Elucidation of a Causal Relationship Between Platelet Count and Hypertension: A Bi-Directional Mendelian Randomization Study

Gender differences in the relationship between the systemic immune-inflammation index and all-cause and cardiovascular mortality among adults with hypertension: evidence from NHANES 1999-2018

Background

There are gender differences in hypertension and the effect of gender on the relationship between systemic immune-inflammation index (SII) and mortality in hypertensive patients is unclear.

Methods

Hypertensive patients (n=7444) from ten cycles of the National Health and Nutrition Examination Survey (NHANES) spanning 1999 to 2018 were enrolled in this study. The maximally selected rank statistics method was employed to identify the optimal cut-off value for the SII. Survey-weighted Cox regression analysis was utilized to explore the links between SII and all-cause and cardiovascular mortality. Kaplan-Meier method and time-dependent receiver operating characteristic curve analysis was conducted to assess the predictive accuracy of SII for mortality.

Results

Whether SII was considered as a numerical variable or as a binary variable (higher- and lower-SII groups), higher SII levels were associated with a higher risk of all-cause and cardiovascular mortality in female hypertensive patients (all P < 0.001), but no such association was observed in the males. The area under the curve of the SII was 0.602, 0.595, and 0.569 for 3-, 5-, and 10-year all-cause mortality, respectively, in females, but was 0.572, 0.548, and 0.554 in males. High SII levels interacted with the poverty income ratio and physical activity to affect mortality in the male population (P for interaction < 0.05), and there was an interaction between race and SII in the female cardiovascular mortality rate (P for interaction < 0.05).

Conclusion

Higher levels of SII may be closely related to the high risk of all-cause and cardiovascular mortality in hypertensive patients, and the results showed that this relationship is more significant and stable in the female group. High SII interacts with PIR, physical activity, and race to affect the mortality rate in different gender populations.

Systemic inflammation markers and the prevalence of hypertension in 8- to 17-year-old children and adolescents: A NHANES cross-sectional study

BACKGROUND AND AIMS

The recent emphasis on systemic inflammation markers has focused primarily on their association with cardiac disorders, particularly the prevalence of hypertension, in adults but not children and adolescents. This research aimed to explore the associations between systemic inflammation markers and the occurrence of hypertension in 8- to 17-year-old children and adolescents in the United States.

METHODS AND RESULTS

Data from 6095 participants under 18 years of age were obtained from the National Health and Nutritional Examination Survey (NHANES: 1999-2020). This study examined the associations between the incidence of hypertension and four indicators of systemic inflammation: the systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR). Multivariate logistic regression analysis results are represented as odds ratios (ORs) and 95 % confidence intervals (CIs), and subgroup analyses were conducted to further explore associations. After fully adjusting for potential confounding covariates, the SII, NLR, and PLR were positively associated with hypertension. Compared with individuals in the bottom quartiles, those in the top SII, NLR, and PLR quartiles were 2.12, 2.11, and 1.57 times more likely to have hypertension, respectively. Conversely, the LMR was negatively associated with hypertension incidence, particularly among those in the highest LMR quartiles (OR = 0.59, 95 % CI = 0.39-0.88; P = 0.009). Subgroup analyses revealed that the four indicators exhibited strong correlations with hypertension in male subjects.

CONCLUSION

This study revealed significant relationships between systemic inflammatory markers and hypertension incidence, highlighting the potential of these markers as hypertension risk indicators, particularly among male patients.

Association of complete blood count parameters with the risk of incident pulmonary heart disease in pneumoconiosis: a retrospective cohort study

BACKGROUND

Pneumoconiosis mostly combines pulmonary and cardiovascular diseases, among which pulmonary heart disease (PHD) is of major concern due to its significant impact on the survival of pneumoconiosis patients. White cell count (WCC), red cell distribution width (RDW) and platelet parameters are thought to affect inflammatory responses and may be predictors of various cardiovascular diseases. However, very few studies have focused on PHD.

OBJECTIVES

To examine the relationship between baseline complete blood count parameters (WCC, RDW, platelet parameters) and the risk of incident PHD in pneumoconiosis patients.

DESIGN

A retrospective cohort study.

