Measuring out-of-pocket healthcare cost (OOPC) and its impact on health-seeking behavior (HSB) in cancer: A systematic review.

10 Background: High OOPC represents the objective dimension of financial toxicity and may lead to adverse HSB, such as disengagement from care. However, methodology for OOPC measurement is inconsistent and limited studies have linked OOPC to behavioral patterns. Understanding how OOP influences HSB can help identify patients at risk of cost-related forgone care and inform insurance plan design. In this systematic review, we examined OOPC measurement and the relationship between OOPC and HSB among individuals with a history of cancer. Methods: A search was performed in PubMed and EMBASE with keywords associated with OOPC and cancer, supplemented by citation searching of relevant reviews. Studies were included if the target population was cancer patients/survivors and OOPC was reported quantitatively. Secondary research was excluded, or if OOPC was not based on empirical data or only for a specific treatment/procedure. Study screening and data extraction were performed independently by two researchers using Covidence. Data elements that were extracted included study characteristics, OOPC measures/methodology and if reported, any relationship between OOPC and HSB. For this review, HSB refers to behavior in response to health issues experienced or perceived. Results: Our search yielded 8,598 unique papers; 149 (representing 147 studies) met inclusion criteria. Among eligible studies, 44.9% were from the United States. Breast cancer was the most common among studies with 1 tumor site (15.6%) while 44.9% included > 1 cancer types. Cost outcomes were reported only for the treatment phase in 32.7% of studies while 36.7% extended the study period to the survivorship phase; 25.2% did not specify the phase of care. Average OOPC varied widely depending on study setting and OOPC measurement approaches. Some studies (41.5%) included non-medical costs in OOPC such as transportation (40.8%), accommodation (27.9%) and meals (19.7%). Additionally, 28.6% incorporated deductibles in OOPC. When reporting OOPC, a few studies accounted for the capacity to pay, either household/individual income (19.0%) or expenses (surrogate of disposable income) (7.5%). Only 7 (4.7%) studies examined how OOPC influence HSB, primarily medication/treatment adherence (71.4%) and healthcare resource utilization (28.6%). Across all studies, lower adherence and higher risk of cost-related care avoidance were consistently observed with increased OOPC. OOPC thresholds where nonadherence or forgone care substantially increased were not reported or different due to variability in OOP components and measurement approaches. Conclusions: OOPC measurement is heterogenous, warranting best practices to be established to allow comparison and synthesis of published OOPC data. Minimal research has been conducted to examine OOPC and HSB but OOPC can potentially be used to predict and monitor for risk of forgone care.