Prescribing statins for cardiovascular disease prevention in the old: an absence of evidence and an absence of guidelines.

Australia's oldest old are potentially being harmed by the under- and over- use of statins. Variations in prescription of statins are in part due to the vacuum of clinical research trial evidence and paucity of contemporary guidelines that are needed to address the use of lipid lowering therapy in the oldest old. There are a few randomised placebo-controlled trials that recruited an older population. Therefore evidence of statins efficacy in the oldest old is based on an extrapolation of results from those studies. The extensive exclusion criteria of those studies, the relative youth of the study participants, the low levels of comorbidity and functional impairment limit the external validity and the generalisability of the findings. Current guidelines are silent or generally non-specific about statin therapy for the oldest old deferring decisions to individual medical practitioners. Life expectancy, time to benefit, functional status and medication related adverse events, polypharmacy, adherence to treatment are factors that need to be considered when forming appropriate guidelines for statin prescription in the very old. Well-designed clinical trials that account for the heterogeneity of this population are needed. While waiting for this research evidence better clinical guidelines are needed to address this issue.