According to a new report from the Johns Hopkins Center for Injury Research and Policy, a dramatic increase in the fall death rate in older Americans is likely the effect of improved reporting quality, specifically from the 1999 update to the International Classification of Diseases (ICD-10). The researchers say this suggests a major change in the way deaths were classified. Several research studies, including one by the report’s authors, found that rates of fatal falls among seniors had risen as much as 42 percent between 2000 and 2006.

“We had been perplexed by the sudden increase because neither the nonfatal fall rate nor the fall-hospitalization rate increased significantly,” Susan P. Baker, a professor with the Johns Hopkins Center for Injury Research and Policy, part of the Johns Hopkins Bloomberg School of Public Health, said in a statement. “By ruling out these variables, we found that a change in how the underlying cause of death gets reported explains much of the widely-reported increase.”

The researchers say, the largest increase was in the coding subgroup “other falls on the same level.” This refers to when an individual falls on the same surface they are standing or walking on; such falls generally do not result in injury that is immediately life-threatening. According to study author Guoqing Hu, PhD, faculty with the Central South University School of Public Health in China, the many of these deaths were coded as the illness rather than the fall.

Hu said in a statement, “After ICD-10 went into effect in 1999, the rate of deaths from this type of fall jumped, suggesting a major change in death certification practices.”

According to the study, the annual direct and indirect cost of fall injuries is expected to reach $55 billion by 2020. The researchers say interpretation of recent trends is critical for understanding the effect of ongoing measures designed to prevent fall injuries in the elderly. Falls in older adults are indeed a major public health problem, and this report should not suggest otherwise,” said Baker, who said falls were probably under-reported before ICD-10.

The results of the study are published in the May-June issue of Public Health Reports.