages. ^median (25th, 75th percentiles). Abbreviations: OA = osteoarthritis. BMI = Body Mass Index. MET = Metabolic Equivalent of Task.

Disclosure of Interests:

None declared

POS0258 REAL-TIME VERSUS STATIC SCORING IN MUSCULOSKELETAL ULTRASONOGRAPHY IN PATIENTS WITH INFLAMMATORY HAND OSTEOARTHRITIS

Background:

Ultrasound (US) is used in rheumatic musculoskeletal diseases (RMDs) such as hand osteoarthritis (OA) as outcome measure. Traditionally scoring is performed real-time, but central reading of static US images could avoid issues of inter-rater reliability. However, agreement between real-time and static assessment has not been studied

Objectives:

To study the agreement between real-time and static scoring of US in inflammatory hand OA.

Methods:

Ultrasound was performed of 30 joints obtained in 75 patients with hand osteoarthritis, treated with prednisolone or placebo in a randomized double-blind trial. Hand joints were assessed for synovial thickening, effusion, Doppler signal and osteophytes by ultrasound (score 0-3 per joint) at baseline and after treatment. Two ultrasonographers blinded for clinical data scored the live images together (simultaneously) in real-time. A consensus score for each joint was recorded. Representative images stored during scanning were scored by one ultrasonographer minimally 6 months after real-time scoring. For each patient, images of each visit were scored paired, with known chronological order.

Agreement between scoring methods was studied at joint level with quadratic weighted kappa. At patient level, intra-class correlations (ICC; mixed effect model, absolute agreement, with clustering taken into account) were calculated at both timepoints. ICCs were also calculated for the delta of sum scores. Responsiveness of scoring methods was analyzed with generalized estimating equations (GEE) with treatment as independent and ultrasonography findings as dependent variable.

Results:

Thirty-nine patients (52%) were treated with prednisolone and 36 (48%) were treated with placebo. Patient characteristics were well-balanced between treatment groups.

All patients had signs of synovial thickening and osteophytes as assessed by real-time ultrasonography, and almost all signs of effusion (99%) or a positive Doppler signal (95%) in at least one joint. Total ultrasonography sum score for osteophytes was high (mean 45 ±SD 12), whereas sum score was low for positive Doppler signal (mean 5.9 ±SD 4.4), with intermediate sum scores for synovial thickening and effusion (mean 16 ±SD 6.3 and 11 ±SD 6.0 respectively). Static sum scores were overall slightly higher (osteophytes mean 48 ±SD 10; Doppler mean 6.9 S±D 5.0; synovial thickening mean 20 ±SD 7.0 and effusion 13 ±SD 6.5)

Agreement at baseline was good to excellent at joint level (kappa 0.72-0.88) and moderate to excellent at patient level (ICC 0.59-0.86). Agreement for delta sum scores was poor to fair for synovial thickening and effusion (ICC 0.18 and 0.34 respectively), but excellent for Doppler signal (ICC 0.80) (Table 1).

Real-time ultrasonography showed responsiveness to prednisolone with a mean between-group difference of synovial thickening sum score of -2.5 (CI:-4.7 to-0.3). Static ultrasonography did not show a decrease in synovial thickening (Figure 1). No difference in ultrasonography scores was seen for the other ultrasonography features, neither with real-time nor static scoring.

Conclusion:

While cross-sectional agreement between real-time and static ultrasonography was good, agreement of delta sum scores was not and paired static ultrasonography measurement of synovial thickening did not show responsiveness to prednisone therapy where real-time ultrasonography did. Therefore, when using ultrasonography in clinical trials, real-time dynamic scoring should remain the standard.

Table 1.

Agreement on patient level

BaselineWeek 6Delta W6-BLICC (95% CI)ICC (95% CI)ICC (95% CI)Synovitis0.59 (0.26-0.76)0.58 (0.24-0.77)0.18 (0 - 0.40)Effusion0.84 (0.66-0.92)0.84 (0.75-0.89)0.34 (0.12-0.53)Osteophytes0.82 (0.50-0.92)0.78 (0.56-0.88)NDDoppler0.86 (0.75-0.92)0.91 (0.85-0.94)0.80 (0.70 -0.87)

ICC: intra-class correlation coefficient linear mixed model (random patient, fixed rating), absolute agreement. ND: Not Dertermined

Disclosure of Interests:

Lotte van de Stadt: None declared, Féline Kroon: None declared, Monique Reijnierse Grant/research support from: Dutch Arthritis Foundation, Désirée van der Heijde Consultant of: bbVie, Amgen, Astellas, AstraZeneca, Bayer, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead, Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma, Frits Rosendaal: None declared, Naghmeh Riyazi: None declared, R. de Slegte: None declared, Jende van Zeben: None declared, Cornelia Allaart: None declared, Margreet Kloppenburg Consultant of: Abbvie, Pfizer, Levicept, GlaxoSmithKline, Merck-Serono, Kiniksa, Flexion, Galapagos, Jansen, CHDR, Grant/research support from: MI-APPROACH, Marion Kortekaas: None declared

Hormonal Contraceptives and the Risk of Venous Thrombosis

The risk of venous thrombosis (VT) varies according to the type of progestogen that is found in combined oral contraceptives (COCs). When combined with the estrogen component ethinylestradiol (EE), the androgenic progestogens are better able to counteract the EE-induced stimulation of liver proteins and hence are associated with a twofold decreased risk of VT compared with non- or antiandrogenic progestogens, which exert limited counteraction of EE. Because EE is responsible for the increased risk, novel estrogens such as estradiol were developed and seem to have a lower risk of VT than EE. Besides COCs, there are other methods of hormonal contraceptives, such as progestogen-only contraceptives, which do not increase VT risk, except for injectables. Other nonoral contraceptives are combined vaginal rings and patches. There is insufficient evidence regarding the risk of VT associated with these two methods compared with COCs. The increased risk associated with COCs is more pronounced in women with inherited thrombophilia. In these women, the progestogen levonorgestrel seems to be associated with the lowest risk of VT. Currently, there are no studies that have investigated the risk of VT in women who switch COCs. We hypothesize that switching COCs, even when switching from a high- to a low-risk COC, increases the risk of VT. Finally, risk prediction models in women who use COCs are lacking. Since there is a large number of VT cases associated with COC use, it is important to identify women at risk of VT and advise them on alternative contraception methods.

AB0430 MORTALITY IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS AND NEUROPSYCHIATRIC SYMPTOMS

Background:

Little is known about mortality in patients with systemic lupus erythematosus (SLE) presenting with neuropsychiatric (NP) symptoms.

Objectives:

We aimed to evaluate all-cause and cause-specific mortality in patients with SLE and NP symptoms.

Methods:

All patients with the clinical diagnosis of SLE of 18 years and older that visited the tertiary referral NPSLE clinic of the Leiden University Medical Center between 2007-2018 and signed informed consent were included in this study. Patients were classified as NPSLE if NP symptoms were attributed to SLE and immunosuppressive or anticoagulant therapy was initiated, otherwise patients were classified as non-NPSLE. Municipal registries were checked for current status (alive/deceased). Electronical medical files were studied for clinical characteristics and cause of death. Standardized mortality ratios (SMRs) and 95% confidence intervals were calculated using data from the general Dutch population. In addition, a rate ratio (RR) was calculated using direct standardization to compare mortality in NPSLE with non-NPSLE patients.

