Statistical approaches applicable in managing OMICS data: Urinary proteomics as exemplary case.

With urinary proteomics profiling (UPP) as exemplary omics technology, this review describes a workflow for the analysis of omics data in large study populations. The proposed workflow includes: (i) planning omics studies and sample size considerations; (ii) preparing the data for analysis; (iii) preprocessing the UPP data; (iv) the basic statistical steps required for data curation; (v) the selection of covariables; (vi) relating continuously distributed or categorical outcomes to a series of single markers (e.g., sequenced urinary peptide fragments identifying the parental proteins); (vii) showing the added diagnostic or prognostic value of the UPP markers over and beyond classical risk factors, and (viii) pathway analysis to identify targets for personalized intervention in disease prevention or treatment. Additionally, two short sections respectively address multiomics studies and machine learning. In conclusion, the analysis of adverse health outcomes in relation to omics biomarkers rests on the same statistical principle as any other data collected in large population or patient cohorts. The large number of biomarkers, which have to be considered simultaneously requires planning ahead how the study database will be structured and curated, imported in statistical software packages, analysis results will be triaged for clinical relevance, and presented.

Association of serum uric acid levels with cardiovascular and all-cause mortality in hypertensive patients in China: a cohort study.

PURPOSE: The present study aimed to assess the association of elevated serum uric acid (SUA) and hypouricemia with all-cause mortality and cardiovascular mortality in Chinese hypertensive patients. METHODS: In the present prospective cohort, 9325 hypertensive patients from Dongguan, China were enrolled from 2014 to 2018 for analysis. Participants were categorised by quintiles of SUA. The HRs and 95% CIs for the association between SUA, all-cause and cardiovascular mortality were evaluated using the multivariate Cox regression model. After adjusting for multiple confounders, restricted cubic spline analysis was conducted to demonstrate the shape of relationship. RESULTS: After a median follow-up of 4.18 years for 9325 participants, there were 409 (4.4%) and 151 (1.6%) reported cases of all-cause and cardiovascular mortality, respectively. By using the third quintile of SUA (6.68 mg/dL to <7.55 mg/dL for men, 5.63 mg/dL to <6.42 mg/dL for women) as reference, the highest quintiles of SUA were associated with an elevated risk of all cause (HR: 1.34, 95% CI 1.00 to 1.80) in the crude model, but the association was not significant after adjusting for multiple comparisons. The association between low SUA and mortality and the dose-response analysis on the non-linearity of SUA-mortality relationship were not statistically significant. CONCLUSIONS: Although the association between SUA levels, all-cause and cardiovascular disease mortality did not appear to be significant among Chinese hypertensive patients, the findings might be confounded by their medical conditions. Further studies are needed to verify the optimal SUA levels for hypertensive patients.

QTc intervals are not prolonged in former ELBW infants at pre-adolescent age.

BACKGROUND: Whether preterm birth is associated with cardiac conduction or repolarization abnormalities in later life is still poorly explored, with conflicting data on QTc prolongation in former extreme low birth weight (ELBW, <1000 g) infants. METHODS: Twelve lead electrocardiograms (ECG) at rest, collected in the PREMATurity as predictor of children's Cardiovascular-renal Health (PREMATCH) study in former ELBW cases and term controls during pre-adolescence (8-14 years) were analyzed on corrected QT time (QTc, Bazett) and QT dispersion (QTd). ECG findings were compared between groups (Mann-Whitney), and associations with clinical and biochemical findings were explored (Spearman). In ELBW cases, associations between QTc and perinatal characteristics (at birth, neonatal stay) were explored (Mann-Whitney, Spearman). RESULTS: QTc and QTd were similar between 93 ELBW cases and 87 controls [409 (range 360-465) versus 409 (337-460); 40 (0-100) versus 39 (0-110)] ms. Age, height, weight, or body mass index were not associated with the QTc interval, while female sex (median difference 11.4 ms) and lower potassium (r = -0.26) were associated with longer QTc interval. We could not observe any significant association between QTc interval and perinatal characteristics. CONCLUSIONS: There were no differences in QTc or QTd between ELBW and term controls in ECGs at rest in pre-adolescents. IMPACT: This study aimed to assess the differences in QTc and QTd intervals between extreme low birth weight infants (ELBW) and term controls in electrocardiographic measurements at rest during pre-adolescence. This analysis confirmed the absence of significant differences in QTc or QTd findings between ELBW cases and term controls, while female sex and lower potassium were associated with a prolonged QTc interval. These data suggest that QTc screening strategies-including for pharmacovigilance-should not differentiate between former ELBW cases and term controls. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02147457.

