The application of IMPACT prognostic models to elderly adults with traumatic brain injury: A population-based observational cohort study

• Published in: Brain injury 2016-06, Vol.30 (7), p.899-907
• Main Authors: Staples, John A., Wang, Jin, Zaros, Mark C., Jurkovich, Gregory J., Rivara, Frederick P.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Brain Injuries, Traumatic - diagnosis; Cohort Studies; Female; geriatric patients; Humans; IMPACT score; Male; Middle Aged; Models, Theoretical; Prognosis; Traumatic brain injury; Young Adult
• ISSN: 0269-9052; 1362-301X
• DOI: 10.3109/02699052.2016.1146964

Objective: To examine the performance of the International Mission for Prognosis and Clinical Trial Design in Traumatic Brain Injury (IMPACT) prognostic models in older patients. Methods: Using data from the National Study on Costs and Outcomes of Trauma (NSCOT), this study identified adult patients presenting to US hospitals in 2001 and 2002 with non-penetrating moderate or severe traumatic brain injury (GCS ≤ 12). IMPACT model calibration and discrimination in the older stratum (65-84 years) was compared to that in the younger stratum (18-64 years). Results: IMPACT model discrimination did not differ significantly between the older (n = 202; weighted n = 268) and younger strata (n = 613; weighted n = 1632) and was generally adequate (c-statistic for the core-death model = 0.81 [0.77-0.84] vs 0.75 [0.66-0.84], respectively; p = 0.26). IMPACT model calibration was poor for both older and younger strata (Hosmer-Lemeshow p-value for the core-death model = 0.01 vs < 0.0001, respectively). Pre-specified qualitative graphical evaluation suggested substantial under-prediction of mortality in the oldest decades of life, but not among younger patients. Conclusions: The examined IMPACT prognostic models demonstrated adequate discrimination and poor calibration in both older and younger patients, yet particular caution may be required when applying these models to the elderly.