Warfarin exhibits wide interpatient variability in dosing requirements. Recent studies have shown a novel polymorphism (rs2108622, V433M) in the CYP4F2 gene to be associated with variability in warfarin requirements in Caucasians. The purpose of this study was to evaluate the impact of rs2108622 on warfarin dose requirements in the Asian population. The mean warfarin dose was found to be significantly lower in patients carrying homozygous wild-type allele CC when compared with patients carrying variant alleles CT and TT (CC vs CT+TT: 3.0 mg/day vs 3.75 mg/day, p = 0.033). In patients harboring VKORC1 diplotypes associated with low warfarin requirements, a linear regression model which included age, weight, CYP2C9 and CYP4F2 variants accounted for 38% of the variability in warfarin dose. Approximately 11% of the dose variation was explained by CYP4F2 rs2108622 (p = 0.004). The influence of rs2108622 in patients harboring VKORC1 diplotypes associated with high warfarin requirements was not significant. This study suggests that CYP4F2 rs2108622 may significantly affect warfarin dose requirements in carriers of VKORC1 low-dose-associated diplotypes.
Objective
Many patients with advanced illness are unrealistically optimistic about their prognosis. We test for the presence of several cognitive biases, including optimism bias, illusion of superiority, self‐deception, misattribution, and optimistic update bias, that could explain unrealistically optimistic prognostic beliefs among advanced cancer patients and quantifies the extent to which hope exacerbates these biases.
Methods
A cross‐sectional survey was administered to 200 advanced cancer patients with physician‐estimated prognoses of one year or less. Hope was measured using the Herth Hope Index (HHI). Hypotheses were tested using linear and logistic regressions and a structural‐equation model.
Results
Results are consistent with the presence of optimism bias, illusion of superiority, self‐deception, and misattribution. All of these biases are amplified by higher levels of hope. Each 1‐point higher HHI is associated with a 6% (OR: 1.06; 95% CI: 1.01–1.11) greater odds of believing their illness is curable, a 0.33‐year (95% CI: 0.17–0.49) longer expected survival, a 6% (OR: 1.06; 95% CI: 1.02–1.11) higher probability of believing that survival outcomes are better than the average patient, a 5% higher odds of believing primary intent of treatment is curative (OR: 1.05; 95% CI: 1.00–1.10), and a 12% (OR: 1.12; 95% CI: 1.05–1.17) higher odds of believing they are well‐informed. Mediation analyses revealed that hope significantly mediates the effect of mental‐well‐being and loneliness on expected survival.
Conclusions
Results suggest advanced cancer patients succumb to several cognitive biases which are exacerbated by greater levels of hope. As a result, they are susceptible to possible over‐treatment and regret.
BackgroundFamily caregivers of patients with advanced cancer have been reported to provide long hours of care and be at risk for poor psychological outcomes. Although research has focused on the nature of caregiving burden, little attention has been paid to identifying protective factors that improve caregiver psychological outcomes.AimWe examined the relationship between caregivers’ time spent caregiving and the following psychological outcomes: anxiety, depression and caregiving esteem. Subsequently, we explored the main and moderating effects of caregiver-perceived self-competency and sense of meaning on caregiver psychological outcomes.Design/participantsCross-sectional analysis was conducted using the baseline data from an ongoing cohort study. Family caregivers of advanced cancer patients (n=287) were recruited from two tertiary hospitals in Singapore.ResultsTime spent caregiving was not significantly associated with caregiver anxiety, depression or caregiving esteem. However, significant main effects of self-competency on anxiety and caregiving esteem; and sense of meaning on anxiety, depression and caregiving esteem were observed. Moderator analyses further indicated that self-competency attenuated the positive relationship between time spent caregiving and anxiety, while sense of meaning attenuated the negative relationship between time spent caregiving and caregiving esteem.ConclusionGreater perceived self-competency and sense of meaning are related to better caregiver psychological outcomes, and protect caregivers from worsening outcomes as caregiving hours increase. Our findings suggest that screening caregivers for distress is an important part of care, and that supportive interventions for caregivers should aim to enhance their perceived caregiving competencies and the ability to make meaning of their caregiving role.
Warfarin-induced bleeding complications and high inter-patient variability are major hindrances to oral anticoagulant therapy. The present study identifies the influence of VKORC1 diplotypes, CYP2C9 and CYP2C19 variants on warfarin disposition and dose requirements in Chinese patients (n=107). The study subjects were genotyped for VKORC1, CYP2C9 and CYP2C19 polymorphic variants. Weekly warfarin dose requirements and S-warfarin clearance were stratified by VKORC1, CYP2C9 and CYP2C19 pharmacogenetics. The major VKORC1 diplotypes were H1-H1 (62%), H1-H7 (18%) and H1-H(*)(b) (10%). Warfarin dose requirements were significantly lower in patients with VKORC1 H1-H1 and H1-H(*)(a) diplotypes compared to patients harboring the H1-H7 and H1-H(*)(b) diplotypes (P<0.05). Hepatic tissues with H1-H1 diplotype had significantly lower expression of VKORC1 mRNA compared with liver tissues carrying the H1-H7 and H1-H(*)(b) diplotypes (P=0.006). The percent variability explained by VKORC1 diplotype status was 59.1% while the CYP2C9 genotype status accounted for 6.9% variability in warfarin dose requirements. Patient age and weight were significant covariates accounting for 29% and 8.6% of warfarin dose variability, respectively. The present study shows that VKORC1 diplotype status, CYP2C9 genotype, age and weight are significant covariates, accounting for 73.4% of interindividual variability in warfarin dose requirements among Chinese patients. Translation of these findings into clinical guidelines for warfarin dosing may be required to assess its impact on the safety and efficacy of warfarin.
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