Characteristics Associated with Statin Prescribing for Primary Prevention of Cardiovascular Disease Among People with Diabetes

Background Diabetes is a risk factor for cardiovascular disease (CVD) and guidelines recommend that people with diabetes ought to have their blood lipid levels monitored and, if necessary, controlled to ensure that they are at a safe level to prevent avoidable morbidity and mortality resulting from CVD. Guidelines are not necessarily followed and the differences in treatment which this leads to could give rise to health inequalities according to socio-economic status, sex, or other patient characteristics. This study investigated the association between patient characteristics and statin prescribing in people who were eligible to receive a statin for primary prevention of CVD according to the contemporary Scottish Intercollegiate Guideline Network guidelines (SIGN 55).

Methods Data from the Scottish Care Information – Diabetes Collaboration dataset for the period 2000–2007 were used. This dataset contains socio-demographic and prescribing data for 203,528 people, which is almost every person with diagnosed diabetes in Scotland. The analyses were based on people over 40 years of age, with complete data, with no history of CVD, and with total serum cholesterol exceeding 5mmol/l.

Logistic regression was used to calculate odds ratios (OR) for ever having a record of a statin prescription by age, sex, socio-economic status (defined using quintiles of the Scottish Index of Multiple Deprivation, SIMD, where Q1 reflects the most deprived and Q5 the most affluent), smoking habits, body mass index, diastolic blood pressure, and type of diabetes.

Results Of 83,666 people identified as eligible for statin treatment as defined by SIGN 55 guidelines, 29% had no record of a statin prescription. In both men and women, the OR for having a statin prescribed when compared to Q1 from multi-variate models were ORmen 0.93 ORwomen 0.91 for Q2, ORmen 0.77 ORwomen 0.77 for Q3, and ORmen 0.71 ORwomen 0.71 for Q4. Current and former smokers, overweight and obese people, and people with high blood pressure or treated hypertension had greater odds of statin prescription, whereas underweight people and women with type one diabetes had reduced odds of being prescribed a statin than each comparison group.

Conclusion Almost one third of people with diagnosed diabetes have no record of having ever received a statin prescription as recommended by SIGN 55. The odds of having a record of treatment were higher among more deprived people even after adjusting for potential confounding factors.