Results:

351 patients with the clinical diagnosis of SLE were included, of which 149 patients were classified as NPSLE (42.5%). Compared with the general population, mortality was increased five times in NPSLE (SMR 5.0, 95% CI: 2.6-8.5) and nearly four times in non-NPSLE patients (SMR 3.7, 95% CI: 2.2-6.0), as shown in Table 1. Risk of death due to cardiovascular disease (CVD) was increased in non-NPSLE patients (SMR 6.2, 95% CI: 2.0-14.6) and an increased risk of death to infections was present in both NPSLE and non-NPSLE patients ((SMR 29.9, 95% CI: 3.5 – 105) and SMR 91.3 (95% CI: 18.8 – 266) respectively). However, mortality did not differ between NPSLE and non-NPSLE patients (RR 1.0, 95% CI: 0.5 – 2.0).

Table 1.

All-cause mortality in SLE patients presenting with neuropsychiatric symptoms attributed to SLE (NPSLE) or to other causes (non-NPSLE)

NPSLE(N = 149)Non-NPSLE(N = 202)Deaths (N, %)13 (8.7)17 (8.4)Age at death (median, range)49 (32 – 79)59 (20 – 89)Follow-up time (years)9061047Crude mortality rate (per 1000 PY)14.316.2All-cause mortality*Female5.5 (2.8 – 9.6)3.4 (1.9 – 5.7)Male2.3 (0.1 - 12.8)6.2 (1.3 – 18.2)Combined5.0 (2.6 – 8.5)3.7 (2.2 – 6.0)

*Standardized mortality ratio, ratio of the observed and expected number of deaths

Conclusion:

Mortality was increased in both NPSLE and non-NPSLE patients in comparison with the general population, but there was no difference in mortality between NPSLE and non-NPSLE patients. Risk of death due to infections was increased in both groups.

Disclosure of Interests:

Rory Monahan: None declared, Rolf Fronczek: None declared, Jeroen Eikenboom: None declared, Huub Middelkoop: None declared, L.J.J. Beaart- van de Voorde: None declared, Gisela Terwindt: None declared, Nic van der Wee: None declared, Frits Rosendaal: None declared, Thomas Huizinga Grant/research support from: Ablynx, Bristol-Myers Squibb, Roche, Sanofi, Consultant of: Ablynx, Bristol-Myers Squibb, Roche, Sanofi, Margreet Kloppenburg: None declared, G.M. Steup-Beekman: None declared

P0810DOSAGE REDUCTION OF LOW MOLECULAR WEIGHT HEPARIN IN PATIENTS WITH RENAL DYSFUNCTION: EFFECTS ON ANTI-XA LEVELS AND CLINICAL OUTCOMES

Background and Aims

To prevent bio-accumulation of low molecular weight heparins (LMWHs) in patients with an impaired kidney function, guidelines recommend dosage reduction and anti-Xa monitoring. The aim of this study was to investigate the effect of pre-emptive dosage reduction of LMWH on anti-Xa levels. Furthermore, we investigated the association between anti-Xa levels and bleeding, thrombotic events and mortality.

Method

In this single center study, we followed 499 patients with an estimated glomerular filtration rate (eGFR) below 60 ml/min/1.73m2 in whom anti-Xa levels were measured. We observed how many patients had anti-Xa levels that fell within the target range (between 1.0 U/ml and 2.0 U/ml with once daily LMWH and between 0.6 U/ml and 1.0 U/ml with twice daily LMWH), with a standard protocol of a pre-emptive dosage reduction of LMWH (25% reduction in patients with an eGFR between 30 and 60 ml/min/1.73m2 and a reduction of 50% in in patients with an eGFR below the 30 ml/min/1.73m2).

Furthermore, Cox proportional hazard analyses were used to estimate hazard ratios with 95% confidence intervals (CIs) to investigate the association between anti-Xa levels and major bleeding, thrombotic events (ischemic stroke or venous thrombosis) and mortality within three months of follow-up. Hazard ratios were adjusted for age, sex, body mass index, type of LMWH, once or twice daily dosing, antiplatelet drug use, indication for anticoagulation, comorbidities, hemoglobin concentration and eGFR.

Results

In a cohort of 499 patients (445 dalteparin and 54 nadroparin users), the median anti-Xa level was 0.44 U/ml (IQR 0.21-0.75) for the total group (n=499). A pre-emptive dosage reduction of LMWH led to adequate levels of anti-Xa in only 19% of the patients (12% for the dalteparin users and 50% for nadroparin users).

Of the 499 patients, 104 patients had a major bleeding, 27 had a thrombotic event and 146 died within three months. We did not find an association between anti-Xa levels and bleeding or mortality (Table 1). An anti-Xa level below the target range was associated with a non-significant increased risk estimate for thrombosis (HR 2.5, 95% CI 0.7-8.8) after adjustment (Table 1).

Conclusion

Pre-emptive dosage reduction of LMWH leads to low anti-Xa levels in a large proportion of patients and may lead to an undertreatment of patients with an impaired kidney function.

FRI0413 THE ASSOCIATION OF OBESITY WITH OSTEOARTHRITIS IS LIMITEDLY MEDIATED BY HYPERTENSION AND SUBCLINICAL ATHEROSCLEROSIS

Background:

Obesity-related metabolic dysregulation may lead to atherosclerotic vascular changes. It has been hypothesized that a compromised blood flow may cause detrimental changes to the subchondral bone and decrease nutrient supply to the cartilage. To which extent atherosclerosis may explain the association between obesity and OA has not been investigated.

Objectives:

To investigate the role of hypertension and subclinical atherosclerosis (carotid intima-media thickness (IMT), popliteal vessel wall thickness (VWT), aortic pulse wave velocity (PWV)) as mediators of the association of obesity with hand and knee OA.

Methods:

We used cross-sectional data from the population-based NEO study, excluding participants with concomitant rheumatic diseases (n = 323), resulting in 6,334 participants. Clinical hand and knee OA were defined by the ACR classification criteria. Popliteal VWT was assessed on MR images in a subpopulation (n = 1,095), using VesselMASS for semi-automated detection of the vessel wall boundaries. Aortic PWV was estimated on abdominal velocity-encoded MR images in a subpopulation (n = 2,580). Carotid IMT was assessed by ultrasonography. Hypertension was defined as a systolic blood pressure ≥ 130 mmHg or a diastolic blood pressure ≥ 85 mmHg, or using antihypertensive medication. Continuous variables were standardized (mean 0, standard deviation 1). Associations between BMI and OA were assessed with logistic regression analyses, adjusted for age, sex and education. Subsequently, possible mediators were added to the model and the percentage mediation was calculated.

Results:

The population consisted of 55% women, with a mean (SD) age of 56 (6) years and BMI of 26 (4) kg/m2. Hand OA was present in 8% and knee OA in 10% of participants. Hypertension was present in 61.6% of participants. Mean (SD) carotid IMT was 0.62 (0.09) mm, popliteal VWT was 0.53 (0.05) mm, and aortic PWV was 6.56 (1.30) m/s. BMI was associated with the presence of hand OA and knee OA (table 1). BMI was positively associated with hypertension and carotid IMT, but not with popliteal VWT and aortic PWV. The association between BMI and hand OA was partially mediated by hypertension (5.9%) and carotid IMT (10.6%). Hypertension (4.9%) showed a weak mediating effect for the association between BMI and knee OA.