The relationship between famine exposure during early life and ascending aorta dilatation in adults.

The relationship between exposure to famine in early life and the risk of ascending aorta dilatation (AAD) in adulthood is still unclear; therefore, we aimed to examine the association in the Chinese population. We investigated the data of 2598 adults who were born between 1952 and 1964 in Guangdong, China. All enrolled subjects were categorised into five groups: not exposed to famine, exposed during fetal period, and exposed during early, mid or late childhood. AAD was assessed by cardiac ultrasound. Multivariate logistic regression and interaction tests were performed to estimate the OR and CI on the association between famine exposure and AAD. There were 2598 (943 male, mean age 58·3 ± 3·68 years) participants were enrolled, and 270 (10·4 %) subjects with AAD. We found that famine exposure (OR = 2·266, 95 % CI 1·477, 3·477, P = 0·013) was associated with elevated AAD after adjusting for multiple confounders. In addition, compared with the non-exposed group, the adjusted OR for famine exposure during fetal period, early, mid or late childhood were 1·374 (95 % CI 0·794, 2·364, P = 0·251), 1·976 (95 % CI 1·243, 3·181, P = 0·004), 1·929 (95 % CI 1·237, 3·058, P = 0·004) and 2·227 (95 % CI 1·433, 3·524, P < 0·001), respectively. Subgroup analysis showed that the effect of famine exposure on the association with AAD was more pronounced in female, current smokers, people with BMI ≥ 24 kg/m2 and hypertensive patients. We observed that exposure to famine during early life was linked to AAD in adulthood.

Effects of waist to height ratio, waist circumference, body mass index on the risk of chronic diseases, all-cause, cardiovascular and cancer mortality.

BACKGROUND: Given the fat redistribution in later stages of life, how the associations between abdominal obesity and the risk of morbidity and mortality have changed with age have not been elucidated, especially for waist to height ratio (WHtR). OBJECTIVE: To compare the strength of association between obesity indices and chronic diseases at baseline, and the subsequent mortality risk among US adults. METHODS: We included 21 109 participants from National Health and Nutrition Examination Survey 1999-2014. We performed logistic regression and receiver operating curve analysis to examine the discriminatory power of obesity indicators on cardiometabolic diseases and cancer at baseline. Sex-stratified and age-stratified Cox models were constructed to explore the prospective association between obesity indices and all-cause, cardiovascular and cancer mortality. RESULTS: Elevated WHtR, elevated waist circumference (WC) and body mass index (BMI)-classified obesity are associated with higher odds of hypertension (OR: 1.37-2.13), dyslipidemia (OR: 1.06 to 1.75, all p<0.05) and diabetes (OR: 1.40-3.16, all p<0.05). WHtR had significantly better discriminatory power to predict cardiometabolic health than BMI, especially for diabetes (area under the curve: 0.709 vs 0.654). After multivariable adjustment, all obesity indicators are associated with lower risk of all-cause mortality among females aged ≥65 years (HR: 0.64 to 0.85), but the association was only significant for BMI when obesity indicators were mutually adjusted (HR: 0.79). CONCLUSIONS: WHtR and WC appeared to be the better indicators for cardiometabolic health than BMI. However, BMI had a stronger and inverse association with a greater risk of all-cause mortality among older females.

Relationship between body mass index and ischaemic stroke in Chinese elderly hypertensive patients.

