Reliability of the revised Scoliosis Research Society-22 and Oswestry Disability Index (ODI) questionnaires in adult spinal deformity when administered by telephone.

BACKGROUND CONTEXT: The non-response rates are as high as 20% to 50% after 5 years of follow-up in adult spinal deformity (ASD) surgery. Minimizing loss to follow-up is essential to protect the quality of data in long-term studies. Phone and internet administration of outcomes instruments has grown in popularity and has been found to not only provide a convenient way of collecting data, but also show improved response rates.

PURPOSE: The study aimed to examine the reliability of the revised Scoliosis Research Society-22 (SRS-22r) and the Oswestry Disability Index (ODI) questionnaires in ASD patients when administered by telephone.

STUDY DESIGN/SETTING: This is a single-center, randomized crossover phone validation of ASD patients.

PATIENT SAMPLE: The study included ASD patients presenting to a tertiary spine care center.

OUTCOME MEASURES: The outcome measures were ODI and SRS-22r.

METHODS: Forty-nine patients (mean age: 55.7 years) with ASD were randomized in a 1:1 ratio to either phone completion of the SRS-22r and ODI followed by in-office completion, or to in-office completion followed by phone completion. An interval of 2 to 4 weeks was placed between administrations of each version. A paired t test was used to assess the difference between the written and phone versions, and intraclass correlation coefficients were used to assess homogeneity. Finally, goodness-of-fit testing was used to assess version preference.

RESULTS: There was no significant difference between the phone and in-office versions of the SRS-22r (p=.174) or the ODI (p=.320). The intraclass correlation coefficients of the SRS-22r and ODI were 0.91 and 0.86, respectively. Completion over the phone was the most popular option (57% preferred phone, 29% preferred in-office, and 14% had no preference).

CONCLUSIONS: Phone administration of the SRS-22r and ODI to ASD patients provides a convenient and reliable tool for reducing loss of follow-up data.