Association between underweight and hospitalization, emergency room visits, and mortality among patients in community medical homes

Figures & data

Table 1 Characteristics of 21,019 patients ≥ 60 years by BMI classification

Patient characteristics	Overall n = 21019	<18.5 n = 220	18.5–24.9 n = 4909	25.0–29.9 n = 7874	30.0–34.9 n = 4948	35.0–35.9 n = 1988	≥40.0 n = 1080	P-value
Age (mean, SD)	72.03, 8.88	78.1, 9.59	73.8, 9.73	72.5, 8.80	71, 8.26	69.6, 7.56	68.4, 7.08	<0.001a
Sex, female, n (%)	11664 (55)	192 (87)	3401 (69)	3904 (50)	2374 (48)	1121 (56)	672 (62)	<0.001b
Race, white, n (%)	19826 (94)	209 (95)	4545 (93)	7438 (94)	4707 (95)	1889 (95)	1038 (96)	<0.001b
Marital status, single, n (%)	6240 (30)	111 (50)	1691 (34)	2161 (27)	1350 (27)	593 (30)	334 (31)	<0.001b
Charlson score (mean, SD)	2.05, 2.57	2.71, 2.96	1.95, 2.61	1.94, 2.51	2.09, 2.54	2.31, 2.61	2.55, 2.63	<0.001a
Outcomes
Hospitalization, n (%)	3480 (17)	68 (31)	871 (18)	1165 (15)	793 (16)	375 (19)	208 (19)	<0.001b
ER visit, n (%)	4898 (23)	90 (41)	1209 (25)	1692 (21)	1122 (23)	507 (26)	278 (26)	<0.001b
Mortality, n (%)	544 (3)	28 (13)	200 (4)	171 (2)	101 (2)	29 (1)	15 (1)	<0.001b

Notes:

a Test for comparison: ANOVA;

b Pearson Chi square test.

Abbreviations: BMI, body mass index; ER, emergency room; SD, standard deviation.

Table 2 Associations between low BMI (<18.5) and adverse outcomes in 2011

Outcome	Unadjusted		Age-adjusted		Age-sex-single-status-Charlson score adjusted
	OR	95% CI	OR	95% CI	OR	95% CI
Hospitalization	2.28	1.71, 3.04	1.68	1.25, 2.27	1.64	1.21, 2.22
ER visit	2.30	1.76, 3.02	1.76	1.34, 2.33	1.70	1.28, 2.25
Mortality	5.73	3.82, 8.61	3.26	2.13, 5.01	3.64	2.33, 5.69

Abbreviations: BMI, body mass index; CI, confidence interval; ER, emergency room; OR, odds ratio.

Table 3 ORs and 95% CIs assessing the interactions between sex and BMI

Category	n	ER visit in 2011a		Hospitalization in 2011b		Death in 2011c
		ORd	95% CI	ORd	95% CI	ORd	95% CI
Women, BMI ≥ 18.5	11472	Referent	–	Referent	–	Referent	–
Men, BMI ≥ 18.5	9327	0.99	0.92–1.06	1.00	0.92–1.08	0.97	0.97–0.97
Women, BMI < 18.5	192	1.54	1.14–2.10	1.42	1.03–2.01	3.36	3.32–3.39
Men, BMI < 18.5	28	3.06	1.41–6.64	3.45	1.59–7.48	16.80	6.65–42.41

Notes:

a Interaction term P-value = 0.10;

b interaction term P-value = 0.04;

c interaction term P-value = <0.01;

d ORs adjusted for age, single status, and Charlson score.

Abbreviations: BMI, body mass index; CI, confidence interval; ER, emergency room; OR, odds ratio.