BACKGROUND: Despite obesity being a major risk factor for ischaemic stroke (IS), the association between body mass index (BMI) and IS in patients with hypertension remains uncertain. OBJECTIVE: To assess the association between BMI and IS among elderly hypertensive patients in China. METHODS AND RESULTS: We recruited 3500 hypertensive patients aged ≥60 between 1 January 2010 and 31 December 2011 in China and ascertained their stroke status until December 2016. Multivariate Cox regression was used to evaluate the association between BMI and IS with interaction tests for exposure and covariates. A total of 3315 subjects (mean age 71.41±7.20 years, 44.5% were men) were included for data analysis. During an average follow-up period of 5.5 years, there were 206 onset cases (6.21%) of IS. When BMI was treated as a continuous variable, it was positively associated with the incidence of new onset IS (HR=1.14; 95% CI: 1.05 to 1.34; p=0.005) after adjusting for potential confounders. Meanwhile, when BMI was treated as a categorical variable, the highest category (≥28 kg/m2) was strongly associated with an increased risk for IS compared with normal BMI category (18.5 to 24 kg/m2) (HR=1.36, 95% CI: 1.09 to 1.80; p<0.001) in the fully adjusted model. Subgroup and interaction analysis also demonstrated that BMI independently associated with IS among males, smokers, alcohol drinkers, diabetic patients, people with uncontrolled blood pressure, decreased estimated glomerular filtration rate and those aged ≥70 years. CONCLUSION: BMI was significantly associated with IS and was an independent risk of IS in Chinese elderly hypertensive patients.

Association between pulse pressure and ischaemic stroke in elderly patients with hypertension.

BACKGROUND: The association between pulse pressure (PP) and the risk of first ischaemic stroke (IS) is inconsistent. Therefore, we evaluated the association between PP and the risk of first IS among elderly hypertensive population in China. METHODS: This was a retrospective cohort study. Patients with hypertension and aged ≥60 years were recruited. Multivariate Cox regression was performed to evaluate the association between PP and the risk of IS. We further stratified the regression models into subgroups and test for interaction to assess whether the associations were modified by other covariates. RESULTS: A total of 3315 patients with hypertension (44.49% male; mean age 71.41±7.20 years) were included, and 206 cases of IS occurred with a median follow-up of 5.5 years. The results showed that per SD mm Hg increment in PP was associated with a 17% (95% CI 1.05 to 1.40, p=0.0172) increased risk of IS. Moreover, the HR of IS for the highest quartile of PP was 1.46 (95% CI 1.18 to 1.73, p=0.0011, p for trend <0.001) comparing with the lowest quartile of PP. Subgroup analysis showed that population aged ≥70 years, male, patients with smoking or drinking habit, diabetes at baseline, being overweight, with uncontrolled blood pressure or did not take antihypertensive drugs have a higher risk for IS. CONCLUSIONS: We found that PP was significantly associated with IS and was an independent risk factor for IS.

J-shaped association between serum uric acid and acute coronary syndrome in patients with essential hypertension.

BACKGROUND: The prognostic value of serum uric acid (SUA) for incident acute coronary syndrome (ACS) in hypertensive subjects is uncertain. Therefore, the present study examined the association between SUA and incident ACS in a large cohort of Chinese hypertensive adults. METHODS: This was a retrospective cohort study, which enrolled 5473 Chinese community-dwelling hypertensive patients from 1 January 2012 to 31 December 2012. Study outcomes were ACS events, and patients were followed until 31 December 2016. Cox regression analyses were conducted to determine adjusted HRs and 95% CIs for baseline SUA tertiles (low, middle and high group) and for men and women separately. RESULTS: A total of 5473 participants were included in the analysis (median follow-up was 4.5 years). Participants were divided into tertiles based on SUA levels. During follow-up, 9 (0.49%), 14 (0.77%) and 25 (1.37%) patients developed ACS in the lowest, middle and highest tertiles, respectively. When compared with the lowest tertile of SUA, the highest tertile of SUA was associated with ACS risk in all subjects and in men and women separately (HR: 2.62, 95% CI 1.14 to 7.01, p=0.0233; 2.15, 95% CI 1.08 to 6.04, p=0.021, and 3.49, 95% CI 1.25 to 7.74, p=0.017, respectively). CONCLUSIONS: Higher SUA levels were independently associated with an elevated risk of ACS incidence. The relationship between SUA levels and ACS in hypertensive patients was J-shaped.

Relationship between triglyceride levels and ischaemic stroke in elderly hypertensive patients.

