Researchers determined that among more than 61,000 men who had their prostates removed to treat cancer, those with private insurance had fewer complications from surgery and were less likely to die in the hospital.
Men covered by Medicare or Medicaid were more likely to need a blood transfusion to treat blood loss: almost eight percent and 11 percent, respectively, had a transfusion, compared with just over five percent of men with private insurance.
Their overall risk of surgical complications was also higher, researchers report in the journal Cancer.
After surgery, 13 percent of Medicare patients had a complication, such as heart or breathing problems or incontinence. That compared with just under 10 percent of men with private insurance.
There were similar gaps when the researchers looked at men covered by Medicaid, the government insurance program for the poor: 13 percent had some type of post-surgery complication.
Few men in the study died, but the risk was higher for those on Medicaid, 0.3 percent of whom died in the hospital.
The reasons for the findings cannot be pinned down, according to lead researcher Dr. Quoc-Dien Trinh, a urologist at Henry Ford Hospital in Detroit.
He and his colleagues were able to account for a number of other factors -- like age, race, the men's overall health and some characteristics of the hospitals (like how often they perform prostate removal). And private insurance, itself, was still linked to fewer complications.
There may still be other reasons for the connection, Trinh told Reuters Health in an e-mail.
"Yet," he added, "it is quite possible that when everything is accounted for, patients with private insurance just do better."
The "why?" is a question for future studies, according to Trinh. "What is urgently needed," he said, "are studies designed to identify specific processes that are responsible for the reported disparities."
The findings are based on a government database that collects information from hospitals in 40 U.S. states. The researchers looked at data from 61,167 men who had their prostates removed to treat cancers confined to the prostate gland.
Of those men, 67 percent were privately insured, about 31 percent were on Medicare, and just under two percent were on Medicaid.
Questions surrounding when and how to treat prostate cancer are controversial. That's because many men now have their cancers diagnosed at a very early stage through screening with prostate-specific antigen (PSA) blood tests.
While that sounds like a good thing, the problem is that prostate cancer is often slow-growing and may never progress far enough to threaten a man's life. So finding and treating early tumors can do more harm than good for some men.
Along with the short-term risk of surgery complications, long-term side effects can include urinary incontinence and erectile dysfunction. (See Reuters Health story of September 20, 2011).
According to the National Cancer Institute, about half of the more than 190,000 U.S. men diagnosed with prostate cancer in 2009 fell into the "low-risk" category -- meaning their cancer had low odds of progression. Because there's no way to predict for sure, those men may end up receiving treatment they do not necessarily need.
As for the men in the current study, Trinh said there was no information on the stage of their cancer at diagnosis, or the "grade" of their tumors (a measure of how aggressive the cancer appears to be).
So it's not possible to tell how many men may have been "overtreated," Trinh said.
He added, though, that the findings add another layer to the bigger issue: "Some patients, based on their insurance type, might be receiving sub-optimal surgical care for an overdiagnosed and overtreated disease," he said.
The study is not the first to spot differences in surgery outcomes between privately insured and publicly insured patients. Trinh noted that disparities have also been found when it comes to colorectal surgery, neurosurgery and orthopedic procedures, among others.
"At the end of the day," he said, "it is hard to decipher the root causes of this effect, but it is very real and has significance as we approach changes to the healthcare system in the coming years."