The minimal important difference of one-minute-sit-to-stand test in subjects with chronic pulmonary aspergillosis.

Background and objective: There is a need for simple functional test to assess treatment response in chronic pulmonary aspergillosis (CPA) in resource-constrained settings. The one-minute-sit-to-stand test (1-min-STS) is one such test. However, the minimal important difference (MID) for 1-min-STS in subjects with CPA remains unknown. Herein, we estimate the MID for 1-min-STS for CPA subjects.

Materials and methods: We retrospectively reviewed the clinical details of CPA subjects treated with oral azoles for 6 months. We included only subjects who completed the 1-min-STS test at baseline and 6 months. We used the change in VAS (visual analogue scale, for overall improvement) as an external anchor. We used the anchor and the distribution (standard deviation-based) methods to determine the MID estimates. We used the anchor-based method only if there was correlation of 0.3 with the 1-min-STS test.

Results: One hundred-eight subjects completed the 1-min-STS test at baseline and 6 months. We did not find significant correlation between the change in VAS for overall improvement (r2 = 0.024, P value = 0.809) and the 1-min-STS test. The MID for the 1-min-STS test was 2 repetitions (range, 1.5-2.8 repetitions).

Conclusion: The MID for the 1-min-STS test in subjects with CPA was 2 repetitions. Future studies using a global rating of change scale as an anchor must confirm our findings.