Table 1.

Mediation of the association of BMI with OA by hypertension and atherosclerosis

Hand OAOR (95% CI)MediatorOR/β (95% CI)Hand OAOR (95% CI)Mediation% (95% CI)BMI1.21 (1.08; 1.36)1.72 (1.56; 1.90)1.20 (1.06; 1.36)5.9 (3.4; 17.4)Hypertension1.15 (0.82; 1.60)BMI1.21 (1.08; 1.36)0.23 (0.19; 0.27)1.19 (1.05; 1.34)10.6 (6.2; 30.5)Carotid IMT1.09 (0.94; 1.25)BMI1.56 (1.17; 2.08)0.01 (-0.06; 0.09)1.55 (1.16; 2.07)0.5 (0.3; 1.7)Popliteal VWT1.14 (0.84; 1.55)BMI1.41 (1.15; 1.73)0.05 (-0.01; 0.11)1.41 (1.15; 1.73)0.7 (0.4; 2.0)Aorta PWV1.04 (0.81; 1.33)Knee OAOR (95% CI)MediatorOR/β (95% CI)Knee OAOR (95% CI)BMI1.46 (1.32; 1.62)1.70 (1.55; 1.87)1.43 (1.29; 1.59)4.9 (3.7; 7.0)Hypertension1.25 (0.93; 1.67)BMI1.46 (1.32; 1.62)0.24 (0.20; 0.27)1.47 (1.33; 1.62)-1.6 (-2.4; -1.2)Carotid IMT0.97 (0.86; 1.09)BMI1.20 (0.88; 1.64)0.03 (-0.04; 0.11)1.21 (0.89; 1.64)-0.5 (-7.4; 13.3)Popliteal VWT0.95 (0.74; 1.24)BMI1.37 (1.12; 1.67)0.05 (-0.00; 0.11)1.37 (1.12; 1.67)-0.5 (-1.8; -0.3)Aorta PWV0.96 (0.76; 1.21)

Results are based on analyses weighted towards the BMI distribution of the general population (n = 6,334). Analysis regarding popliteal VWT (n = 1,095) and aorta PWV (n = 2,580) were assessed in a subpopulation Continuous variables were standardized (mean 0, SD 1), SD BMI = 4.41, SD carotid IMT = 0.09, SD popliteal VWT = 0.05, SD aorta PWV = 1.30.

Conclusion:

We assessed whether the association between BMI and OA was mediated by hypertension and atherosclerosis. Our results imply that either such mediation is absent or trivial, or that the atherosclerosis measures were too weak.

Disclosure of Interests:

None declared

FFP2-mondmasker of chirurgisch mondkapje bij COVID-19

Het aantal patiënten met COVID-19 neemt in rap tempo toe. Bescherming van medisch personeel is van groot belang om de ziekte onder medisch personeel te voorkomen en continuïteit in de zorg te waarborgen. Welk mondkapje heeft dan de voorkeur voor huisartsen: een FFP2-mondmasker of een chirurgisch mondkapje? Er is hiernaar nog geen specifiek onderzoek verricht bij het coronavirus, maar bij kortdurend contact in de eerste lijn lijkt er geen verschil tussen beide te zijn. Daarnaast is het nog onduidelijk of chirurgische mondkapjes vergelijkbare bescherming bieden bij langdurig of meervoudig contact.

The association between overall and abdominal adiposity and depressive mood: A cross-sectional analysis in 6459 participants

OBJECTIVE

We aimed to evaluate the association between measures of adiposity with depressive mood and specific depressive symptoms.

METHODS

This study was performed in the Netherlands Epidemiology of Obesity (NEO) study, a population-based study that consists of 6671 middle-aged individuals. We examined the association between measures of overall adiposity (BMI and total body fat), and abdominal adiposity (waist circumference and visceral adipose tissue), with depressive mood severity subgroups and 30 depressive symptoms. Multinomial logistic regression was performed adjusting for potential confounding.

RESULTS

Measures of adiposity were associated with depressive mood in a graded fashion. Total body fat showed the strongest association with mild (Odds Ratio (OR): 1.59 per standard deviation, 95% Confidence Interval (95% CI): 1.41-1.80) and moderate to very severe (OR: 1.97, 95% CI: 1.59-2.44) depressive mood. Regarding individual symptoms of depressive mood, total body fat was associated with most depressive symptoms (strongest associations for hyperphagia and fatigability).

CONCLUSIONS

In the general population, overall and abdominal adiposity measures were associated with depressive mood. This association encompasses most of the depressive symptoms and appeared to be the strongest with specific ''atypical'' neurovegetative symptoms, which may be an indication of an alteration in the energy homeostasis.

Metabolomics: a search for biomarkers of visceral fat and liver fat content

INTODUCTION

Excess visceral and liver fat are known risk factors for cardiometabolic disorders. Metabolomics might allow for easier quantification of these ectopic fat depots, instead of using invasive and costly tools such as MRI or approximations such as waist circumference.

OBJECTIVE

We explored the potential use of plasma metabolites as biomarkers of visceral adipose tissue (VAT) and hepatic triglyceride content (HTGC).

METHODS

We performed a cross-sectional analysis of a subset of the Netherlands Epidemiology of Obesity study. Plasma metabolite profiles were determined using the Biocrates AbsoluteIDQ p150 kit in 176 individuals with normal fasting plasma glucose. VAT was assessed with magnetic resonance imaging and HTGC with proton-MR spectroscopy. We used linear regression to investigate the associations of 190 metabolite variables with VAT and HTGC.

RESULTS

After adjustment for age, sex, total body fat, currently used approximations of visceral and liver fat, and multiple testing, three metabolite ratios were associated with VAT. The strongest association was the lysophosphatidylcholines to total phosphatidylcholines (PCs) ratio [- 14.1 (95% CI - 21.7; - 6.6) cm² VAT per SD of metabolite concentration]. Four individual metabolites were associated with HTGC, especially the diacyl PCs of which C32:1 was the strongest at a 1.31 (95% CI 1.14; 1.51) fold increased HTGC per SD of metabolite concentration.

CONCLUSION

Metabolomics may be a useful tool to identify biomarkers of visceral fat and liver fat content that have added diagnostic value over current approximations. Replication studies are required to validate the diagnostic value of these metabolites.

Consumption of Alcoholic and Sugar-Sweetened Beverages is Associated with Increased Liver Fat Content in Middle-Aged Men and Women

BACKGROUND

Fatty liver is the leading cause of chronic liver diseases and increases the risk of cardiovascular disease. Besides alcohol consumption, energy-containing nonalcoholic beverages may contribute to liver fat accumulation.

OBJECTIVE

We aimed to study the consumption of alcoholic and nonalcoholic beverages and their mutual replacement in relation to hepatic triglyceride content (HTGC) in middle-aged men and women.

METHODS

In this cross-sectional analysis, HTGC was assessed by proton magnetic resonance spectroscopy. Habitual consumption of alcoholic and nonalcoholic beverages was assessed using a validated food-frequency questionnaire. All beverages were converted to standard servings and to percentage of total energy intake (En%). We performed linear regression to examine the association of alcoholic and nonalcoholic beverages with HTGC, adjusted for age, sex, smoking, education, ethnicity, physical activity, total energy intake, and total body fat. We studied replacement of alcoholic beverages with nonalcoholic beverages per 1 serving/d and per 5 En%/d.

