Original Investigation
January 8, 2024
Population-Based Trends in Complexity of Hospital Inpatients
Hiten Naik, Tyler M. Murray, Mayesha Khan, et al
JAMA Intern Med. Published online January 8, 2024. doi:10.1001/jamainternmed.2023.7410
Question Are hospital inpatients becoming more complex over time?
Findings In this cohort study of 3.4 million nonelective hospitalizations in British Columbia, Canada, measures of patient complexity that increased over a 15-year interval included the presence of advanced age, multimorbidity, polypharmacy, recent hospitalization, admission via the emergency department, multiple acute medical problems, more than 1 adverse event, and prolonged hospital length of stay. The proportion of hospitalizations with intensive care unit admission and in-hospital death declined, but readmissions and deaths within 30 days of discharge increased.
Meaning By most measures, the complexity of hospital inpatients has increased over time.
Abstract
Importance Clinical experience suggests that hospital inpatients have become more complex over time, but few studies have evaluated this impression.
Objective To assess whether there has been an increase in measures of hospital inpatient complexity over a 15-year period.
Design, Setting and Participants This cohort study used population-based administrative health data from nonelective hospitalizations from April 1, 2002, to January 31, 2017, to describe trends in the complexity of inpatients in British Columbia, Canada. Hospitalizations were included for individuals 18 years and older and for which the most responsible diagnosis did not correspond to pregnancy, childbirth, the puerperal period, or the perinatal period. Data analysis was performed from July to November 2023.
Exposure The passage of time (15-year study interval).
Main Outcomes and Measures Measures of complexity included patient characteristics at the time of admission (eg, advanced age, multimorbidity, polypharmacy, recent hospitalization), features of the index hospitalization (eg, admission via the emergency department, multiple acute medical problems, use of intensive care, prolonged length of stay, in-hospital adverse events, in-hospital death), and 30-day outcomes after hospital discharge (eg, unplanned readmission, all-cause mortality). Logistic regression was used to estimate the relative change in each measure of complexity over the entire 15-year study interval.
Results The final study cohort included 3 367 463 nonelective acute care hospital admissions occurring among 1 272 444 unique individuals (median [IQR] age, 66 [48-79] years; 49.1% female and 50.8% male individuals). Relative to the beginning of the study interval, inpatients at the end of the study interval were more likely to have been admitted via the emergency department (odds ratio [OR], 2.74; 95% CI, 2.71-2.77), to have multimorbidity (OR, 1.50; 95% CI, 1.47-1.53) and polypharmacy (OR, 1.82; 95% CI, 1.78-1.85) at presentation, to receive treatment for 5 or more acute medical issues (OR, 2.06; 95% CI, 2.02-2.09), and to experience an in-hospital adverse event (OR, 1.20; 95% CI, 1.19-1.22). The likelihood of an intensive care unit stay and of in-hospital death declined over the study interval (OR, 0.96; 95% CI, 0.95-0.97, and OR, 0.81; 95% CI, 0.80-0.83, respectively), but the risks of unplanned readmission and death in the 30 days after discharge increased (OR, 1.14; 95% CI, 1.12-1.16, and OR, 1.28; 95% CI, 1.25-1.31, respectively).
Conclusions and Relevance By most measures, hospital inpatients have become more complex over time. Health system planning should account for these trends.
