Håkan Melhus

Common VKORC1 and GGCX polymorphisms associated with warfarin dose

We report a novel combination of factors that explains almost 60% of variable response to warfarin. Warfarin is a widely used anticoagulant, which acts through interference with vitamin K epoxide reductase that is encoded by VKORC1. In the next step of the vitamin K cycle, gamma-glutamyl carboxylase encoded by GGCX uses reduced vitamin K to activate clotting factors. We genotyped 201 warfarin-treated patients for common polymorphisms in VKORC1 and GGCX. All the five VKORC1 single-nucleotide polymorphisms covary significantly with warfarin dose, and explain 29–30% of variance in dose. Thus, VKORC1 has a larger impact than cytochrome P450 2C9, which explains 12% of variance in dose. In addition, one GGCX SNP showed a small but significant effect on warfarin dose. Incorrect dosage, especially during the initial phase of treatment, carries a high risk of either severe bleeding or failure to prevent thromboembolism. Genotype-based dose predictions may in future enable personalised drug treatment from the start of warfarin therapy.

A comprehensive pharmacist intervention to reduce morbidity in patients 80 years or older: a randomized controlled trial.

BACKGROUND Patients 80 years or older are underrepresented in scientific studies. The objective of this study was to investigate the effectiveness of interventions performed by ward-based pharmacists in reducing morbidity and use of hospital care among older patients. METHODS A randomized controlled study of patients 80 years or older was conducted at the University Hospital of Uppsala, Uppsala, Sweden. Four hundred patients were recruited consecutively between October 1, 2005, and June 30, 2006, and were randomized to control (n = 201) and intervention (n = 199) groups. The interventions were performed by ward-based pharmacists. The control group received standard care without direct involvement of pharmacists at the ward level. The primary outcome measure was the frequency of hospital visits (emergency department and readmissions [total and drug-related]) during the 12-month follow-up period. RESULTS Three hundred sixty-eight patients (182 in the intervention group and 186 in the control group) were analyzed. For the intervention group, there was a 16% reduction in all visits to the hospital (quotient, 1.88 vs 2.24; estimate, 0.84; 95% confidence interval [CI], 0.72-0.99) and a 47% reduction in visits to the emergency department (quotient, 0.35 vs 0.66; estimate, 0.53; 95% CI, 0.37-0.75). Drug-related readmissions were reduced by 80% (quotient, 0.06 vs 0.32; estimate, 0.20; 95% CI, 0.10-0.41). After inclusion of the intervention costs, the total cost per patient in the intervention group was

Plasma parathyroid hormone and the risk of cardiovascular mortality in the community

230 lower than that in the control group. CONCLUSION If implemented on a population basis, the addition of pharmacists to health care teams would lead to major reductions in morbidity and health care costs.

Serum intact FGF23 associate with left ventricular mass, hypertrophy and geometry in an elderly population ☆

Background— Diseases with elevated levels of parathyroid hormone (PTH) such as primary and secondary hyperparathyroidism are associated with increased incidence of cardiovascular disease and death. However, data on the prospective association between circulating PTH levels and cardiovascular mortality in the community are lacking. Methods and Results— The Uppsala Longitudinal Study of Adult Men (ULSAM), a community-based cohort of elderly men (mean age, 71 years; n=958), was used to investigate the association between plasma PTH and cardiovascular mortality. During follow-up (median, 9.7 years), 117 participants died of cardiovascular causes. In Cox proportional-hazards models adjusted for established cardiovascular risk factors (age, systolic blood pressure, diabetes, smoking, body mass index, total cholesterol, high-density lipoprotein cholesterol, antihypertensive treatment, lipid-lowering treatment, and history of cardiovascular disease), higher plasma PTH was associated with higher risk for cardiovascular mortality (hazard ratio for 1-SD increase in PTH, 1.38; 95% confidence interval, 1.18 to 1.60; P<0.001). This association remained essentially unaltered in participants without previous cardiovascular disease and in participants with normal PTH (<6.8 pmol/L) with no other signs of a disturbed mineral metabolism (normal serum calcium, 2.2 to 2.6 mmol/L; normal glomerular filtration rate, >50 mL · min−1 · 1.73 m−2 and without vitamin D deficiency, plasma 25-OH vitamin D >37.5 nmol/L). Interestingly, elevated plasma PTH (>5.27 pmol/L) accounted for 20% (95% confidence interval, 10 to 26) of the population-attributable risk proportion for cardiovascular mortality. Conclusions— Plasma PTH levels predict cardiovascular mortality in the community, even in individuals with PTH within the normal range. Further studies are warranted to evaluate the clinical implications of measuring PTH in cardiovascular risk prediction and to elucidate whether PTH is a modifiable risk factor.

