Low skeletal muscle area is a risk factor for mortality in mechanically ventilated critically ill patients

Table 2 Backward stepwise (Wald) regression analyses

	Muscle area (continuous) (per 10 cm²)			Low-muscle area versus normal			Low and medium muscle area versus high
				Low < 110 cm²for females			Low <110 cm²
				Low < 170 cm²for males			Medium 110 to 170 cm²
				Low < 170 cm²for males			High >170 cm²
Step 1	OR	95% CI	P value	OR	95% CI	P value	OR	95% CI	P value
Muscle area	0.82	.73 – .93	.001	3.86	1.80 – 8.26	.001	2.93	1.58 – 5.42	.001
Sex	1.50	.67 – 3.34	.320	.54	.29 – 1.01	.053	1.43	.66 – 3.09	.365
BMI	0.96	.89 – 1.03	.268	.95	.88 – 1.03	.222	.96	.89 – 1.03	.238
APACHE II score	1.06	1.03 – 1.11	.001	1.07	1.03 – 1.11	.001	1.07	1.03 – 1.11	.001
Admission diagnosis	0.96	.85 – 1.10	.577	.97	.85 – 1.11	.666	.97	.85 – 1.10	.625
Constant	3.01		.341	.16		.118	.02		.012
Step 3 or 4
Muscle area	0.84	.77 – .92	<.001	4.27	2.03 – 9.00	<.001	2.71	1.69 – 4.34	<.001
Sex				.50	.27 – .92	.025
APACHE II score	1.06	1.02 – 1.1 7	.002	1.07	1.03 – 1.11	.001	1.07	1.03 – 1.11	.001
Constant	0.83		.812	.04		<0.001	.01		<.001

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