Population Characteristics and Study Quality of Included Trials , by Combination Therapy Agent and Potency Comparison Long-Term Clinical Outcomes We found insufficient evidence to compare long-term clinical outcomes ( mortality , acute coronary events , cerebrovascular events , and revascularization procedures ) for all combination therapy and statin intensity comparisons .
Figure 1 presents an evidence map of studies that evaluated these
Atherosclerotic cardiovascular disease ( ASCVD ) affects more than 15 million Americans ( 1 ) and is the leading cause of death for both men and women in the United States ( 2 ) .
Trials have demonstrated reductions in low-density lipoprotein ( LDL ) cholesterol levels ( 3 ) and decreased ASCVD risk with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor ( statin ) monotherapy ( 4 ) .
Over the past decade , statins have often been used in combination with other lipid-modifying agents .
Recently , several high-profile r and omized , controlled trials ( RCTs ) have evaluated add-on therapy ( 57 ) , wherein statin monotherapy is compared with the combination of the same statin dose and another lipid-modifying agent .
Add-on combination therapy can lead to superior lipid outcomes , but studies have not shown decreased rates of cardiovascular death , myocardial infa rct ion , revascularization , or stroke ( 57 ) .
Therefore , the 2013 American College of Cardiology ( ACC ) and American Heart Association ( AHA ) guidelines recommend moderate- or high-intensity statin monotherapy as the first-line strategy for ASCVD risk reduction among patients with LDL cholesterol levels of 4.91 mmol/L or greater ( 190 mg/dL ) , preexisting ASCVD , diabetes mellitus ( DM ) , or estimated 10-year ASCVD risk of 7.5 % or greater ( 8) .
Adverse effects are more common with higher-intensity statin regimens ( 9 ) , and musculoskeletal adverse events occur frequently among patients with the C variant in the SLCO1B1 gene ( 10 ) .
The 2013 ACC/AHA guidelines suggest that clinicians consider moderated combination therapy with a lower-intensity statin and another lipid-modifying medication among high-risk patients ( LDL cholesterol level 4.91 mmol/L [ 190 mg/dL ] , preexisting ASCVD , or DM ) who are intolerant of or unresponsive to statins ( evidence grade E : expert opinion ) ( 8) .
Yet , it is unclear whether this strategy results in similar ASCVD risk reductions and fewer adverse effects compared with higher-intensity statin monotherapy .
A 2009 systematic review that examined these questions found insufficient evidence to weigh benefits and risks of moderated combination therapy ( 12 ) .
We aim ed to compare the effectiveness , safety , and tolerability of moderated combination therapy of statin with another lipid-modifying medication ( bile acid sequestrant , ezetimibe , fibrate , niacin , or -3 fatty acid ) with those of higher-intensity statin monotherapy among high-risk patients .
We sought to compare the long-term clinical benefits and short-term lipid effects of moderated combination therapy with those of higher-intensity statin monotherapy , as well as to determine whether these regimens differ in rates of adherence and harms .
Given the recent release of the 2013 ACC/AHA guidelines ( 8) , we narrowed the scope of this manuscript to focus on evidence most relevant to high-risk population s for whom combination therapy might be considered .
Prior studies have suggested schemes to group statins on the basis of their reported LDL cholesterol reduction ( 17 , 18 ) , which are similar to the strategy used by the ACC/AHA committee ( 8) .
Effects of combination lipid therapy in type 2 diabetes mellitus.
