Jupiter is in the news again. The 18,000-subject trial that made cholesterol-fighter Crestor a hit in late 2008 was so successful that researchers ended it early, allowing subjects receiving the placebo to start taking the AstraZeneca statin.
But a Johns Hopkins study now finds that statins may be effective only when patients have a calcium build-up in their blood vessels. Those having the calcification--about half of the 950 participants--suffered 95 percent of the heart attacks and strokes in the five-year study.
The research suggests that many statin-takers get no benefit from the drug because calcium, not cholesterol, is the culprit.
And by its contrast with the findings from Jupiter, the Johns Hopkins research shows something else, too: statistical analyses and the way they are presented can distort the utility of study data.
The Jupiter study found that Crestor reduced the incidence of heart attacks and strokes compared with placebo by 55 percent and 48 percent, respectively, in volunteers having normal cholesterol levels but elevated C-reactive protein.
But "just like a distinction had to be made between efficacy and effectiveness when it came to the criteria of the study design, a distinction has to be made here between relative and absolute differences. That 55 percent reduction in rate of heart attacks was a relative rate and reflected an absolute decrease in incidence from 0.37 percent to 0.17 percent," writes Bo Wang, the "Doctor's Orders" columnist for Rutgers Daily Targum.
Clinicians have to draw a line between the "efficacy or internal validity of a treatment--the results achieved in a controlled, laboratory setting--and the treatment's effectiveness or external validity--its impact in the real world."
Wang does the math to figure the cost of preventing one heart attack: the 0.2-percent reduction translates to 500 patients being put on Crestor for a year, at a cost of $638,000 plus the risk of side effects for the 500 patients.
- here's the article on the Johns Hopkins study
- get Wang's Targum column