Association between statin use and lipid status in quality improvement initiatives: Statin use, a potential surrogate?

Objective To test the association between statin use and low-density-lipoprotein (LDL)-cholesterol control in outpatient community practices undergoing quality improvement efforts in diabetes care. Design A retrospective observational study of primary care practices that underwent efforts at improving the quality of diabetes care. Each practice provided an electronic registry-based monthly report of the percentage of patients with LDL <130 mg/dl (3.4 mmol/1), LDL <100 mg/dl (2.6 mmol/1) and statin use. Setting Primary care practices in Pennsylvania focused on improving diabetes care by implementing the Chronic Care Model in urban, suburban and rural regions. Participants Consisted of 109 primary care practices, academic practices and federal health centres. Practices typically saw patients from a mix of government-funded and commercial health plan carriers. Results There was a positive linear association between documented statin use and the percentage of patients with LDL <130 mg/dl (3.4 mmol/1) and LDL <100 mg/dl (2.6 mmol/1 = goal for patients with diabetes). The correlation between statin use and LDL <130 was 0.50 (95% CI 0.41-0.64), and between statin use and the percentage of patients with LDL <100 was 0.47 (95% CI 0.29-0.58). Practices with 5% larger statin use had an expected 1.9% larger percentage of patients with LDL <130 (95% CI 1.4 -2.9%) and an expected 1.7% larger percentage of patients with LDL < 100 (95% CI 0.9-2.3%). Conclusion An association exists between statin use and LDL control in the real world of primary care practices undergoing quality improvement. Additional studies are necessary to ultimately test the validity of statin use as a process measure and/or surrogate for LDL-cholesterol control.