BACKGROUND: Although hyperlipidaemia was a well-known risk factor for ischaemic stroke, the association between triglyceride and first ischaemic stroke remains uncertain. OBJECTIVES: The present study attempted to explore the relationship between triglyceride and first ischaemic stroke in a Chinese community elderly patients with hypertension. METHODS AND RESULTS: This was a retrospective cohort study. We enrolled 3249 consecutive elderly patients with hypertension from a community in China between January 2010 and December 2011. Patients were divided into four groups based on the quartiles of triglyceride. Multivariate Cox regression analysis, subgroup and interaction test were performed to evaluate the relationship between triglyceride and first ischaemic stroke. There were a total of 3249 participants including 1455 male and 1794 female, with a mean age of 71.36±7.18 years. At an average follow-up of 5.5 years, 205 patients were identified to have first ischaemic stroke. After adjustment for potential confounders, using the lowest quartiles of triglyceride as the reference, multivariable HR (95% CI) for first ischaemic stroke increased in parallel with the quartiles of triglyceride (HRs were 1.56 (95% CI 1.07 to 2.51), 1.74 (95% CI 1.07 to 2.84) and 1.85 (95% CI 1.05 to 2.89)) from the second to the fourth quartiles, respectively (p=0.002 for trend). Subgroup and interaction analysis showed that there was no interactive effect on triglyceride and first ischaemic stroke. CONCLUSION: Triglyceride was an independent risk factor for first ischaemic stroke among Chinese elderly patients with hypertension.

Relationship between diastolic blood pressure and the first ischaemic stroke in elderly patients with hypertension.

BACKGROUND: It is uncertain how diastolic blood pressure (DBP) may associate with ischaemic stroke in elder patients with hypertension. We aimed to explore this relationship in a Chinese community. METHODS: A total of 3315 participants aged ≥60 years with essential hypertension were enrolled between January 2010 and December 2011, and being followed up until 31 December 2016. DBP levels were categorised into five groups (<60, 60-70, 70-80, 80-90 and ≥90 mm Hg), using 70-80 mm Hg as referent. We performed Cox regression analysis and subgroup analyses to evaluate the relationship between DBP and the incidence of ischaemic stroke. RESULTS: Among the 3315 participants, 44.49% were men and they were 71.4 years old on average. During a median follow-up period of 5.5 years, there were 206 onset cases of ischaemic stroke. The HRs for the first ischaemic stroke in the fully adjusted model were 1.32 (95% CI 0.73 to 2.40) for DBP <70 mm Hg, 1.50 (95% CI 1.13 to 2.73) for DBP between 80 and 89.9 mm Hg and 2.31 (95% CI 1.14 to 4.68) for DBP ≥90 mm Hg compared with DBP between 70 and 79.9 mm Hg (p=0.020 for trend). Subgroup and interaction analysis showed no significant findings. CONCLUSIONS: DBP had a non-linear association with the risk of ischaemic stroke among Chinese elderly patients with hypertension. DBP between 70 and 80 mm Hg may be an appropriate indicator for a lower stroke risk.

U-shaped association between low-density lipid cholesterol and diabetes mellitus in patients with hypertension.

BACKGROUND: The magnitude and direction of association of low-density lipid cholesterol (LDL-C) with diabetes mellitus (DM) might differ by hypertensive status, but there is limited epidemiological evidence in China. METHODS: We examined the association between LDL-C levels and DM in 9892 participants with hypertension using logistic regression. Participants were stratified into three groups according to LDL-C levels (desirable, borderline high or high), then further divided into quartiles. Restricted cubic spline regression models, subgroup analysis and interaction tests were also conducted to evaluate the shape of association. RESULTS: After adjusting for covariates, lower LDL-C had a significant and inverse association with the likelihood of DM in all participants (OR: 0.944, 95% CI = 0.893, 0.998). In participants with desirable LDL-C concentrations (< 3.4 mmol/L), LDL-C protected against DM (OR = 1.240, 95% CI = 1.076, 1.429 per 1 mmol/L decrease). In participants with higher LDL-C concentrations (> 4.1 mmol/L), LDL-C increased the DM likelihood (OR = 1.536, 95% CI = 1.126, 2.096 per 1 mmol/L increase). Restricted cubic spline regression also found a U-shaped association between LDL-C levels and DM prevalence. CONCLUSIONS: There was a U-shaped association between LDL-C levels and DM in Chinese patients with hypertension.

Lead-associated mortality in the US 1999-2020: a time-stratified analysis of a national cohort.