SETTING

This was a single-centre, retrospective cohort study that used data from an Occupational Disease Hospital, Chengdu, Sichuan.

PARTICIPANTS

A total of 946 pneumoconiosis patients from January 2012 to November 2021 were included in the study. Female patients and patients who had PHD, coronary heart disease, hypertensive heart disease, cardiomyopathy, heart failure, oncological disease, multiple organ dysfunction, AIDS at baseline and follow-up time of less than 6 months were also excluded.

OUTCOME MEASURES

We identified PHD according to the patient's discharge diagnosis. We constructed Cox proportional hazard regression models to assess the HR of incident PHD in pneumoconiosis, as well as 95% CIs.

RESULTS

In the multiple Cox proportional hazard regression analysis, platelet count (PLT) and plateletcrit (PCT) above the median at baseline were associated with an increased risk of PHD in pneumoconiosis with adjusted HR of 1.52 (95% CI 1.09 to 2.12) and 1.42 (95% CI 1.02 to 1.99), respectively.

CONCLUSION

Higher baseline PLT and PCT are associated with a higher risk of PHD in pneumoconiosis.

The association of the platelet/high-density lipoprotein cholesterol ratio with self-reported stroke and cardiovascular mortality: a population-based observational study

BACKGROUND

Previous studies have shown that the relationship between high-density lipoprotein cholesterol (HDL-C) and stroke is controversial, and the association between the platelet/high-density lipoprotein cholesterol ratio (PHR), a novel marker for inflammation and hypercoagulability states, and stroke has not been established.

METHODS

This study presents an analysis of cross-sectional data from the 2005-2018 National Health and Nutrition Examination Survey (NHANES). Stroke history, HDL-C levels, and platelet counts were obtained during cross-sectional surveys. The PHR was calculated as the ratio of the number of platelets to HDL-C concentration. Weighted logistic regression was used to assess the associations of HDL-C and the PHR with stroke. Nonlinearity of this relationship was determined through restricted cubic splines (RCSs) and two-piecewise linear regression for identifying inflection points. Furthermore, Cox regression was utilized to prospectively analyze the associations of the PHR and HDL-C concentration with cardiovascular disease (CVD) mortality in stroke survivors.

RESULTS

A total of 27,301 eligible participants were included in the study; mean age, 47.28 years and 50.57% were female, among whom 1,040 had a history of stroke. After full adjustment, the odds ratio (OR) of stroke associated with a per standard deviation (SD) increase in the PHR was estimated at 1.13 (95% confidence interval (CI): 1.03 - 1.24, P = 0.01), and the OR of stroke associated with a per SD increase in HDL-C was 0.95 (95% CI: 0.86-1.05, P = 0.30). The RCS indicated a nonlinear relationship for both variables (PPHR = 0.018 and PHDL-C = 0.003), and further piecewise linear regression identified inflection points at PHR = 223.684 and HDL-C = 1.4 mmol/L. Segmental regression indicated that in the PHR ≥ 223.684 segment, the estimated OR of stroke associated with a per-SD increase in the PHR was 1.20 (95% CI: 1.09 - 1.31, P < 0.001), while the association of stroke with HDL-C was not significant before or after the inflection point (P > 0.05). Furthermore, Cox regression and RCS showed that a per-SD increase in the PHR was linearly associated with a greater risk of CVD mortality among stroke survivors (HR: 1.14, 95% CI: 1.06 - 1.22, P < 0.001; nonlinear, P = 0.956), while HDL-C was not significantly associated with CVD mortality.

CONCLUSION

The association between the PHR and stroke incidence exhibited a significant threshold effect, with an inflection point at 223.684. A PHR exceeding 223.684 was positively associated with stroke, while the association between HDL-C and stroke was not significant. Additionally, the PHR was positively and linearly associated with CVD mortality among stroke survivors.

Systemic immune-inflammation index predicts first stroke and affects the efficacy of folic acid in stroke prevention

Background

Systemic immune-inflammation index (SII) is a novel biomarker of growing interest in predicting stroke. The aim of this study was to investigate its predictive value and explore its effect modification on folic acid supplement for stroke primary prevention in a Chinese population with hypertension.

