TUESDAY, Aug. 10 (HealthDay News) -- Increased antibiotic use by American seniors appears to be associated with improved Medicare drug coverage, a new study suggests.

Broad-spectrum, newer and more expensive antibiotics had the largest increases in use since the introduction of the Medicare Part D drug plan, said the University of Pittsburgh researchers.

Yuting Zhang and colleagues compared antibiotic use among 35,102 seniors two years before and after implementation of Medicare Part D, which was estimated to reduce out-of-pocket prescription drug spending between 13 percent and 23 percent.

"We found that the use of antibiotics increased in response to reductions in out-of-pocket price after Part D implementation," the researchers wrote.

The largest increase in antibiotic use occurred among seniors who had no drug coverage before enrolling in the Medicare plan. Substantial increases were also noted among seniors who previously had limited drug coverage, according to the report.

After implementation of Medicare Part D, the use of antibiotics to treat pneumonia tripled among seniors who previously lacked drug coverage, the researchers found.

"Given the high mortality associated with community-acquired pneumonia among the elderly, the finding that changes in drug coverage improve the likelihood of treatment is encouraging," they wrote.

The study is published in the Aug. 9/23 issue of the Archives of Internal Medicine.

More information

The American Academy of Family Physicians has more about antibiotics.