Demographic comparisons showed that NSQIP patients were older ( average age 48.214.5 years [ meanstandard deviation ] vs. 41.711.8 and 43.011.3 years , respectively [ p < .001 ] ) and had higher body mass index ( 29.66.2 kg/m ( 2 ) vs. 27.85.6 and 28.25.4 kg/m ( 2 ) , respectively [ p < .001 ] ) .