Obesity paradox confirmed in statin users
Obesity appears to decrease the risk of all-cause death in patients receiving statins after acute myocardial infarction (AMI), a recent study from Korea has shown.
“In conclusion, the greater benefit of statin therapy for survival in obese patients is further confirmation of the obesity paradox after AMI,” said the researchers.
The study included 2,754 AMI patients (mean age 67±11 years; 66 percent male), of which 2,196 were given statins while the remaining 549 were not. Participant data were obtained from the Korea AMI Registry and the two groups were propensity score matched, taking into consideration variables such as age, sex, diabetes mellitus, smoking status and medication.
Over a 1-year follow-up period, 84 cardiac deaths and 128 all-cause deaths were reported, the occurrence of both were significantly higher in the nonstatin group (6.2 and 8.4 percent) than in the statin group (2.3 and 3.7 percent; p<0.001 for both). [Medicine 2017;96:e7180]
This was confirmed by Kaplan-Meier survival analysis, which showed that the cumulative incidences of all-cause and cardiac deaths were significantly lower in the statin than in the nonstatin group (p<0.001). Additionally, statin use was associated significantly with reduced risk of all-cause death (HR, 0.44; 95 percent CI, 0.33 to 0.63; p<0.001).
Interestingly, among patients on statins, all-cause (1.7 vs 4.8 percent; p<0.001) and cardiac (1.2 vs 2.9 percent; p<0.05) deaths were significantly less common in obese patients than in nonobese patients.
Multiple Cox hazard regression showed that obesity was significantly and independently associated with lower risk of all-cause death in AMI patients on statins (HR, 0.29; 0.11 to 0.75; p=0.01) after adjusting for all potential confounders.
In contrast, there were no significant differences in the occurrences of all-cause and cardiac deaths between obese and nonobese patients in the nonstatin group.
It is a well-established fact that obesity is strongly associated with various health risks, including type 2 diabetes, dyslipidaemia and hypertension. Moreover, high BMI has been shown to increase mortality in the general population, the researchers noted. [N Engl J Med 1999;341:1097-1105]
However, in what has been known as the obesity paradox, high BMI seems to increase survival in patients who have survived AMI. The general mechanism by which this happens has yet to be discovered.
“In conclusion, the phenomenon of obesity paradox appears to be confined to only patients treated with statin after AMI,” said researchers.
“Statin therapy may be strongly associated with the phenomenon of obesity paradox after the event of AMI in recent clinical practice,” they added.