NSO-03: Validation of the Steroid Symptom Questionnaire Multiple Myeloma (SSQ-MM) with concurrent symptom and quality of life measurement (EORTC QLQ-C30 and MY20)
Myeloma Clinical Nurse Consultant Institute of Haematology, Royal Prince Alfred Hospital Sydney, New South Wales, Australia
Introduction: Steroids, typically included in treatments for multiple myeloma (MM), are associated with significant side-effects. We developed the 20-item Steroid Symptom Questionnaire Multiple Myeloma (SSQ-MM) as a patient-reported outcome measure (PROM) to enable monitoring and management of steroid effects. In pilot testing it demonstrated high levels of feasibility, acceptability, and internal consistency. Here we its further psychometric evaluation.
Methods: Multi-centre cross-sectional study of 140 MM patients taking dexamethasone as part of treatment >4-mnth since diagnosis recruited from five haematology centres in Australia. Participants completed the SSQ-MM, EORTC QLQ-C30 and MY20 PROMs. The SSQ-MM was repeated 1-week later. Internal consistency reliability was tested with Cronbach’s alpha >0.8 for individual patient decision-making. Test-retest using intraclass correlation coefficient >0.7 evaluated SSQ-MM stability reliability. Construct validity was tested with factor analysis and spearman ρ rank-order correlation coefficients for similar domains between the PROMs (high, r > 0.7; moderate, r 0.3-0.7; low, r < 0.3).
Results: Participants were aged between 38-89yrs (Mean: 69.7, SD: 9.9), 54% male, with an average 4.5yrs since diagnosis (range 4mths to 22yrs). Average dexamethasone dose was 26mg weekly (range 4-80), or 84mg per cycle (range 12-180) and participants had completed an average of 4.0 (SD: 3.0) prior lines of treatment. Internal consistency reliability was high: Cronbach’s alpha 0.84, and test-retest indicated SSQ-MM stability (ICC: 0.846). Factor analysis supports a total score reflecting overall symptom bother associated with steroids. Moderate positive correlations were observed between SSQ-MM total scores and MY20 symptom and treatment side-effect scores (r = .466 and .682) providing evidence towards construct validity.
Frequently reported symptoms were disturbed sleep 127/140 (90.7%), fatigue 113/140 (80.7%), and fragile skin/easy bruising 109/140 (77.9%). Patients typically experienced 10 symptoms concurrently (range, 0-19) with four symptoms rated severe (range, 0-12), including: disturbed sleep 91/140 (65 %), fatigue 68/140 (48.6%), and fragile skin/easy bruising 60/140 (42.9%). Longer time since diagnosis (r=0.239; p=0.005), female gender (r=0.194; p=0.022) and higher ECOG (r=0.169; p=0.048) were associated with higher SSQ-MM total scores.
Our descriptive findings highlight Social/Role functioning is impacted by steroid use, which in other studies has been shown to correlate with lowered overall QOL. Fatigue, pain, dyspnoea were reported as high; these are consistently the highest reported symptoms reported across MM studies at each phase of disease.
Conclusions: This study provides evidence in support of the validity and reliability of the SSQ-MM. It is suitable for clinical use to detect steroid toxicity and improve treatment outcomes for MM patients and for use in research settings to assess the impact of steroids in MM.