OBJECTIVES: We undertook time-stratified analyses of the National Health and Nutrition Examination Survey in the US to assess time trends (1999-2020) in the associations of blood lead (BL) with blood pressure, mortality, the BL-associated population attributable fraction (PAF). METHODS: Vital status of participants, 20-79 years old at enrolment, was ascertained via the National Death Index. Regressions, mediation analyses and PAF were multivariable adjusted and standardized to 2020 US Census data. RESULTS: In time-stratified analyses, BL decreased from 1.76 µg/dl in 1999-2004 to 0.93 µg/dl in 2017-2020, while the proportion of individuals with BL < 1 µg/dl increased from 19.2% to 63.0%. Total mortality was unrelated to BL (hazard ratio (HR) for a fourfold BL increment: 1.05 [95% confidence interval, CI: 0.93-1.17]). The HR for cardiovascular death was 1.44 (1.01-2.07) in the 1999-2000 cycle, but lost significance thereafter. BL was directly related to cardiovascular mortality, whereas the indirect BL pathway via BP was not significant. Low socioeconomic status (SES) was directly related to BL and cardiovascular mortality, but the indirect SES pathway via BL lost significance in 2007-2010. From 1999-2004 to 2017-2020, cardiovascular PAF decreased ( P  < 0.001) from 7.80% (0.17-14.4%) to 2.50% (0.05-4.68%) and number of lead-attributable cardiovascular deaths from 53 878 (1167-99 253) to 7539 (160-14 108). CONCLUSION: Due to implementation of strict environmental policies, lead exposure is no longer associated with total mortality, and the mildly increased cardiovascular mortality is not associated with blood lead via blood pressure in the United States.

OSTEO18, a novel urinary proteomic signature, associated with osteoporosis in heart transplant recipients.

Background: Immunosuppressive treatment in heart transplant (HTx) recipient causes osteoporosis. The urinary proteomic profile (UPP) includes peptide fragments derived from the bone extracellular matrix. Study aims were to develop and validate a multidimensional UPP biomarker for osteoporosis in HTx patients from single sequenced urinary peptides identifying the parent proteins. Methods: A single-center HTx cohort was analyzed. Urine samples were measured by capillary electrophoresis coupled with mass spectrometry. Cases with osteoporosis and matching controls were randomly selected from all available 389 patients. In derivation case-control dataset, 1576 sequenced peptides detectable in ≥30 % of patients. Applying statistical analysis on these, an 18-peptide multidimensional osteoporosis UPP biomarker (OSTEO18) was generated by support vector modeling. The 2 replication datasets included 118 and 94 patients. For further validation, the whole cohort was analyzed. Statistical methods included logistic regression and receiver operating characteristic curve (ROC) analysis. Results: In derivation dataset, the AUC, sensitivity and specificity of OSTEO18 were 0.83 (95 % CI: 0.76-0.90), 74.3 % and 87.1 %, respectively. In replication datasets, results were confirmatory. In the whole cohort (154 osteoporotic patients [39.6 %]), the ORs for osteoporosis increased (p < 0.0001) across OSTEO18 quartiles from 0.39 (95 % CI: 0.25-0.61) to 3.14 (2.08-4.75). With full adjustment for known osteoporosis risk factors, OSTEO18 improved AUC from 0.708 to 0.786 (p = 0.0003) for OSTEO18 categorized (optimized threshold: 0.095) and to 0.784 (p = 0.0004) for OSTEO18 as continuously distributed classifier. Conclusion: OSTEO18 is a clinically meaningful novel biomarker indicative of osteoporosis in HTx recipients and is being certified as in-vitro diagnostic.

Osteoporosis in Relation to a Bone-Related Aging Biomarker Derived from the Urinary Proteomic Profile: A Population Study.

