Table 1.
Prespecification of predictor variables for a mortality risk prediction tool among hospitalized patients with dementia with initial degrees of freedom allocation
| Variable | Scale | Initial variable specification | Degrees of freedom |
|---|---|---|---|
| Sociodemographic factors | |||
| Age | Continuous | 5-knot spline: valid range: 65 to 105 years | 4 |
| Sex | Categorical | Male; female | 1 |
| Living status | Categorical | 5 categories: home, independent; home, home care; nursing home; rehabilitation; chronic hospital | 4 |
| Comorbidities | |||
| Cerebrovascular disease | Categorical | Yes; no | 1 |
| Heart failure | Categorical | Yes; no | 1 |
| Cardiovascular disease | Categorical | Yes; no | 1 |
| Arrhythmia | Categorical | Yes; no | 1 |
| Cardiac arrest | Categorical | Yes; no | 1 |
| Chronic obstructive pulmonary disease | Categorical | Yes; no | 1 |
| Asthma | Categorical | Yes; no | 1 |
| Pneumonia | Categorical | Yes; no | 1 |
| Pneumonitis | Categorical | Yes; no | 1 |
| Adult respiratory distress syndrome | Categorical | Yes; no | 1 |
| Interstitial lung disease | Categorical | Yes; no | 1 |
| Respiratory failure | Categorical | Yes; no | 1 |
| Gastrostomy site infection | Categorical | Yes; no | 1 |
| Liver cirrhosis | Categorical | Yes; no | 1 |
| Urinary tract infection | Categorical | Yes; no | 1 |
| Fecal incontinence | Categorical | Yes; no | 1 |
| Urinary incontinence | Categorical | Yes; no | 1 |
| Renal failure | Categorical | Yes; no | 1 |
| Decubitus ulcer | Categorical | Yes; no | 1 |
| Parkinson’s disease | Categorical | Yes; no | 1 |
| Multiple sclerosis | Categorical | Yes; no | 1 |
| Osteoporosis | Categorical | Yes; no | 1 |
| Fracture | Categorical | Yes; no | 1 |
| Malignancy | |||
| Lip, oral cavity, pharynx | Categorical | Yes; no | 1 |
| Digestive organs | Categorical | Yes; no | 1 |
| Respiratory, intrathoracic organs | Categorical | Yes; no | 1 |
| Skin | Categorical | Yes; no | 1 |
| Mesothelium, soft tissue | Categorical | Yes; no | 1 |
| Breast | Categorical | Yes; no | 1 |
| Female genital organs | Categorical | Yes; no | 1 |
| Male genital organs | Categorical | Yes; no | 1 |
| Urinary tract | Categorical | Yes; no | 1 |
| Central nervous system | Categorical | Yes; no | 1 |
| Endocrine glands | Categorical | Yes; no | 1 |
| Bone | Categorical | Yes; no | 1 |
| Unspecified | Categorical | Yes; no | 1 |
| Blood | Categorical | Yes; no | 1 |
| Multiple | Categorical | Yes; no | 1 |
| Sepsis | Categorical | Yes; no | 1 |
| Diabetes mellitus | Categorical | Yes; no | 1 |
| Hypertension | Categorical | Yes; no | 1 |
| Peripheral arterial disease | Categorical | Yes; no | 1 |
| Shock | Categorical | Yes; no | 1 |
| Mood disorder | Categorical | Yes; no | 1 |
| Schizophrenia | Categorical | Yes; no | 1 |
| Complication from benzodiazepine | Categorical | Yes; no | 1 |
| Complication from antipsychotic | Categorical | Yes; no | 1 |
| Fall | Categorical | Yes; no | 1 |
| vChronic kidney disease | Categorical | Yes; no | 1 |
| Rheumatoid arthritis | Categorical | Yes; no | 1 |
| Polypharmacy | Categorical | Yes; no | 1 |
| Previous interventions | |||
| Heart resuscitation | Categorical | Yes; no | 1 |
| Mechanical ventilation lasting ≥ 96 h | Categorical | Yes; no | 1 |
| Mechanical ventilation lasting < 96 h | Categorical | Yes; no | 1 |
| Dialysis | Categorical | Yes; no | 1 |
| Cardioversion | Categorical | Yes; no | 1 |
| Chemotherapy | Categorical | Yes; no | 1 |
| Radiotherapy | Categorical | Yes; no | 1 |
| Tracheostomy | Categorical | Yes; no | 1 |
| Functional status | |||
| Hospital Frailty Risk Score | Continuous | 5-knot spline: valid range 0 to 99 | 4 |
| Dysphasia and aphasia | Categorical | Yes; no | 1 |
| Dysarthria and anarthria | Categorical | Yes; no | 1 |
| Dysphagia | Categorical | Yes; no | 1 |
| Dependence on wheelchair | Categorical | Yes; no | 1 |
| Blindness | Categorical | Yes; no | 1 |
| Hearing loss | Categorical | Yes; no | 1 |
| Hospital-based occupational therapy consultation in past 3 years | Categorical | Yes; no | 1 |
| Hospital-based physiotherapy consultation in past 3 years | Categorical | Yes; no | 1 |
| Hospital-based social worker consultation in past 3 years | Categorical | Yes; no | 1 |
| Hospital-based speech language pathology consultation in past 3 years | Categorical | Yes; no | 1 |
| Nutritional status | |||
| Weight | Continuous | 5-knot spline | 4 |
| Height | Continuous | 5-knot spline | 4 |
| Parenteral nutrition | Categorical | Yes; no | 1 |
| Feeding tube | Categorical | Yes; no | 1 |
| Anorexia | Categorical | Yes; no | 1 |
| Abnormal weight loss | Categorical | Yes; no | 1 |
| Volume depletion | Categorical | Yes; no | 1 |
| Admission information | |||
| Admitting service | Categorical | 15 categories: General internal medicine; Cardiology; Gastroenterology; Palliative care; Medical oncology; General surgery; Cardiovascular surgery; Neurosurgery; Orthopedic surgery; Plastic surgery; Thoracic surgery; Trauma; Urology; Gynecology; Psychiatry | 14 |
| Admission urgency | Categorical | 3 categories: elective; urgent, without ambulance; urgent, with ambulance | 2 |
| Admission directly to ICU | Categorical | Yes; no | 1 |
| Urgent 30-day readmission | Categorical | Yes; no | 1 |
| Previous healthcare utilization | |||
| ED visits in past 12 months | Ordinal | 7 categories: 0, 1, 2, 3, 4, 5, 6 + | 6 |
| Admissions by ambulance in past 12 months | Ordinal | 4 categories: 0, 1, 2, 3 + | 3 |
| Hospital-based palliative care in past 3 years | Categorical | Yes; no | 1 |
Age will be interacted with all variables except those listed under sociodemographic factors, admission information, and previous health care utilization; renal failure will be interacted with dialysis; each site of malignancy will be interacted with chemotherapy
ICU Intensive care unit, ED Emergency department