Abstract
Objective
Current advice for patients being discharged from hospital suggests a body mass index of 18.5 to 24 kgm−2, although this aspirational target may often not be achieved. We examined the relationship between body mass index on discharge from hospital and subsequent mortality over a maximum follow-up of 3.8 years.
Design
We conducted a survival analysis using linked hospital records data with national hospital episode statistics and national death certification data.
Participants & Setting
The analysis included adult patients who were admitted to University Hospitals Birmingham NHS Foundation Trust for a period of over 24 h during 2011, excluding day cases and regular day case attenders.
Main outcome measures
The relationship between body mass index and mortality at medium term was estimated separately in both men and women, after accounting for case-mix.
Results
For both males and females, the relationship between body mass index at discharge and the loge hazard of death was strongly non-linear (p = 0.0002 for females and p < 0.0001 for males) and predictive (both p < 0.0001). In all models, the optimal body mass index range associated with best survival was 25 to 35 kgm−2, with a sharp increase in risk for lower body mass index.
Conclusions
There was little evidence to support current aspirational body mass index targets in the discharge population. Hospitals should ensure adequate nutrition especially among those with a reduced body mass index.
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