Overdose and Fall Risk Concentration among Benzodiazepine Users
Unintentional injury is a significant burden and source of premature mortality for aging Americans: in 2016, there were 53,141 deaths due to unintentional injury among adults 65 and older (“older adults”) and an additional 5.1 million non-fatal injuries. Falls are the leading cause of injury for older adults, accounting for 56% of injury deaths and 63% of non-fatal injuries. Prescription drug overdose is another leading cause of injury among older adults, which is unsurprising given older adults consume the most prescription medications, have the highest rates of polypharmacy overall, and have growing use of potentially harmful polypharmacy of opioids and psychotropic medications. With the population of older adults in the U.S. expected to double to 83.7 million by 2050, identifying older adults at highest risk of unintentional injury has high public health significance, and benzodiazepine (BZD) use is a key factor underlying both of these causes of unintentional injury among older adults.
Benzodiazepines (BZDs) are the medication class most strongly associated with fall and fracture risk in older adults. In addition to their association with falls, BZDs are the second-most common cause of prescription drug overdose (OD) after opioids, as well as the medication most commonly combined with opioids. Compared to fall risk, there have been no studies of how OD risk varies with short- or long-term use.
Aim 1: Among older adults newly-prescribed a BZD, identify clinical characteristics—focused on opioid and other potentially-modifiable co-prescribing—associated with high risk for fall-related injury and OD within 30 days of the new prescription. Using Medicare claims, we will identify adults ≥65 who receive a new BZD prescription and then determine the demographic and clinical characteristics most strongly associated with fall-related injury within 30 days, such as a concurrent new start of an antidepressant or opioid or a high burden of other psychotropic medications. We will complete parallel analyses using OD as the outcome.
Aim 2: Among regular BZD users, determine how the fall and OD risk vary across the intensity of BZD use (e.g., daily vs. less than daily). We will use the BZD medication possession ratio (i.e., [total days prescribed in 12 months] / 365) among regular BZD users to determinate how the risk of fall-related injury or overdose varies with the intensity of BZD consumption (e.g., daily user [MPR=>0.95] vs. intermittent [MPR <0.5]). As in Aim 1, we will determine whether co-prescribing of opioids and psychotropic medications increases injury risk.
Public Health Impact: BZD prescribing to older adults continues despite decades of evidence demonstrating the risk for significant injury from both falls and OD. In the face of continued use, specific recommendations for prescribing have the potential to have greater uptake into clinical practice, but a lack of scientific evidence prevents this approach at this time. We will develop a Policy Brief on Benzodiazepine Prescribing for Older Adults to help address the smoldering but largely unrecognized public health problem of BZD prescribing in older adults, which will have impact in the CDC Injury Center Research Priorities of prescription drug OD and older adult falls.