BACKGROUND We investigated whether combination therapy with a statin plus a fibrate , as compared with statin monotherapy , would reduce the risk of cardiovascular disease in patients with type 2 diabetes mellitus who were at high risk for cardiovascular disease . METHODS We r and omly assigned 5518 patients with type 2 diabetes who were being treated with open-label simvastatin to receive either masked fenofibrate or placebo .  The primary outcome was the first occurrence of nonfatal myocardial infa rct ion , nonfatal stroke , or death from cardiovascular causes . The mean follow-up was 4.7 years . RESULTS The annual rate of the primary outcome was 2.2 % in the fenofibrate group and 2.4 % in the placebo group ( hazard ratio in the fenofibrate group , 0.92 ; 95 % confidence interval [ CI ] , 0.79 to 1.08 ; P=0.32 ) . There were also no significant differences between the two study groups with respect to any secondary outcome . Annual rates of death were 1.5 % in the fenofibrate group and 1.6 % in the placebo group ( hazard ratio , 0.91 ; 95 % CI , 0.75 to 1.10 ; P=0.33 ) . Prespecified subgroup analyses suggested heterogeneity in treatment effect according to sex , with a benefit for men and possible harm for women ( P=0.01 for interaction ) , and a possible interaction according to lipid subgroup , with a possible benefit for patients with both a high baseline triglyceride level and a low baseline level of high-density lipoprotein cholesterol ( P=0.057 for interaction ) . CONCLUSIONS The combination of fenofibrate and simvastatin did not reduce the rate of fatal cardiovascular events , nonfatal myocardial infa rct ion , or nonfatal stroke , as compared with simvastatin alone . These results do not support the routine use of combination therapy with fenofibrate and simvastatin to reduce cardiovascular risk in the majority of high-risk patients with type 2 diabetes . ( Clinical Trials.gov number , NCT00000620 .
Population Characteristics and Study Quality of Included Trials , by Combination Therapy Agent and Potency Comparison Long-Term Clinical Outcomes We found insufficient evidence to compare long-term clinical outcomes ( mortality , acute coronary events , cerebrovascular events , and revascularization procedures ) for all combination therapy and statin intensity comparisons .
Figure 1 presents an evidence map of studies that evaluated these
Atherosclerotic cardiovascular disease ( ASCVD ) affects more than 15 million Americans ( 1 ) and is the leading cause of death for both men and women in the United States ( 2 ) .
Trials have demonstrated reductions in low-density lipoprotein ( LDL ) cholesterol levels ( 3 ) and decreased ASCVD risk with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor ( statin ) monotherapy ( 4 ) .
Over the past decade , statins have often been used in combination with other lipid-modifying agents .
Recently , several high-profile r and omized , controlled trials ( RCTs ) have evaluated add-on therapy ( 57 ) , wherein statin monotherapy is compared with the combination of the same statin dose and another lipid-modifying agent .
Add-on combination therapy can lead to superior lipid outcomes , but studies have not shown decreased rates of cardiovascular death , myocardial infa rct ion , revascularization , or stroke ( 57 ) .
Therefore , the 2013 American College of Cardiology ( ACC ) and American Heart Association ( AHA ) guidelines recommend moderate- or high-intensity statin monotherapy as the first-line strategy for ASCVD risk reduction among patients with LDL cholesterol levels of 4.91 mmol/L or greater ( 190 mg/dL ) , preexisting ASCVD , diabetes mellitus ( DM ) , or estimated 10-year ASCVD risk of 7.5 % or greater ( 8) .
Adverse effects are more common with higher-intensity statin regimens ( 9 ) , and musculoskeletal adverse events occur frequently among patients with the C variant in the SLCO1B1 gene ( 10 ) .
The 2013 ACC/AHA guidelines suggest that clinicians consider moderated combination therapy with a lower-intensity statin and another lipid-modifying medication among high-risk patients ( LDL cholesterol level 4.91 mmol/L [ 190 mg/dL ] , preexisting ASCVD , or DM ) who are intolerant of or unresponsive to statins ( evidence grade E : expert opinion ) ( 8) .
Yet , it is unclear whether this strategy results in similar ASCVD risk reductions and fewer adverse effects compared with higher-intensity statin monotherapy .
A 2009 systematic review that examined these questions found insufficient evidence to weigh benefits and risks of moderated combination therapy ( 12 ) .
We aim ed to compare the effectiveness , safety , and tolerability of moderated combination therapy of statin with another lipid-modifying medication ( bile acid sequestrant , ezetimibe , fibrate , niacin , or -3 fatty acid ) with those of higher-intensity statin monotherapy among high-risk patients .
We sought to compare the long-term clinical benefits and short-term lipid effects of moderated combination therapy with those of higher-intensity statin monotherapy , as well as to determine whether these regimens differ in rates of adherence and harms .
Given the recent release of the 2013 ACC/AHA guidelines ( 8) , we narrowed the scope of this manuscript to focus on evidence most relevant to high-risk population s for whom combination therapy might be considered .
Prior studies have suggested schemes to group statins on the basis of their reported LDL cholesterol reduction ( 17 , 18 ) , which are similar to the strategy used by the ACC/AHA committee ( 8) .