Predictive factors for body weight loss and its impact on quality of life following gastrectomy

Table 1 Characteristics of patients after conventional gastrectomy

Sex [male: n (%)]	1188 (66.9)
Age (yr, mean ± SD)	62.1 ± 9.2
Type of gastrectomy (n: TGRY/DGBI/DGRY)	393/909/475
Period after gastrectomy (mo: mean ± SD)	37.0 ± 26.8
Change in body weight (%, mean ± SD)	-9.5 ± 8.0
Preoperative BMI (kg/m2, mean ± SD)	22.8 ± 3.1
Postoperative BMI (kg/m2, mean ± SD)	20.6 ± 2.8
Approach (n, open/laparoscopic)	1102 ± 664
Preservation of celiac branch of vagus (Y/N)	173/1567

BMI: Body mass index.

Table 2 Structure of postgastrectomy syndrome assessment scale-45 (domains/subdomains/items/subscales)

Domains	Subdomains		Items	Subscales
QOL	SF-8 (QOL)	1	Physical functioning1	Physical component summary1 (item 1-8)
		2	Role physical1	Mental component summary1 (item 1-8)
		3	Bodily pain1
		4	General health1
		5	Vitality1
		6	Social functioning1
		7	Role emotional1
		8	Mental health1
Symptoms	GSRS (Symptoms)	9	Abdominal pains	Esophageal reflux subscale (item 10, 11, 13, 24)
		10	Heartburn	Abdominal pain subscale (item 9, 12, 28)
		11	Acid regurgitation	Meal-related distress subscale (item 25-27)
		12	Sucking sensations in the epigastrium	Indigestion subscale (item 14-17)
		13	Nausea and vomiting	Diarrhea subscale (item 19, 20, 22)
		14	Borborygmus	Constipation subscale (item 18, 21, 23)
		15	Abdominal distension	Dumping subscale (item 30, 31, 33)
		16	Nausea and vomiting
		17	Increased flatus	Total symptom scale (above seven subscales)
		18	Decreased passage of stools
		19	Increased passage of stools
		20	Loose stools
		21	Hard stools
		22	Urgent need for defecation
		23	Feeling of incomplete evacuation
	Symptoms	24	Bile regurgitation
		25	Sense of foods sticking
		26	Postprandial fullness
		27	Early satiation
		28	Lower abdominal pains
		29	Number and type of early dumping symptoms
		30	Early dumping general symptoms
		31	Early dumping abdominal symptoms
		32	Number and type of late dumping symptoms
		33	Late dumping symptoms
Living status	Meals (amount) 1	34	Ingested amount of food per meal1
		35	Ingested amount of food per day1
		36	Frequency of main meals
		37	Frequency of additional meals
	Meals (quality)	38	Appetite1	Quality of ingestion subscale1 (item 38-40)
		39	Hunger feeling1
		40	Satiety feeling1
	Meals (amount) 2	41	Necessity for additional meals
	Social activity	42	Ability for working
QOL	Dissatisfaction (QOL)	43	Dissatisfaction with symptoms	Dissatisfaction for daily life subscale (item 43-45)
		44	Dissatisfaction at the meals
		45	Dissatisfaction at working

¹Higher scores indicate better conditions. Each subscales is calculated as the mean of its composite items or subscales, except the physical and mental component summaries of SF-8. Items 29 and 32 do not have scores; these were analyzed separately. PGSAS-45: Postgastrectomy syndrome assessment scale-45; SF-8: Short form-8; QOL: Quality of life; GSRS: Gastrointestinal symptom rating scale.

Table 3 Main outcome measures of postgastrectomy syndrome assessment scale-45 quality of life domain in patients after conventional gastrectomy (n = 1777)

Subdomains	Item in PGSAS-45	Main outcomes measures	Scale	mean ±SD
Dissatisfaction	43	Dissatisfaction with symptoms	Five-point Likert scale	1.87 ± 0.95
	44	Dissatisfaction at the meals		1.13
	45	Dissatisfaction at working		1.79 ± 0.97
	43-45	Dissatisfaction for daily life subscale		0.87
SF-8	1-8	Physical component summary1	Five or six-point Likert scale	50.4 ± 5.6
	1-8	Mental component summary1		49.7 ± 5.8

¹Higher score indicating better condition. Integrated subscales (SS) are underlined in the Table. PGSAS-45: Postgastrectomy syndrome assessment scale-45; SF-8: Short form-8.

Table 4 Factors influencing body weight loss after gastrectomy (multiple regression analysis)

Variables	Change in body weight
	β	P value
Type of gastrectomy (DGBI)	0.204	< 0.0001
Type of gastrectomy (DGRY)	0.116	< 0.0001
Postoperative period (mo)	(-0.02)	NS
Age (yr)	(-0.04)	0.0746
Gender (male)	0.120	< 0.0001
Preoperative BMI (kg/m2)	-0.3561	< 0.0001
Approach (Laparoscopic)	(0.01)	NS
Celiac branch of vagus (Preserved)	(0.074)	0.0010
R2 (P value)	0.216	< 0.0001
The interpretation of effect size	β	R2
None-very small	< (0.100)	< (0.020)
Small	> 0.100	> 0.020
Medium	> 0.3001	> 0.1301
Large	> 0.500	> 0.260

¹Integrated subscales. Higher score indicative of a better condition. If β is positive, the score of the outcome measure of the patients belonging to the category in (brackets) is higher in cases when the factor is a nominal scale, and the score of outcome measure of the patients with larger values is higher in cases when the factor is a numeral scale. DGBI: Distal gastrectomy with Billroth-I; DGRY: Distal gastrectomy with Roux-en-Y.

Table 5 Impact of postoperative lower body mass index and body weight loss on the quality of life (multiple regression analysis)

Variables	Ability for working		Dissatisfaction with symptoms		Dissatisfaction at the meals		Dissatisfaction at working		Dissatisfaction for daily life subscale		PCS		MCS
	β	P value	β	P value	β	P value	β	P value	β	P value	β	P value	β	P value
Postoperative BMI (kg/m2)	-0.134	< 0.0001	-0.189	< 0.0001	0.216	< 0.0001	-0.185	< 0.0001	-0.231	< 0.0001	0.148	< 0.0001	0.109	< 0.0001
Change in body weight (%)	(-0.081)	0.0018	(-0.073)	0.0040	-0.112	< 0.001	(-0.097)	<0.0001	-0.109	< 0.0001	(0.047)	0.066	(0.025)	NS
R2 (P value)	0.031	< 0.0001	0.048	< 0.0001	0.073	< 0.001	0.054	< 0.0001	0.080	< 0.0001	0.028	< 0.0001	(0.014)	< 0.0001

BMI: Body mass index; QOL: Quality of life; PCS: Physical component summary; MCS: Mental component summary.

Table 6 Regression analysis of effect size

The interpretation of effect size	β	R2
None-very small	< (0.100)	< (0.020)
Small	> 0.100	> 0.020
Medium	> 0.300	> 0.130
Large	> 0.500	> 0.260