The study, funded and conducted by Lipitor's maker Pfizer Inc., was prepared for presentation Tuesday at an American Heart Association meeting in Dallas. It also appears in Wednesday's Journal of the American Medical Association.

Lowering LDL Cholesterol

Many heart specialists recommend aggressively lowering LDL cholesterol levels, the bad kind, to help heart patients avoid future cardiovascular problems. So Pfizer tried that with a much higher dose of its statin drug, Lipitor.

Lipitor patients did appear to fare better when the researchers grouped together any cardiovascular problem including strokes and heart surgery, results that echo findings in previous research on aggressively lowering cholesterol.

The latest study involved 8,888 mostly male Scandinavian patients aged 61 on average who had previous heart attacks and were given either a high dose of Lipitor or a standard dose of Merck's Zocor.

Major Coronary Events

The researchers didn't find the main difference they were looking for -- fewer "major coronary events" in the Lipitor group during an average follow-up of almost five years.

That category lumped together cardiovascular deaths, nonfatal heart attacks and nonfatal cardiac arrest. These events totaled 463 in the Zocor patients and 411 in the Lipitor patients, a difference that was not statistically significant.

The results can't be considered a direct comparison because different doses of the competing drugs were used.

Dr. Terje Pedersen of Ulleval University Hospital in Oslo, Norway, was the study's lead author. Two Pfizer employees were among the co-authors.