Conversion to atorvastatin in patients intolerant or refractory to simvastatin therapy: the CAPISH study

To examine the safety and efficacy of switching from simvastatin to atorvastatin in patients who had either an inadequate lipid-lowering response with, or an adverse reaction to, simvastatin.

The Conversion to Atorvastatin in Patients Intolerant or Refractory to Simvastatin Therapy (CAPISH) study was designed in 2 parts: a retrospective cohort study of patients (group A), identified from a large pharmacy database, who converted from simvastatin to atorvastatin at a single academic military medical center (between April 1998 and March 2002) and a prospective cohort study of patients (group B) monitored in a lipid clinic at the same institution (between April 2002 and March 2003). Group A was identified by 2 or more simvastatin prescription fills and at least 1 atorvastatin prescription fill. Group B was identified by a physician-perceived need to switch from simvastatin to atorvastatin. Clinical, pharmaceutical, and laboratory records of both cohorts were reviewed.

Approximately 1 in 4 simvastatin-treated patients discontinued therapy during a 4-year period. The most common reason for switching to atorvastatin was inadequate low-density lipoprotein (LDL) cholesterol control, although asymptomatic creatine kinase (CK) elevation and myalgias were also common. In most cases of myositis and in nearly all cases of rhabdomyolysis, patients were taking 80 mg of simvastatin. Achievement of National Cholesterol Education Program LDL cholesterol goals increased from 25% to 63% in group A and from 13% to 78% in group B, both P<.001. Significant reductions in CK also were seen in both groups. Adherence to atorvastatin was greater than 80% in both groups after 28.1+/-13.2 months (group A, 841 patients) and 8.1+/-3.8 months (group B, 104 patients). Among patients not taking atorvastatin at follow-up, 58% were no longer taking statins.

Atorvastatin was well tolerated in patients who previously were taking simvastatin. Serum lipid panels were improved substantially and CK levels were decreased without compromise to patient safety.