Association between percent decline in serum total homocysteine and risk of first stroke
To examine whether a change in serum total homocysteine (tHcy) levels is associated with first stroke risk in a post hoc analysis of the China Stroke Primary Prevention Trial (CSPPT).
We analyzed 16,867 participants of the CSPPT with tHcy measurements at both baseline and exit visits. The primary outcome was first stroke. The secondary outcome was a composite of cardiovascular events consisting of cardiovascular death, myocardial infarction, and stroke. The percent decline in tHcy was calculated as [(baseline tHcy – exit tHcy)/baseline tHcy x 100].
Over the median treatment duration of 4.5 years, participants who developed a first stroke had a significantly lower percent decline in tHcy (β = –5.7; 95% confidence interval [CI] –8.8 to –2.6) compared to their counterparts. A 20% tHcy decline was associated with a reduction in stroke risk of 7% (hazard ratio [HR] 0.93; 95% CI 0.90–0.97). When percent decline in tHcy was assessed as tertiles, a significantly lower stroke risk was found in those in tertiles 2–3 (HR 0.79; 95% CI 0.64–0.97) compared with participants in tertile 1. Similar results were observed for the composite of cardiovascular events. The beneficial effect associated with greater tHcy reduction was observed across strata for age, sex, treatment group (with vs without folic acid), MTHFR C677T genotypes, baseline tHcy and serum folate levels, and blood pressure control.
Percent lowering in tHcy was significantly associated with a reduction in first stroke risk in Chinese adults with hypertension, and if further confirmed, may serve as a useful indicator for folic acid treatment efficacy on stroke prevention.