Prescription of lipid-lowering medications for patients with type 2 diabetes mellitus and risk-associated LDL cholesterol: a nationwide study of guideline adherence from the Swedish National Diabetes Register.

BACKGROUND: Management of type 2 diabetes mellitus (T2DM) encompasses intensive glycaemic control, along with treatment of comorbidities and complications to handle the increased risk of cardiovascular disease (CVD). Improved control of LDL-cholesterol (LDL-C) with lipid-lowering medications is associated with reduced CVD risk in T2DM patients. Thus, treatment guidelines recommend lipid-lowering medications for T2DM patients with LDL-C above risk-associated thresholds. This study aimed to assess healthcare provider adherence to guidelines regarding lipid-lowering medication prescription among T2DM patients and to analyse factors associated with lipid-lowering medication prescription.

METHODS: Observations in 2007 - 2014 for T2DM patients age ≥ 18 were collected from the Swedish National Diabetes Register. Observations were excluded if they lacked information about LDL-C, lipid-lowering medication prescription or CVD. Observations with established CVD were attributed to secondary prevention; remaining observations were attributed to primary prevention. The analyses included primary and secondary prevention observations with LDL-C above risk-associated thresholds (LDL-C ≥ 2.5 mmol/l and LDL-C ≥ 1.8 mmol/l respectively). Guideline adherence was analysed as the probability of prescribing lipid-lowering medications using mixed-effect model regression adjusted for potential confounders. Factors associated with prescribing lipid-lowering medications were analysed for patient and healthcare provider characteristics using mixed-effect model regression and odds ratio.

RESULTS: A total of 1,204,376 observations from 322,046 patients reported by 1352 healthcare providers were included. Primary prevention accounted for 63%; 52% were men, mean age was 64 and mean LDL-C was 3.4 mmol/l. For secondary prevention, 60% were men, mean age was 72 and mean LDL-C was 2.7 mmol/l. During 2007-2014, guideline adherence ranged from 36 to 47% for primary prevention and 59 to 69% for secondary prevention. In general, concomitant prescription of diabetes medications, antiplatelets and antihypertensives along with smoking and specialised care were associated with higher prescription of lipid-lowering medications. Patients age ≥ 80 were associated with lower prescription of lipid-lowering medications. Higher prescription was associated with longer diabetes duration in primary prevention and men in secondary prevention.

CONCLUSIONS: Adherence to treatment guidelines levelled off after an initial increase in both prevention groups. Lipid-lowering medication prescription was based on individualised CVD risk.