Selected candidate predictors to derive the risk prediction model
| Variable | Data source and measurement | Prevalence* | Unadjusted OR (95% CI) on univariable analysis | Adjusted OR (95% CI) multivariable regression based on backwards elimination based on Akaike Information Criterion (p>0.157) | β-Coefficients of variables included in model | P value in multivariable analysis |
| Age (years) | Self-report and medical records | 81.2 | 1.03 (1.00 to 1.06) | 1.03 (1.00 to 1.05) | 0.025 | 0.078 |
| Gender (reference female) | Self-report and medical records | 43.3 (male) 56.7 (female) | 0.57 (0.38 to 0.86) | 0.67 (0.43 to 1.04) | −0.398 | 0.075 |
| Past ADR† | Self-report and medical records | 31.1% | 1.79 (1.20 to 2.67) | 1.61 (1.06 to 2.45) | 0.477 | 0.026 |
| Antiplatelet drug | Discharge summary and medical records. Drugs coded B01AC on WHO-ATC system | 43.3% | 1.78 (1.20 to 2.63) | 1.67 (1.11 to 2.53) | 0.515 | 0.014 |
| Antidiabetic drug | Discharge summary and medical records. Drugs coded A10A or A10B on WHO-ATC system | 19.7% | 1.89 (1.22 to 2.94) | 1.81 (1.12 to 2.91) | 0.591 | 0.016 |
| Living alone† | Self-report and medical records | 47.9% | 1.61 (1.08 to 2.38) | 1.49 (0.98 to 2.27) | 0.397 | 0.064 |
| Sodium level (mmol/L) | Last recorded inpatient biochemistry prior to discharge | 137 | 0.97 (0.93 to 1.01) | 0.96 (0.92 to 1.00) | −0.042 | 0.069 |
| Number of medicines | Discharge summary and medical records. Total number of medicines at discharge | 9 | 1.08 (1.04 to 1.13) | 1.06 (1.00 to 1.11) | 0.056 | 0.033 |
| Hand grip strength (kg)† | Southampton Protocol for Adult Grip strength Measurement using the JAMAR Hydraulic Hand Dynamometer93 | 25.6 (male) 14.3 (female) | 0.98 (0.96 to 1.00) | Eliminated from model (p>0.157) | N/A | 0.911 |
| Medication compliance aid | Multicompartment compliance aid on discharge | 33.5% | 1.54 (1.03 to 2.29) | Eliminated from model (p>0.157) | N/A | 0.302 |
| Renal impairment (eGFR <60 mL/min/1.73 m2 )† | Last recorded inpatient biochemistry prior to discharge | 41.9% | 1.67 (1.13 to 2.47) | Eliminated from model (p>0.157) | N/A | 0.216 |
| Charlson Comorbidity Index | Discharge summary and medical records Total number of diseases defined by Charlson Comorbidity Index94 | 48.7% (<2) 51.3% (≥2) | 1.12 (0.95 to 1.31) | Eliminated from model (p>0.157) | N/A | 0.403 |
Past ADR was defined as any adverse drug reaction documented in the medical records and confirmed, where possible, during the process of medicines reconciliation.
*Percentage of patients for categorical predictor or average value for continuous predictor.
†Incomplete data for predictors; renal impairment (n=56) hand grip strength (n=100), past ADR (n=7), sodium level (n=4), lives alone (n=2).
ADR, adverse drug reaction; eGFR, estimated glomerular filtration rate; N/A, not available.