Cinacalcet use patterns and effect on laboratory values and other medications in a large dialysis organization, 2004 through 2006

Abstract

Background and objectives: Cinacalcet was introduced in mid-2004 to treat secondary hyperparathyroidism in dialysis patients. We aimed to characterize adult patients who received cinacalcet prescriptions and to determine (1) dosage titration and effects on laboratory values, active intravenous vitamin D use, and phosphate binder prescriptions and (2) percentage who achieved National Kidney Foundation Kidney Disease Outcomes Quality Initiative targets for serum parathyroid hormone, calcium, and phosphorus and experienced biochemical adverse effects.

Design, setting, participants, & measurements: This observational study evaluated 45,487 prevalent patients from a dialysis organization database linked with the Centers for Medicare and Medicaid Services End-Stage Renal Disease database. Patient characteristics, laboratory values (albumin, parathyroid hormone, calcium, phosphorus), intravenous vitamin D, and oral medication (cinacalcet, phosphate binders) prescriptions were evaluated for cinacalcet patients.

Results: By June 2006, almost 32% of patients had received cinacalcet prescriptions. Mean baseline corrected calcium was 9.8 mg/dl and phosphorus was 6.3 mg/dl, and median parathyroid hormone was 577 pg/ml, versus 9.5 mg/dl, 5.3 mg/dl, and 215 pg/ml, respectively, for noncinacalcet patients. Patients with cinacalcet prescriptions for > or =6 mo had corrected calcium reduced by 4.2%, phosphorus by 7.0%, and parathyroid hormone by 29.9% by 12 mo. More cinacalcet patients attained Kidney Disease Outcomes Quality Initiative targets with less hyperparathyroidism, hypercalcemia, and hyperphosphatemia but more hypoparathyroidism and hypocalcemia. Over 12 mo, vitamin D use and use consistency increased, phosphate binder dosages increased, and mean cinacalcet daily dosage reached 55 mg.

Conclusions: Patients with cinacalcet prescriptions exhibited more severe hyperparathyroidism and hyperphosphatemia than noncinacalcet patients. Positive effects were less dramatic than in Phase III clinical trials, possibly as a result of modest, slow dosage titration.

Figure 1.

Number of patients remaining in study each quarter (bars) and percentage of cinacalcet patients during each quarter of the study period (line). Cinacalcet patients were defined by at least one prescription for cinacalcet during the quarter.

Figure 2.

Mean cinacalcet daily dosage and mean monthly serum phosphorus and corrected calcium values in each month during 12-mo time frame for patients with cinacalcet prescriptions for ≥6 mo.

Figure 3.

Median intact parathyroid hormone (iPTH) values (pg/ml) in each month during 12 mo time frame for patients with cinacalcet prescriptions for ≥6 mo.

Figure 4.

Percentage of patients who reached KDOQI target ranges for corrected calcium (8.4 to 9.5 mg/dl), phosphorus (3.5 to 5.5 mg/dl), iPTH (150 to 300 pg/ml), and all three targets in each month during 12-mo time frame for patients with cinacalcet prescriptions for ≥6 mo.

Figure 5.

Percentage of patients who experienced a biochemical adverse event: Hyperparathyroidism (iPTH >600 pg/ml), hypercalcemia (corrected calcium >10.2 mg/dl), hyperphosphatemia (phosphorus >6 mg/dl), hypoparathyroidism (iPTH <150 pg/ml), or hypocalcemia (calcium <8.4 mg/dl) in each month during the 12-mo time frame for patients with cinacalcet prescriptions for ≥6 mo.