Data from: Performance and agreement of risk stratification instruments for postoperative delirium in persons aged 50 years or older

Several risk stratification instruments for postoperative delirium in
older people have been developed because early interventions may prevent
delirium. We investigated the performance and agreement of nine commonly
used risk stratification instruments in an independent validation cohort
of consecutive elective and emergency surgical patients aged ≥50 years
with ≥1 risk factor for postoperative delirium. Data was collected
prospectively. Delirium was diagnosed according to DSM-IV-TR criteria. The
observed incidence of postoperative delirium was calculated per risk score
per risk stratification instrument. In addition, the risk stratification
instruments were compared in terms of area under the receiver operating
characteristic (ROC) curve (AUC), and positive and negative predictive
value. Finally, the positive agreement between the risk stratification
instruments was calculated. When data required for an exact implementation
of the original risk stratification instruments was not available, we used
alternative data that was comparable. The study population included 292
patients: 60% men; mean age (SD), 66 (8) years; 90% elective surgery. The
incidence of postoperative delirium was 9%. The maximum observed incidence
per risk score was 50% (95%CI, 15–85%); for eight risk stratification
instruments, the maximum observed incidence per risk score was ≤25%. The
AUC (95%CI) for the risk stratification instruments varied between 0.50
(0.36–0.64) and 0.66 (0.48–0.83). No AUC was statistically significant
from 0.50 (p≥0.11). Positive predictive values of the risk stratification
instruments varied between 0–25%, negative predictive values between
89–95%. Positive agreement varied between 0–66%. No risk stratification
instrument showed clearly superior performance. In conclusion, in this
independent validation cohort, the performance and agreement of commonly
used risk stratification instruments for postoperative delirium was poor.
Although some caution is needed because the risk stratification
instruments were not implemented exactly as described in the original
studies, we think that their usefulness in clinical practice can be
questioned.