Methods

A total of 10,013 participants from the China Stroke Primary Prevention Trial with available neutrophil, platelet and lymphocyte count were included, including 5,019 subjects in the enalapril group and 4,994 in the enalapril-folic acid group. SII was calculated as (platelet × neutrophil)/lymphocyte. The primary endpoint was first stroke. Cox proportional hazards models were used to evaluate the association between SII and first stroke.

Results

A U-shape association between SII and first stroke risk was observed in enalapril group. Compared with the reference group (Quartile 2: 335.1 to <443.9 × 109 cell/L), the adjusted HRs were 1.68 (95 % CI: 1.06-2.66, P = 0.027) in Quartile 1 (<335.1 × 109 cell/L), 1.43 (95 % CI: 0.90-2.27, P = 0.126) in Quartile 3 (443.9 to <602.6 × 109 cell/L), and 1.61 (95 % CI: 1.03-2.51, P = 0.035) in Quartile 4 (≥602.6 × 109 cell/L). There was no significant association between SII and first stroke in the enalapril-folic acid group, with adjusted HR of 0.92 (95%CI: 0.54-1.56, P = 0.749) in Quartile 1(<334.7 × 109 cell/L), 1.36 (95%CI: 0.84-2.21, P = 0.208) in Quartile 3 (446.2 to <595.2 × 109 cell/L), and 1.41 (95%CI: 0.87-2.27, P = 0.163) in Quartile 4 (≥595.2 × 109 cell/L). A remarkable interaction between baseline SII and folic acid supplement for stroke prevention was observed, with particularly reduced risk by 44 % (HR: 0.56; 95 % CI: 0.34-0.90; P = 0.018) in the lowest SII group (P for interaction = 0.041).

Conclusions

Among Chinese adults with hypertension, both low and high SII at baseline predicted increased first stroke risk. And compensatory folic acid particularly reduced first stroke risk in the lowest SII subgroup.

Association between systemic immune inflammatory/inflammatory response index and hypertension: A cohort study of functional community

BACKGROUND AND AIMS

In prospective studies, there is limited evidence of the association between inflammation and hypertension. We aimed to explore the relationship between systemic immune inflammatory index (SII)/systemic inflammatory response index (SIRI) and hypertension in a prospective cohort study to identify the best inflammatory cell markers that predict hypertension.

METHODS AND RESULTS

This study was conducted in a functional community cohort in Beijing. In 2015, a total of 6003 individuals without hypertension were recruited and followed up until 2021. Using a restriction cubic spline with baseline SII/SIRI as a continuous variable, the dose-response relationship between hypertension and SII/SIRI was explored. Logistic regression was used to analyze the correlation between hypertension and SII/SIRI trajectory groups. At a mean follow-up of 6 years, 970 participants developed hypertension. SII showed a significant nonlinear dose-response relationship with hypertension (P < 0.05). Higher SII/SIRI was associated with an increased risk of hypertension (SII: RR = 1.003, 95%CI: 1.001-1.004; SIRI: RR = 1.228, 95%CI: 1.015-1.486). Both SII and SIRI were more predictive in males than females (SII: 0.698 vs. 0.695; SIRI: 0.686 vs. 0.678).

CONCLUSION

Both systemic immune inflammatory index (SII) and systemic inflammatory response Index (SIRI) independently increased the risk of hypertension, and both were effective inflammatory cell indicators that predict the risk of hypertension.

Effects of Platelet Count on Blood Pressure: Evidence from Observational and Genetic Investigations

Platelet count has been associated with blood pressure, but whether this association reflects causality remains unclear. To strengthen the evidence, we conducted a traditional observational analysis in the Lifelines Cohort Study (n = 167,785), and performed bi-directional Mendelian randomization (MR) with summary GWAS data from the UK Biobank (n = 350,475) and the International Consortium of Blood Pressure (ICBP) (n = 299,024). Observational analyses showed positive associations between platelet count and blood pressure (OR = 1.12 per SD, 95% CI: 1.10 to 1.14 for hypertension; B = 0.07, 95% CI: 0.07 to 0.08 for SBP; B = 0.07 per SD, 95% CI: 0.06 to 0.07 for DBP). In MR, a genetically predicted higher platelet count was associated with higher SBP (B = 0.02 per SD, 95% CI = 0.00 to 0.04) and DBP (B = 0.03 per SD, 95% CI = 0.01 to 0.05). IVW models and sensitivity analyses of the association between platelet count and DBP were consistent, but not all sensitivity analyses were statistically significant for the platelet count-SBP relation. Our findings indicate that platelet count has modest but significant effects on SBP and DBP, suggesting causality and providing further insight into the pathophysiology of hypertension.

