Statin Use and Its Facility‐Level Variation in Patients With Diabetes: Insight From the Veterans Affairs National Database

Abstract

Summary Background To determine use of any and at least moderate intensity statin therapy in a national sample of patients with diabetes. Hypothesis Nationwide frequency and facility-level variation in statin therapy is suboptimal. Methods We sampled 40–75 years old patients with diabetes receiving primary care between October 1, 2012 to September 30, 2013 at 130 parent facilities and associated community based outpatient clinics in the Veterans Affairs Health Care System. We examined frequency and facility-level variation in use of any or at least moderate intensity statin therapy (mean daily dose associated with ≥30% low-density lipoprotein cholesterol lowering). Results In 911,444 patients with diabetes, 68.3% and 58.4% were receiving any and moderate to high intensity statin therapy, respectively. Patients receiving statin had higher burden of cardiovascular disease, were more likely to be on non-statin lipid lowering therapy and to receive care at a teaching facility, and had more frequent primary care visits. The median facility-level use of any and at least moderate intensity statin therapy were 68.7% (IQR, 65.9–70.8%) and 58.6% (55.8–61.4%), respectively. After adjusting for several patient and some facility related characteristics, the median rate ratios for any and moderate to high intensity statin therapy were 1.20 (95% CI, 1.18–1.22) and 1.29 (1.24–1.33) respectively, indicating 20–29% variation in statin use between 2 identical patients receiving care at 2 random facilities. Conclusion Statin use was sub-optimal in a national sample of patients with diabetes with modest facility-level variation, likely indicating differences in statin prescribing patterns.

Facility‐level variation in diabetes and blood pressure control in patients with diabetes: Findings from the Veterans Affairs national database

“…We identified patients with DM ages 18 to 75 years with a primary care visit in 130 VA healthcare facilities or their associated community‐based outpatient clinics between October 2013 and September 2014. Cohort details have been described previously . We identified patients as having DM if any of the following were documented: 2 outpatient or 1 inpatient diagnosis code indicating DM, from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD‐9‐CM) (250.xx, 357.2, 366.41), filled prescription for DM medication, or any fasting glucose ≥126 mg/dL, hemoglobin A1C >6.5%, or ≥2 outpatient blood glucose readings >200 mg/dL on 2 separate days .…”

“…We identified insulin use through filled prescriptions. ICD‐9‐CM diagnosis and procedure codes were used along with procedure terminology codes to identify presence of CVDs (ischemic heart disease, peripheral arterial disease, or ischemic cerebrovascular disease) as described in prior studies …”

“…We used patient‐level variables to calculate Diagnostic Cost Group (DCG) relative risk scores (RRS), which serve as an indirect measure of a patient's overall illness burden. DCG RRS has been used and validated in prior studies as a surrogate marker for disease burden . A patient with a DCG RRS score of 1.5, for example, reflects a 50% greater expected cost of care compared with an average patient (DCG RRS score = 1), reflecting a 50% greater disease burden.…”

“…For example, an MRR of 1 suggests no facility‐level variation, whereas an MRR of 1.50 suggests a 50% probability of differing treatment for identical DM patients receiving care at 2 random facilities. This methodology to study variation in care has been described before . MRRs for glycemic control were initially derived from an unadjusted model, followed by a model adjusting for patient variables (age, gender, race [white vs others], history of hypertension and CVD, use of insulin, DCG RSS) and then for patient and nonpatient variables (provider type [physician vs APP]), receipt of care at a teaching vs nonteaching facility, and the number of primary‐care and endocrinology visits in the prior 12 months).…”

“…Prior studies have shown significant variation in the use of statin therapy among patients with diabetes. 8,9 In this study, we examined the frequency and facility-level variation in glycemic and BP control in DM patients receiving care in primary care facilities in the entire Veterans Affairs (VA) Health Care System. Furthermore, we assessed the degree of variation attributable to patient-related variables.…”