ABSTRACT Long-term stellar activity variations can affect the detectability of long-period and Earth-analogue extrasolar planets. We have, for 54 stars, analysed long-term trend five indicators: log $R^{\prime }_\mathrm{{HK}}$, cross-correlation function (CCF) bisector span, CCF full-width-at-half-maximum, contrast, area Gaussian fit to CCF; studied their correlation with RVs. The sign correlat...