PF721 MINIMAL CLINICALLY IMPORTANT DIFFERENCE AND RESPONSIVENESS FOR HM‐PRO IN PATIENTS WITH HAEMATOLOGICAL MALIGNANCIES

Background: Minimal clinically important difference (MCID) of a patient‐reported outcome (PRO) measure is the smallest change in the scores that is meaningful from a patient's perspective. The responsiveness, on the other hand, is an important measurement property which is required to show that the instrument is capable of detecting change over time or after a therapeutic intervention. Evaluating both responsiveness and MCID of a newly developed PRO instrument is a measurement necessity. A novel haematological malignancy (HM) specific PRO, HM‐PRO, has been developed for use in daily clinical practice as well as clinical research. The HM‐PRO is a composite measure consisting of two scales: Part A‐measuring the impact on patients’ quality of life (QoL); and Part B‐measuring the effect of signs and symptoms experienced by the patients. Aims: The aims of this study were to evaluate the responsiveness and estimate the MCID of the newly developed HM‐PRO. Methods: In a prospective multicenter cross‐sectional study, a total of 299 patients: male 167 (55.9%); mean age 64.9 (±11.5) years, range 17.9–88.5 years; mean time since diagnosis 4.9 (±4.8) years, range 0.003 – 27.4 years; with different HMs (acute lymphoid leukaemia‐8, acute myeloid leukaemia‐18, aggressive non‐Hodgkin lymphoma‐21, chronic lymphoid leukaemia‐24, chronic myeloid leukaemia‐11, Hodgkin lymphoma‐12, indolent non‐Hodgkin lymphoma‐8, myelodysplastic syndrome‐65, multiple myeloma‐85, myeloproliferative neoplasm‐47); in different disease state (stable‐139, remission‐82, progressing‐78), were recruited. Patients were asked to complete the HM‐PRO at baseline (t0) and after three months (t1). Data analysis was performed using IBM SPSS 23 statistical software. Paired t‐test, effect size (ES) and standard response mean (SRM) analysis were performed to test HM‐PRO's responsiveness as the ability to detect change. An anchor question (5‐point Likert scale from ‘much worse’ to ‘much better’) measuring change in HRQoL from patients’ perspective was used. The distribution‐based approach was employed to estimate the MCID, using standard deviation (SD) and the standard error of measurement (SEM). Results: Both parts of the HM‐PRO were assessed individually for responsiveness. The paired sample t‐test was significant in the ‘slightly better’ group for Part A (mean score change = 6.8, SD = 13.7, t = 3.343, df = 44, p = 0.002; Cohen's d = 0.35; SRM = 0.50), and Part B (mean score change = 3.68, SD = 8.7, t = 2.7, df = 42, p = 0.009; Cohen's d = 0.31; SRM = 0.42) showing significant decrease in score over time and with moderate effect size. In contrast, patient group with ‘about the same’ HRQoL did not show significant change in scores over time for both Part A (mean score change = 1.7, SD = 12.7, t = 1.7, df = 154, p = 0.09; Cohen's d = 0.08; SRM = 0.13) and Part B (mean score change = 0.57, SD = 8.93, t = 0.80, df = 153, p = 0.42; Cohen's d = 0.04; SRM = 0.06) (Table 1a). In order to establish MCID, statistical characteristics of a sample of baseline patient response were studied for both Part A and Part B. The analysis of Part A showed an SEM of 6.2 and 1/2 SD of 11.2, and for Part B showed an SEM of 5.9 and 1/2 SD of 7.3 (Table 1b). Summary/Conclusion: This study has established the responsiveness and MCID for both Part A and Part B of the HM‐PRO. The HM‐PRO is capable of detecting a small but clinically important change in patients’ HRQoL over time. The MCID for Part A based on SEM was 6.2 and for PART B 5.9 points. It would, therefore, be prudent, for practical reason, to propose an MCID of ‘6’ for the HM‐PRO.