RESULTS

After exclusion of individuals with missing values, 1966 participants (47% men) were analyzed, with a mean ± SD age of 55 ± 6 y, BMI of 26 ± 4 kg/m2, and HTGC of 5.7% ± 7.9%. Each extra alcoholic serving per day was associated with more liver fat (1.09 times; 95% CI: 1.05, 1.12). Replacing 5 En% of alcoholic beverages with milk was associated with less liver fat (0.89 times; 95% CI: 0.81, 0.98), whereas replacement with 5 En% of sugar-sweetened beverages was associated with liver fat to an extent similar to alcoholic beverages (1.00 times; 95% CI: 0.91, 1.09).

CONCLUSION

In a population-based cohort, consumption of each extra daily alcoholic beverage was associated with more liver fat. In isocaloric replacement of alcoholic beverages, milk was associated with less liver fat, whereas sugar-sweetened beverages were equally associated with liver fat. This suggests that intake of alcohol and sugars may contribute to liver fat accumulation. This trial was registered at clinicaltrials.gov as NCT03410316.

Associations of Abdominal Subcutaneous and Visceral Fat with Insulin Resistance and Secretion Differ Between Men and Women: The Netherlands Epidemiology of Obesity Study

BACKGROUND

Abdominal obesity is a well-established risk factor for the development of type 2 diabetes. However, sex differences may exist. We aimed to investigate the associations of abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) with insulin resistance and insulin secretion in men and women.

METHODS

In this cross-sectional analysis of the Netherlands Epidemiology of Obesity study, fasting and postprandial concentrations of glucose and insulin were measured and abdominal fat depots were assessed using magnetic resonance imaging in 2253 participants (53% women). With linear regression analysis, we examined associations of abdominal SAT and VAT with measures of insulin resistance and insulin secretion in men and women, while adjusting for age, ethnicity, education, smoking habits, alcohol consumption, menopausal state and hormone use in women, and models with VAT additionally for total body fat.

RESULTS

Participants had a mean [standard deviation (SD)] age of 56 (6) years, body mass index: 25.9 (3.9) kg/m², VAT: 89 (55) cm², and SAT: 235 (95) cm². In the multivariate models in men, per SD of VAT the homeostatic model assessment of insulin resistance (HOMA-IR) was 20% (95% CI: 14-26) higher, and per SD SAT 21% (15-27) higher. In women, per SD of VAT the HOMA-IR was 40% (29-52) higher, and per SD SAT 12% (6-19) higher. Associations with measures of insulin secretion were weaker than with insulin resistance.

CONCLUSIONS

In men, abdominal SAT and VAT were associated with insulin resistance to a similar extent, whereas in women particularly VAT was associated with insulin resistance and insulin secretion. Future studies need to unravel the mechanisms underlying the metabolic effects of visceral fat in women. Simple and less expensive measures that can distinct abdominal subcutaneous and visceral fat are needed for an improved metabolic risk stratification.

Effects of (Pre-)analytical Variables on Activated Protein C Resistance Determined Via a Thrombin Generation-based Assay

The normalized activated protein C sensitivity ratio (nAPC-sr) determined with an assay that quantifies the effect of APC on thrombin formation initiated via the extrinsic coagulation pathway identifies hereditary and acquired defects of the protein C system. We investigated the influence of assay conditions (analytical variables) and plasma handling (pre-analytical variables) on nAPC-sr obtained with this APC resistance test. The effect of the analytical variables (CaCl2, phospholipid and APC concentrations and the concentration and source of tissue factor) was determined in pooled normal plasma. Inhibition of thrombin formation by APC was dependent on the APC concentration and was also affected by the tissue factor, Ca2+ and phospholipid concentrations. Thus, strict standardization of reactant concentrations is required to obtain reproducible nAPC-sr. Three different tissue factor preparations were compared by determining nAPCsr in plasma samples obtained from 90 healthy individuals. nAPC-sr were similar for all three tissue factor preparations although, compared with the noncommercially available tissue factor used in earlier studies, values determined with commercial tissue factor preparations showed larger variation. Pre-analytical variables, investigated in plasma of nine volunteers (3 normal individuals and 6 individuals with an APCresistant phenotype) were: concentration of anticoagulant (3.2% vs. 3.8% trisodiumcitrate), time before processing of blood (0, 4 and 24 h), centrifugation speed, storage temperature of plasma (–20° C vs. –80° C) and sample thawing. Multiple linear regression analysis showed that only the citrate concentration affected the nAPC-sr, which was higher in samples collected in 3.2% trisodiumcitrate than in samples collected in 3.8% trisodiumcitrate.

The HR2 Haplotype of Factor V Is not Associated with the Risk of Myocardial Infarction

The HR2 haplotype of the factor V gene, which contains the histidine to arginine substitution at position 1299, has been reported to be associated with reduced factor V levels. Because high factor V levels have been found to be associated with an increased risk of myocardial infarction, we examined how the presence of the R2 allele affected the risk of myocardial infarction in the case-control “Study of Myocardial Infarctions Leiden”.

Among 560 men with a first myocardial infarction before the age of 70 years, 9.5% were heterozygous carriers of the R2 allele. The control group consisted of 646 men, in which 9.9% were heterozygous and 0.2% homozygous carriers of the R2 allele. The risk of myocardial infarction in the presence of the R2 allele was not increased (odds ratio, 0.9; 95% confidence interval 0.6 to 1.4). Exclusion of factor V Leiden carriers did not change this result. The risk was 4.4-fold increased for smokers who carried the R2 allele compared to non-smoking noncarriers. No synergy was found between metabolic risk factors and the presence of the R2 allele.

We conclude that the risk of myocardial infarction for men in the presence of the R2 allele of the His1299Arg polymorphism is neither increased nor decreased.

The Factor VIII/Von Willebrand Factor Ratio Discriminates between Reduced Synthesis and Increased Clearance of Von Willebrand Factor

It is often stated that a decrease in Von Willebrand factor (VWF), the carrier protein of factor VIII, results in a concordant change in factor VIII. Clinical data suggest that this is not always the case and we hypothesized that the ratio between factor VIII and VWF depends on the genetic defect that causes the VWF deficiency. We have analyzed the ratio between plasma factor VIII and VWF in several subtypes of Von Willebrand Disease and we show that the ratio is increased when VWF synthesis is reduced, but that the ratio remains one when VWF clearance is increased. These observations could be of clinical importance as an increased factor VIII/VWF ratio in combination with a borderline VWF level may indicate the presence of a true genetic defect, possibly a VWF null allele.

