Minimal important difference of target lobar volume reduction after endobronchial valve treatment for emphysema

作者：Welling Jorrit B A^*; Hartman Jorine E; van Rikxoort Eva M; Ten Hacken Nick H T; Kerstjens Huib A M; Klooster Karin; Slebos Dirk Jan

来源：Respirology, 2018, 23(3): 306-310.

DOI：10.1111/resp.13178

• chronic obstructive pulmonary disease
• emphysema
• lung volume reduction
• minimal important difference
• valves

Background and objectiveTarget lobar volume reduction (TLVR) is an important efficacy outcome measure for bronchoscopic lung volume reduction (BLVR) treatment using one-way endobronchial valves (EBV) in patients with severe emphysema. The commonly used cut-off value for TLVR that expresses a perceivable clinical benefit is -350mL. However, a scientifically determined minimal important difference (MID) for TLVR never has been published. The objective of the present study was to determine the MID for TLVR on HRCT in patients who were treated with EBV.
MethodsA total of 318 patients with severe emphysema from two BLVR trials were analysed. Anchor-based methods were used to define the TLVR MID at 6months follow-up. Forced expiratory volume in 1s (FEV1), residual volume (RV) and St. George's Respiratory Questionnaire (SGRQ) were used as anchors.
ResultsThe calculated TLVR MID with each anchor was: FEV1 -587mL, RV -534mL and SGRQ -560mL. The combined MID (average of the three anchor-based MIDs) was -563mL.
ConclusionUsing the anchor-based method, we established a TLVR MID of -563mL in patients with severe emphysema at 6months follow-up after EBV treatment. This value can be useful for both interpreting the results from trials and clinical practice, as well as for designing future studies on lung volume reduction.

• 出版日期2018-3