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

Abstract

Background and aimsWe 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 resultsA 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 (plinearity < 0.001) and updated mean PLT (plinearity = 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. ConclusionThis 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.