Total mortality after changes in leisure time physical activity in 50 year old men: 35 year follow-up of population based cohort

Fibroblast growth factor-23 (FGF23) is a hormonal regulator of circulating phosphate and vitamin D levels. Serum FGF23 is elevated in chronic kidney disease (CKD) and is a prognostic marker of poor outcomes, such as faster CKD progression and increased mortality in hemodialysis patients. Despite the high prevalence of cardiovascular disease in CKD, the relation between circulating FGF23 and cardiovascular risk factors, both in CKD and in the community, has not been studied in detail. We evaluated the relation between FGF23, left ventricular mass index (LVMI), hypertrophy (LVH) and LV geometry, employing the community-based PIVUS cohort. In total, 795 Swedish men and women aged 70 were included of which 164 had an age-adjusted diminished renal function (estimated glomerular filtration rate<60mL/min/1.73m(2)). FGF23 was positively associated with LVMI (beta=0.11, CI 0.01-0.18), with increased odds for the presence of LVH (OR 1.28, CI 1.09-1.51) and for concentric hypertrophy (OR 1.45, CI 1.19-1.77) in the whole population. All associations were stronger in subjects with eGFR<60mL/min/1.73m(2) (beta=0.30, CI 0.15-0.46 for LVMI; OR 1.86, CI 1.30-2.67 for the presence of LVH; OR 1.83, CI 1.17-2.85 and OR 1.87, CI 1.08-3.22 for concentric and eccentric hypertrophy, respectively). The results were essentially unaltered in multivariate models. In summary, elevated serum FGF23 levels, even within the normal range, are associated with increased LVMI and increased risk for the presence of LVH in elderly subjects. Additional longitudinal studies that evaluate the predictive power of FGF23 and whether FGF23 has additional clinical applications are needed.

Smoking, Antioxidant Vitamins, and the Risk of Hip Fracture

Objective To examine how change in level of physical activity after middle age influences mortality and to compare it with the effect of smoking cessation. Design Population based cohort study with follow-up over 35 years. Setting Municipality of Uppsala, Sweden. Participants 2205 men aged 50 in 1970-3 who were re-examined at ages 60, 70, 77, and 82 years. Main outcome measure Total (all cause) mortality. Results The absolute mortality rate was 27.1, 23.6, and 18.4 per 1000 person years in the groups with low, medium, and high physical activity, respectively. The relative rate reduction attributable to high physical activity was 32% for low and 22% for medium physical activity. Men who increased their physical activity level between the ages of 50 and 60 continued to have a higher mortality rate during the first five years of follow-up (adjusted hazard ratio 2.64, 95% confidence interval 1.32 to 5.27, compared with unchanged high physical activity). After 10 years of follow-up their increased physical activity was associated with reduced mortality to the level of men with unchanged high physical activity (1.10, 0.87 to 1.38). The reduction in mortality associated with increased physical activity (0.51, 0.26 to 0.97, compared with unchanged low physical activity) was similar to that associated with smoking cessation (0.64, 0.53 to 0.78, compared with continued smoking). Conclusions Increased physical activity in middle age is eventually followed by a reduction in mortality to the same level as seen among men with constantly high physical activity. This reduction is comparable with that associated with smoking cessation.

Cardiovascular Diseases and Risk of Hip Fracture

Smoking increases the concentrations of free radicals, which have been suggested to be involved in bone resorption. We examined whether the dietary intake of antioxidant vitamins may modify the increased hip fracture risk associated with smoking. We prospectively studied 66,651 women who were 40–76 years of age. Forty‐four of the cohort members who sustained a first hip fracture within 2–64 months of follow‐up (n = 247) and 93 out of 873 age‐matched controls were current smokers. Information on diet was obtained by a validated food‐frequency questionnaire. The relative risk of hip fracture for current versus never smokers was analyzed in relation to the dietary intake of antioxidant vitamins stratified into two categories (low/high), where median intakes among the controls were used as cut‐off points. After adjustment for major osteoporosis risk factors, the odds ratio (OR) for hip fracture among current smokers with a low intake of vitamin E was 3.0 (95% confidence interval 1.6–5.4) and of vitamin C 3.0 (1.6–5.6). In contrast, the OR decreased to 1.1 (0.5–2.4) and 1.4 (0.7–3.0) with high intakes of vitamin E and C, respectively. This effect was not seen for beta‐carotene, selenium, calcium, or vitamin B6. In current smokers with a low intake of both vitamins E and C, the OR increased to 4.9 (2.2–11.0). The influence of the intake of these two antioxidant vitamins on hip fracture risk was less pronounced in former smokers. Our results suggest a role for oxidant stress in the adverse effects on the skeleton of smoking, and that an insufficient dietary intake of vitamin E and C may substantially increase the risk of hip fracture in current smokers, whereas a more adequeate intake seems to be protective.

