title: Multiple Regression Analysis of Factors Affecting Health-Related Quality of Life in Adult Spinal Deformity.
abstract: BACKGROUND
  Previous studies demonstrated the adult spinal deformity (ASD) population is heterogeneous. Multiple parameters may affect health-related quality of life (HRQL).
  
  
  OBJECTIVE
  To understand the ranking of parameters affecting HRQL in ASD using multiple regression analysis.
  
  
  METHODS
  A total of 483 patients enrolled in a prospective multicenter ASD database from the population. Multiple regression analysis was performed for Scoliosis Research Society-22 (SRS-22) and Oswestry Disability Index (ODI) separately. Initially proposed primary variables of diagnosis (highest correlation), age, lordosis gap (L gap), and coronal curve location were regressed for each response variable (SRS-22 and ODI) univariately. Age and L gap could not be used together because of high colinearity. Coronal curve location was removed owing to an insignificant correlation. Two initial models were considered per response, consisting of diagnosis and age in one and diagnosis and L gap in the other. The rest of the potentially predictive variables were introduced in these models one at a time. Final models were evaluated using stepwise automatic model selection.
  
  
  RESULTS
  For ODI, body mass index (BMI), gender, and sagittal and spinopelvic parameters were in the basic model but only BMI and gender in the model with L gap and only gender in the model with age were highly predictive. For SRS-22, a large number of parameters were in the basic model but BMI, gender, coronal balance, lordosis curve, and sagittal vertical axis in the model with L gap and only gender in the model with age were highly predictive. Coronal curve location was not significantly predictive in any model.
  
  
  CONCLUSIONS
  These findings reiterate the importance of patient diagnosis, age, and/or the amount of lordosis as the most important factors affecting HRQL in ASD. Gender, BMI, and sagittal vertical axis appear to be consistently important co-variables whereas coronal balance and magnitude of L curves may also be important in SRS-22. These may aid in better understanding the problem in ASD and may be useful in future classifications.
authors.affiliation: Ankara Spine Center, Iran Caddesi 45/2 Kavaklidere, Ankara 06700, Turkey. Electronic address: acaroglue@gmail.com.
authors.forename: Emre
authors.initials: E
authors.lastname: Acaroglu
authors.affiliation: Ankara Spine Center, Iran Caddesi 45/2 Kavaklidere, Ankara 06700, Turkey.
authors.forename: Umit O
authors.initials: UO
authors.lastname: Guler
authors.affiliation: Ankara Spine Center, Iran Caddesi 45/2 Kavaklidere, Ankara 06700, Turkey.
authors.forename: Z Deniz
authors.initials: ZD
authors.lastname: Olgun
authors.affiliation: Clinist Statistics, Ankara, Turkey.
authors.forename: Yalcin
authors.initials: Y
authors.lastname: Yavuz
authors.affiliation: Department of Orthopedic Surgery, Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: Ferran
authors.initials: F
authors.lastname: Pellise
authors.affiliation: Department of Orthopedic Surgery, Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: Montse
authors.initials: M
authors.lastname: Domingo-Sabat
authors.affiliation: Ankara Spine Center, Iran Caddesi 45/2 Kavaklidere, Ankara 06700, Turkey.
authors.forename: Sule
authors.initials: S
authors.lastname: Yakici
authors.affiliation: Department of Orthopedic Surgery, Acibadem Maslak Hospital, Istanbul, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Alanay
authors.affiliation: Department of Orthopedic Surgery, Hospital La Paz, Madrid, Spain.
authors.forename: Francesco Sanchez
authors.initials: FS
authors.lastname: Perez-Grueso
authors.affiliation: Ankara University, Department of Biostatistics, Ankara, Turkey.
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Yavuz
keywords: Adult spinal deformity; Health-related quality of life; Multiple regression analysis; Statistics