低ボディマス指数と集中治療患者の再挿管との関連：多施設共同後ろ向きコホート研究

Underweight critical care patients are at an increased risk of in-hospital mortality. This vulnerability is attributed to the lack of physiological reserve, which may increase the risk of reintubation in these patients. However, the association between underweight and reintubation remains unclear. We aimed to assess the association between a lower body mass index (BMI) and the risk of reintubation in mechanically ventilated patients.

We performed a retrospective cohort study using data from the Japanese Intensive care PAtient Database (JIPAD). We included adult patients who received mechanical ventilation for at least 24 h from intensive care unit (ICU) admission between 2018 and 2023. The primary outcome was reintubation, which was defined as the reimplementation of mechanical ventilation within 72 h after extubation. BMI was categorized into five groups: underweight (< 18.5 kg/m²), slightly underweight (18.5-21.9 kg/m²), normal weight (22.0-24.9 kg/m²), overweight (25.0-29.9 kg/m²), and obesity (≥ 30.0 kg/m²). We examined the relationship between BMI and reintubation and using a multivariable logistic regression analysis. We adjusted for established reintubation risk factor as a fixed effect, and facilities as a random effect. Additionally, we performed age-stratified subgroup analysis.

Of the 41,016 eligible patients from 131 ICUs, the mean BMI was 23.4 kg/m², and the overall reintubation rate within 72 h was 5.9% (2,436 patients). This rate was the highest in the underweight group (8.4%) and the lowest in the obesity group (4.3%). Using normal weight as the reference, being underweight correlated with a higher risk of reintubation (adjusted odds ratio 1.58, [95% confidence interval 1.39-1.80]), whereas being obese correlated with a lower risk of reintubation (adjusted odds ratio, 0.69 [95% confidence interval: 0.57-0.84]). In the subgroup analysis stratified by age category, being underweight was associated with an increased risk of reintubation.

A lower BMI was associated with an increased risk of reintubation. This relationship remained consistent in the age-stratified subgroup analysis. The present results indicate that a lower BMI needs to be considered an important factor when assessing an underweight patient's risk of reintubation.