Quality of life assessment using the Short Form-12 (SF-12) questionnaire in patients with cervical spondylotic myelopathy: Comparison with SF-36

Study Design. Clinical outcome study comparing the Short Form-36 (SF-36) and Short Form-12 (SF-12) assessment scales in patients with cervical spondylotic myelopathy (CSM). Objectives. To compare the validity, reliability, and sensitivity to change of the SF-12 and SF-36 scales in CSM patients undergoing decompressive surgery. Summary of Background Data. The SF-36 is a generic Health Related Quality of Life (HRQoL) questionnaire, consisting of 36 questions that can be reported as a Physical (PCS) and Mental Component Summary (MCS). Recently, an abbreviated version of SF-36, the SF-12, which uses only 12 questions drawn from the SF-36, has been described. Methods. In this prospective study, patients with CSM undergoing decompressive surgery, self-completed the SF-36 questionnaire before surgery and at 6 months after surgery. SF-12 item responses were abstracted from the responses given to the SF-36 questionnaire. The validity, reliability, and sensitivity to change of the PCS and MCS components of SF-12 and SF-36 scales were compared. Results. Overall, 105 patients underwent anterior (N = 58) or posterior (N = 47) decompressive surgery. After surgery, there were improvements in the PCS components of both the SF-36 (40 ± 2 to 54 ± 2) and SF-12 (34 ± 2 to 48 ± 3), as well as in the MCS component of the SF-36 (48 ± 2 to 63 ± 2) and SF-12 (43 ± 2 to 59 ± 2) (P <0.001). The sensitivity to change and absolute sensitivity for both SF-12 and SF-36 were comparable, but the reliability of SF-36 was marginally greater. There were close and linear correlations between the SF-36 and SF-12 scores for both the PCS and MCS components, before and after surgery (R = 0.86 to 0.93; P <0.0001). Conclusions. Both the SF-12 and SF-36 scales are valid and sensitive to changes in physical and mental health status in CSM patients, undergoing decompressive surgery. Despite its abbreviated nature, the SF-12 appears to be an adequate substitute for SF-36, and its brevity should increase its attractiveness to both clinicians and patients. ©2006, Lippincott Williams & Wilkins, Inc.