Trials on hormone therapy and hypertension treatment change practice, medication usage of patients

12/30/03

Recent results from clinical trials on hormone therapy and treating hypertension have changed the way physicians prescribe and the way patients use certain medications, according to two studies in the January 7 issue of The Journal of the American Medical Association (JAMA).

In the first article, Adam L. Hersh, M.D., Ph.D., of the Stanford University School of Medicine, Stanford, Calif., and colleagues examined the national trends in hormone therapy use and prescriptions since 1995 to determine the impact of recent evidence on hormone therapy.

According to background information in the article, postmenopausal hormone therapy use increased dramatically over the past 2 decades because of a prevailing belief in its health benefits. But recent evidence from randomized trials published in July 2002 (the Heart and Estrogen/Progestin Replacement Study follow-up [HERS II]; the Women's Health Initiative [WHI]) either demonstrated no benefit or indicated adverse cardiovascular disease events and other risks with hormone therapy in the form of oral estrogen combined with progestin.

The researchers used two databases to determine national trends in hormone therapy use from January 1995 to July 2003: the National Prescription Audit database provided data on the number of hormone therapy prescriptions filled by retail pharmacies; and the National Disease and Therapeutic Index database provided data on patient visits to office-based physicians during which hormone therapy was prescribed.

The researchers found that annual hormone therapy prescriptions increased from 58 million in 1995 to 90 million in 1999, representing approximately 15 million women per year, then remained stable through June 2002. Adoption of new oral estrogen/progestin combinations, primarily Prempro, accounted for most of this growth.

"Following the publication of [WHI] trial results in July 2002, hormone therapy prescriptions declined in successive months. Relative to January-June 2002, prescriptions from January-June 2003 declined by 66 percent for Prempro and 33 percent for Premarin. Small increases were observed in vaginal formulations and in new prescriptions for low-dose Premarin. If prescription rates observed through July 2003 remain stable, a decline to 57 million prescriptions for 2003, similar to the rate in 1995, is projected," the authors write.

"This example shows effective information dissemination of scientific evidence and clinical guidelines to patients and physicians, which has resulted in prompt changes in clinical practice. In addition, the subsequent media cascade undoubtedly enhanced dissemination. Our findings support prior literature suggesting that physicians may rapidly abandon well-established therapies when studies demonstrate harm. Whether acting alone or with the involvement of physicians, patients also played a major role in the decline in hormone therapy use that we observed," the researchers write.

(JAMA. 2004; 291:47-53. Available post-embargo at JAMA.com)

Editor's Note: This study was supported by an institutional National Research Service Award funded by the National Heart, Lung, and Blood Institute and by a research grant from the Agency for Healthcare Research and Quality.

USE OF CERTAIN HYPERTENSION MEDICATION DECLINED FOLLOWING RELEASE OF TRIAL RESULTS

In the second article, Randall S. Stafford, M.D., Ph.D., of the Stanford Prevention Research Center, Stanford University, Stanford, Calif., and colleagues tracked trends in alpha-blocker prescriptions filled by retail pharmacies and reports of alpha-blocker use in patient encounters with office-based physicians from 1996-2002.

In spring 2000, significant changes in recommendations for alpha-blocker use occurred as a result of early, unfavorable results from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), according to background information in the article.

The ALLHAT was designed to evaluate the possible superiority of alpha-blockers, calcium channel blockers, and angiotensin-converting enzyme (ACE) inhibitors over less expensive, generic diuretics in lowering blood pressure and preventing coronary heart disease and other cardiovascular events in high-risk hypertensive persons 55 years and older. In January 2000, a decision was made to terminate the doxazosin arm of the ALLHAT study after finding that the risk of combined cardiovascular events with the alpha-blocker doxazosin was more than 25 percent greater than that in patients treated with chlorthalidone, a thiazide diuretic.

The results were widely disseminated in news releases and journal publications. With 50 million individuals in the United States diagnosed as having hypertension incurring annual treatment costs of $15.5 billion, these early ALLHAT results would be expected to have broad implications on prescribing decisions.

The authors used data on alpha-blocker prescription orders reported in the National Prescription Audit, a random, computerized sample of about 20,000 of 29,000 retail, independent and mail order pharmacies and mass merchandise and discount houses; and office-based physician alpha-blocker prescribing patterns reported in the National Disease and Therapeutic Index, a random sample of about 3,500 physician offices.

The researchers found that there were steady increases in alpha-blocker new prescriptions, dispensed prescriptions, and physician drug use from 1996 through 1999. "There was a moderate reversal in these trends following ALLHAT early termination and subsequent publications in early 2000," they write. "Between 1999 and 2002, new annual alpha-blocker prescription orders declined by 26 percent (from 5.15 million to 3.79 million), dispensed prescriptions by 22 percent (from 17.2 million to 13.4 million), and physician-reported drug use by 54 percent (from 2.26 million to 1.03 million). Other potential influences did not appear to have contributed significantly to this decline although cessation of alpha-blocker marketing may have hastened the decline."

" ... our findings are clearly consistent with ALLHAT early termination results having a significant impact on alpha-blocker use. Declining pharmaceutical industry promotion also may have contributed further to decreased alpha-blocker use. The lack of an abrupt and more pronounced decline in prescribing shortly after the ALLHAT results, however, suggests slow and potentially incomplete diffusion of information from this clinical trial. Combined with past work that questions the potency of clinical trial results on physician practice, our analysis suggests the need for additional strategies to augment the dissemination of results from clinical trials," the authors conclude.

(JAMA. 2004; 291:54-62. Available post-embargo at JAMA.com)

Editor's Note: This study was supported by a research grant from the Agency for Healthcare Research and Quality.

EDITORIAL: THE COMPLEX WORLD OF PRESCRIBING BEHAVIOR

In an accompanying editorial, C. David Naylor, M.D., D.Phil., of the University of Toronto, Ontario, Canada, discusses the articles in this week's JAMA examining how clinical trials and other factors influence how physicians prescribe medications.

"In the complex realm of prescribing behaviors, physicians now process ever-increasing amounts of evolving evidence in contexts with their own unique micro- and macro-sociology, where the economic incentives are not infrequently perverse. Prescribers must individualize therapy and consider combinations of drugs for which randomized evidence may be limited," he writes.

"The pharmaceutical industry markets its wares relentlessly to physicians and consumers alike and exerts its own steering effects on basic and clinical research. Third-party payers are pressing for drug cost containment, patients' expectations have increased rapidly, and medicolegal pitfalls are omnipresent. Moreover, pharmacogenomics heralds a phase in which prescribing may be more elegantly tailored to the patient's biology but more dependent on technological support than ever before. At this critical juncture in the evolution of pharmaceuticals and health care, the time has come for much more systematic study of the myriad factors that affect what physicians prescribe for their patients," Dr. Naylor concludes.

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