Prostate biopsies among Medicare beneficiaries are associated with a significant rise in complications requiring hospitalization, according to a study to published online in the November issue of Journal of Urology.

Edward Schaeffer, MD, PhD, the study’s senior investigator, and colleagues from Johns Hopkins Medical Institutions in Baltimore, observed a 6.9 percent rate of hospitalization within 30 days of biopsy compared with a 2.9 percent hospitalization rate among a control group of men who did not have a prostate biopsy.

“Together these findings highlight the importance of careful patient selection and counseling regarding prostate biopsy,” wrote the authors.

The study was the largest analysis ever performed of Medicare records of men age 65 and older who underwent prostate biopsies in the last two decades. Data from more than 17,400 men age 65 and older who underwent biopsies from 1991 to 2007 were compared with a cohort of 134,977 men with similar characteristics. The researchers only looked at hospital admissions, not men whose complications were treated in an emergency department or outpatient setting.

Schaeffer and colleagues found that having a prostate biopsy made patients more than twice as likely to need hospitalization in the immediate post-procedure period. Among the complications were bleeding, infection and flare-ups of underlying medical conditions, such as heart failure or breathing disorders.

While the procedure is largely considered benign, the results of the study showed that, if the difference was similar to what would be found in a randomized trial, for every 24 biopsies performed in a 30-day period, there would be one additional hospitalization.

The rate of serious infection-related complications actually experienced a steady rise over the course of the study period. In 1991, less than 0.5 percent of men were admitted to the hospital because of an infection diagnosed following a prostate biopsy. This rate remained stable until 2000, when rates of infection-related complications began to increase to more than 1.2 percent in 2007.

“A likely explanation for the increase in infectious complications is increasing antimicrobial resistance,” wrote the authors, who pointed out that the American Urological Association recommends anti-microbial prophylaxis for all patients undergoing prostate biopsy.

Prostate biopsies are performed with transrectal ultrasound guidance, and bacteria from the rectum may be introduced into the prostate making infection a potential risk, according to the authors.

Mortality rates in men undergoing prostate biopsies did not increase overall, which the researchers attributed to improved patient selection of healthier men for prostate biopsy whose early mortality rate decreased as a result. However, men hospitalized with biopsy-related infections had a 12-fold higher risk of death compared to men who did not have a biopsy.

More than one million prostate biopsy procedures are performed each year in the U.S. to diagnose and monitor prostate cancer, which is the second most common cause of cancer death among men. The age adjusted rate of prostate biopsy per 100,000 Medicare beneficiaries is 1,580 in white men and 1,851 in black men, according to the study.

Further studies are needed to examine prostate biopsy-related complications in younger men, the authors said.