Short Physical Performance Battery Can Be Utilized to Evaluate Physical Function in Patients After Cardiac Surgery

Purpose: The Short Physical Performance Battery (SPPB) is a test used to assess physical function; however, the minimal clinically important difference (MCID) in patients after cardiac surgery is unknown. The aim of this study was to determine the MCID of the SPPB after cardiac surgery. Methods: Seventy-two participants performed the SPPB at 4 weeks and 3 months postoperatively. The Short Form-36 version 2 was used to assess physical function and the Global Rating of Change (GRC) scale was used to assess patients' perceived change. Distribution-based methods were used to determine the MCID. Results: The mean (95% confidence intervals [CIs]) change of the SPPB between testing time points was +1.04 (0.67–1.42) points. Ninety-eight percent of patients rated their function as “changed” on the GRC scale. The MCID calculated using distribution-based methods ranged from 0.44 points (95% CI [0.191, 0.613]) for the effect size-based estimate to 1.35 points for the standard error of measurement–based estimate. No participants scored 0/12; however, 45% and 69% of participants scored 12/12 at 4 weeks and 3 months postoperatively, respectively. Conclusion: The MCID for SPPB is estimated to be between 0.44 and 1.35 points out of 12 for patients in the early postoperative period. Nearly half of the participants scored the maximum score at 4 weeks, increasing to two-thirds at 3 months meaning that the SPPB may be too easy as time from surgery increases and patients recover. Further research is required to confirm the MCID in patients closer to surgery where the ceiling effect is likely to be lower.