Developing a Scoring Model to Predict the Risk of Injurious Falls in Elderly Patients: A Retrospective Case–Control Study in Multicenter Acute Hospitals

Figures & data

Table 1 Circumstances of Injurious Fall Events

Variables	n	%
Degree of injury
Minor	31	27.0
Moderate	12	10.4
Major	69	60.0
Death	3	2.6
Department
Internal	95	82.6
Surgical	17	14.8
Others	3	2.6
Disease diagnosis
Circulatory system	21	18.3
Nervous system	20	17.4
Urinary system	13	11.3
Musculoskeletal system	14	12.2
Endocrine system	12	10.4
Cancer	22	19.1
Others	13	11.3
Admission stage (days)
0–3	37	32.2
4–6	19	16.5
7–14	39	33.9
15–21	14	12.2
>21	6	5.2
Month
1–3	32	27.8
4–6	37	32.2
7–9	27	23.5
10–12	19	16.5
Date
1–10	45	39.1
11–20	36	31.3
≥21	34	29.6
Time
7:00–13:00	24	20.9
13:01–19:00	21	18.3
19:01–24:00	30	26.1
00:01–06:59	40	34.8
Accompanied by
Family	25	21.7
Care workers	41	35.7
None	49	42.6
Location
Bedside	42	36.5
Bathroom	39	33.9
Ward	16	13.9
Others	18	15.7
Type of reporting
Patient him(her)self	14	12.2
Family and care workers	41	35.7
Other patients in the same ward	35	30.4
Medical staff	20	17.4
Others	5	4.3
Activity related events
Change position	39	33.9
Excretion	36	31.3
Bathing	7	6.1
Hanging around	16	13.9
Examination	5	4.3
Others	12	10.4
Main cause
Weakness	51	44.3
Dizziness/Vertigo	23	20.0
Slipping	25	21.7
Stumbling	9	7.8
Others	7	6.1

Table 2 Demographic and Clinical Characteristics of the Training Set and Validation Set

Variables	All Patients (N=345)		Training Set (N=242)		Validation Set (N=103)		P-value
	n	%	n	%	n	%
Age (Mean±SD)	78.20 (9.01)		78.27 (9.15)		78.05 (8.70)		0.839
Sex							0.819
Male	188	54.5	132	54.5	56	54.4
Female	157	45.5	110	45.5	47	45.6
BMI							0.599
<18.5	27	7.8	16	6.6	11	10.7
18.5–24.9	237	68.7	168	69.4	69	67.0
25.0–29.9	71	20.6	51	21.1	20	19.4
≥30	10	2.9	7	2.9	3	3.0
Number of comorbidities							0.979
0–2	146	42.3	101	41.7	45	43.7
3–6	173	50.1	123	50.8	50	48.5
≥7	26	7.5	18	7.4	8	7.8
History of fall							0.331
Yes	100	29.0	67	27.7	33	32.0
No	245	71.0	175	72.3	70	68.0
History of fractures							0.405
Yes	82	23.8	53	21.9	29	28.2
No	263	76.2	189	78.1	74	71.8
OH							0.846
Yes	56	16.2	39	16.1	17	16.5
No	289	83.8	203	83.9	86	83.5
Altered or limited mobility gait problems							0.096
Yes	147	42.6	95	39.3	52	50.5
No	198	57.4	147	60.7	51	49.5
Functional status							0.402
Independent	55	15.9	42	17.4	13	12.6
Partially dependent	275	79.7	188	77.7	87	84.5
Completely dependent	15	4.3	12	5.0	3	2.9
Sedative-hypnotics							0.806
Yes	79	22.9	53	21.9	26	25.2
No	266	77.1	189	78.1	77	74.8
Antipsychotics							0.411
Yes	23	6.7	18	7.4	5	4.9
No	322	93.3	224	92.6	98	95.1
Antihypertensive drugs							0.412
Yes	207	60.0	141	58.3	66	64.1
No	138	40.0	101	41.7	37	35.9
Insulin or oral hypoglycemics							0.305
Yes	120	34.8	89	36.8	31	30.1
No	225	65.2	153	63.2	72	69.9
Diuretics							0.077
Yes	103	29.9	64	26.4	39	37.9
No	242	70.1	178	73.6	64	62.1
Level of hemoglobin							0.111
Normal	151	43.8	113	46.7	38	36.9
Low	193	55.9	129	53.3	64	62.1
High	1	0.3	0	0.0	1	1.0
Level of serum albumin							0.120
Normal	165	47.8	119	49.2	46	44.7
Low	180	52.2	123	50.8	57	55.3
High	0	0.0	0	0.0	0	0.0
Level of serum potassium							0.598
Normal	281	81.4	198	81.8	83	80.6
Low	55	15.9	39	16.1	16	15.5
High	9	2.6	5	2.1	4	3.9
Level of INR							0.456
Normal	308	89.3	217	89.7	91	88.3
Low	7	2.0	6	2.5	1	1.0
High	30	8.7	19	7.9	11	10.7