Screening for and prevention of osteoporosis and osteoporotic fractures is imperative, given the high burden on individuals and society. This study constructed and validated an aging-related biomarker derived from the urinary proteomic profile (UPP) indicative of osteoporosis (UPPost-age). In a prospective population study done in northern Belgium (1985-2019), participants were invited for a follow-up examination in 2005-2010 and participants in the 2005-2010 examination again invited in 2009-2013. Participants in both the 2005-2010 and 2009-2013 examinations (n = 519) constituted the derivation (2005-2016 data) and time-shifted validation (2009-2013 data) datasets; 187 participants with only 2005-2010 data formed the synchronous validation dataset. The UPP was assessed by capillary electrophoresis coupled with mass spectrometry. Analyses focused on 2372 sequenced urinary peptides (101 proteins) with key roles in maintaining the integrity of bone tissue. In multivariable analyses with correction for multiple testing, chronological age was associated with 99 urinary peptides (16 proteins). Peptides derived from IGF2 and MGP were upregulated in women compared to men, whereas COL1A2, COL3A1, COL5A2, COL10A1 and COL18A1 were downregulated. Via application of a 1000-fold bootstrapped elastic regression procedure, finally, 29 peptides (10 proteins) constituted the UPPost-age biomarker, replicated across datasets. In cross-sectional analyses of 2009-2013 data (n = 706), the body-height-to-arm-span ratio, an osteoporosis marker, was negatively associated with UPPost-age (p&;lt0.0001). Over 4.89 years (median), the 10-year risk of osteoporosis associated with chronological age and UPPost-age (53 cases including 37 fractures in 706 individuals) increased by 21% and 36% (p ≤ 0.044). Among 357 women, the corresponding estimates were 55% and 60% for incident osteoporosis (37 cases; p ≤ 0.0003) and 42% and 44% for osteoporotic fractures (25 cases; p ≤ 0.017). In conclusion, an aging-related UPP signature with focus on peptide fragments derived from bone-related proteins is associated with osteoporosis risk and available for clinical and trial research.

Mortality and Cardiovascular End Points In Relation to the Aortic Pulse Wave Components: An Individual-Participant Meta-Analysis.

BACKGROUND: Wave separation analysis enables individualized evaluation of the aortic pulse wave components. Previous studies focused on the pressure height with overall positive but differing results. In the present analysis, we assessed the associations of the pressure of forward and backward (Pfor and Pref) pulse waves with prospective cardiovascular end points, with extended analysis for time to pressure peak (Tfor and Tref). METHODS: Participants in 3 IDCARS (International Database of Central Arterial Properties for Risk Stratification) cohorts (Argentina, Belgium, and Finland) aged ≥20 years with valid pulse wave analysis and follow-up data were included. Pulse wave analysis was done using the SphygmoCor device, and pulse wave separation was done using the triangular method. The primary end points consisted of cardiovascular mortality and nonfatal cardiovascular and cerebrovascular events. Multivariable-adjusted Cox regression was used to calculate hazard ratios. RESULTS: A total of 2206 participants (mean age, 57.0 years; 55.0% women) were analyzed. Mean±SDs for Pfor, Pref, Tfor, and Tfor/Tref were 31.0±9.1 mm Hg, 20.8±8.4 mm Hg, 130.8±35.5, and 0.51±0.11, respectively. Over a median follow-up of 4.4 years, 146 (6.6%) participants experienced a primary end point. Every 1 SD increment in Pfor, Tfor, and Tfor/Tref was associated with 27% (95% CI, 1.07-1.49), 25% (95% CI, 1.07-1.45), and 32% (95% CI, 1.12-1.56) higher risk, respectively. Adding Tfor and Tfor/Tref to existing risk models improved model prediction (∆Uno's C, 0.020; P<0.01). CONCLUSIONS: Pulse wave components were predictive of composite cardiovascular end points, with Tfor/Tref showing significant improvement in risk prediction. Pending further confirmation, the ratio of time to forward and backward pressure peak may be useful to evaluate increased afterload and signify increased cardiovascular risk.

Urinary proteomic signature of mineralocorticoid receptor antagonism by spironolactone: evidence from the HOMAGE trial.

