Muscle weakness, cognitive impairment and their interaction on altered balance in elderly outpatients: results from the TRIP observational study

Figures & data

Table 1 Characteristics of the study population (N=263)

	Mean	SD
Age (years)	81.44	7.36
Female (n, %)	159	60.46
Balance deficit* (n, %)	185	70.34
Low grip strength** (n, %)	152	57.8
Cognitive impairment*** (n, %)	162	61.6
Low grip strength with cognitive impairment (n, %)	114	43.35
Low grip strength without cognitive impairment (n, %)	38	14.45
Cognitive impairment with normal grip strength (n, %)	48	18.25
Normal grip strength without cognitive impairment (n, %)	63	23.95
Falls in the year before evaluation (n, %)	110	42.0
Number of drugs (<5) (n, %)	94	35.7
SPPB score (median, IQR)	5	2–11
BMI (kg/m^2)	26.64	5.14
MMSE score	20.79	6.50
Grip strength (kg)	18.54	9.14
4m-WS§ (m/s)	0.60	0.22–0.88
MNA-SF	10.58	2.71
GDS-15 points	3	1–5

Notes:

* Defined as inability to maintain Tandem position for at least 10 seconds.

** Defined as grip strength below 26 kg in men and 16 kg in women.

*** Defined as MMSE below 24.

§ 4-m walking speed usual pace.

Abbreviations: SPPB, short physical performance battery; IQR, interquartile range; BMI, body mass index; MMSE, mini-mental state examination; MNA-SF, mini nutritional assessment short-form; GDS, geriatric depression scale.

Table 2A Factors associated with balance deficit

	β	p-value*
Grip strength	−0.39	<0.0001
MMSE	−0.17	0.01
BMI	0.05	0.42
MNA-SF	−0.25	0.0002
Number of drugs	0.19	0.005
GDS	0.20	0.16

Note:

* Age- and sex-adjusted Pearson’s correlation analysis.

Abbreviations: MMSE, mini-mental state examination; BMI, body mass index; MNA-SF, mini nutritional assessment short-form; GDS, geriatric depression scale.

Table 2B Association between muscle strength, cognitive performance and their interaction term on balance deficit

	Balance deficit
	β	SE	p-value
Grip strength	−0.002	0.009	0.87
MMSE	0.009	0.007	0.25
“Grip strength*MMSE”	−0.01	0.0004	0.02
Age	0.01	0.003	0.0007
Sex (M versus F)	−0.02	0.06	0.69

Abbreviations: SE, standard error; MMSE, mini-mental state examination; M, male; F, female.

Table 3 Age- and sex-adjusted muscle strength and MMSE with the balance deficit among 4 categories

Balance deficit	β ± SE	p-value
1. Low grip strength with cognitive impairment (n =114)
MMSE	−0.002 ± 0.004	0.73
Grip strength	−0.04 ± 0.005	0.46
2. Low grip strength without cognitive impairment (n =38)
MMSE	−0.08 ± 0.3	0.04
Grip strength	−0.0017 ± 0.0049	0.73
3. Cognitive impairment with normal grip strength (n =48)
MMSE	−0.004 ± 0.014	0.77
Grip strength	−0.05 ± 0.02	0.02
4. Normal grip strength without cognitive impairment (n =63)
MMSE	−0.04 ± 0.03	0.30
Grip strength	−0.01 ± 0.01	0.35

Abbreviations: MMSE, mini-mental state examination; SE, standard error.

Figure 1 Association between grip strength and MMSE (p<0.0001).

Abbreviation: MMSE, mini-mental state examination.

Figure 2 Relationship between cognitive impairment, grip strength and balance deficit: almost all patients with both impairments had a balance deficit (91%), 70% of those with low grip strength and 61% of those with cognitive impairment had a balance deficit, while only 38% of patients without muscle and cognitive impairment showed a balance deficit (Chi-square p<0.0001).

Table 4 Relationship between balance deficit and characteristics derived from the CGA among four categories

	1. Low grip strength with cognitive impairment		2. Low grip strength without cognitive impairment		3. Cognitive impairment with normal grip strength		4. Normal grip strength without cognitive impairment
	β ± SE	p-value	β ± SE	p-value	β ± SE	p-value	β ± SE	p-value
Age	0.009 ± 0.004	0.05	0.001 ± 0.009	0.87	0.03 ± 0.02	0.05	0.03 ± 0.009	0.005
Sex	−0.08 ± 0.07	0.11	−0.07 ± 0.22	0.75	0.03 ± 0.34	0.37	0.029 ± 0.22	0.87
MNA-SF	−0.02 ± 0.01	0.04	−0.02 ± 0.03	0.16	0.027 ± 0.037	0.46	0.024 ± 0.037	0.52
Grip strength	0.004 ± 0.005	0.47	−0.03 ± 0.009	0.01	−0.02 ± 0.02	0.001	−0.02 ± 0.008	0.01
MMSE	−0.001 ± 0.005	0.83	−0.051 ± 0.04	0.22	−0.018 ± 0.015	0.23	−0.02 ± 0.04	0.51
Number of drugs	−0.036 ± 0.037	0.34	0.17 ± 0.09	0.07	0.17 ± 0.08	0.04	0.042 ± 0.064	0.52

Abbreviations: CGA, comprehensive geriatric assessment; SE, standard error; MNA-SF, mini nutritional assessment short-form; MMSE, mini-mental state examination.