Table 4.
Mediation analysis predicting cognition at 1 month after hospital discharge
| Number of Patients Taking Medication | Total Effect of Medication on Cognitiona | Direct Effect of Medication on Cognitionb | Indirect Effect of Medication on Cognitionc | ||||
|---|---|---|---|---|---|---|---|
| Slope (SE) | P-value | Slope (SE) | p-value | Slope (SE) | P-value | ||
| Antipsychotics | 32 (5.7%) | −0.15 (0.61) | .81 | 0.19 (0.61) | 0.75 | −0.34 (0.16) | .03 |
| Benzodiazepines | 127 (22.7%) | −0.01 (0.34) | .98 | 0.11 (0.34) | 0.74 | −0.12 (0.07) | .09 |
| Beta blockers | 229 (40.9%) | 0.03 (0.29) | .91 | 0.13 (0.29) | 0.66 | −0.10 (0.05) | .07 |
| NSAIDs | 339 (60.5%) | 0.12 (0.29) | .67 | 0.15 (0.29) | 0.59 | −0.03 (0.05) | .49 |
| Statins | 323 (57.7%) | −0.16 (0.29) | .58 | −0.07 (0.28) | 0.80 | −0.08 (0.05) | .09 |
| Hydromorphone | 402 (71.8%) | −0.07 (0.31) | .82 | −0.01 (0.31) | 0.97 | −0.06 (0.05) | .23 |
| Morphine | 127 (22.7%) | 0.26 (0.33) | .43 | 0.34 (0.33) | 0.30 | −0.08 (0.05) | .20 |
| Oxycodone | 416 (74.3%) | 0.37 (0.32) | .25 | 0.31 (0.32) | 0.33 | 0.07 (0.05) | .23 |
| Tramadol | 72 (12.9%) | −0.28 (0.41) | .50 | −0.16 (0.41) | 0.69 | −0.11 (0.08) | .14 |
Medication categories reflect use prior to hospitalization, during hospitalization, and at hospital discharge. All models are adjusted for age, gender, surgery type, Charlson comorbidity index, APACHE-II score, and cognition at baseline.
The total effect represents the combined direct and indirect effect of the medication on cognition at 1 month.
The direct effect represents the effect of the medication on cognition that is not mediated by delirium.
The indirect effect represents the effect of the medication on cognition that is mediated by the effects the medication has on delirium.
Abbreviations: APACHE, Acute Physiologic and Chronic Health Evaluation; NSAIDs = Non-steroidal anti-inflammatory drugs; SE, standard error; Statins = HMG-CoA reductase inhibitors