OBJECTIVE: Heart failure (HF) is characterised by collagen deposition. Urinary proteomic profiling (UPP) followed by peptide sequencing identifies parental proteins, for over 70% derived from collagens. This study aimed to refine understanding of the antifibrotic action of spironolactone. METHODS: In this substudy (n=290) to the Heart 'Omics' in Ageing Study trial, patients were randomised to usual therapy combined or not with spironolactone 25-50 mg/day and followed for 9 months. The analysis included 1498 sequenced urinary peptides detectable in ≥30% of patients and carboxyterminal propeptide of procollagen I (PICP) and PICP/carboxyterminal telopeptide of collagen I (CITP) as serum biomarkers of COL1A1 synthesis. After rank normalisation of biomarker distributions, between-group differences in their changes were assessed by multivariable-adjusted mixed model analysis of variance. Correlations between the changes in urinary peptides and in serum PICP and PICP/CITP were compared between groups using Fisher's Z transform. RESULTS: Multivariable-adjusted between-group differences in the urinary peptides with error 1 rate correction were limited to 27 collagen fragments, of which 16 were upregulated (7 COL1A1 fragments) on spironolactone and 11 downregulated (4 COL1A1 fragments). Over 9 months of follow-up, spironolactone decreased serum PICP from 81 (IQR 66-95) to 75 (61-90) µg/L and PICP/CITP from 22 (17-28) to 18 (13-26), whereas no changes occurred in the control group, resulting in a difference (spironolactone minus control) expressed in standardised units of -0.321 (95% CI 0.0007). Spironolactone did not affect the correlations between changes in urinary COL1A1 fragments and in PICP or the PICP/CITP ratio. CONCLUSIONS: Spironolactone decreased serum markers of collagen synthesis and predominantly downregulated urinary collagen-derived peptides, but upregulated others. The interpretation of these opposite UPP trends might be due to shrinking the body-wide pool of collagens, explaining downregulation, while some degree of collagen synthesis must be maintained to sustain vital organ functions, explaining upregulation. Combining urinary and serum fibrosis markers opens new avenues for the understanding of the action of antifibrotic drugs. TRIAL REGISTRATION NUMBER: NCT02556450.

Heart rate reactivity, recovery, and endurance of the incremental shuttle walk test in patients prone to heart failure.

AIMS: Few randomized trials assessed the changes over time in the chronotropic heart rate (HR) reactivity (CHR), HR recovery (HRR) and exercise endurance (EE) in response to the incremental shuttle walk test (ISWT). We addressed this issue by analysing the open HOMAGE (Heart OMics in Aging) trial. METHODS: In HOMAGE, 527 patients prone to heart failure were randomized to usual treatment with or without spironolactone (25-50 mg/day). The current sub-study included 113 controls and 114 patients assigned spironolactone (~70% on beta-blockers), who all completed the ISWT at baseline and at Months 1 and 9. Within-group changes over time (follow-up minus baseline) and between-group differences at each time point (spironolactone minus control) were analysed by repeated measures ANOVA, unadjusted or adjusted for sex, age and body mass index, and additionally for baseline for testing 1 and 9 month data. RESULTS: Irrespective of randomization, the resting HR and CHR did not change from baseline to follow-up, with the exception of a small decrease in the HR immediately post-exercise (-3.11 b.p.m.) in controls at Month 9. In within-group analyses, HR decline over the 5 min post-exercise followed a slightly lower course at the 1 month visit in controls and at the 9 month visits in both groups, but not at the 1 month visit in the spironolactone group. Compared with baseline, EE increased by two to three shuttles at Months 1 and 9 in the spironolactone group but remained unchanged in the control group. In the between-group analyses, irrespective of adjustment, there were no HR differences at any time point from rest up to 5 min post-exercise or in EE. Subgroup analyses by sex or categorized by the medians of age, left ventricular ejection fraction or glomerular filtration rate were confirmatory. Combining baseline and Months 1 and 9 data in both treatment groups, the resting HR, CHR and HRR at 1 and 5 min averaged 61.5, 20.0, 9.07 and 13.8 b.p.m. and EE 48.3 shuttles. CONCLUSIONS: Spironolactone on top of usual treatment compared with usual treatment alone did not change resting HR, CHR, HRR and EE in response to ISWT. Beta-blockade might have concealed the effects of spironolactone. The current findings demonstrate that the ISWT, already used in a wide variety of pathological conditions, is a practical instrument to measure symptom-limited exercise capacity in patients prone to developing heart failure because of coronary heart disease.

An outcome-driven threshold for pulse pressure amplification.

