Temporal Trends in the Complexity of Nephrology Inpatients: A Population-Based Cohort Study

Patients seen by nephrologists are highly complex, and clinical experience suggests this complexity has increased over time. This study compared temporal trends in the complexity profiles of inpatients seen by nephrologists to those seen by other physicians.

Retrospective-cohort study.

Adult inpatients hospitalized between 2011 and 2020 in Alberta, Canada.

(1) Physician groups involved during hospitalization and (2) calendar time.

Ten markers of complexity were evaluated before hospital admission, and 2 outcomes (death and placement in long-term care) were assessed after hospitalization.

Generalized linear models to estimate absolute changes over the study period.

Between 2011 and 2020, there were 1,621,630 hospital admissions among 971,051 patients. The number of nephrology inpatients seen annually rose by 44%, an increase larger than observed with other specialties (95% CI, 28.9-59.8). The percentage of inpatients seen by nephrologists in 2020 with complexity markers related to the number of specialty caregivers, number of physician caregivers, number of prescriptions, emergency department visits, and number of drug reactions increased by 6.1% (95% CI, 5.0-7.1), 6.0% (95% CI, 4.9-7.1) 1.9% (95% CI, 1.0-2.8), 1.5% (95% CI, 0.9-2.1), and 1.2% (95% CI, 0.4-2.0), respectively. The percentage of inpatients with frailty seen by nephrologists and with low primary-care attachment increased by 5.1% (95% CI, 4.2-6.0) and 3.5% (95% CI, 2.4-4.6), respectively. Except for frailty and number of prescriptions, the magnitude of the increases in these markers was larger for nephrology inpatients than for those cared for by other physicians. Secular changes in complexity were largely due to increases in characteristics other than age. Risks of death or placement in long-term care within 1 year of discharge decreased to a greater extent for inpatients cared for by nephrologists than among those cared for by other physicians.

Various markers of patient complexity were not evaluated.

Volume and complexity of inpatients cared for by nephrologists have increased over time, a trend not explained by the increasing age of the population. However, the risks of death or need for long-term care fell more among patients cared for by nephrologists.

Patients seen by nephrologists are highly complex, and clinical experience suggests that this complexity has increased over time. This study evaluated changes in various markers of patient complexity among hospitalized patients seen by nephrologists in Alberta, Canada, between 2011 and 2020. This study found increasing clinical complexity among patients seen by nephrologists, with changes greater than those observed among patients seen by other physician groups. Despite these changes showing increasing complexity among patients cared for by nephrologists, the risks of death or placement in long-term care within a year of hospital discharge decreased over time, and the decrease was greater among patients seen by nephrologists.