Change in the Estimated Glomerular Filtration Rate Over Time and Risk of First Stroke in Hypertensive Patients

BACKGROUND

The association between changes in estimated glomerular filtration rate (eGFR) over time and the risk of stroke remains inconclusive. We aimed to evaluate the relation of eGFR change during the China Stroke Primary Prevention Trial (CSPPT) with the risk of first stroke during the subsequent post-trial follow-up.

METHODS

A total of 11,742 hypertensive participants with two eGFR measurements (median measure interval, 4.4; interquartile range, 4.2-4.6 years) and without a history of stroke from the CSPPT were included in this analysis.

RESULTS

Over a median post-trial follow-up of 4.4 years, 729 first strokes were identified, of which 635 were ischemic, 88 were hemorrhagic, and 6 were uncertain types of strokes. Compared with those with 1 to <2% per year increase in eGFR (with the lowest stroke risk), those with an increase in eGFR of ≥4% per year had significantly increased risks of first stroke (adjusted hazard ratio [HR] 1.96; 95% confidence interval [CI], 1.10-3.50) and first ischemic stroke (adjusted HR 2.14; 95% CI, 1.17-3.90). Similarly, those with a decline in eGFR of ≥5% per year also had significantly increased first stroke (adjusted HR 2.13; 95% CI, 1.37-3.31) and first ischemic stroke (adjusted HR 1.89; 95% CI, 1.19-3.02) risk. However, there was no significant association between eGFR change and first hemorrhagic stroke. A similar result was found when the change in eGFR was quantified as an absolute annual change.

CONCLUSION

In Chinese hypertensive patients, both the decline and increase of eGFR levels were independently associated with the risks of first stroke or first ischemic stroke.

Positive Association Between Serum Alkaline Phosphatase and First Stroke in Hypertensive Adults

The relation of alkaline phosphatase (ALP) with stroke risk remains uncertain. We aimed to examine the association between serum ALP and the risk of first stroke, and explore the possible effect modifiers in the association, among adults with hypertension. A total of 19,747 participants with baseline ALP measurements and without liver disease at baseline from the China Stroke Primary Prevention Trial (CSPPT) were included. The primary outcome was a first stroke. Over a median follow-up of 4.5 years, there was a positive association between serum ALP levels and the risk of first stroke (per SD increment, adjusted HR, 1.10; 95%CI: 1.01, 1.20). When serum ALP was evaluated as quartiles, a significantly higher risk of first stroke was observed in those in quartile 2–4 (ALP ≥79 IU/L; adjusted HR, 1.38; 95% CI: 1.11, 1.71), compared with participants in quartile 1 (ALP <79 IU/L). Similar results were found for first ischemic or hemorrhagic stroke. Similar findings were also found in those with a normal range of baseline ALP levels (20–140 IU/L) (per SD increment, adjusted HR, 1.15; 95%CI: 1.05, 1.27). None of the variables, including sex, age, body mass index, smoking, alcohol drinking, blood pressure, total cholesterol, fasting glucose levels at baseline, and blood pressure levels during the treatment period, significantly modified the association. In summary, our study suggests that higher serum ALP levels, even in normal range, were significantly related to higher risk of first stroke among Chinese hypertensive adults.

Plasma Vitamin E and the Risk of First Stroke in Hypertensive Patients: A Nested Case-Control Study

Background: The association between plasma vitamin E levels and first stroke risk in men and women remains unclear. Objective: We aimed to examine the prospective association between plasma vitamin E and first stroke, and evaluate the effect modifiers for the association, among hypertensive patients. Design: The study sample was drawn from the China Stroke Primary Prevention Trial (CSPPT), which randomized a total of 20,702 hypertensive patients to a double-blind, daily treatment with either 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. This nested case-control study, including 618 first stroke cases and 618 controls matched for age, sex, treatment group, and study site, was conducted after the completion of the CSPPT. Results: The median follow-up duration was 4.5 years. Among men, a significantly higher risk of first stroke (adjusted OR, 1.67; 95%CI: 1.01, 2.77) was found for those with plasma vitamin E ≥7.1 μg/mL (≥quartile 1) compared with those with plasma vitamin E < 7.1 μg/mL. Subgroup analyses further showed that the association between vitamin E (≥7.1 vs. <7.1 μg/mL) and first stroke in men was significantly stronger in non-drinkers (adjusted OR, 2.64; 95%CI: 1.41, 4.96), compared to current drinkers (adjusted OR, 0.84; 95% CI: 0.43, 1.66, P-interaction = 0.008). However, there was no significant association between plasma vitamin E and first stroke in women (P-interaction between sex and plasma vitamin E = 0.048). Conclusions: Among Chinese hypertensive patients, there was a statistically significant positive association between baseline plasma vitamin E and the risk of first stroke in men, but not in women. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT00794885, Identifier: NCT00794885.

