Associations between frailty, physical performance, and renal biomarkers in older people with advanced chronic kidney disease.

PURPOSE: Impaired physical performance and frailty are common in older people with advanced chronic kidney disease but it is unclear which metabolic derangements contribute to these impairments. We, therefore, examined associations between renal biochemical markers and both physical performance and frailty in older people with advanced chronic kidney disease. METHODS: Secondary analysis of data from the BiCARB trial, which enrolled non-dialysing patients aged 60 and over, with chronic kidney disease stage 4/5, with serum bicarbonate < 22 mmol/L. Participants undertook the Short Physical Performance Battery, maximum grip strength and six-minute walk test at baseline, 3, 6, 12 and 24 months. Renal biochemistry (serum creatinine, cystatin C, phosphate, and bicarbonate), haemoglobin, 25-hydroxyvitamin D and NT-pro-B-type natriuretic peptide were measured at baseline. Associations between baseline renal biochemistry and physical performance, and between baseline biochemistry and the monthly rate of change in physical performance were assessed. RESULTS: We analysed data from 300 participants (mean age 74 years; 86 [29%] women). 148 (49%) were pre-frail, 86 (29%) were frail. In multivariable cross-sectional baseline analyses, only age and BMI were significantly associated with baseline short physical performance battery; age, sex, body mass index, NT-pro-BNP and 25-hydroxyvitamin D were significantly associated with baseline six-minute walk distance. No significant associations were found between biochemical markers and change in physical performance over time, except between baseline 25-hydroxyvitamin D concentration and change in six-minute walk distance. CONCLUSIONS: Biochemical markers associated with chronic kidney disease did not consistently associate with baseline physical performance or the rate of change of physical performance measures. TRIAL REGISTRATION: ISRCTN09486651.

Vitamin K Supplementation to Improve Vascular Stiffness in CKD: The K4Kidneys Randomized Controlled Trial.

BACKGROUND: Vascular calcification, a risk factor for cardiovascular disease, is common among patients with CKD and is an independent contributor to increased vascular stiffness and vascular risk in this patient group. Vitamin K is a cofactor for proteins involved in prevention of vascular calcification. Whether or not vitamin K supplementation could improve arterial stiffness in patients with CKD is unknown. METHODS: To determine if vitamin K supplementation might improve arterial stiffness in patients in CKD, we conducted a parallel-group, double-blind, randomized trial in participants aged 18 or older with CKD stage 3b or 4 (eGFR 15-45 ml/min per 1.73 m2). We randomly assigned participants to receive 400 µg oral vitamin K2 or matching placebo once daily for a year. The primary outcome was the adjusted between-group difference in carotid-femoral pulse wave velocity at 12 months. Secondary outcomes included augmentation index, abdominal aortic calcification, BP, physical function, and blood markers of mineral metabolism and vascular health. We also updated a recently published meta-analysis of trials to include the findings of this study. RESULTS: We included 159 randomized participants in the modified intention-to-treat analysis, with 80 allocated to receive vitamin K and 79 to receive placebo. Mean age was 66 years, 62 (39%) were female, and 87 (55%) had CKD stage 4. We found no differences in pulse wave velocity at 12 months, augmentation index at 12 months, BP, B-type natriuretic peptide, or physical function. The updated meta-analysis showed no effect of vitamin K supplementation on vascular stiffness or vascular calcification measures. CONCLUSIONS: Vitamin K2 supplementation did not improve vascular stiffness or other measures of vascular health in this trial involving individuals with CKD. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Vitamin K therapy to improve vascular health in patients with chronic kidney disease, ISRCTN21444964 (www.isrctn.com).

Lung cancer screening: does pulmonary nodule detection affect a range of smoking behaviours?

BACKGROUND: Lung cancer screening can reduce lung cancer mortality by 20%. Screen-detected abnormalities may provide teachable moments for smoking cessation. This study assesses impact of pulmonary nodule detection on smoking behaviours within the first UK trial of a novel auto-antibody test, followed by chest x-ray and serial CT scanning for early detection of lung cancer (Early Cancer Detection Test-Lung Cancer Scotland Study). METHODS: Test-positive participants completed questionnaires on smoking behaviours at baseline, 1, 3 and 6 months. Logistic regression compared outcomes between nodule (n = 95) and normal CT groups (n = 174) at 3 and 6 months follow-up. RESULTS: No significant differences were found between the nodule and normal CT groups for any smoking behaviours and odds ratios comparing the nodule and normal CT groups did not vary significantly between 3 and 6 months. There was some evidence the nodule group were more likely to report significant others wanted them to stop smoking than the normal CT group (OR across 3- and 6-month time points: 3.04, 95% CI: 0.95, 9.73; P = 0.06). CONCLUSION: Pulmonary nodule detection during lung cancer screening has little impact on smoking behaviours. Further work should explore whether lung cancer screening can impact on perceived social pressure and promote smoking cessation.

