Factors associated with achieving minimum clinically important differences in EuroQol-5 Dimensions-5 levels scores following surgery for adult spinal deformity.

BACKGROUND

The EuroQol-5 Dimensions-5 Levels (EQ-5D) is a concise, validated patient-reported outcome measure that captures health status from the patient perspective across five core domains. Its simplicity, reliability, and applicability to health-economic evaluation make it particularly suitable for assessing postoperative health-related quality of life in older adults with adult spinal deformity (ASD). The minimum clinically important difference (MCID) represents improvements from baseline status that are clinically notable. This study aimed to identify factors associated with achieving MCID for the EQ-5D in patients with ASD who underwent multilevel corrective fusion surgery.

METHODS

Patients who achieved MCID for the EQ-5D at 2-years after deformity correction fusion were compared with those who did not. We retrospectively evaluated patient demographics, radiographic measurements and clinical assessments. Sagittal correction was assessed based on age-adjusted ideal alignment, which was categorized into undercorrection, ideal correction, and overcorrection. Multivariate analysis was used to identify factors associated with achieving the MCID for EQ-5D scores.

RESULTS

This study included 85 patients with a 2-year follow-up. The MCID achievement rate was 45.8% (39/85). In logistic regression analysis, age-adjusted ideal correction was a significant factor for achieving MCID. In clinical outcomes, a negative correlation was observed between pre-operative EQ-5D scores and MCID achievement (r = -0.627, p < 0.01). In a correlation analysis of factors related to pre-operative EQ-5D scores, age, previous lumbar fusion surgery, and pre-operative sagittal vertical axis demonstrated negative correlations with pre-operative EQ-5D scores.

CONCLUSIONS

Patients with age-adjusted ideal correction exhibited significantly better achievement of the MCID for the EQ-5D. Furthermore, patients with lower EQ-5D scores were more likely to achieve MCID after corrective fusion for ASD.

LEVEL OF EVIDENCE: III.