Single Rib Fractures in Geriatric Patients: Analysis to Determine Age Cutoff at Which Mortality Sharply Increases

Although rib fracture (RF) is a well-known risk factor for morbidity and mortality in older adults, there is no definitive “geriatric” age cutoff above which RF-related mortality sharply increases. This study aims to identify an age threshold at which a single RF clearly increases mortality, informing evidence-based Emergency Department disposition pathways after falls in older adults.

Using the American College of Surgeons National Trauma Data Bank (ACS NTDB), six years (2017-2022) of data was analyzed. Eligible cases were 35 or older with fall as the mechanism of injury, with no RF or a single RF. Prespecified subset analysis focused on alert patients with stable vitals. Modeling with evaluation of non-linear age effects using locally weighted scatterplot smoothing (LOWESS), multivariable fractional polynomial (MFP) transformation, and generation of restricted cubic splines (RCS). Multivariable logistic regression (adjusted for operations and demographic factors) assessed effect of age, RF, and the age×RF interaction with estimation of odds ratio (OR) and its 95% confidence interval (CI).

Of 6,715,941 cases, 2,122,722 met eligibility criteria; the median age was 73 and 55.62% were female. Single RF was present in 56,154 (2.65%). Death in the index visit occurred in 94,274 (4.44%). 1,215,282; 57.25% of the all-cases dataset presented alert with stable vital signs. MFP and RCS confirmed non-linear relationship between age and risk of death, and all operations and demographics variables were also significantly associated with mortality. In models assessing the overall dataset and in the subset of alert patients with stable vital signs, both age and RF were strong predictors of mortality. However, neither LOWESS plots of observed mortality nor modeling’s interaction terms identified signs of effect modification, in either the overall dataset (interaction terms’ p values for RF and the two transformed age variables were p=.557 and p=.970) or in the alert patients with stable vitals subset (interaction term p=.562).

Age and single RF both increase mortality risk after a fall. However, there is no indication in these NTDB data – even in the subset of alert patients with stable vital signs – that there is a particular “geriatric” age cutoff above which there is markedly accelerated risk of death after a single RF.