Baseline Nutritional Status and In-Hospital Step Count are Associated with Muscle Quantity, Quality, and Function: Results of an Exploratory Study

Figures & data

Figure 1. Study schema showing timing of assessments performed at each timepoint in study.

Table 1. Baseline characteristics of participants separated by nutritional status and step count.

		Overall (N = 79)	Nutrition				Step count
			Normal (N = 33)	At risk (N = 40)	Malnourished (N = 6)	p Value	<900/day (N = 20)	≥900/day (N = 15)	p Value
Age (years)—mean (SD)		79.1 (6.6)	77.6 (6.4)	80.7 (7.0)	77.7 (2.7)	0.114	79.7 (7.8)	75.9 (4.2)	0.098
Sex—% females (N)		44.3% (35)	42.4% (14)	42.5% (17)	66.7% (4)	0.518	50.0% (10)	40.0% (6)	0.557
Ethnicity—% (N)	White British	93.7% (74)	97.0% (32)	92.5% (37)	83.3% (5)	0.336	90.0% (18)	93.3% (14)	0.416
	White Irish	2.5% (2)	0% (0)	2.5% (1)	16.7% (1)		0% (0)	6.7% (1)
	Indian	2.5% (2)	3.0% (1)	2.5% (1)	0% (0)		5% (1)	0% (0)
	Arab	1.3% (1)	0% (0)	2.5% (1)	0% (0)		5% (1)	0% (0)
Group—% (N)	Elective surgery	30.4% (24)	54.5% (18)	15.0% (5)	0% (0)	0.001*	30.0% (6)	40.0% (6)	0.826
	Emergency surgery	17.7% (14)	15.2% (5)	22.5% (9)	0% (0)		15.0% (3)	13.3% (2)
	Medical	51.9% (41)	30.3% (10)	62.5% (25)	100%		55.0% (11)	46.7% (7)
Body mass index (kg/m^2)—mean (SD)		26.5 (6.5)	28.4 (5.2)	25.8 (7.2)	20.4 (2.7)	0.010*	26.0 (7.8)	26.9 (5.2)	0.715
Baseline nutrition—% (N)	Normal	37.1% (13)	100% (33)	0% (0)	0% (0)	NA	30.0% (6)	46.7% (7)	0.135
	At risk	51.4% (18)	0% (0)	100% (40)	0% (0)		65.0% (13)	33.3% (5)
	Malnourished	11.4% (4)	0% (0)	0% (0)	100% (6)		5.0% (1)	20.0% (3)
Step count	Median (IQR)	708 (250–1,690)	1,028 (386–2,366)	491 (180–951)	2,023 (735–4,454)	0.072	338 (95–642)	1,812 (1,232–2,792)	<0.001
	<900—% (N)	57.1% (20)	46.2% (6)	72.2% (13)	25.0% (1)	0.135	100% (0)	0% (0)	NA
	≥900—% (N)	42.9% (15)	53.8% (7)	27.8% (5)	75.0% (3)		0% (0)	100% (0)
Baseline frailty index—mean (SD)		0.27 (0.11)	0.22 (0.10)	0.31 (0.11)	0.33 (0.05)	0.001*	0.29 (0.10)	0.26 (0.11)	0.491
Baseline CFS—median (IQR)		4 (3–5)	3 (2.5–3)	4.5 (4–5)	4.5 (3.75–5.25)	<0.001*	5 (3–5)	3 (3–4)	0.006*
C-reactive protein (48 hours post-surgery or admission)—median (IQR)		109 (75.75–181.25)	100 (70–151.5)	113 (78–194)	177.5 (94.25–248.75)	0.234	91 (76–145)	100 (65–163)	0.849

*Statistical significance at p < 0.05 level.

Figure 2. Estimated marginal means of muscle quantity and quality, and physical function measurements according to nutritional status and step count. BATT: bilateral anterior thigh thickness; PROMIS: Patient-Reported Outcomes Measurements Information System, T-score for physical function; SMMSergi: skeletal muscle mass (Sergi equation).

Table 2. Estimated marginal means with 95% confidence intervals for muscle quantity and quality measures derived from mixed models for nutritional status and step count across timepoints.