Pulse pressure amplification (PPA) is the brachial-to-aortic pulse pressure ratio and decreases with age and cardiovascular risk factors. This individual-participant meta-analysis of population studies aimed to define an outcome-driven threshold for PPA. Incidence rates and standardized multivariable-adjusted hazard ratios (HRs) of cardiovascular and coronary endpoints associated with PPA, as assessed by the SphygmoCor software, were evaluated in the International Database of Central Arterial Properties for Risk Stratification (n = 5608). Model refinement was assessed by the integrated discrimination (IDI) and net reclassification (NRI) improvement. Age ranged from 30 to 96 years (median 53.6). Over 4.1 years (median), 255 and 109 participants experienced a cardiovascular or coronary endpoint. In a randomly defined discovery subset of 3945 individuals, the rounded risk-carrying PPA thresholds converged at 1.3. The HRs for cardiovascular and coronary endpoints contrasting PPA < 1.3 vs ≥1.3 were 1.54 (95% confidence interval [CI]: 1.00-2.36) and 2.45 (CI: 1.20-5.01), respectively. Models were well calibrated, findings were replicated in the remaining 1663 individuals analyzed as test dataset, and NRI was significant for both endpoints. The HRs associating cardiovascular and coronary endpoints per PPA threshold in individuals <60 vs ≥60 years were 3.86 vs 1.19 and 6.21 vs 1.77, respectively. The proportion of high-risk women (PPA < 1.3) was higher at younger age (<60 vs ≥60 years: 67.7% vs 61.5%; P < 0.001). In conclusion, over and beyond common risk factors, a brachial-to-central PP ratio of <1.3 is a forerunner of cardiovascular coronary complications and is an underestimated risk factor in women aged 30-60 years. Our study supports pulse wave analysis for risk stratification.

Blood pressure and hypertension in relation to lead exposure updated according to present-day blood lead levels.

Lead is an environmental hazard that should be addressed worldwide. Over time, human exposure to lead in the Western world has fallen drastically to the levels comparable to those in humans living in the pre-industrial era, who were mainly exposed to natural sources of lead. To re-evaluate the health risks possibly associated with present-day lead exposure, a three-pronged approach was applied. First, we critically assessed the recently published population metrics describing the adverse health effects associated with lead exposure at the population level. Next, we summarized the key results of the Study for Promotion of Health in Recycling Lead (SPHERL; NCT02243904) and analyzed these results in the context of the published population metrics. Last but not least, we performed a brief literature review on the present-day lead exposure level in Poland. To our best knowledge, SPHERL is the first prospective study that accounted for interindividual variation in vulnerability to the toxic effects of lead exposure by assessing the participants' health status before and after occupational lead exposure, with blood pressure and hypertension as the primary outcomes. The overall conclusion of this comprehensive review on blood pressure and hypertension is that mainstream ideas about the public and occupational health risks related to lead exposure need to be urgently updated because a large part of the available literature has become obsolete given present-day exposure levels that sharply declined over the past 40 years.

Blood pressure and renal function responses in workers exposed to lead for up to six years.

The Study for Promotion of Health in Recycling Lead (SPHERL) assessed the blood pressure (BP) and renal function (RF) responses for up to 6 years in the workers without previous occupational lead exposure. BP was the average of five consecutive readings and the estimated glomerular filtration rate was derived from serum creatinine (eGFRcrt) and cystatin C (eGFRcys). Blood lead (BL) was measured by inductively coupled plasma mass spectrometry (detection limit 0.5 µg/dL). The statistical methods included multivariable-adjusted mixed models and interval-censored Cox regression analysis. The 234 workers analyzed were on average 28.5 years old and included 91.9% men. The baseline BL concentration was 4.35 µg/dL and increased 3.17-fold over follow-up (median: 2.03 years; range: 0.92-6.45 years). The changes in BP and RF were not significantly correlated with the follow-up-to-baseline BL ratio (p ≥ .51 and p ≥ .18, respectively). The fully-adjusted changes in systolic/diastolic BP associated with a doubling of BL were -0.25/-0.12 mm Hg (CI: -0.94 to 0.44/-0.66 to 0.42 mm Hg). Accordingly, the incidence of stage-1 or -2 hypertension was not associated with the BL change (p ≥ .063). Similarly, the changes in eGFRcrt and eGFRcys associated with a 3-fold BL increment were not significant, amounting to -0.70 mL/min/1.73 m2 (CI: -1.70 to 0.30 mL/min/1.73 m2 ) and -1.06 mL/min/1.73 m2 (-2.16 to 0.03 mL/min/1.73 m2 ). In conclusion, the BP and RF responses to an over 3-fold BL increment were small and not significant confirming the safety of modern lead-handing facilities operating under current safety rules.