Tracing the flow of knowledge: geographic variability in the diffusion of prazosin use for the treatment of posttraumatic stress disorder nationally in the Department of Veterans Affairs.
BACKGROUND
Passive diffusion of new medical innovations is an important mechanism by which knowledge transitions from research to clinical practice. Preliminary evidence has emerged about the effectiveness of the alpha(1)-adrenergic blocker prazosin hydrochloride in the treatment of nightmares and hyperarousal among patients with posttraumatic stress disorder (PTSD). This treatment has been neither widely accepted nor the subject of active dissemination efforts, and its efficacy was discovered in a discrete geographic location.


OBJECTIVE
To evaluate the pace and reach of the passive dissemination of a promising technology within a national health care system.


METHODS
Geographic surveillance data study.


METHODS
Academic research.


METHODS
We tracked the use of prazosin in the treatment of patients diagnosed as having PTSD in the Department of Veterans Affairs during fiscal years 2004 (n = 203 414) and 2006 (n = 319 670).


METHODS
The percentage of patients diagnosed as having PTSD who received a prescription for prazosin.


RESULTS
Whereas 37.6% of patients with PTSD treated within the Veterans Affairs Puget Sound Health Care System, Tacoma, Washington, in 2004 were prescribed prazosin, only 18.2% were treated with prazosin at medical centers up to 499 miles (to convert miles to kilometers, multiply by 1.6) away, 6.7% at centers 500 to 999 miles away, 4.0% at centers 1000 to 2499 miles away, and 1.9% at centers 2500 miles away or farther. Adjusting for patient characteristics, patients with PTSD treated up to 499 miles from Puget Sound were about 49% less likely in 2006 and about 63% less likely in 2004 to be prescribed prazosin than their counterparts treated within Puget Sound, while those who were treated 2500 miles away or farther were about 94% less likely in 2006 and about 97% less likely in 2004 to be treated with prazosin than patients within Puget Sound.


CONCLUSIONS
Passive diffusion of a new treatment can be rapid in the immediate area in which it is developed, but the geographic gradient of use seems to be steep and enduring even when cost and organizational barriers are minimal.
Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA. ilan.harpaz-rotem@yale.edu
Ilan
I
Harpaz-Rotem
Robert A
RA
Rosenheck
D000317:Adrenergic alpha-Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D003130:Combat Disorders / Q000175:diagnosis / Q000188:drug therapy* / Q000523:psychology; D004059:Diffusion of Innovation; D004346:Drug Information Services; D019317:Evidence-Based Medicine; D006297:Health Services Accessibility; D006801:Humans; D011224:Prazosin / Q000009:adverse effects / Q000627:therapeutic use*; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000188:drug therapy* / Q000523:psychology; D016896:Treatment Outcome; D014481:United States; D014493:United States Department of Veterans Affairs; D014728:Veterans / Q000523:psychology*
D000317:Adrenergic alpha-Antagonists; D011224:Prazosin