D-Dimer as a Risk Factor for Deep Vein Thrombosis: The Leiden Thrombophilia Study

We studied the association of D-dimer with the risk of deep vein thrombosis (DVT). D-dimer was measured in 474 patients more than 6 months after diagnosis of a first DVT and in 474 age-and sexmatched controls. For D-dimer above the 70th percentile (130.5 ng/ml), the odds ratio (OR) for DVT was 2.2 (95% CI, 1.6-2.9). The association was unchanged with adjustment for other risk factors. Excluding participants with Factor V Leiden, prothrombin 20210A, or factors VIIIc or IX above the 90th percentile, the OR was 1.6 (95% CI, 1.1-2.3). The risks of DVT with the joint presence of high D-dimer and either factor V Leiden or prothrombin 20210A were increased 12.4-fold (95% CI 5.6-27.7) and 7.2-fold (95% CI 2.1-25.1), respectively. Higher Ddimer concentration was associated with the risk of DVT, and was supra-additive to the risks associated with factor V Leiden and the prothrombin 20210A variant. Persistence of this association in the absence of other hemostatic risk factors for DVT suggests that high D-dimer may be related to other, as yet unknown, risk factors for venous thrombosis. Confirmation of these findings is desirable.

Factor X Levels, Polymorphisms in the Promoter Region of Factor X, and the Risk of Venous Thrombosis

Elevated levels of procoagulant proteins factor II, factor VIII, factor IX, factor XI and fibrinogen are associated with an increased risk of venous thrombosis. In a population-based case-control study on venous thrombosis (Leiden Thrombophilia Study, LETS) we investigated whether elevated coagulation factor X (FX) levels are a risk factor for venous thrombosis and whether FX levels are determined by polymorphisms in the promoter region of the FX gene. We found that subjects with high FX levels (above the 90th percentile, ≥ 126 U/dl) had a 1.6-fold increased risk of venous thrombosis. The highest risk (OR = 4.3, 95% confidence interval: 1.5-12) was found in the subgroup of premenopausal women who are not using oral contraceptives. However, these estimated risks disappeared after adjustment for other vitamin K-dependent coagulation factors II, VII and IX. To study the influence of genotypic variation on plasma FX levels we assessed four polymorphisms in the promoter region of the FX gene: a TTGTGA insertion between position -343A and -342G, a C/T polymorphism at position -222, a C/A polymorphism at position -220 and a C/T polymorphism at position -40. No relationship between these investigated genotypes and FX levels was observed. We conclude that high FX levels predict risk of thrombosis, but are not a risk factor for venous thrombosis when the levels of other vitamin K-dependent proteins are taken into account.

Characteristics of Anticoagulant Therapy and Comorbidity Related to Overanticoagulation

The risk of hemorrhage when using coumarin anticoagulants sharply increases when the International Normalised Ratio (INR) is ≥6.0. We performed a prospective cohort study with a nested case-control design among 17,056 outpatients of an anticoagulation clinic to determine the incidence of overanticoagulation and to study the association between overanticoagulation and characteristics of anticoagulant therapy and comorbidity. The incidence rate of an INR ≥6.0 was 7.8 per 10,000 treatment days in prevalent users on the starting date and 22.5 per 10,000 treatment days in incident users during the study period. 300 cases with an INR ≥6.0 were compared with 302 randomly selected matched controls with an INR within the target zone. Patients on acenocoumarol had an increased risk of an INR ≥6.0 compared to patients on phenprocoumon. Regarding comorbidity, impaired liver function, congestive heart failure, diarrhea and fever were risk factors for overanticoagulation. Increased monitoring of INR values if risk factors are present or avoidance of risk factors could prevent excess anticoagulation and potential bleeding complications.

Obesity: risk of venous thrombosis and the interaction with coagulation factor levels and oral contraceptive use

Deep vein thrombosis (DVT) is a common disease with an annual incidence of about 1 in 1000. Many risk factors have already been studied, both genetic and acquired. It is unclear whether obesity affects thrombotic risk in unselected patients. Obesity is common, with a prevalence of 20-25% and may therefore have a considerable impact on the overall incidence of thrombosis. We evaluated the risk of thrombosis due to overweight and obesity using data from a large population based case-control study.

Four hundred and fifty-four consecutive patients with a first episode of objectively diagnosed thrombosis from three Anticoagulation Clinics in the Netherlands were enrolled in a case-control study. Controls were matched on age and sex to patients and were introduced by the patients. All patients completed a standard questionnaire and interview, with weight and height measured under standard conditions. The associations of obesity with clotting factor levels were studied to investigate possible mechanisms.

Obesity (BMI ≥30 kg/m2) increased the risk of thrombosis twofold (CI95: 1.5 to 3.4), adjusted for age and sex. Obese individuals had higher levels of factor VIII and factor IX, but not of fibrinogen. The effect on risk of obesity was not changed after adjustment for coagulation factors levels (fibrinogen, F VIII, F IX, D-dimer). The relative risk estimates were similar in different age groups and in both sexes, indicating a larger absolute effect in older age groups. Evaluation of the combined effect of obesity and oral contraceptive pills among women aged 15-45 revealed that oral contraceptives further increased the effect of obesity on the risk of thrombosis, leading to 10-fold increased risk amongst women with a BMI greater than 25 kg/m2 who used oral contraceptives.

Obesity is a risk factor for deep vein thrombosis. Among women with a BMI greater than 25 kg/m2 the synergistic effect with oral contraceptives should be considered when prescribing these.

Increased Levels of Factor VIII and Fibrinogen in Patients with Venous Thrombosis Are not Caused by Acute Phase Reactions

Factor VIII activity (factor VIII:C) levels ≥150 IU/dl are associated with a 5- to 6-fold increased risk of venous thrombosis compared to levels <100 IU/dl, and fibrinogen levels ≥5.0 g/l increase the thrombosis risk 4-fold. These high levels are present in 25% resp. 3% of the patients with a first episode of venous thrombosis. These findings were based on measurements after the thrombotic event, so the factor VIII and fibrinogen levels in thrombosis patients may have been influenced by acute phase reactions or ongoing inflammatory responses. In the present study we measured plasma C-reactive protein (CRP) as a sensitive marker of an acute phase reaction in 474 thrombosis patients and 474 age- and sex-matched healthy controls, that were part of the Leiden Thrombophilia Study (LETS). Mean and median CRP levels were higher in thrombosis patients than in the controls, suggesting inflammation in some patients. CRP affected both factor VIII and fibrinogen levels, in patients and controls alike. After adjustment for the effect of CRP, high factor VIII:C levels still increased the thrombosis risk 6-fold and high fibrinogen levels 4-fold, which is for both very similar to the risk before correction for CRP levels. These results show that although systemic inflammation may be present in some of the patients, elevated levels of factor VIII:C and fibrinogen were in general not caused by acute phase reactions. This further supports a causal relationship between both high factor VIII:C and fibrinogen levels and venous thrombosis.

No Indication for APTT Screening in Patients on Oral Anticoagulant Therapy

Patients on oral anticoagulant therapy (OAT) may bleed due to a very low factor IX level caused by a mutation at Ala-10 in the propeptide region of the factor IX gene. We evaluated screening of patients on OAT with an APTT to detect patients with this abnormality.

In 734 patients an APTT was assessed. Twenty-three patients had a disproportionately prolonged APTT. In these patients the factor IX level, the mutation at Ala-10 and the frequency of bleeding complications were assessed. No severely lowered factor IX levels were found (1 patient with 5% factor IX). No mutations at Ala-10 were found and bleeding complications were not more frequent in these patients. Conclusion: Routine APTT screening of patients on OAT is not useful to detect patients with increased bleeding or with the Ala-10 mutation in the factor IX gene.

