Cumulative complexity: a functional, patient-centered model of patient complexity can improve research and practice

• Published in: Journal of clinical epidemiology Vol. 65; no. 10; pp. 1041 - 1051
• Main Authors: Shippee, Nathan D., Shah, Nilay D., May, Carl R., Mair, Frances S., Montori, Victor M.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.10.2012; Elsevier; Elsevier Limited
• Subjects: Access barriers; Adherence; Biological and medical sciences; Burden; Chronic conditions; Chronic Disease - therapy; Comorbidity; Cost of Illness; Design; Epidemiology; General aspects; Health Literacy; Health Services Accessibility; Humans; Illnesses; Internal Medicine; Literacy; Literature reviews; Medical sciences; Models, Theoretical; Nonlinear Dynamics; Outcomes; Patient complexity; Patient Compliance; Patient-Centered Care; Patients; Planification. Prevention (methods). Intervention. Evaluation; Public health. Hygiene; Public health. Hygiene-occupational medicine; Quality of life; Self Care; Socioeconomic Factors; Workload; Workloads; Adherence; Chronic conditions; Patient complexity; Comorbidity; Burden; Access barriers; Outcomes; Human; Patient-centered approach; Social influence; Prognosis; Accessibility; Chronic disease; Patient; Barrier; Adhesion; Care; Complexity; Improvement; Polypathology; Professional practice; Scientific research; Treatment compliance; Models
• ISSN: 0895-4356; 1878-5921; 1878-5921
• DOI: 10.1016/j.jclinepi.2012.05.005

To design a functional, patient-centered model of patient complexity with practical applicability to analytic design and clinical practice. Existing literature on patient complexity has mainly identified its components descriptively and in isolation, lacking clarity as to their combined functions in disrupting care or to how complexity changes over time. The authors developed a cumulative complexity model, which integrates existing literature and emphasizes how clinical and social factors accumulate and interact to complicate patient care. A narrative literature review is used to explicate the model. The model emphasizes a core, patient-level mechanism whereby complicating factors impact care and outcomes: the balance between patient workload of demands and patient capacity to address demands. Workload encompasses the demands on the patient's time and energy, including demands of treatment, self-care, and life in general. Capacity concerns ability to handle work (e.g., functional morbidity, financial/social resources, literacy). Workload-capacity imbalances comprise the mechanism driving patient complexity. Treatment and illness burdens serve as feedback loops, linking negative outcomes to further imbalances, such that complexity may accumulate over time. With its components largely supported by existing literature, the model has implications for analytic design, clinical epidemiology, and clinical practice.