The association between long-term platelet count and disability-free survival among middle-aged and older Chinese: Evidence from the China Health and Retirement Longitudinal Study

BACKGROUND AND AIMS

We aimed to assess the associations of baseline and long-term platelet count (PLT) with disability-free survival (DFS) among middle-aged and older Chinese.

METHODS AND RESULTS

A total of 7296 participants were recruited in the analysis. Updated mean PLT was defined as the mean of the two PLT measurements (4 years between wave 1-3). The long-term status of PLT was defined as persistent low, attenuated, increased and persistent high PLT according to the optimal cut points from the receiver operating characteristic curves of the two PLT measurements, respectively. The primary outcome was DFS, evaluated by the first occurrence of either disability or mortality. During 6-year visit, 1579 participants experienced disability or all-cause mortality. The rates of primary outcome were significantly higher among participants with elevated baseline PLT and updated mean PLT. Multivariable adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of primary outcome were 1.253 (1.049-1.496) for highest baseline PLT tertile and 1.532 (1.124-2.088) for highest updated mean PLT tertile, comparing to the lowest tertiles. Multivariable-adjusted spline regression models showed a linear association of baseline PLT (p_linearity < 0.001) and updated mean PLT (p_linearity = 0.005) with primary outcome. Moreover, participants with persistent high PLT and increased PLT had increased risk of primary outcome (ORs [95% CIs]: 1.825 [1.282-2.597] and 1.767 [1.046-2.985], respectively), compared with the reference of those with persistent low PLT.

CONCLUSION

This study proved elevated baseline PLT, especially long-term persist high or increased PLT was associated with less likelihood of DFS among middle-aged and older Chinese.

Platelet indices and blood pressure: a multivariable mendelian randomization study

BACKGROUND

Platelet indices are blood-based parameters reflecting the activation of platelets. Previous studies have identified an association between platelet indices and blood pressure (BP). However, causal inferences are prone to bias by confounding effects and reverse causation. We performed a Mendelian randomization (MR) study to compare the causal roles between genetically determined platelet indices and BP levels.

METHODS

Single-nucleotide polymorphisms (SNPs) associated with platelet count (PLT), plateletcrit (PCT), mean platelet volume (MPV), platelet distribution width (PDW), and BP at the level of genome-wide significance (p < 5 × 10^- 8) in the UK Biobank were used as instrumental variables. In bidirectional univariable MR analyses, inverse variance-weighted (IVW), MR‒Egger, and weighted median methods were used to obtain estimates for individual causal power. In addition, heterogeneity and sensitivity analyses were performed to examine the pleiotropy of effect estimates. Finally, multivariable MR analyses were undertaken to disentangle the comparative effects of four platelet indices on BP.

RESULTS

In the univariable MR analyses, increased levels of PLT and PCT were associated with higher BP, and PDW was associated with higher DBP alone. In the reverse direction, SBP had a minor influence on PLT and PCT. In multivariable MR analysis, PDW and PLT revealed an independent effect, whereas the association for PCT and MPV was insignificant after colinear correction.

CONCLUSION

These findings suggest that platelets and BP may affect each other. PDW and PLT are independent platelet indices influencing BP. Increased platelet activation and aggregation may be involved in the pathogenesis of hypertension, which may provide insights into evaluating thromboembolic events in people with high BP. The necessity of initiating antiplatelet therapy among hypertension groups needs further investigation.

Components of the Complete Blood Count as a Risk Predictor for Incident Hypertension in a Large Taiwanese Population Follow-up Study

BACKGROUND

Previous studies investigating the relationship between hypertension (HT) and hematological parameters report inconsistent results, and most them included a small number of participants or only conducted a cross-sectional analysis of 1 or 2 hematological factors. Moreover, no large cohort follow-up studies have investigated this topic. The aim of this longitudinal study was to explore associations between components of the complete blood count (CBC) and incident HT using data from a large Taiwanese biobank.

