Clinicians are encouraged to follow evidence-based guidelines in managing their patients’ conditions, and frequently they must rely on guidelines that have been designed for a single chronic condition. The presence of Multiple Chronic Conditions (MCC) creates many challenges for clinicians, including the need to decide what evidence to use in making clinical decisions and the need to consider patients’ context and personal preferences in relation to clinical decision-making. This study will examine the records of patients with multiple chronic conditions (MCC) to test the feasibility of characterizing their clinical pathophysiological presentation using cross-sectional and longitudinal data to encourage a change from an approach focused on single chronic diseases to an integrated approach that systematically generates practice-based evidence to inform quality improvement, clinical research, “institutional learning” about the population served, and on-going clinical practice guideline development and updates.
Capturing more granular clinical pathophysiological presentation will lead to better understanding of MCC groups and their clinical impact. Analyses of outcomes within and between MCC groups may reveal sub-groups at risk for different comorbidities leading ultimately to development of models to improve patient-centric diagnosis, prognosis, and prediction of treatment response. This study also provides an opportunity to examine the validity of the Rothman Index (RI) across a spectrum of patient characteristics and disease burden contexts. The RI was developed independently of demographics, medical history, diagnosis, and treatment regimens.

Specific aims are:
1.     Identify and characterize cross-sectional clinical pathophysiological presentation of MCC groups and examine associations with attendant outcomes for patients at least 18 years old.
2.     Examine longitudinal stability / instability of clinical pathophysiological presentation and outcome patterns in each patient undergoing multiple admissions in one of the five most prevalent MCC groups. Cross-sectional characterization (SA1) of the most recent admission will be the baseline.
3.     Test assumption that the excess 1-year mortality risk computed for each of the 26 variables included in the Rothman Index is invariant across age, sex, race and chronological periods of hospital care, and subgroups of patients experiencing various illnesses including MCC