Whole-body cardiovascular MRI for the comparison of atherosclerotic burden and cardiac remodelling in healthy South Asian and European adults.

OBJECTIVE: To determine the feasibility of using whole-body cardiovascular MRI (WB-CVMR) to compare South Asians (SAs)-a population known to have a higher risk of cardiovascular disease (CVD) but paradoxically lower prevalence of peripheral arterial disease-and Western Europeans (WEs). METHODS: 19 SAs and 38 age-, gender- and body mass index-matched WEs were recruited. All were aged 40 years and over, free from CVD and with a 10-year risk of CVD <20% as assessed by the adult treatment panel (ATP) III risk score. WB-CVMR was performed, comprising a whole-body angiogram (WBA) and cardiac MR (CMR), on a 3-T MRI scanner (Magnetom(®) Trio; Siemens, Erlangen, Germany) following dual-phase injection of gadolinium-based contrast agent. A standardized atheroma score (SAS) was calculated from the WBA while indexed left ventricular mass and volumes were calculated from the CMR. RESULTS: SAs exhibited a significantly lower iliofemoral atheroma burden (regional SAS 0.0 ± 0.0 vs 1.9 ± 6.9, p = 0.048) and a trend towards lower overall atheroma burden (whole-body SAS 0.7 ± 0.8 vs 1.8 ± 2.3, p = 0.1). They had significantly lower indexed left ventricular mass (46.9 ± 11.8 vs 56.9 ± 13.4 ml m(-2), p = 0.008), end diastolic volume (63.9 ± 10.4 vs 75.2 ± 11.4 ml m(-2), p=0.001), end systolic volume (20.5 ± 6.1 vs 24.6 ± 6.8 ml m(-2), p = 0.03) and stroke volume (43.4 ± 6.6 vs 50.6 ± 7.9 ml m(-2), p = 0.001), but with no significant difference in ejection fraction, mass-volume ratio or global functioning index. These differences persisted after accounting for CVD risk factors. CONCLUSION: WB-CVMR can quantify cardiac and atheroma burden and can detect differences in these metrics between ethnic groups that, if validated, may suggest that the paradoxical high risk of CVD compared with PVD risk may be due to an adverse cardiac haemodynamic status incurred by the smaller heart rather than atherosclerosis. ADVANCES IN KNOWLEDGE: WB-CVMR can be used to stratify and compare disease between ethnicities.

Does oral sodium bicarbonate therapy improve function and quality of life in older patients with chronic kidney disease and low-grade acidosis (the BiCARB trial)? Study protocol for a randomized controlled trial.

BACKGROUND: Metabolic acidosis is more common with advancing chronic kidney disease, and has been associated with impaired physical function, impaired bone health, accelerated decline in kidney function and increased vascular risk. Although oral sodium bicarbonate is widely used to correct metabolic acidosis, there exist potential risks of therapy including worsening hypertension and fluid overload. Little trial evidence exists to decide whether oral bicarbonate therapy is of net benefit in advanced chronic kidney disease, particularly in older people who are most commonly affected, and in whom physical function, quality of life and vascular health are at least as important outcomes as decline in renal function. METHODS/DESIGN: BiCARB is a multi-centre, double-blind, placebo controlled, randomised trial evaluating the clinical and cost-effectiveness of oral sodium bicarbonate in the management of older people with chronic kidney disease and severely reduced glomerular filtration rate (GFR) who have a mild degree of metabolic acidosis. The trial will recruit 380 patients from renal, Medicine for the Elderly, and primary care services across centres in the United Kingdom. Male and female patients aged 60 years and older with an estimated glomerular filtration rate of <30 mL/min/1.73 m(2), not on dialysis, and with serum bicarbonate concentrations <22 mmol/L will be eligible for participation. The primary clinical outcome for the trial is the between-group difference in the Short Physical Performance Battery score at 12 months. Secondary outcomes include muscle strength, quality of life measured using the EQ-5D score and KDQoL tools, cost effectiveness, renal function, presence of albuminuria and blood pressure. Markers of bone turnover (25-hydroxyvitamin D, 1,25-hydroxyvitamin D, tartrate-resistant acid phosphatase-5b and bone-specific alkaline phosphatase) and vascular health (B-type natriuretic peptide) will be measured. Participants will receive a total of 24 months of either bicarbonate or placebo. The results will provide the first robust test of the overall clinical and cost-effectiveness of this commonly used therapy in older patients with severely reduced kidney function. TRIAL REGISTRATION: www.isrctn.com; ISRCTN09486651, registered 17 February 2012.