Conducted by the federal Institute of Medicine, the study says costs for the nearly 2 million veterans of the two wars will expand over the next 30 years before tapering off.
The VA's budget is almost $113 billion and has almost doubled since 2003.
"VA does not have the personnel, the funding or the mandate from Congress to produce broad forecasts," the study says, adding that "the human burdens of war extend far beyond the period of active conflict."
These projections are crucial for anticipating how much money and how many services the government must set aside for helping Iraq and Afghanistan veterans, the report says. Gauging those needs is difficult because the wars in Iraq and Afghanistan are "fundamentally different" than previous wars. For example:
• Troops serve multiple combat deployments for cumulatively longer periods.
• Body armor and improved battlefield care save lives, but many wounded servicemembers are left with complex psychological and physical problems.
• The heavy use of National Guard and reservists means older troops serve more than in previous wars.
• Troops are more likely to be married with children than in the past, complicating the impact of deployments. Research has shown that spouses and children can suffer emotional problems linked to deployments.
• More women than ever serve in combat zones, and they tend to have more health issues than male troops. That will lead to higher costs.
History shows that health care costs keep rising after wars end, the study says. Disability compensation or pension payouts for veterans of World War I, World War II and the Korean conflict increased for 25 to 47 years after the end of hostilities.
The VA agreed with many of report's recommendations, says Victoria Cassano, who is managing the department's response to the study. She said some 30-year projections on benefits and veteran populations are possible.