The Boston Collaborative Drug Surveillance Program, a Boston University-affiliated research group, has used an international database to link the anti-inflammatory drug Diclofenac to an increased risk of heart attack.

The observational study showed Diclofenac increases the risk of heart attack two-fold, a result comparable to those of Celebrex and Vioxx, two similar drugs notorious for their links to an increased risk of heart attack.

Diclofenac was one of five drugs of its kind tested. Other drugs included Rofecoxib, Celecoxib, Ibuprofen and Naproxen. The study found that both Rofecoxib and Celecoxib, if used extensively, also increase the risk of heart attack.

The information for the study, which was run through the Medicine Department and the School of Public Health, was gathered using the United Kingdom General Practice Research Database, whose main objective is to test drug safety, as reported by the BCDSP in a paper published by the medical journal Pharmacotherapy.

We have what’s called a computerized medical database … from the UK, BCDSP Medicine and Drug Surveillance associate professor Dr. Hershel Jick said. We received the data and began the research on it, which gave us the medical records of about six million people. It covers over 30 million person years of time.

Person years, he explained, are the cumulative number of years each of the 6 million people represents, so if a person was monitored for 40 years, that person represents 40 person years.

Authors Jick, James Kaye, Stefan Russmann and Susan Jick reported that the study was different from others in that it was designed to minimize important biases present in other observational studies. Kaye, Russman and Susan Jick all refused to comment on their work.

Experimental studies actually get a group of people randomly together, Jick said. When you do observational studies, everyone is different, so you have the big job of trying to make them look as similar as possible.

Jick said although the database began recording information in 1988, the study actually began about four months ago.

The BCDSP now works exclusively with the United Kingdom General Practice Research Database.

The general practices, which on the average have three general practitioners, were asked way back in the late 80s to record their patients’ data, Jick said. It is essentially representative of the entire population of England, Wales and Scotland. It’s all totally anonymous. We have no idea who the patients, practitioners or the practices are.

We are doing five or more studies on this database at any given time, Jick continued. Right now, we’re doing a study on the efficacy of the morning-after pill, and we have recently done studies on antidepressants and suicidal behavior.

Jick said this is not the first time the BCDSP has studied the effects of certain drugs.

We were the first ones to describe in the 70s that aspirin might be preventative of heart attacks, he said.

Jick said he has no comment on whether he thought there would be litigation against the makers of Diclofenac.