Association Between Body Mass Index and Severe Infection in Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis: A Retrospective Cohort in Japan
Background: Although previous studies have evaluated risk factors for the incidence of severe infection in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), the relationship between body mass index (BMI) and severe infection in AAV has not been elucidated. We hypothesized that elderly AAV patients with a low BMI would be at a higher risk of infection. To evaluate this hypothesis, we investigated the association between underweight at AAV diagnosis and subsequent severe infection in elderly AAV patients.
Methods: This single-center retrospective cohort study included 98 consecutive elderly AAV patients treated at the Aichi Medical University Hospital in Japan between 2004 and 2018. The relationships between BMI at diagnosis and subsequent first severe infection were assessed using multivariate Cox proportional hazards models.
Results: During the entire follow-up period (median, 22 months; interquartile range, 7‒52 months), 32 (32.7%) patients developed at least one severe infection. Low BMI (< 18.5 kg/m2 compared with normal BMI [18.5‒23.0 kg/m2], adjusted hazard ratio [HR] = 2.70, 95% confidence interval [CI]: 1.18–6.17; P = 0.018) and use of methylprednisolone pulse therapy (adjusted HR = 3.09, 95% CI: 1.37–6.99; P = 0.007) were the significant predictors of severe infection. Furthermore, an interaction effect between unintentional body weight loss (> 10%) within 6 months before diagnosis and low BMI was observed (P < 0.001).
Conclusions: Low BMI was associated with a higher risk of severe infection in elderly AAV patients, suggesting that careful management may be required to prevent the development of infection in patients with a low BMI. Further studies are needed to elucidate the optimal treatment strategy for these patients.
Figure 1
Figure 2
This is a list of supplementary files associated with this preprint. Click to download.
Posted 22 Sep, 2020
On 10 Nov, 2020
Received 02 Nov, 2020
On 26 Oct, 2020
Received 24 Oct, 2020
On 30 Sep, 2020
Invitations sent on 29 Sep, 2020
On 28 Sep, 2020
On 18 Sep, 2020
On 16 Sep, 2020
On 14 Sep, 2020
Association Between Body Mass Index and Severe Infection in Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis: A Retrospective Cohort in Japan
Posted 22 Sep, 2020
On 10 Nov, 2020
Received 02 Nov, 2020
On 26 Oct, 2020
Received 24 Oct, 2020
On 30 Sep, 2020
Invitations sent on 29 Sep, 2020
On 28 Sep, 2020
On 18 Sep, 2020
On 16 Sep, 2020
On 14 Sep, 2020
Background: Although previous studies have evaluated risk factors for the incidence of severe infection in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), the relationship between body mass index (BMI) and severe infection in AAV has not been elucidated. We hypothesized that elderly AAV patients with a low BMI would be at a higher risk of infection. To evaluate this hypothesis, we investigated the association between underweight at AAV diagnosis and subsequent severe infection in elderly AAV patients.
Methods: This single-center retrospective cohort study included 98 consecutive elderly AAV patients treated at the Aichi Medical University Hospital in Japan between 2004 and 2018. The relationships between BMI at diagnosis and subsequent first severe infection were assessed using multivariate Cox proportional hazards models.
Results: During the entire follow-up period (median, 22 months; interquartile range, 7‒52 months), 32 (32.7%) patients developed at least one severe infection. Low BMI (< 18.5 kg/m2 compared with normal BMI [18.5‒23.0 kg/m2], adjusted hazard ratio [HR] = 2.70, 95% confidence interval [CI]: 1.18–6.17; P = 0.018) and use of methylprednisolone pulse therapy (adjusted HR = 3.09, 95% CI: 1.37–6.99; P = 0.007) were the significant predictors of severe infection. Furthermore, an interaction effect between unintentional body weight loss (> 10%) within 6 months before diagnosis and low BMI was observed (P < 0.001).
Conclusions: Low BMI was associated with a higher risk of severe infection in elderly AAV patients, suggesting that careful management may be required to prevent the development of infection in patients with a low BMI. Further studies are needed to elucidate the optimal treatment strategy for these patients.
Figure 1
Figure 2