Relationship Between “Nurse Dose” and Improvement in Depression Symptoms Among Disadvantaged Women: Findings from the Community-based participatory research to Reduce Women's Health Disparities thru Temporary Assistance for Needy Families Study

Background: Studies that test public health nursing (PHN) interventions are increasingly needed to inform policy and practice. Often, the extent of intervention ‘exposure' is measured at the level of a prescribed number of visits, phone calls, or other event-count data. When interventions are tailored to individual patient needs or involve cost-effectiveness analyses, more precise estimates of ‘nurse dose' are needed to better understand the effect of nursing care on study outcomes.

Methods: This analysis uses data from a randomized controlled trial (RCT) that tested an individualized PHN case-management intervention to meet the chronic health needs of women in this population. This analysis focuses on the relationship between nurse dose and reductions in depressive symptoms from baseline to the three month follow-up in the intervention group (n=146). Nurse dose was calculated in the number of direct minutes the PHN spent with study participants. Regression analyses conducted in the intervention group included nurse dose, history of depression, and a dose X depression history interaction, while controlling for age, race, and education.

Results: Depression scores improved in the total sample (mean = -2.6, SD=6.0). Within the intervention group, although those with a depression history received a higher nurse dose, nurse dose was not significantly related to the change in depression over time in the final model (p<0.05 for all).

Conclusions: Within the intervention group, although PHN's spent approximately 17% more time with participants who had a history of depression, this measure of ‘nurse dose' did not contribute to depressive symptom reductions at the 3 month follow-up when history of depression was a covariate. Continued analyses of the 6 and 9 month follow-up data are warranted to better examine longer-term outcomes related to nurse dose.