Minimal Clinically Important Difference in the Integrated Palliative Care Outcome Scale for Cancer Dyspnea.

CONTEXT: Dyspnea is a common and distressing symptom in patients with cancer. The Integrated Palliative care Outcome Scale (IPOS) provides health care providers with a proxy tool for assessing dyspnea; however, the minimal clinically important difference (MCID) in the IPOS for dyspnea is unknown.

OBJECTIVES

To determine the MCID in the IPOS improvement for dyspnea.

METHODS

This secondary analysis used data from a multicenter prospective observational study initially designed to evaluate the effectiveness and safety of opioids for dyspnea in patients with cancer. We included patients with available IPOS scores and Patient's Global Impression (PGI) at baseline and 24, 48, and 72 h after starting opioid therapy, comprising cohorts 1, 2, and 3, respectively. The MCID for IPOS improvement in dyspnea was determined using a sensitivity-specificity approach, specifically Youden's J statistic and the top-left approach.

RESULTS

A total of 354, 308, and 272 patients were included in cohorts 1, 2, and 3, respectively. Based on Youden's J statistic, the optimal MCID cutoff for improvement in the IPOS score for dyspnea was ≥+1 in all cohorts. The sensitivities of these cutoffs were 0.86, 0.885, and 0.909 and the specificities were 0.770, 0.593, and 0.560 for cohorts 1, 2, and 3, respectively. The top-left approach confirmed this MCID cutoff of ≥+1 in all cohorts.

CONCLUSION

The MCID for IPOS improvement in dyspnea was determined to be ≥+1 across all time points. This can facilitate the design and interpretation of future studies using IPOS scores as study outcomes.

CLINICAL TRIAL REGISTRATION: UMINCTR: UMIN 000038918.