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/l), LDL <100 mg/dl (2.6 mmol/l) 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/l) and LDL <100 mg/dl (2.6 mmol/l = 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.

The relative influence of calcium intake and vitamin D status on serum parathyroid hormone and bone turnover biomarkers in a double-blind, placebo-controlled parallel group, longitudinal factorial design.

BACKGROUND: Adequate calcium and vitamin D are needed to maintain calcium balance. OBJECTIVE: Our objective was to examine the influence of calcium intake and vitamin D exposure separately and their interaction on biomarkers of calcium sufficiency. DESIGN: Healthy men and women, age 20-80 yr, were randomly allocated to four groups: 1) double placebo, 2) calcium (1200 mg daily) plus placebo, 3) vitamin D(3) (100 microg) plus placebo, and 4) vitamin D(3) and calcium. Fasting serum and urine as well as serum and urine 2 h after a calcium load (600 mg of calcium carbonate) were obtained at baseline and 3 months. RESULTS: Ninety-nine participants were randomized; 78 completed the study. Baseline demographics, protein intake and laboratory studies did not differ among the four groups. Study medication compliance was 90%. Fasting bone turnover markers declined after 3 months only in the two groups given calcium supplements and increased in the vitamin D(3) plus placebo calcium group. The calcium load resulted in a decrease in PTH and in bone turnover markers that did not differ among groups. Urinary calcium excretion increased in the combined group. Mean serum 25-hydroxyvitamin D increased from a baseline of 67 (18 sd) nmol/liter to 111 (30 sd) nmol/liter after vitamin D supplementation. CONCLUSION: Increased habitual calcium intake lowered markers of bone turnover. Acute ingestion of a calcium load lowered PTH and bone turnover markers. Additional intake of 100 microg/d vitamin D(3) did not lower PTH or markers of bone turnover.