Evidence of a Founder Effect for the Protein C Gene 3363 Inserted C Mutation in Thrombophilic Pedigrees of French Origin

We have previously reported that the 3363 inserted (Ins) C mutation in exon 6 of the protein C gene was present in four unrelated French patients and in four French Canadian families with type I protein C deficiency as well as in a large Vermont protein C deficient kindred of French Canadian origin. The present study was designed to investigate the likelihood of the existence of a founder effect for this mutation in protein C deficient individuals of French origin living in France, Québec and Vermont. In order to demonstrate a possible founder effect for the 3363 InsC mutation, we have previously constructed a high-resolution genetic map to locate several highly polymorphic markers close to the protein C locus. Thereafter, the markers D2S347, D2S2339, D2S383, D2S2271 and D2S2215 were genotyped in 117 heterozygotes from France (n = 7), Québec (n = 36) or Vermont (n = 74). The allelic frequency distribution of these five markers was also determined in fifty control French Canadian subjects and thirty-two unaffected members of the Vermont kindred with normal protein C levels and compared with their frequency in our cohort of heterozygotes. Our data suggest that patients from Québec and Vermont carry a common haplotype at the protein C locus. Moreover, in order to study the evolutionary history of the 3363 InsC mutation, we traced back the ascending genealogy of one proband in each of the families with this mutation. These results showed that the 3363 InsC mutation was most probably introduced in North America by a couple of French settlers who established themselves in 1669 on Isle d‘Orleans located near Québec City. All heterozygotes for the 3363 InsC mutation living in North America are related to these founders within 10 generations. Thus, these families afford a unique opportunity to evaluate the role of the protein C system in thrombophilia due to the high degree of linkage disequilibrium at the protein C gene, which in essence holds that variable more constant than in a more heterogeneous population.

The HR2 Haplotype of Factor V: Effects on Factor V Levels, Normalized Activated Protein C Sensitivity Ratios and the Risk of Venous Thrombosis

We studied the HR2 haplotype of the factor V gene in a case-control study for venous thrombosis including 474 patients with a first deep-vein thrombosis and 474 age- and sex-matched healthy controls (Leiden Thrombophilia Study, LETS). We investigated both the original His1299Arg (A4070G) polymorphism and the Met385Thr (T1328C) polymorphism. This latter polymorphism, located in exon 8 (heavy chain), is always present in the HR2 haplotype, but also occurs on its own in a His1299 (wt) background. The HR2 haplotype was not associated with an increased risk of venous thrombosis (OR = 1.2, 95% confidence interval: 0.8-2.0). We did not find an association between the HR2 haplotype and a reduced sensitivity for activated protein C (APC) in non-carriers of factor V Leiden (FVL). However, in compound heterozygous FVL/HR2 carriers the sensitivity for APC was reduced. The HR2 haplotype was also associated with reduced factor V antigen levels in both patients and controls. Sequence analysis of the promoter region of factor V in HR2 homozygotes did not reveal any sequence variations that could explain the reduced FV levels. Our results show that the HR2 haplotype is not associated with an increased risk of venous thrombosis or with a reduced sensitivity for APC in non-FVL carriers. However, the HR2 haplotype is associated with a reduced sensitivity for APC in carriers of FVL and with reduced factor V antigen levels.

Interaction Between Hyperhomocysteinemia, Mutated Methylenetetrahydrofolatereductase (MTHFR) and Inherited Thrombophilic Factors in Recurrent Venous Thrombosis

Venous thrombosis is a multicausal disease involving acquired and genetic factors. In this study we investigated a possible interaction between hyperhomocysteinemia (fasting or postload) and factor V Leiden or prothrombin G20210A on the risk of recurrent venous thrombosis. We also looked at the risk due to mutations in the MTHFR-gene (C677T and A1298C).

We performed a case-control study in 171 patients with a history of recurrent venous thrombosis and 461 control subjects from the general population. Hyperhomocysteinemia (fasting or 6 h after an oral methionine load) was defined as a homocysteine concentration above the 90th percentile of the distributions in the control group.

The odds ratio (adjusted for age and sex) for recurrent venous thrombosis was 1.8 (95%CI: 1.1 to 3.0) for fasting hyperhomocysteinemia, 5.1 (95%CI: 3.0 to 8.6) for factor V Leiden and 1.8 (95%CI: 0.7 to 4.2) for prothrombin G20210A. We found 14 patients and 3 controls with both hyperhomocysteinemia and factor V Leiden, which yielded an odds ratio of 11.6 (95%CI: 3.2 to 42.5). We found no interaction between hyperhomocysteinemia and prothrombin G20210A. The relative risk for MTHFR 677CT was 1.6 (95%CI: 1.1 to 2.4) and for MTHFR 677TT was 1.4 (95%CI: 0.7 to 2.8). The combined risk for MTHFR 677TT and factor V Leiden was 18.7 (95%CI: 3.3 to 108).

We conclude that hyperhomocysteinemia and factor V Leiden are risk factors for recurrent venous thrombosis. The risk of thrombosis appeared high for individuals who had both risk factors.

Hemostatic Risk Factors and Arterial Thrombotic Disease

The pathogenesis of arterial thrombotic disease involves multiple genetic and environmental factors related to atherosclerosis and thrombosis. Acute thrombosis at the site of a ruptured, lipid-rich atherosclerotic plaque is the usual precipitating event in the transition from stable or subclinical atherosclerotic disease to acute myocardial infarction (MI), stroke, or peripheral arterial occlusion (1). Pathologic studies of coronary arteries in acute MI suggest that the acute thrombosis likely involves activation of both platelets and the coagulation system.

Hemostatic Effects of Oral Contraceptives in Women who Developed Deep-vein Thrombosis while Using Oral Contraceptives

Objective: Comparison of the effect of oral contraceptives on hemostatic variables in venous thrombosis patients (thrombosis while using oral contraceptives) with the effect in healthy control subjects. Our aim was to assess whether some of these effects were more pronounced in women who had suffered thrombosis, i.e., whether these were “hemostatic hyperresponders”. Study Design: A population-based case-control study, the Leiden Thrombophilia Study. Materials and Methods: We investigated 99 pre-menopausal women, age 15-49 years, who had used oral contraceptives at the time of a first, objectively confirmed episode of deep-vein thrombosis. They were not pregnant, nor in puerperium, nor had had a recent miscarriage, and were not using injectable progestogens, nor suffering from inherited coagulation defects. The median time between occurrence of deep-vein thrombosis and venepuncture was 18 months, and 30 of the 99 women were still using oral contraceptives, while 69 had discontinued oral contraceptive use. In addition, a group of 153 control women (54 of them were oral contraceptive users and 99 were non-users) were studied. The following hemostatic variables were measured: APTT, factor VII, factor VIII, factor XII, fibrinogen, prothrombin, total antithrombin, normalised activated protein C sensitivity ratio (n-APC-sr), protein C, protein S and free protein S. Results: We found marked and significant effects of oral contraceptive use on the levels of several clotting factors, with an increase in factor VII, factor XII, protein C and a decrease in antithrombin, n-APC-sr and protein S. Less marked effects that were non-significant or only significant in either patients or controls, were an increase in factor VIII, fibrinogen and prothrombin and a decrease in the APTT and free protein S. In the former thrombosis patients several of these effects of oral contraceptives were more pronounced than in healthy women: specifically on factor VII, antithrombin, n-APC-sr and protein C. Conclusions: Our results of the effects of oral contraceptives generally confirm previous reports in healthy volunteers. Our data also show that in former deep-vein thrombosis patients these effects are more pronounced. Apparently some women become “high hemostatic responders” when exposed to oral contraceptives, and they may be the women most vulnerable to its thrombogenic effects.

