Analysis and modelling of cholesterol and high-density lipoprotein cholesterol changes across the range of C-reactive protein levels in clinical practice as an aid to better understanding of inflammation–lipid interactions

Objectives Raised total cholesterol (TC) and reduced high-density lipoprotein (HDL) cholesterol levels are established cardiovascular disease (CVD) risk factors. However, in autoimmune conditions the lipid–CVD association appears paradoxical, with inflammation as a potential confounding factor. We therefore sought to model the relationship between systemic inflammatory illness and lipid levels using C-reactive protein (CRP) as the prototypical marker of inflammation. Our hypothesis was that there would be an inverse association between raised CRP levels and both TC and HDL-cholesterol levels. Methods Results from samples analysed simultaneously for CRP and lipids in a 6-month period were collected retrospectively from a large city hospital laboratory database that collates results from both primary and secondary care. The relationships between CRP and lipids were determined using graphical techniques and empirical, non-parametric, best fit models. Results A total of 11 437 blood samples was included. We identified a significant (p