Data from: Are statin trials in diabetes representative of real-world diabetes care: a population-based study on statin initiators in Finland

Objective: To assess the representativeness of the Heart Protection Study
(HPS) and the Collaborative Atorvastatin Diabetes Study (CARDS) for
incident statin users. Design: A population based analysis with linked
register data. Setting: Finland. Population: 56 963 diabetic patients
initiating statin use in 2005 to 2008. Main outcome measures: We
determined the proportions of real-world patients who fulfilled the
eligibility criteria for HPS and CARDS trials and assessed the
cardiovascular disease (CVD) event rates, assumed to reflect the
background CVD risk, for those eligible and ineligible. We used
descriptive statistics to identify the patient characteristics,
lipid-lowering interventions, and adherence to statin therapy. Results: Of
the real-world patients 57% (N=32 582) fulfilled the eligibility criteria
for HPS(DM) and 49% (N=20 499) of those without CVD for CARDS. The
patients ineligible for HPS(DM) had a higher cumulative risk for CVD
events than those eligible, whereas regarding CARDS the cumulative risks
were of similar magnitude. The overall CVD event rates seemed comparable
to those in the reviewed trials. Both trials were under-representative for
women, users of antihypertensive agents and metformin. 27% and 29% of real
world patients had an initial statin dose corresponding to <20mg of
simvastatin. The proportions of patients deemed adherent were 57% in the
real world and 85% in both trials. Conclusions: Only half of the
real-world patients would have qualified for the HPS(DM) and CARDS,
limiting their representativeness for clinical practice. Women and users
of antihypertensive agents and of metformin were under-represented in both
trials. These deviations reflect the changes in diabetes treatment over
the years and are not expected to modify the average treatment effects of
statins on CVD. Prescribing of lower statin doses in clinical practice
than used in the trials and lower adherence may, however, attenuate the
benefits in the real-world.