Abstract
To the Editor,
We read with great interest the recent article, “Sarcopenia as a Predictor of Mortality Following Vertebral Compression Fractures Treated With Vertebroplasty,” which revealed how sarcopenia shapes outcomes after vertebroplasty. 1 We would like to offer a few points for the authors’ consideration.
First, the high mortality in the sarcopenia group raises a competing-risk concern. When death precludes the event of interest, Kaplan–Meier estimates of subsequent fracture incidence are biased upward. 2 A Fine–Gray sub–distribution hazard model would be more appropriate here, and the conclusions on fracture recurrence should be re-examined accordingly.
Second, the comorbidity adjustment appears insufficient. Individual conditions such as diabetes and cardiovascular disease were entered separately, but a composite measure, such as the Charlson Comorbidity Index, 3 being the most widely used, would better capture overall frailty. Without this, residual confounding likely inflates the apparent independent effect of sarcopenia on mortality.
Third, anti-osteoporotic treatment was mentioned but not modeled. Bisphosphonates and denosumab reduce both refracture and mortality, 4 so unbalanced treatment between groups could itself drive the observed association. Reporting the agents used, treatment duration, and adherence by group would address this.
Finally, the clinical implications are important. If sarcopenia is indeed an independent predictor, the next question is whether preoperative nutritional support and prehabilitation modify outcomes.
