Baseline pain and disability in the Investigational Vertebroplasty Efficacy and Safety Trial

Multiple case series of vertebroplasty outcomes have been published, though no large, placebo controlled trial has yet been performed. Our aim was to report baseline characteristics for the Investigational Vertebroplasty Efficacy and Safety Trial (INVEST), a randomized blinded controlled study of vertebroplasty.

We compared baseline demographics, pain scores, and scores on the modified Roland-Morris Disability Scale (RMDS), a back pain-specific metric, between 2 groups. One group included subjects enrolled at the lead INVEST site (n = 27 to date). The second group consisted of eligible patients seen concurrently at the lead INVEST site, who declined enrollment (n = 70). Comparisons were made by using 2-sample t tests.

Mean ages were similar between groups, averaging approximately 74 years among study participants and 77 years among nonenrolled eligible patients (P = .17). Approximately 75% of subjects were female in both groups. RMDS scores of enrolled patients at the lead site (18.0 +/- 4.2) were not statistically different from those of eligible nonenrolled patients at the lead site (18.6 +/- 3.6, P = .49). Pain scores in the enrolled subjects were measured as "average intensity over the prior 24 hours" with mean scores of 7.6 +/- 2.1 among enrolled patients at the lead site. Pain scores in eligible nonenrolled patients were measured as "pain at rest," with mean score of 3.4 +/- 3.3, and "pain with activity," with mean score of 8.5 +/- 2.0.

Patient demographics among subjects enrolled in the INVEST are similar to those in a cohort of eligible nonenrolled patients. Back pain-specific disability was similar between subjects enrolled in the INVEST study and eligible nonenrolled patients at the lead site.