Limitations
Only three of the reviewed studies were rated with a high level of evidence based on rigorous experimental prospective RCT designs that included power analysis. Although kyphosis and QOL may track along the same direction (correlation), a causal inference cannot be made without a true experimental controlled study. The reviewed studies did not include equal representation of the sex demographic variable (i.e., recruited participants were primarily female) or pediatric oncology patients. Perhaps the underlying pathophysiology of osteoporosis or scoliosis affected the kyphosis in a different way than cancer would. Furthermore, characteristics of the study populations including previous life experiences were not well defined, which could impact their baseline QOL and/or posture status. Inconsistency in utilized posture and QOL measures make the findings less generalizable. Finally, we did not find evidence that posture is a more sensitive and precise measure of QOL than existing self-report or proxy-report questionnaires, so it fits better as a physical sign to augment QOL measurement than a surrogate biomarker.14