		Nutrition			p Value		Step count		p Value
		Normal	At risk	Malnourished	Nutrition	Nutrition ×  timepoint	<900/day	≥900/day	Steps	Steps ×  timepoint	Steps ×  nutrition ×  timepoint
BATT (cm)	Baseline	5.07 (4.33–5.82)	4.03 (3.33–4.73)	3.05 (1.51–4.60)	0.021*	0.741	3.86 (2.87–4.86)	4.24 (3.51–4.97)	0.315	0.543	0.909
	7 days	4.66 (3.95–5.37)	3.82 (3.15–4.49)	2.71 (1.24–4.18)			3.29 (2.34–4.24)	4.17 (3.47–4.87)
	13 weeks	5.05 (4.17–5.93)	4.10 (3.26–4.94)	2.39 (0.53–4.25)			3.59 (2.43–4.74)	4.11 (3.17–5.04)
Echogenicity	Baseline	58.5 (51.0–65.9)	68.5 (61.3–75.7)	81.2 (65.7–96.8)	0.025*	0.461	71.4 (61.4–81.4)	67.4 (60.0–74.8)	0.466	0.989	0.065
	7 days	58.2 (51.6–64.8)	65.0 (58.1–72.0)	75.2 (61.4–89.0)			67.6 (58.7–76.5)	64.6 (57.9–71.3)
	13 weeks	62.7 (54.6–70.8)	71.8 (64.1–79.6)	73.2 (56.7–89.8)			71.1 (61.0–81.1)	67.5 (58.7–76.3)
SMMSergi (kg)	Baseline	21.6 (18.9–24.3)	18.2 (15.6–20.7)	12.0 (6.6–17.5)	0.007*	0.363	16.2 (12.6–19.7)	18.3 (15.7–20.9)	0.302	0.472	0.265
	7 days	22.0 (19.0–25.0)	18.0 (15.3–20.8)	11.8 (5.8–17.7)			16.4 (12.6–20.3)	18.1 (15.3–21.0)
	13 weeks	22.3 (19.5–25.1)	17.3 (14.5–20.0)	13.1 (7.4–18.8)			16.0 (12.4–19.7)	19.0 (16.2–21.9)
SMMJanssen (kg)	Baseline	25.0 (21.2–29.5)	20.6 (17.6–24.0)	13.4 (9.6–18.7)	0.004*	0.209	18.1 (14.6–22.5)	20.0 (17.0–23.4)	0.369	0.164	0.022
	7 days	25.8 (21.3–31.4)	20.0 (16.7–23.9)	12.3 (8.4–18.1)			17.8 (13.8–22.8)	19.3 (16.0–23.3)
	13 weeks	24.6 (21.1–28.7)	19.2 (16.6–22.2)	13.9 (10.2–19.1)			17.1 (14.0–20.9)	20.5 (17.6–23.9)
	7 days	0.52 (0.39–0.69)	0.47 (0.31–0.69)	0.62 (0.35–1.08)			0.47 (0.32–0.68)	0.60 (0.46–0.80)
	13 weeks	0.72 (0.54–0.97)	0.53 (0.40–0.71)	0.52 (0.28–0.95)			0.53 (0.36–0.77)	0.65 (0.47–0.89)

BATT: bilateral anterior thigh thickness; SMMSergi: skeletal muscle mass (Sergi equation); SMMJanssen: skeletal muscle mass (Janssen equation).

p values are shown in italic. *Statistical significance at p < 0.05 level.

Table 3. Estimated marginal means with 95% confidence intervals for physical function measures derived from mixed models for nutritional status and step count across timepoints.

		Nutrition			p value		Step count		p value
		Normal	At risk	Malnourished	Nutrition	Nutrition ×  timepoint	<900/day	≥900/day	Steps	Steps ×  timepoint	Steps ×  nutrition ×  timepoint
PROMIS	Baseline	45.9 (41.5–50.3)	38.9 (34.7–43.0)	37.7 (28.6–46.8)	0.145	0.081	37.1 (13.2–43.0)	44.5 (40.2–48.8)	0.010*	0.988	0.848
	7 days	38.0 (33.6–42.4)	35.7 (31.4–40.1)	38.3 (29.1–47.5)			33.6 (27.6–39.5)	41.1 (36.7–45.6)
	13 weeks	45.30 (39.9–50.7)	38.7 (33.9–43.6)	51.1 (39.2–63.0)			38.0 (33.2–42.7)	47.7 (42.4–53.1)
Handgrip strength (kg)	Baseline	20.8 (15.3–26.2)	17.7 (12.6–22.9)	13.7 (2.4–25.0)	0.285	0.598	15.8 (8.6–23.1)	19.0 (13.6–24.3)	0.357	0.845	0.977
	7 days	21.5 (16.3–26.7)	16.1 (11.2–21.0)	13.5 (2.8–24.3)			15.1 (8.2–22.0)	19.0 (13.8–24.1)
	13 weeks	24.9 (19.1–30.7)	19.9 (14.3–25.5)	17.3 (4.9–29.7)			18.4 (10.8–25.9)	23.1 (16.7–29.4)
Gait speed (m/s)	Baseline	0.71 (0.58–0.87)	0.70 (0.55–0.89)	0.47 (0.31–0.69)	0.498	0.202	0.58 (0.45–0.76)	0.64 (0.53–0.79)	0.262	0.734	0.485
	7 days	0.52 (0.39–0.69)	0.47 (0.31–0.69)	0.62 (0.35–1.08)			0.47 (0.32–0.68)	0.60 (0.46–0.80)
	13 weeks	0.72 (0.54–0.97)	0.53 (0.40–0.71)	0.52 (0.28–0.95)			0.53 (0.36–0.77)	0.65 (0.47–0.89)

PROMIS: Patient-Reported Outcomes Measurements Information System, T-score for physical function.

p values are shown in italic. *Denotes statistical significance at p < 0.05 level.

Data availability statement

The anonymized dataset is available from the corresponding author upon reasonable request.