METHODS AND RESULTS

Hematological parameters including white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin, hematocrit (HCT), and platelet count were evaluated. We included 21,293 participants who did not have HT at baseline and followed them for a mean period of 3.9 years. During follow-up, 3,002 participants with new-onset HT (defined as incident HT) were identified. Univariable analysis revealed that high WBC count, high RBC count, high hemoglobin, high HCT, and low platelet count were associated with incident HT. Multivariable analysis after adjusting potential confounding factors found high WBC count (odds ratio [OR], 1.057; 95% confidence interval [CI], 1.028 to 1.087; P<0.001) and high HCT (OR, 1.023; 95% CI, 1.010 to 1.036; P<0.001) were still significantly associated with incident HT.

CONCLUSIONS

High WBC count and high HCT were associated with incident HT.

Systemic inflammation markers and the prevalence of hypertension: A NHANES cross-sectional study

Systemic inflammation markers have been highlighted recently as related to cardiac and non-cardiac disorders. However, few studies have estimated pre-diagnostic associations between these markers and hypertension. In the National Health and Nutritional Examination Survey from 1999 to 2010, 22,290 adult participants were included for analysis. We assessed associations between four systemic inflammation markers based on blood cell counts: systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and hypertension prevalence in multivariate logistic regression analysis with odds ratio (OR) and 95% confidence interval (CI). To further explore their associations, subgroup and sensitivity analyses were performed. In continuous analyses, the ORs for hypertension prevalence per ln-transformed increment in SII and NLR were estimated at 1.115 and 1.087 (95% CI: 1.045-1.188; 1.008-1.173; respectively). Compared to those in the lowest tertiles, the hypertension risks for subjects in the highest SII and NLR tertiles were 1.20 and 1.11 times, respectively. Conversely, we found that PLR and LMR were negatively associated with hypertension prevalence in continuous analyses (1.060, 0.972-1.157; 0.926, 0.845-1.014; respectively), and the highest PLR and LMR tertiles (1.041, 0.959-1.129; 0.943, 0.866-1.028; respectively). Also, subgroup and sensitivity analyses indicated that SII had a greater correlation to hypertension. In conclusion, we find positive associations between SII and NLR and the prevalence of hypertension in this cross-sectional study. Our findings highlight that SII may be a superior systemic inflammation warning marker for hypertension.

Association of systemic immune inflammatory index with all-cause and cause-specific mortality in hypertensive individuals: Results from NHANES

Background

The relationship between the systemic immune inflammatory index (SII) and the prognosis of hypertensive patients is unclear. This study aims to explore the association of SII with all-cause and cause-specific mortality in patients with hypertension.

Methods

This study included 8524 adults with hypertension from the National Health and Nutritional Examination Surveys (NHANES) 2011-2018, and followed for survival through December 31, 2019. Cox proportional hazards models were used to investigate the associations between SII and mortality from all causes, cardiovascular disease (CVD), and cancer. Restricted cubic spline, piecewise linear regression, subgroup and sensitivity analyses were also used.

Results

During a median follow-up of 4.58 years, 872 all-cause deaths occurred. After adjusting for covariates, higher SII was significantly associated with an elevated risk of CVD mortality. There was a 102% increased risk of CVD mortality per one-unit increment in natural log-transformed SII (lnSII) (P < 0.001). Consistent results were also observed when SII was examined as categorical variable (quartiles). The associations of SII with all-cause and cancer mortality were detected as U-shaped with threshold values of 5.97 and 6.18 for lnSII respectively. Below thresholds, higher SII was significantly associated with lower all-cause mortality (HR=0.79, 95%CI=0.64-0.97) and cancer mortality (HR=0.73, 95%CI=0.53-1.00). Above thresholds, SII was significantly positive associated with all-cause mortality (HR=1.93, 95%CI=1.55-2.40) and cancer mortality (HR=1.93, 95%CI=1.22-3.05). The results were robust in subgroup and sensitivity analyses.

Conclusion

Higher SII (either as a continuous or categorical variable) were significantly associated with a higher risk of CVD mortality. The U-shaped associations were observed between SII and all-cause and cancer mortality.