Paul B. Jacobsen

Severity, course, and predictors of sleep disruption following hematopoietic cell transplantation: a secondary data analysis from the BMT CTN 0902 trial

Sleep disruption has received little attention in hematopoietic cell transplantation (HCT). The goal of this study was to describe severity, course, and predictors of sleep disruption following HCT. A secondary data analysis was conducted of the Blood and Marrow Transplantation Clinical Trials Network (BMT CTN) 0902 study. Participants completed a modified version of the Pittsburgh Sleep Quality Index prior to transplant and 100 and 180 days posttransplant. Growth mixture models were used to characterize subgroups of patients based on baseline sleep disruption and change over time. A total of 570 patients (mean age 55 years, 42% female) were included in the current analyses. Patients could be grouped into four distinct classes based on sleep disruption: (1) clinically significant sleep disruption at baseline that did not improve over time (20%); (2) clinically significant sleep disruption at baseline that improved over time (22%); (3) sleep disruption that did not reach clinical significance at baseline and did not improve over time (45%); and (4) no sleep disruption at baseline or over time (13%). These data provide a more comprehensive understanding of sleep disruption that can be used to develop interventions to improve sleep in HCT recipients.

The Impact of Using Different Reference Populations on Measurement of Breast Cancer-Related Cognitive Impairment Rates

Objective To evaluate how use of different reference populations affects estimates of breast cancer-related cognitive impairment rates. Methods Patients aged ≥60 years with stage 0-3 breast cancer (n = 371) and matched non-cancer controls (n = 370) completed 13 neuropsychological tests prior to systemic therapy or at enrollment (controls). The tests captured three domains: attention, processing speed and executive function; learning and memory; and visual-spatial function. Domain-specific impairment was defined as having one test score 2 SD below or two or more test scores 1.5 SD below the reference population means. Different reference populations were used to define impairment: published normative data, study-specific controls, age and education-stratified controls, and age and education-adjusted controls. The associations between the resultant impairment rates and breast cancer (vs. control) were evaluated using chi-square tests and logistic regression models. Cohens kappa coefficients were used to evaluate agreement of impairment rates between study-specific control performance and the other reference population groups. Results The patients and controls were aged 68.0 (SD 6.0) and 67.9 (SD 7.0) years, respectively. The association of breast cancer-control status with impairment did not differ based on reference group. Cognitive impairment based on published normative data yielded less agreement on impairment rates (κ = 0.22-0.89) than study-specific age and education-stratified control performance (κ = 0.62-1.00). Conclusion The choice of reference populations did not affect conclusions about the association of cognition with breast cancer. However, while study-specific reference populations provided greater internal consistency in defining cognitive impairment, benchmarking against published normative data will enhance the ability to compare results across studies.