Using Qualitative Interviews to Improve Quantitative Assessments of Quality of Life in Patients with Neurofibromatosis 2
Liesel Von Imhof1, Scott Plotkin1, Kaleb Yohay2, Leia Nghiemphu3, Dusica Babovic-Vuksanovic4, Vanessa Merker1
1Massachusetts General Hospital, 2NYU Langone Medical Center, 3UCLA, 4Mayo Clinic
Objective:
To use qualitative interviews to elucidate seemingly discordant quantitative ratings in patient reported outcomes for quality of life (QOL).
Background:
Neurofibromatosis 2 (NF2) is a progressive, neurogenetic disease. Assessing QOL is important in demonstrating that new drugs improve how NF2 patients feel and function. The NFTI-QOL is the currently recommended measure to assess NF2-specific QOL in clinical trials.
Design/Methods:
We interviewed 16 participants enrolled in stage one of the brigatinib arm of INTUITT-NF2 (NCT04374305) –a multicenter, adaptive platform-basket trial targeting progressive NF2-related tumors – after one year of treatment or at time of trial discontinuation.
Interviews included cognitive debriefings of the NFTI-QoL and global impression of change (GIC) scale. We also analyzed NFTI-QoL scores collected over the same time period, using a MCID of ±2 points to classify improvement or worsening in QOL.
Results:
11/16 (69%) participants reported a GIC rating discordant with their change in NFTI-QoL scores. 8/13 (62%) of participants who improved on their GIC had stable (N=6) or worsened (N=2) NFTI-QoL scores. This group cited tumor stability as a major contributor to improved GIC ratings and also had lower baseline NFTI-QoL scores (median=8) than those with concordant ratings (median=12). Participants with lower NFTI-QoL scores disproportionally reported that a meaningful improvement in their symptoms would not lead to an accompanying score improvement due to inadequate NFTI-QOL response options.
Conclusions:
Qualitative interviews revealed two reasons for conflicting patient reported outcome results. In the setting of a progressive disease, participants can view tumor volume stability as an improvement, even with stable or worsening symptoms. Also, the NFTI-QoL may not be capturing improvement in people with a lower symptom burden. In order for the NFTI-QoL and GIC to better reflect changes in NF2 patients QOL, we recommend adding another response option to the NFTI-QoL and altering the instructions of the GIC.