Development and validation of the sickle cell stress scale-adult

Disease-specific stress can partly explain Sickle Cell Disease (SCD) healthcare utilization. We developed and validated two measures of adult SCD-specific stress for research and clinical care. A large cohort of adults with SCD completed both the 3-item Likert-scale adapted from a previous disease stress measure and a 10-item Likert-scale questionnaire drafted specifically to measure SCD stress. They concurrently completed a psychosocial and health-related quality of life scale battery, then subsequently daily pain diaries. Diaires measured: daily intensity, distress and interference of pain; self-defined vaso-occlusive crises (VOC), opioid use, and types of healthcare utilization for up to 24 weeks. Analyses tested Cronbach's alpha, correlation of the three-item and 10-item stress scales with the concurrent battery, with percentages of pain days, VOC days, opioid use days, and healthcare utilization days, and correlation of baseline stress and 6-month stress for the 10-item scale. Cronbach's alpha was high for both the 3-item (0.73) and 10-item (0.83) SCD stress scales, test-retest correlation of 0.55, expected correlation with the concurrent battery, and correlation with diary-measured healthcare utilization over 6 months. The correlations with the 3-item scale were stronger, but only statistically significant for depression-anxiety. The correlation between the two stress scales was 0.59. Both the 3-item and the 10-item stress scales exhibited good face, construct, concurrent, and predictive validity as well as moderate test-retest reliability. Further scale validation should determine population norms and response to interventions.