Abbreviations: BMI, body mass index; OH, orthostatic hypotension; INR, international normalized ratio.

Table 3 Univariate Analysis and Multivariate Logistic Analysis for Injurious Falls in the Training Set

Variables	Injurious Falls Group (n=74)		No-Fall Group (n=168)		P-value^a	P-value^b	OR	95% CI
	n	%	n	%
Factors selected
History of fractures					0.000	0.000	5.298	2.311–12.145
No	47	63.5	142	84.5
Yes	27	36.5	26	15.5
OH					0.003	0.001	5.570	2.063–15.038
No	54	73.0	149	88.7
Yes	20	27.0	19	11.3
Functional status					0.000	0.028	2.915	1.125–7.553
Independent	5	6.8	37	22.0
Partially dependent	59	79.7	129	76.8
Completely dependent	10	13.5	2	1.2
Sedative-hypnotics					0.000	0.000	8.280	3.631–18.883
No	40	54.1	149	88.7
Yes	34	45.9	19	11.3
Level of serum albumin					0.000	0.000	12.505	5.123–30.522
Normal	16	21.6	103	61.3
Low	58	78.4	65	38.7
High	0	0.0	0	0.0
Factors not selected
Age (Mean±SD)	80.91 (8.72)		77.07 (9.11)		0.002
Sex					0.806
Male	42	56.8	90	53.6
Female	32	43.2	78	46.4
BMI					0.157
<18.5	4	5.4	12	7.1
18.5–24.9	57	77.0	111	66.1
25.0–29.9	13	17.6	38	22.6
≥30	0	0.0	7	4.2
Number of comorbidities					0.946
0–2	29	39.2	72	42.9
3–6	39	52.7	84	50.0
≥7	6	8.1	12	7.1
History of fall					0.000
No	41	55.4	134	79.8
Yes	33	44.6	34	20.2
Altered or limited mobility gait problems					0.001
No	34	45.9	113	67.3
Yes	40	54.1	55	32.7
Antipsychotics					0.206
No	66	89.2	158	94.0
Yes	8	10.8	10	6.0
Antihypertensive drugs					0.476
No	34	45.9	67	39.9
Yes	40	54.1	101	60.1
Insulin or oral hypoglycemics					0.713
No	45	60.9	108	64.3
Yes	29	39.1	60	35.7
Diuretics					0.000
No	43	58.1	135	80.4
Yes	31	41.9	33	19.6
Level of hemoglobin					0.001
Normal	23	31.1	90	53.6
Low	51	68.9	78	46.4
High	0	0.0	0	0.0
Level of serum potassium					0.026
Normal	53	71.6	145	86.3
Low	18	24.3	21	12.5
High	3	4.1	2	1.2
Level of INR					0.040
Normal	61	82.4	156	92.9
Low	4	5.4	2	1.2
High	9	12.2	10	6.0

Notes: ^aP-value was calculated by univariate analysis. ^bP-value was calculated by multivariate logistic analysis. Bolded figures: P<0.05.

Abbreviations: BMI, body mass index; OH, orthostatic hypotension; INR, international normalized ratio; OR, odds ratio; 95% CI, 95% confidence interval.

Figure 1 The nomogram to predict the probability of injurious falls in elderly inpatients.

Figure 2 Calibration curve of the nomogram for the training set (A) and validation set (B). The model-predicted probability of the clinical model is illustrated on the X-axis, and the observed probability of older adults with injury in a fall event is displayed on the Y-axis.

Figure 3 The ROC curve and AUC of the nomogram and fall risk assessment tools to predict the probability of injurious falls in the training set (A) and validation set (B).

Abbreviations: ROC, receiver operating characteristic; AUC, area under the curve.