Plasma vitamin D and mortality in older men: a community-based prospective cohort study

CONTEXT Recent studies indicate common etiologies for cardiovascular disease (CVD) and osteoporotic fractures. OBJECTIVES To examine the relation between CVD and risk of hip fracture in twins and evaluate the relative importance of genetics and lifestyle factors in this association. DESIGN, SETTING, AND PARTICIPANTS A cohort of all 31,936 Swedish twins born from 1914-1944 was followed up from the age of 50 years. The National Patient Registry identified twins with CVDs and fractures from 1964 through 2005. Time-dependent exposures using Cox proportional hazard regression models were evaluated. MAIN OUTCOME MEASURE Time to hip fracture after diagnosis of CVD. RESULTS The crude absolute rate of hip fractures was 12.6 per 1000 person-years after a diagnosis of heart failure, 12.6 per 1000 person-years after a stroke, 6.6 per 1000 person-years after a diagnosis of peripheral atherosclerosis, and 5.2 per 1000 person-years after a diagnosis of ischemic heart disease compared with 1.2 per 1000 person-years for those without a CVD diagnosis. The multivariable-adjusted hazard ratio (HR) of hip fracture after a diagnosis of heart failure was 4.40 (95% confidence interval [CI], 3.43-5.63); after a stroke, the HR was 5.09 (95% CI, 4.18-6.20); after a diagnosis of peripheral atherosclerosis, the HR was 3.20 (95% CI, 2.28-4.50); and after an ischemic heart disease event, the HR was 2.32 (95% CI, 1.91-2.84). Identical twins without heart failure and stroke also had, after their co-twins had been exposed to these respective diseases, an increased rate of hip fracture. These sibling twins pseudoexposed for heart failure had a multivariable-adjusted HR of 3.74 (95% CI, 1.97-7.10) for hip fracture, whereas pseudoexposure for stroke had an HR of 2.29 (95% CI, 1.20-4.35). CONCLUSIONS A diagnosis of CVD was significantly associated with risk of subsequent hip fracture. Increased risks in co-twins without an index diagnosis suggest genetic factors in the association between CVD and osteoporotic fractures.

Warfarin sensitivity related to CYP2C9, CYP3A5, ABCB1 (MDR1) and other factors

BACKGROUND Vitamin D status is known to be important for bone health but may also affect the development of several chronic diseases, including cancer and cardiovascular diseases, which are 2 major causes of death. OBJECTIVE We aimed to examine how vitamin D status relates to overall and cause-specific mortality. DESIGN The Uppsala Longitudinal Study of Adult Men, a community-based cohort of elderly men (mean age at baseline: 71 y; n = 1194), was used to investigate the association between plasma 25-hydroxyvitamin D [25(OH)D] and mortality. Total plasma 25(OH)D was determined with HPLC atmospheric pressure chemical ionization mass spectrometry. Proportional hazards regression was used to compute hazard ratios (HRs). RESULTS During follow-up (median: 12.7 y), 584 (49%) participants died. There was a U-shaped association between vitamin D concentrations and total mortality. An approximately 50% higher total mortality rate was observed among men in the lowest 10% (<46 nmol/L) and the highest 5% (>98 nmol/L) of plasma 25(OH)D concentrations compared with intermediate concentrations. Cancer mortality was also higher at low plasma concentrations (multivariable-adjusted HR: 2.20; 95% CI: 1.44, 3.38) and at high concentrations (HR: 2.64; 95% CI: 1.46, 4.78). For cardiovascular death, only low (HR: 1.89; 95% CI: 1.21, 2.96) but not high (HR: 1.33; 95% CI: 0.69, 2.54) concentrations indicated higher risk. CONCLUSIONS Both high and low concentrations of plasma 25(OH)D are associated with elevated risks of overall and cancer mortality. Low concentrations are associated with cardiovascular mortality.

Long term calcium intake and rates of all cause and cardiovascular mortality: community based prospective longitudinal cohort study

ABSTRACTThe required dose of the oral anticoagulant warfarin varies greatly, and overdosing often leads to bleeding. Warfarin is metabolised by cytochrome P450 enzymes CYP2C9, CYP1A2 and CYP3A. The target cell level of warfarin may be dependent on the efflux pump P-glycoprotein, encoded by the adenosine triphosphate-binding cassette gene ABCB1 (multidrug resistance gene 1). Genetic variability in CYP2C9, CYP3A5 and ABCB1 was analysed in 201 stable warfarin-treated patients using solid-phase minisequencing, pyrosequencing and SNaPshot. CYP2C9 variants, age, weight, concurrent drug treatment and indication for treatment significantly influenced warfarin dosing in these patients, explaining 29% of the variation in dose. CYP3A5 did not affect warfarin dosing. An ABCB1 haplotype containing the exon 26 3435T variant was over-represented among low-dose patients. Thirty-six patients with serious bleeding complications had higher prothrombin time international normalised ratios than 189 warfarin-treated patients without serious bleeding, but there were no significant differences in CYP2C9, CYP3A5 or ABCB1 genotypes and allelic variants.