Validation and Comparison of Four Mortality Prediction Models in a Geriatric Ward in China

Figures & data

Table 1 Baseline Characteristics of Participants

Characteristic	Participants n=832	Patients with Missing Data n (%)
Age, median (IQR), y	77.0 (74.0–82.0)	0
Sex, n (%)		0
Female	452 (54.3)
Male	380 (45.7)
Length of hospital stay, median (IQR), d	15.0 (11.0–20.0)	0
No. of medications, median (IQR)	5.0 (3.0–7.0)	0
ADL, dependent, n (%)		0
Toilet	167 (20.1)
Feeding	51 (6.1)
Dressing	124 (14.9)
Grooming	131 (15.7)
Physical Ambulation	335 (40.3)
Bathing	220 (26.4)
IADL, median (IQR)	8.0 (4.0–8.0)	0
MNA-SF, median (IQR)	12.0 (9.0–13.5)	1(0.1)
MMSE, median (IQR)	27.0 (24.0–29.0)	52 (6.3)
GDS-15, median (IQR)	3.0 (1.0–5.0)	79 (9.5)
Grip strength, median (IQR), kg	22.0 (17.8–28.7)	111 (13.3)
SPPB, median (IQR)	9.0 (4.0–11.0)	59 (7.1)
Living condition, n (%)		0
Living alone	103 (12.4)
Living with family	721 (86.7)
Institutionalized	8 (1.0)
Cigarette use, n (%)		0
Never	596 (71.6)
Former	113 (13.6)
Current	123 (14.8)
Marital, n (%)		0
Married	642 (77.2)
Not married	190 (22.8)
Laboratory values, median (IQR)
Hemoglobin, g/L	123.0 (110.8–136.0)	0
Albumin, g/dL	3.8 (3.5–4.1)	1 (0.1)
Creatine, mg/dL	0.8 (0.7–1.0)	1 (0.1)
Walter Index, median (IQR)	2.0 (1.0–4.0)	2 (0.2)
GPI, median (IQR)	2.5 (1.5–4.0)	101 (12.1)
CCI, median (IQR)	1.0 (0.0–2.0)	0
FRAIL Scale, median (IQR)	1.0 (0.0–3.0)	13 (1.6)

Abbreviations: IQR, interquartile range; ADL, Activities of daily living; IADL, Instrumental activities of daily living; GDS-15, Geriatric Depression Scale −15; MMSE, Mini-Mental State Examination; MNA-SF, Mini Nutritional Assessment Short Form; SPPB, Short-Physical Performance Battery, GPI, Geriatric Prognostic Index, CCI, Charlson Comorbidity Index.

Table 2 Logistic Regression of Associations Between the 4 Models and 1-Year Mortality Risk

	Non-Adjusted		Adjustment I		Adjustment II
	OR (95% CI)	P -value	OR (95% CI)	P- value	OR (95% CI)	P -value
Walter Index risk groups, scores
0–1	Reference		Reference		Reference
2–3	5.58 (1.54, 20.23)	0.009*	5.21 (1.42, 19.06)	0.013*	3.89 (1.03, 14.68)	0.045*
4–6	31.85 (9.63, 105.39)	<0.001^†	23.86 (7.02, 81.07)	<0.001^†	17.36 (4.96, 60.84)	<0.001^†
>6	163.81 (48.56, 552.54)	<0.001^†	111.02 (31.73, 388.39)	<0.001^†	81.43 (22.54, 294.18)	<0.001^†
CCI risk groups, scores
0	Reference		Reference		Reference
1–2	2.58 (1.11, 5.99)	0.027*	2.52 (1.07, 5.96)	0.035*	2.22 (0.93, 5.32)	0.07
3–4	6.28 (2.59, 15.21)	<0.001^†	5.43 (2.14, 13.74)	<0.001^†	3.89 (1.50, 10.08)	0.005*
>4	48.30 (19.88, 117.30)	<0.001^†	31.23 (12.24, 79.67)	<0.001^†	27.06 (10.35, 70.76)	<0.001^†
FRAIL Scale risk groups, scores
0	Reference		Reference		Reference
1–2	3.47 (1.41, 8.51)	0.007*	3.34 (1.33, 8.42)	0.011*	2.76 (1.07, 7.15)	0.036*
3–5	14.06 (5.96, 33.18)	<0.001^†	10.76 (4.33, 26.70)	<0.001^†	7.97 (2.82, 22.56)	<0.001^†
GPI, continuous variable, scores
	1.73 (1.48,2.03)	<0.001^†	1.66 (1.38,1.98)	<0.001^†	1.63 (1.30, 2.04)	<0.001^†

Notes: Adjustment I covariates: marital status; social support network, cigarette use, length of stay, number of medications, hemoglobin. Adjustment II covariates: Adjustment I covariates + handgrip strength and Short Physical Performance Battery. *P<0.05. ^† P<0.001.

Abbreviations: OR, Odds Ratio; CI, Confidence Interval; CCI, Charlson Comorbidity index; GPI, Geriatric Prognostic Index.

Table 3 The Performance of 4 Prediction Models in Predicting 1-Year Mortality

	Overall Performance	Discrimination	Calibration By HOSMER-Lemeshow Goodness-of-Fit Test
	Brier Score	C-Statistic (95% CI)	χ^2	P-value
Walter Index	0.07	0.88 (0.84–0.91)	0.05	0.98
GPI	0.08	0.75 (0.69–0.80)	5.86	0.66
CCI	0.08	0.78 (0.73–0.83)	0.49	0.78
FRAIL Scale	0.10	0.74 (0.69–0.78)	0.01	0.92

Abbreviations: GPI, Geriatric Prognostic Index; CCI, Charlson Comorbidity Index; CI, Confidence Interval.

Figure 1 Distribution of calculated risk scores and the relationship between observed and predicted 1-year mortality.

Notes: The columns show the percentage of patients in different subgroups, and the lines show the 1-year mortality, with the green line is the observed mortality and the orange line is the predicted mortality. Sub-figures A–D represent distribution of calculated risk scores of the Walter Index, GPI, CCI, and FRAIL Scale and the relationship between observed and predicted 1-year mortality, respectively.

Abbreviations: CCI, Charlson Comorbidity Index; GPI, Geriatric Prognostic Index.

Figure 2 Calibration plot for 1-year mortality.

Notes: Calibration plot with predicted mortality on the x-axis and observed mortality on the y-axis. A perfect prediction corresponds to the 45°dotted line (ideal calibration line). Calibration curves were bias-corrected using bootstrapping (B=1000 repetitions), indicating the performance of the observed models.

Abbreviations: CCI, Charlson Comorbidity Index; GPI, Geriatric Prognostic Index.