title: The impact of body mass index on heterotopic ossification.
abstract: OBJECTIVE
  To analyze the impact of different body mass index (BMI) as a surrogate marker for heterotopic ossification (HO) in patients who underwent surgical repair (SR) for displaced acetabular fractures (DAF) followed by radiation therapy (RT).
  
  
  METHODS
  This is a single-institution retrospective study of 395 patients. All patients underwent SR for DAF followed by RT ± indomethacin. All patients received postoperative RT, 7 Gy, within 72 h. The patients were separated into four groups based on their BMI: <18.5, 18.5-24.9, 25-29.9, and >30. The end point of this study was to evaluate the efficacy of RT ± indomethacin in preventing HO in patients with different BMI.
  
  
  RESULTS
  Analysis of BMI showed an increasing incidence of HO with increasing BMI: <18.5, (0%) 0/6 patients; 18.5-24.9 (6%), 6 of 105 patients developed HO; 25-29.9 (19%), 22 of 117; >30 (31%), 51 of 167. Chi-square and multivariate logistic regression analysis showed that the correlation between odds of HO and BMI is significant, p < 0.0001. As the BMI increased, the risk of HO and Brooker Classes 3, 4 HO increased. The risk of developing HO is 1.0× (10%) more likely among those with higher BMI compared with those with lower BMI. For a one-unit increase in BMI the log odds of HO increases by 1.0, 95% CI (1.06-1.14). Chi-square test shows no significant difference among all other factors and HO (e.g., indomethacin, race, gender).
  
  
  CONCLUSIONS
  Despite similar surgical treatment and prophylactic measures (RT ± indomethacin), the risk of HO appears to significantly increase in patients with higher BMI after DAF. Higher single-fraction doses or multiple fractions and/or combination therapy with nonsteroidal inflammatory drugs may be of greater benefit to these patients.
authors.affiliation: Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS, USA. Waleed246@gmail.com
authors.forename: Waleed Fouad
authors.initials: WF
authors.lastname: Mourad
authors.forename: Satya
authors.initials: S
authors.lastname: Packianathan
authors.forename: Rania A
authors.initials: RA
authors.lastname: Shourbaji
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Mathew
authors.initials: M
authors.lastname: Graves
authors.forename: Majid A
authors.initials: MA
authors.lastname: Khan
authors.forename: Michael C
authors.initials: MC
authors.lastname: Baird
authors.forename: George
authors.initials: G
authors.lastname: Russell
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Vijayakumar
mesh_terms: D000077:Acetabulum / Q000293:injuries*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D015992:Body Mass Index; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy / Q000379:methods; D005260:Female; D050723:Fractures, Bone / Q000532:radiotherapy / Q000601:surgery*; D006801:Humans; D015994:Incidence; D007213:Indomethacin / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D011182:Postoperative Care / Q000379:methods; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D012044:Regression Analysis; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007213:Indomethacin