The Added Value of Combined Timed Up and Go Test, Walking Speed, and Grip Strength on Predicting Recurrent Falls in Chinese Community-dwelling Elderly

Figures & data

Figure 1 The flowchart of selecting included participants.

Table 1 Baseline Characteristics of Study Participants (No-fall Group, Any-falls Group and Recurrent-falls Group) During the Follow-up Period

	Total	No-fall Group	Any-falls Group	Recurrent-falls Group	P-value
	N=875	N=675	N=200	N=66
Demographics
Age (years)	67.10±5.94	66.82±5.81	68.03±6.29*	69.95±5.29*,**	<0.001
Gender (male/female)	361/513	292/382	69/131*	22/44	0.082
Height (cm)	162.85±8.91	162.88±8.82	162.76±9.22	161.86±8.91	0.602
Weight (kg)	67.69±11.53	67.54±11.38	68.18±12.01	66.69±11.91	0.347
BMI (kg/m^2)	25.47±3.51	25.40±3.44	25.71±3.76	25.40±3.72	0.365
Illiterate (%)	38.3	38.9	36.4	40.0	0.619
Widowed (%)	13.8	12.7	17.5*	12.1**	0.070
Cohabit with spouse (%)	89.7	91.2	84.7*	90.3**	0.008
Living alone (%)	11.9	11.7	12.6	6.1**	0.130
Fall history (%)	19.7	14.0	39.0*	47.0*	<0.001
Walking aid (%)	0.6	0.3	1.5*	3.0	0.020
Drinking (%)					0.202
Never	64.1	62.3	70.1	63.6
Former	10.0	10.7	7.6	9.1
Current	25.9	27.0	22.3	27.3
Smoking (%)					0.497
Never	49.7	48.7	53.0	47.0
Former	18.2	18.4	22.2	22.7
Current	32.1	32.9	29.3	30.3
Objective parameters
Grip/weight (kg/kg)	0.38±0.12	0.38±0.12	0.35±0.13*	0.34±0.12*	0.010
4-meter walking test (m/s)	1.00±0.21	1.01±0.21	0.96±0.22*	0.92±0.23*	0.001
TUGT (s)	10.32±2.70	10.09±2.63	11.10±2.79*	12.07±3.18*,**	<0.001
IPAQ (MET-min/week)	2548.21±4390.84	2586.21±4450.92	2404.32±4654.63	1738.08±2881.79	0.360
Depression
GDS ≥11 (%)	10.8	6.8	24.1*	32.3*	<0.001
Diseases (%)
Diabetes	12.1	10.0	19.0*	18.2*	0.515
Hypertension	50.2	48.9	54.5	47.0	0.111
Hyperlipidemia	25.3	25.1	26.0	31.8	0.403
Heart disease	24.6	24.4	25.0	28.8	0.674
Peptic ulcer	5.2	4.6	7.0	10.6*	0.115
Stroke	7.3	7.0	8.0	6.1	0.685
Gout	1.4	1.3	1.5	1.5	0.987
Cancer	1.3	1.5	0.5	1.5	0.361
Kidney disease	2.9	2.4	4.5	4.5	0.297
Hepatic disease	1.7	1.8	1.5	3.0	0.487
Biliary tract disease	4.2	3.7	5.5	0.0*,**	0.013
Thyroid disease	1.7	1.9	1.0	0.0	0.498
Osteoarthritis	21.7	22.3	19.5	31.8*,**	0.009
Anemia	0.6	0.7	0.0	0.0	0.770

Notes: Data are presented as means ±SD for age, body mass index (BMI), timed up and go test (TUGT), four-meter walking test, grip strength and International Physical Activity Questionnaire (IPAQ). All other variables are presented in percentages; *P<0.05 vs no-fall group. **P<0.05 vs any-falls group; overall P-value of the ANOVA among the three groups.

Abbreviations: GDS, geriatric depression; MET-min/week, metabolic equivalent task minutes per week.

Table 2 Cutoff Points of TUGT, GS, and WS Toward Any-falls and Recurrent-falls According to the Receiver Operating Characteristic Curve (ROC)

Variables	Cutoff Point of Any-falls	Sensitivity	Specificity	ROC	95%CI	P-value
TUGT	10.31	0.555	0.626	0.618	0.575–0.661	<0.001
GS	0.3742	0.578	0.523	0.567	0.521–0.614	0.004
WS	0.9467	0.435	0.614	0.570	0.523–0.616	0.003
TUGT	10.31	0.652	0.603	0.685	0.618–0.753	<0.001
GS	0.3742	0.576	0.506	0.576	0.506–0.647	0.039
WS	0.9467	0.530	0.613	0.605	0.527–0.683	0.004

Abbreviations: TUGT, timed up and go test; GS, grip strength/weight; WS, four-meter walking speed; 95%CI, 95% confidence interval.

