Functional capacity assessment and Minimal Clinically Important Difference in post-acute cardiac patients: the role of Short Physical Performance Battery

The Short Physical Performance Battery (SPPB) test is a well-established tool to assess physical performance, and to identify frail patients. Assessment of the SPPB in a specific population of elder patients in cardiac rehabilitation phase after a cardiac event is missing.

The aim of this study was to correlate SPPB and the cardiac rehabilitation outcome in a group of elder patients after a cardiac event and to identify the Minimal Clinically Important Difference (MCID) of the SPPB.

Consecutive (n = 392) patients aged ≥75 years, in the rehabilitation phase after cardiac surgery (70.1%), congestive heart failure (7.4%), or acute coronary syndrome (22.5%), were enrolled. SPPB was performed twice: on admission and discharge. The MCID was assessed with the ‘anchor method’, and the Patient Global Impression of Change was employed as the anchor.

On admission, SPPB classified 56, 117, 116, and 94 patients as severe, moderate, mild, or minimal/no limitations, respectively. Patients with the lower SPPB had the longer length of stay, and the higher complications rate. At receiver operating characteristic analysis, an SPPB improvement >1 was identified as the MCID (area-under-curve 0.77, 95% CI 0.67–0.85). Overall, 285 patients (74.2%) had a ‘clinically significant’ improvement in SPPB, with a rate of improvement higher in patients with severe/moderate limitations (83.0%) and lower in those with mild (78.9%) or minimal/no limitations (53.6%).

A lower SPPB score is associated with a higher complications rate in the post-acute phase. An improvement >1 point of SPPB was identified as the MCID; this reference value could serve as the goal for rehabilitation interventions.