Baseline Serum Bilirubin and Risk of First Stroke in Hypertensive Patients

Background

Data on the association between serum bilirubin and the risk of stroke are limited and inconclusive. We aimed to evaluate the association between serum bilirubin and the risk of first stroke and to examine any possible effect modifiers in hypertensive patients.

Methods and Results

Our study was a post hoc analysis of the CSPPT (China Stroke Primary Prevention Trial). A total of 19 906 hypertensive patients were included in the final analysis. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% CIs for the risk of first stroke associated with serum bilirubin levels. The median follow‐up period was 4.5 years. When serum total bilirubin was assessed as tertiles, the adjusted HR of first ischemic stroke for participants in tertile 3 (12.9–34.1 μmol/L) was 0.75 (95% CI, 0.59–0.96), compared with participants in tertile 1 (<9.3 μmol/L). When direct bilirubin was assessed as tertiles, a significantly lower risk of first ischemic stroke was also found in participants in tertile 3 (2.5–24.8 μmol/L) (adjusted HR, 0.77; 95% CI, 0.60–0.98), compared with those in tertile 1 (<1.6 μmol/L). However, there was no significant association between serum total bilirubin (tertile 3 versus 1: adjusted HR, 1.45; 95% CI, 0.89–2.35) or direct bilirubin (tertile 3 versus 1: adjusted HR, 1.27; 95% CI, 0.76–2.11) and first hemorrhagic stroke.

Conclusions

In this sample of Chinese hypertensive patients, there was a significant inverse association between serum total bilirubin or direct bilirubin and the risk of first ischemic stroke.

Plasma copper and the risk of first stroke in hypertensive patients: a nested case-control study

BACKGROUND

Previous studies indicated that trace elements may play an important role in cardiovascular diseases. However, data concerning the association between blood copper and the risk of stroke are limited.

OBJECTIVE

The aim of this study was to evaluate the association between plasma copper and the risk of first stroke, and examine any possible effect modifiers in hypertensive patients.

METHODS

We conducted a nested case-control study, using data from the China Stroke Primary Prevention Trial. Hypertension is defined as systolic blood pressure ≥ 140 mm Hg or diastolic blood pressure ≥ 90 mm Hg, or taking antihypertensive medication. A total of 618 first stroke cases and 618 controls matched for age, sex, treatment group, and study site were included in this study. The crude and adjusted risks of first stroke were estimated by ORs and 95% CIs using conditional logistic regression, without or with adjusting for pertinent covariates, respectively.

RESULTS

There were significant positive associations of plasma copper with risk of first stroke (per SD increment-OR: 1.20; 95% CI: 1.03, 1.39) and first ischemic stroke (OR: 1.26; 95% CI: 1.07, 1.50). When plasma copper was categorized in quartiles, significantly higher risks of first stroke (OR: 1.72; 95% CI: 1.12, 2.65) and first ischemic stroke (OR: 1.91; 95% CI: 1.18, 3.11) were found in participants in quartile 4 (≥ 117.0 μg/dL) than in those in quartile 1 (< 91.2 μg/dL). Furthermore, the plasma copper-first stroke association was significantly stronger in participants with higher BMI (< 25.0 compared with ≥ 25.0 kg/m2, P-interaction = 0.024). However, there was no significant association between plasma copper and first hemorrhagic stroke.

CONCLUSIONS

In Chinese hypertensive patients, there was a significant positive association between baseline plasma copper and the risk of first stroke, especially among those with higher BMI.This trial was registered at clinicaltrials.gov as NCT00794885.