title: Low body mass index and blood loss in primary total hip arthroplasty: results from 236 consecutive ankylosing spondylitis patients.
abstract: OBJECTIVE
  To evaluate the effect of low body mass index (BMI) on blood loss during primary total hip arthroplasty (THA) in ankylosing spondylitis (AS) patients.
  
  
  METHODS
  Two hundred seventy-seven consecutive AS patients who underwent primary THA were retrospectively studied. The patients were divided by BMI into an underweight group (BMI < 18.5 kg/m(2)) and a normal weight group (18.5 kg/m(2) < BMI < 25 kg/m(2)). Demographics, perioperative laboratory values, intraoperative data, blood loss, transfusion rate, transfusion reactions, surgical complications, hospitalization cost, and length of stay (LOS) were collected and analyzed.
  
  
  RESULTS
  Of 277 AS patients, 236 were eligible for inclusion in the study. A total of 91 (39%) patients were underweight. The hidden blood loss, transfusion rate, transfusion reactions, and hospitalization cost in the underweight group were significantly higher than those in the normal weight group.
  
  
  CONCLUSIONS
  For AS patients, BMI appears to be correlated with blood loss during primary THA. Compared with patients of normal weight, low BMI patients have the potential to suffer more postoperative hidden blood loss and to require a higher transfusion rate.
authors: Department of Orthopedics, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433, China ; Department of Orthopedics, No. 401 Hospital, Jinan Military Region of PLA, Qingdao, Shandong 266071, China.
authors: Jinzhu
authors: J
authors: Zhao
authors: Department of Orthopedics, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433, China.
authors: Jia
authors: J
authors: Li
authors: Department of Orthopedics, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433, China.
authors: Wei
authors: W
authors: Zheng
authors: Department of Orthopedics, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433, China.
authors: Denghui
authors: D
authors: Liu
authors: Department of Orthopedics, No. 401 Hospital, Jinan Military Region of PLA, Qingdao, Shandong 266071, China.
authors: Xiaofeng
authors: X
authors: Sun
authors: Department of Orthopedics, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433, China.
authors: Weidong
authors: W
authors: Xu
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D015992:Body Mass Index; D015519:Bone Density; D005260:Female; D006470:Hemorrhage / Q000150:complications* / Q000473:pathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D012189:Retrospective Studies; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000473:pathology / Q000601:surgery*