Understanding Patient Complexity in Canadian Hospitals: Insights from Recent Literature
The landscape of inpatient medical care in Canada is increasingly shaped by a population that is both aging and burdened by multiple chronic conditions. General Medicine (GM) services, often led by hospitalists (both family medicine and internal medicine-trained) and “traditional” general internists (mainly working in Clinical teaching Units at academic hospitals), represent a significant portion of hospital admissions, particularly from the emergency department, and consume a substantial share of healthcare resources. A comprehensive understanding of the characteristics of these patients is crucial for ensuring the quality and sustainability of the healthcare system. Recent studies from various Canadian provinces offer valuable insights into the demographics, multimorbidity, and social factors that define patient complexity in this setting.
Demographic Characteristics: An Older, Broadly Represented Population
Studies consistently indicate that GM services primarily care for an older patient demographic, yet one that spans a wide age range. In the Greater Toronto Area (GTA), the median age of GM inpatients was 73 years (interquartile range [IQR] 57–84), with a significant proportion (37.6%) being over 80 years old, and nearly three in ten (28.6%) under 60 years. Similarly, in British Columbia, patients managed by hospitalists and traditional family physicians exhibited comparable mean ages of 71.22 and 70.86 years, respectively. Internal Medicine (IM) specialists, however, typically managed a younger cohort, with a mean age of 61.00 years. Across these settings, the sex distribution was generally balanced, with women accounting for approximately 50% of admissions to GM services broadly. A more recent, large-scale study across 28 hospitals in Ontario (2015-2021) reinforced these trends, showing median ages of 73 years at community hospitals and 70 years at academic hospitals, with similar sex distributions.
Multimorbidity: The Dominant Feature of Patient Complexity
Perhaps the most defining characteristic of general medicine patients is their high degree of multimorbidity, defined as the co-existence of two or more chronic conditions. The GTA study found a median of six coexisting conditions per hospital stay (IQR 3–9). Notably, similar proportions of admissions were associated with high (42.1%) and low (42.8%) levels of comorbidity, as measured by the Charlson Comorbidity Index. The most prevalent coexisting conditions included hypertension (37.6%) and type 2 diabetes mellitus (33.3%), followed by atrial fibrillation, dyslipidemia, electrolyte abnormality, and heart failure.
Insights from British Columbia suggest that hospitalists often manage more complex cases, with their patients exhibiting a higher mean of 1.03 comorbidities compared to those of family physicians (0.74) or IM specialists (0.78). Furthermore, an Ontario study focusing on older adults with diabetes, dementia, or stroke revealed exceptionally high multimorbidity rates: 76% of diabetes patients, 83% of dementia patients, and 92% of stroke patients had two or more comorbid conditions in addition to their index condition. Across all three of these specific disease cohorts, hypertension and arthritis were overwhelmingly the most common comorbidities, affecting over 75% and 61% of patients, respectively. This consistent finding across diverse studies underscores that multimorbidity is a pervasive and defining feature of general medicine patients in Canada, regardless of the specific disease or hospital setting.
Common Diagnoses and Inherent Heterogeneity
The primary reasons for GM admissions reflect a range of acute and often severe medical issues. The GTA study identified the most common primary discharge diagnoses as pneumonia (5.0%), heart failure (4.7%), chronic obstructive pulmonary disease (COPD) (4.1%), urinary tract infection (4.0%), and stroke (3.6%). These conditions are among the most costly causes of hospitalisation in Canada. While hospitalists and family physicians in British Columbia saw similar common diagnoses, IM providers predominantly managed cardiac conditions. The extensive Ontario study found similar distributions of discharge diagnoses between academic and community hospitals, with heart failure, pneumonia, COPD, and urinary tract infection remaining the most frequent conditions. Despite these common diagnoses, general medicine patient populations are characterised by marked heterogeneity in individual characteristics, the conditions leading to admission, and resource use, even for the same diagnosis.
Social Factors and Overall Complexity
The latest Ontario study (Colacci et al., 2025) provided crucial insights into the role of social factors. It revealed that patients admitted to general medicine at academic and community hospitals had similar neighbourhood-level social characteristics, including after-tax income, education levels, and the proportion of racial/ethnic minority and immigrant residents. This suggests that observed patient complexity differences between academic and community hospitals are not primarily driven by socioeconomic or broader demographic disparities. Instead, the complexity largely stems from the interplay of age, high multimorbidity, and the acute nature of their presenting conditions.
Addressing Patient Complexity in the Health System
Collectively, these studies paint a picture of GIM patients in Canada as an older, highly multimorbid, and clinically heterogeneous population that consumes significant hospital resources. The consistent patterns across different regions and hospital types underline the systemic nature of this complexity. To effectively address this, the Canadian healthcare system can consider several strategies:
• Shift to Multimorbidity-Centric Care: Current guidelines often focus on single conditions, but the high prevalence of multimorbidity necessitates a patient-focused approach that integrates care for multiple conditions, rather than a fragmented, disease-specific model. This includes considering the impact of co-existing conditions on the management of other chronic diseases. This also underscores the need to re-organize acute care facilities to address this new reality. Gone are the days when inpatient units were categorized based on specific organ systems (eg. the “respiratory” unit, the “oncology” ward etc.). Now, all patients on all patient care units present with a multitude of acute and chronic conditions.
• Strengthening Community-Based Care: The findings that acute care services drive costs at higher levels of comorbidity suggest a potential for community-based programmes to better support patients with complex conditions, potentially preventing avoidable and costly acute care episodes.
• Enhanced Data Collection and Research: The heterogeneity of the patient population highlights the need for comprehensive data capture, including patient-level socioeconomic factors, functional status, and frailty, which are crucial for understanding outcomes and developing quality improvement initiatives.
• Optimising Provider Models: The insights regarding hospitalists' lower mortality and readmission rates, potentially linked to higher patient volumes and dedicated on-site availability, suggest that specialised inpatient care models can contribute positively to quality and efficiency. Training programmes and care models should reflect the actual case mix encountered across different hospital settings to adequately prepare healthcare professionals.
Advancing our understanding and adapting our healthcare delivery models to these complex patient characteristics are fundamental steps towards building a high-quality, sustainable healthcare system in Canada.
References
• Colacci, M., Loffler, A., Roberts, S.B., Straus, S., Verma, A.A., & Razak, F. (2025). Patient Complexity, Social Factors, and Hospitalization Outcomes at Academic and Community Hospitals. JAMA Network Open, 8(1), e2454745.
• Griffith, L.E., Gruneir, A., Fisher, K., Panjwani, D., Gafni, A., Patterson, C., Markle-Reid, M., & Ploeg, J. (2019). Insights on multimorbidity and associated health service use and costs from three population-based studies of older adults in Ontario with diabetes, dementia and stroke. BMC Health Services Research, 19, 313.
• Verma, A.A., Guo, Y., Kwan, J.L., Lapointe-Shaw, L., Rawal, S., Tang, T., Weinerman, A., Cram, P., Dhalla, I.A., Hwang, S.W., Laupacis, A., Mamdani, M.M., Shadowitz, S., Upshur, R., Reid, R.J., & Razak, F. (2017). Patient characteristics, resource use and outcomes associated with general internal medicine hospital care: The General Medicine Inpatient Initiative (GEMINI) retrospective cohort study. CMAJ Open, 5(4), E842-E849.
• Yousefi, V., Hejazi, S., & Lam, A. (2020). Impact of Hospitalists on Care Outcomes in a Large Integrated Health System in British Columbia. Journal of Clinical Outcomes Management, 27(2), 60-68