Investigational vertebroplasty safety and efficacy trial (INVEST): patient-reported outcomes through 1 year

Abstract

Purpose: To evaluate 1-year outcomes of the Investigational Vertebroplasty Safety and Efficacy Trial (INVEST), a blinded, randomized, controlled trial to investigate the effectiveness of percutaneous vertebroplasty in the treatment of osteoporotic vertebral compression fractures.

Materials and methods: Patients were enrolled at 11 sites in the United States, the United Kingdom, and Australia by using an institutional review board-approved protocol and HIPAA compliance, and all patients provided written informed consent. Patients were randomized to undergo vertebroplasty or a control procedure. After 1 month, patients were allowed to cross over and undergo the alternate procedure. Coprimary outcomes were patient-reported function, measured with the modified Roland-Morris Disability Questionnaire (RDQ), and pain (on a scale of one to 10) at 1 year. Intention-to-treat (ITT) and as-treated (AT) analyses were used to compare outcomes.

Results: One hundred thirty-one participants (68 in the vertebroplasty group and 63 in the control group) were included in the analyses. Patients in both groups showed improvements in pain and function at 1 year. In ITT analyses, patients randomized to vertebroplasty did not differ from control subjects in terms of RDQ results (difference, 1.37 points; 95% confidence interval [CI]: -0.88, 3.62; P = .231) but reported lower levels of pain (difference, 1.02 points; 95% CI: 0.04, 2.01; P = .042). Eleven of 68 patients who underwent vertebroplasty (16%) and 38 of 63 control subjects (60%) crossed over and elected to undergo the alternate procedure (P < .001). In AT analyses, patients treated with vertebroplasty did not differ from control subjects in terms of RDQ results (difference, 0.66 points; 95% CI: -1.98, 3.30; P = .625) or pain (difference, 0.85 points; 95% CI: -0.35, 2.05; P = .166).

Conclusion: Vertebroplasty may provide a modest reduction in pain at 1 year compared with a control procedure; however, no difference in functional disability was observed. Clinical trial registration no. NCT00068822.

Figure 1:

Flowchart shows treatment and follow-up of study participants. Assessment was considered to be complete at a given time if both primary outcome measures were collected. Data are cumulative, with the exception of total crossover.

Figure 2:

Graphs show mean RDQ scores (top) and average pain intensity scores (bottom), with 95% CIs, according to treatment adherence over time. AT vertebroplasty effect estimates and 95% CIs were obtained by using mixed-effects models with random intercepts and a time-varying indicator of when treatment was received. Treatment effects are coded such that negative treatment effects favor the control procedure and positive treatment effects favor vertebroplasty.