Preventing acute kidney injury should be a priority when discharging patients with chronic obstructive pulmonary disease (COPD), according to a recent study.
Patients with acute renal failure (AKI) and hospitalized for an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) were at higher risk of readmission over 30 and 90 days, according to an article published in BMC Nephrology.
Investigators from Massachusetts General Hospital in Boston retrospectively studied 356,990 patients hospitalized for AECOPD to determine the link between AKI and the risks of readmission in this population. Previous studies have indicated a relationship between AKI and AECOPD, but the study authors wrote that there is a gap in the literature for longitudinal studies.
Patients in the analysis were hospitalized adults over the age of 40 with a diagnosis of primary COPD discharge. Investigators collected data on patient sex, age, race / ethnicity, type of primary insurance, estimated household income, patient residence, diagnostic and procedure codes, co-morbidities , the hospital course and the disposition.
Most of the patients were older (median age: 71), male (42%), and white (74%), the study authors determined. During the index hospitalization, 7% of patients had a new diagnosis of AKI. The study authors noted that the AKI group was more likely to be elderly and male.
In total, 16% of patients had at least 1 readmission within 30 days of their first hospitalization, found the investigators. After 90 days of index hospitalization, 31% of patients had at least 1 readmission, they added.
However, for AKI patients, the investigators noted a significant difference between the 30 and 90 day all-cause readmission rates compared to the whole group. The AKI group had a significantly higher risk of 30-day readmission and 90-day readmission, according to the study authors. This remained true when the investigators then disaggregated the data to include patients 65 years of age or older only, women only, or patients without chronic kidney disease. After the study authors stratified the data by dialysis use, the AKI group had higher readmission rates at 30 and 90 days than those without AKI.
The most common cause of readmission in patients without AKI was COPD, followed by pneumonia, respiratory failure, and asthma. The study authors learned that AKI patients were more likely to be readmitted due to non-respiratory illnesses, such as sepsis, acute renal failure, or congestive heart failure. The reasons for the readmission were no different for 30- or 90-day readmissions, the study authors found after listing the top 5.
The study authors also said that patients with AKI hospitalized for AECOPD had a mortality rate about 2 times higher within 6 months than those without AKI. While previous research has shown that AKI is a risk factor for later infections like tuberculosis and sepsis, the study authors’ results “deserve to be clarified,” they said.
“We found that patients with AKI had a 50% higher risk of all-cause readmissions for 30 days after index hospitalization compared to those without AKI,” the study authors concluded. “This significant association persisted after adjustment for potential confounders … For clinicians, our results underscore the importance of AKI prevention and post-release care in this population.”
Hirayama A, Goto T, Hasegawa K. Association of acute renal injury with readmission after hospitalization for acute exacerbation of chronic obstructive pulmonary disease: a population-based study. BMC Nephrol. 2020;21 (116) doi: 10.1186 / s12882-020-01780-2.