Table 3 Odds Ratio (OR) and 95% Confidence Interval of Performance-based Models for New Onset of Any-falls

Variables	Any-Fallers, N (%)	Crude		Model 1		Model 2
		OR	95%CI	OR	95%CI	OR	95%CI
TUGT–	112 (30.9)	2.396*	1.749–3.283	2.187*	1.563–3.059	2.025*	1.425–2.877
GS–	116 (26.7)	1.703*	1.243–2.332	1.467*	1.013–2.124	1.498*	1.032–2.173
TUGT–, GS–	70 (32.7)	1.924*	1.365–2.711	1.642*	1.125–2.399	1.520*	1.015–2.278
TUGT–, WS+	41 (37.3)	3.341*	2.211–5.048	3.382*	2.226–5.136	2.943*	1.885–4.592
TUGT–, GS–, WS+	20 (40.8)	6.056*	3.311–11.076	5.544*	3.009–10.214	5.499*	2.982–10.140

Notes: Logistic regression analysis of the relationship between functional tests and any-falls or recurrent-falls. Model 1 adjusted for age and sex. Model 2 additionally adjusted for widowed, cohabit with spouse, walking aid, fall history, diabetes, and depression. *P<0.05 vs no-fall group.

Abbreviations: GS, grip strength/weight; TUGT, timed up and go test; WS, walking speed; 95%CI, 95% confidence interval.

Table 4 Odds Ratio (OR) and 95% Confidence Interval of Performance-based Models for New Onset of Recurrent-falls

Variables	Recurrent-fallers N (%)	Crude		Model 1		Model 2
		OR	95%CI	OR	95%CI	OR	95%CI
TUGT–	45 (15.2)	3.586*	2.087–6.160	2.705*	1.526–4.792	2.150*	1.169–3.954
TUGT–, GS–	33 (18.5)	3.641*	2.173–6.102	2.751*	1.539–4.919	2.536*	1.351–4.759
TUGT–, WS+	13 (11.8)	4.684*	2.696–8.139	5.019*	2.832–8.894	3.903*	2.093–7.279
TUGT–, GS–, WS+	20 (44.4)	11.235*	5.809–21.730	10.024*	5.091–19.738	8.260*	3.880–17.585

Notes: Logistic regression analysis of the relationship between functional tests and any-falls or recurrent-falls. Recurrent-falls: model 1 adjusted for age and sex. Model 2 additionally adjusted for widowed, living alone, cohabit with spouse, walking aid, fall history, diabetes, peptic ulcer, biliary tract disease, osteoarthritis, and depression. *P<0.05 vs no-fall group.

Abbreviations: GS, grip strength/weight; TUGT, timed up and go test; WS, walking speed; 95%CI, 95% confidence interval.

Table 5 Added Value of Combined Performance-based Models Than a Single Test

Model	C-Statistics	95%CI	SE	P-value
Any-falls
TUGT–	0.610	0.575–0.645	0.0240
GS–	0.598	0.563–0.633	0.0241	0.363
TUGT–, GS–	0.623	0.587–0.657	0.0239	0.139
TUGT–, WS+	0.609	0.573–0.643	0.0238	0.568
TUGT–, GS–, WS+	0.628	0.593–0.663	0.0237	0.083
Recurrent-falls
TUGT–	0.726	0.690–0.761	0.0309
TUGT–, GS–	0.746	0.710–0.779	0.0289	0.458
TUGT–, WS+	0.722	0.685–0.756	0.0311	0.819
TUGT–, GS–, WS+	0.815*,**,***	0.782–0.844	0.0285	<0.001

Notes: P-value: models vs “TUGT–”. *P<0.05 vs “TUGT–”. **P<0.05 vs “WS+, GS–”. ***P<0.05 vs “TUGT-, GS-”.

Abbreviations: GS, grip strength/weight; TUGT, timed up and go test; WS, walking speed; 95%CI, 95% confidence interval.

Figure 2 Area under curve (AUC) of performance-based models in discriminating new onset of any-falls and recurrent-falls. (A) ROC of all significant functional models in screening any-fallers. (B) ROC of all significant functional models in screening recurrent-fallers. “TUGT+” <10.31 s, “TUGT–” >10.31 s; “GS+” >0.3742 kg/kg, “GS–” <0.3742 kg/kg; “WS+” >0.9467 m/s, “WS–” <0.9467 m/s.

Abbreviations: TUGT, timed up and go test; GS, grip strength/weight; WS, four-m walking speed.