Table 2. Details of included studies.

Authors	Objective	Methods	Theoretical perspective and working definition of BoT
Tran, Barnes et al.	To describe and classify the components of the burden of treatment for patients with chronic conditions	Open-ended questions in an online survey in English, French and Spanish. Content analysis (grounded theory approach). Reinert’s automatic textual analysis. Taxonomy, Bradley et al.’s method	Questionnaire developed after literature review, reviewed by seven experts. BoT defined as “work of being a patient” on functioning and well-being
Sav et al.	To explore treatment burden among people with a variety of chronic conditions and comorbidities	Semi-structured interviews face to face or over phone. Analyzed using iterative thematic approach and constant comparison method (grounded theory analysis)	The study was guided by the interpretive social paradigm, described by Neuman[33]. BoT defined as consequences patients and their families experience as a result of undertaking or engaging in treatment
Noël	To explore the collaborative care needs and preferences in primary care patients with multiple chronic illnesses	Semi-structured interviews in focus groups. Descriptive codes were grouped to generate broader themes. Patterns, interrelationships and overarching categories were discerned among the themes	Results grouped according to Von Korff’s collaborative management of chronic illness care[34]. No definition of the BoT
Eton et al.	To finalize a conceptual framework of treatment burden	1st round: Semi-structured interviews in focus groups. Used Ritchie and Lewis Framework to create a conceptual framework 2nd round: Focus groups. To test the fitness of the framework and clarify new issues	Normalization Process Theory[35] and prior studies of treatment impact informed the questions. BoT defined as the workload of health care and its impact on patient functioning and well-being
Ridgeway et al.	To present the factors that patients with multimorbidity draw on to lessen perceptions of treatment burden	Same as Eton et al. Themes and subthemes were used to identify factors that mitigate treatment burden	Same as Eton et al.
Gallacher et al.	To assess the burden associated with treatment among patients living with chronic heart failure	Secondary analysis of qualitative interviews. Ritchie and Lewis framework analysis informed by Normalization Process Theory	Normalization Process Theory as a conceptual tool. BoT involves complex interactions between factors related to health care professionals and systems and factors related to patients’ characteristics
Kahn et al.	To explore the self-management strategies and treatment burden experienced by low income US primary care patients with chronic kidney disease	Semi-structured interviews one-on-one. Inductive thematic content analysis approach to analyze scripts and identify themes. Themes were reorganized in light of their direct application to Normalization Process Theory and treatment burden	Normalization Process Theory applied to chronic kidney disease. Treatment burden entails the patient’s engagement with providers, the health care system, their family or social support network, and personal self-care regimens
Tran, Montory et al.	To develop and validate an instrument for measuring treatment burden for patients with multiple chronic conditions	Semi-structured interviews one-on-one. The resulting measurement instrument was tested quantitatively on another group of patients	Three experts highlighted topics from a literature review. BoT defined as the impact of healthcare on patients’ functioning and well-being, apart from specific treatment side effects
Bayliss	To identify perceived barriers to self-care among patients with comorbid chronic diseases	Semi-structured interviews one-on-one. Used Qualitative Comparative Analysis to identify barriers to self-care	Interpreted the potential barriers to self-care that emerged from the analysis in light of the four components of chronic disease self-management. No definition of the BoT