Thermolabile Methylenetetrahydrofolate Reductase and Factor V Leiden in the Risk of Deep-Vein Thrombosis

Mild hyperhomocysteinemia is an established risk factor for both arteriosclerosis and thrombosis, and may be caused by genetic and environmental factors. Methylenetetrahydrofolate reductase (MTHFR) catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, the cofactor for the methylation of homocysteine to methionine. Individuals with the thermolabile variant of MTHFR have decreased MTHFR activities, resulting in elevated plasma homocysteine concentrations. A homozygous 677C→T transition in the MTHFR gene has recently been identified as the cause of reduced enzyme activity and thermolability of the protein. We studied the frequency of the homozygous mutant (+/+) genotype in 471 patients with deep-vein thrombosis and 474 healthy controls enrolled in The Leiden Thrombophilia Study (LETS), its interaction with factor V Leiden, and assessed the association between the MTHFR genotypes and plasma homocysteine concentration. Homozygosity for the 677C→T polymorphism was observed in 47 (10%) patients, and in 47 (9.9%) controls (OR 1.01 [95% CI: 0.7-1.5]). No modified risk of the (+/+) genotype was observed in carriers of factor V Leiden. Our data suggest that, although the homozygous mutant genotype is associated with elevated plasma homocysteine concentrations, this homozygous mutation itself is not a genetic risk factor for deep-vein thrombosis, irrespective of factor V Leiden genotype.

Familial Clustering of Factor VIII and von Willebrand Factor Levels

Recently, we found that high levels of clotting factor VIII (>150 IU/dl) are common and make an important contribution to thrombotic risk. The determinants of high factor VIII:C are unclear and might be partly genetic. Therefore, we tested the influence of age, blood group and von Willebrand factor (VWF) levels on factor VIII:C levels, and investigated whether factor VIII:C levels are genetically determined. We performed an analysis of 564 female relatives of hemophilia A patients, who had visited our center for genetic counseling. In univariate analysis, AB0 blood group, age and VWF antigen (VWF:Ag) levels all influenced factor VIII:C levels. After adjustment for the effect of VWF:Ag levels, both blood group and age still had an effect on factor VIII:C levels. In sister pairs, the Pearson correlation coefficient between factor VIII:C levels was 0.17 (p = 0.024) and this correlation remained positive (0.15, p = 0.046) after correction for the influence of VWF:Ag. In mother-daughter pairs, no correlation of factor VIII:C levels was found. The correlation of VWF:Ag levels in sisterpairs was 0.41 (p <0.001) and in mother-daughter pairs 0.44 (p <0.001), in line with the assumption that VWF:Ag levels are under control of autosomal genes. Familial influence on plasma factor VIII:C and VWF:Ag levels was investigated with a recently developed familial aggregation test. This test verifies whether familial aggregation of a particular parameter exists in a set of pedigrees. In 435 women from 168 families, factor VIII:C as well as VWF:Ag levels correlated significantly within families, which suggests a familial influence. The familial aggregation was more prominent for VWF:Ag levels than for factor VIII:C levels, possibly because the genetic effect on VWF:Ag levels is larger than on factor VIII:C levels. Our results support the presence of a familial influence on factor VIII:C as well as on VWF:Ag levels.

Our results support the presence of a familial influence on factor VIII:C as well as on VWF:Ag levels.

Hyperhomocysteinemia and Venous Thrombosis: A Meta-analysis

Hyperhomocysteinemia is an established risk factor for atherosclerosis and vascular disease. Until the early nineties the relationship with venous thrombosis was controversial. At this moment ten case-control studies on venous thrombosis are published. We performed a meta-analysis of these reports.

We performed a MEDLINE-search from 1984 through June 1997 on the keywords “homocysteine” or “hyperhomocysteinemia” and “venous thrombosis”, which yielded ten eligible case-control studies.

We found a pooled estimate of the odds ratio of 2.5 (95% CI 1.8-3.5) for a fasting plasma homocysteine concentration above the 95th percentile or mean plus two standard deviations calculated from the distribution of the respective control groups. For the post-methionine increase in homocysteine concentration we found a pooled estimate of 2.6 (95% CI 1.6-4.4).

These data from case-control studies support hyperhomocysteinemia as a risk factor for venous thrombosis. Further research should focus on the pathophysiology of this relationship and on the clinical effects of reducing homocysteine levels by vitamin supplementation.

Quality of life in venous disease

Quality of life (QOL) can be defined as the functional effect of an illness and its consequent therapy upon a patient, as perceived by the patient. Studies on the impact of chronic venous disease on quality of life are scarce compared to quality of life research in other diseases. The purpose of this paper was to describe instruments that assess the quality of life in patients with chronic venous disease and to review the literature on this topic.

A computer search of the MedLine database was performed to identify papers; the bibliographies of relevant articles were reviewed to obtain additional papers. Papers were included if they described the development or use of a quality of life instrument for patients with chronic venous disease.

A total of 25 papers were identified that fit the inclusion criteria. The studies described in the papers used six different generic instruments and ten disease-specific instruments. Quality of life in chronic venous disease was assessed in 12 studies. Six studies compared different types of treatment for chronic venous disease where QOL was an outcome measure. Despite the wide variety of measures used, results indicate that the quality of life of patients with chronic venous disease is affected in the physical domain mostly with regard to pain, physical functioning and mobility, and that they suffer from negative emotional reactions and social isolation.

We feel that QOL should be a standard measure in future studies in patients with chronic venous disease, preferably with a combination of generic and disease-specific measures.

A Mutation in the Thrombomodulin Gene, 127G to A Coding for Ala25Thr, and the Risk of Myocardial Infarction in Men

Thrombomodulin is an endothelial cell surface receptor that transforms the procoagulant thrombin into an anticoagulant. A mutation in the thrombomodulin gene is a potential risk factor for venous and arterial thrombosis.

We screened a region within the coding sequence of the thrombomodulin gene by single-strand conformation polymorphism analysis (SSCP) in a pilot study of 104 patients with myocardial infarction and 104 age, sex and race matched controls. We identified a 127G to A mutation in the gene, which predicts an Ala25Thr substitution, in 2 out of 104 patients (1 man and 1 woman) with myocardial infarction but in no controls. We assessed the risk of myocardial infarction associated with the mutation in a larger “Study of Myocardial Infarctions Leiden” (SMILE). Among 560 men with a first myocardial infarction before the age of 70, 12 were carriers of the Ala25Thr substitution. In a control group of 646 men, frequency-matched for age, seven were carriers of the Ala25Thr substitution. The allelic frequencies were 1.07% among patients and 0.54% among controls suggesting risk associated with the mutation [odds ratio (OR) 2.0, 95% confidence interval (CI) 0.8-5.1]. In patients aged below 50, the predicted risk was almost seven times increased (OR 6.5, CI 0.8-54.2). In the presence of additional risk factors, such as smoking and a metabolic risk factor, the predicted risk increased to 9-fold (OR 8.8, CI 1.8-42.2) and 4-fold (OR 4.4, CI 0.9-21.3), respectively.

While not conclusive, these results strongly suggest that the Ala25Thr substitution is a risk factor for myocardial infarction, especially in young men, and when in the presence of additional risk factors.

Factor V Leiden mutation is associated with enhanced arterial thrombotic tendency in lean but not in obese mice

The homozygous factorV Leiden mutation is associated with enhanced venous thrombotic risk. Obesity is a major risk factor for development of thrombotic cardiovascular disease. It was the objective of this study to investigate whether obesity affects the thrombotic risk associated with the mutation. Male mice with homozygous factor V Leiden mutation (Arg 504 to Gln) (FVQ/Q) and corresponding wild-type (WT) mice were kept on a standard fat diet (SFD) or high fat diet (HFD) for 14 weeks, and femoral artery thrombosis was induced by FeCl3 treatment. As compared to SFD, HFD feeding for 14 weeks resulted in significantly higher body weight and fat mass associated with adipocyte hypertrophy, which were, however, similar for both geno types. In the FeCl3-induced arterial thrombosis model, FVQ/Q mice kept on SFD had a 40% shorter occlusion time (p = 0.015) and 40% lower blood flow (p = 0.03), as compared to WT mice. However, on HFD the occlusion time and blood flow were not significantly different for both genotypes. This finding could not be explained by differential changes of coagulation factors in either genotype fed on SFD or HFD. In conclusion, on SFD, but not on HFD, the factorV Leiden mutation is associated with enhanced thrombotic tendency after FeCl3 injury of the femoral artery, suggesting that in this model obesity rescues the increased thrombotic risk associated with the factorV Leiden mutation.

The influence of established genetic variation in the haemostatic system on clinical restenosis after percutaneous coronary interventions

Since activation of the haemostatic system is an important feature of the wound healing response triggered by arterial injury, variations in genes involved in thrombus formation may play a role in restenosis after percutaneous coronary interventions (PCI). Therefore, our aim was to examine the relationship between polymorphisms that are known to play a role in the haemostatic system and the risk of clinical restenosis in the GENetic DEterminants of Restenosis (GENDER) study,a multicenter prospective study design that enrolled 3,104 consecutive patients after successful PCI. Target vessel revascularization (TVR) was the primary endpoint. All patients were genotyped for six polymorphisms in the Factor II, Factor V, Factor VII and PAI-1 genes. The PAI-1 4G variant was associated with an increased risk ofTVR. When compared to 5G/5G homozygotes, heterozygous patients were at higher risk for TVR (HR: 1.46, 95%CI: 1.05–2.03), whereas patients with the 4G/4G genotype had an even further increased risk (HR: 1.69, 95%CI: 1.19–2.41). In contrast, the factor V 506Gln (factor V Leiden) amino acid substitution was associated with a decreased risk of TVR (HR: 0.41, 95%CI: 0.19–0.86). Our findings indicate that polymorphisms in the factorV and PAI-1 genes may play a role in the process of restenosis.

Effect of oral contraceptives on thrombin generation measured via calibrated automated thrombography

In a study population consisting of healthy men (n=8), women not using oral contraceptives (OC) (n=28) and women using different kinds of OC (n=187) we used calibrated automated thrombography (CAT) in the absence and presence of added activated protein C (APC) to compare parameters that can be obtained from thrombin generation curves, i.e. lag time, time to peak, peak height and endogenous thrombin potential (ETP). Both with and without APC, plasmas of OC users exhibited the shortest lag time and time to peak, and the highest peak height and ETP. In the absence of APC none of these parameters differed between users of OC containing different progestogens. In contrast, in the presence of APC shorter lag times and time to peak, and higher peak height and ETP were observed in plasma of users of gestodene-,desogestrel-,drospirenone- and cyproterone acetate-containing OC than in plasma of users of levonorgestrel-containing OC. The ETP determined in the absence of APC (ETP-APC) had no predictive value for the APCsr (r=0.11; slope 0.9×10–3; 95%CI: –0.1×10–3 to 2.0×10–3) whereas the ETP measured in the presence of APC (ETP+APC) showed an excellent correlation with the APCsr (r=0.95; slope 6.6×10–3; 95%CI: 6.3×10–3 to 6.9×10–3) indicating that the APCsr is entirely determined by the ETP+APC. In conclusion, OC use increases thrombin generation, but differential effects of second and third generation OCs on the protein C system likely determine the differences in the risk of venous thrombosis between these kinds of OC.

No interaction between factor V Leiden and hyperhomocysteinemia or MTHFR 677TT genotype in venous thrombosis

Homocysteine may have a thrombogenic effect through inhibition of inactivation of factor Va by activated protein C. Because factor V Leiden also leads to resistance of factor V to activated protein C, it would be possible that both factors show interaction for the risk of venous thrombosis. This has been reported in some studies, but not in others. We performed a meta-analysis to investigate a possible interaction between factor V Leiden and hyperhomocysteinemia, including 825 subjects with venous thrombosis and 2,109 controls, for the risk of venous thrombosis. In addition, we assessed a possible interaction between factor V Leiden and MTHFR 677TT genotype (the most common genetic determinant of homocysteine levels), including 2,547 subjects with venous thrombosis and 4,327 controls. We also investigated the interaction effect of factor V Leiden and hyperhomocysteinemia in a large case-only study using data of the VITRO study, including 2,077 subjects with first-time venous thrombosis. The meta-analysis yielded no evidence for additive or multiplicative interaction between factor V Leiden and hyperhomocysteinemia [relative excess risk due to interaction (RERI) –1.77 (95%CI –8.61 to 5.08) and multiplicative interaction term 0.86 (95%CI 0.35 to 2.14)].The case-only study also showed no interaction effect [0.58 (95%CI 0.29 to 1.16)]. Also the metaanalysis on factor V Leiden and MTHFR 677TT yielded no evidence of interaction; RERI 0.13 (95%CI –3.60 to 3.86) and multiplicative interaction term 1.23 (95%CI 0.72 to 2.11). Both the meta-analyses of published studies and a large case-only study did not show evidence for interaction between factor V Leiden and hyperhomocysteinemia for risk of venous thrombosis.

Fluid loss does not explain coagulation activation during air travel

The mechanism of air travel-related venous thrombosis is unclear. Although immobility plays a pivotal role, other factors such as fluid loss may contribute. We investigated whether fluid loss occurred more in individuals with coagulation activation after air travel than in subjects without. As a secondary aim, we investigated whether fluid loss per se occurred during air travel. In this crossover study, 71 healthy volunteers were exposed to eight hours of air travel, eight hours immobilization in a cinema, and a daily-life control situation. Markers of fluid loss (haematocrit, serum osmolality and albumin) and of coagulation activation were measured before and after each exposure. The study included ll volunteers with and 55 volunteers without coagulation activation during the flight. The change in parameters of fluid loss was not different in volunteers with an activated clotting system from those without (difference between groups in haematocrit: −0.6%, 95% confidence interval [CI]: −1.9 to 0.6). On a group level, mean haematocrit values decreased during all three exposures. However, in some individuals it increased, which occurred in more participants during the flight (34%; 95% CI 22 to 46) than during the daily-life situation (l9%; 95% CI 10 to 28). These findings do not support the hypothesis that fluid loss contributes to thrombus formation during air travel.