Adiponectin as a predictor of mortality and readmission in patients with community-acquired pneumonia: a prospective cohort study

Abstract

Background: Adiponectin is secreted by adipocytes and is inversely associated with obesity. Given the association between low body mass index (BMI) and higher mortality risk after community-acquired pneumonia (CAP), we hypothesized that high adiponectin levels are associated with a higher risk of adverse clinical outcomes in patients with CAP.

Methods: In a prospective cohort study of 502 patients hospitalized with CAP, adiponectin was measured in serum at admission. The associations between adiponectin and clinical outcomes were estimated with logistic regression analyses adjusted for age, sex, and measures of obesity (BMI, waist circumference or body fat percentage).

Results: Adiponectin was associated with higher 90-day mortality for each 1 μg/mL increase [OR 1.02, 95% CI (1.00, 1.04), p = 0.048] independent of age and sex. Likewise, adiponectin was associated with a higher risk of 90-day readmission for each 1 μg/mL increase [OR 1.02, 95% CI (1.01, 1.04), p = 0.007] independent of age and sex. The association between adiponectin and 90-day mortality disappeared, while the association with 90-day readmission remained after adjusting for adiposity.

Conclusion: Adiponectin was positively associated with mortality and readmission. The association with mortality depended on low body fat, whereas the association with readmission risk was independent of obesity.

Keywords: adiponectin; body mass index; community-acquired pneumonia; mortality; readmission.

Figure 1

Flow chart of patient enrolment. 2,433 were excluded because they did not fulfill all inclusion criteria. SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

Figure 2

Boxplot of baseline serum adiponectin levels (μg/mL) stratified by CURB-65 score. The line within the box represents the median serum adiponectin levels, and each box represents the upper and lower quartiles. The jittered points around each boxplot represent the distribution of adiponectin. Statistical comparisons were made with Mann–Whitney U tests for two-group comparisons or Kruskal–Wallis tests in case of more than two independent samples, followed by Dunns’s post hoc test for multiple comparisons. p, p-value.

Figure 3

Boxplot of baseline serum adiponectin levels (μg/mL) stratified by outcome status. The line within the box represents the median serum adiponectin levels, and each box represents the upper and lower quartiles. The jittered points around each boxplot represent the distribution of adiponectin. Statistical comparisons were made with Mann–Whitney U tests for two-group comparisons or Kruskal–Wallis tests in case of more than two independent samples, followed by Dunns’s post-hoc test for multiple comparisons. p, p-value.

Figure 4

Kaplan–Meier survival probability curves 90 days after admission according to sex-adjusted adiponectin quartiles for 502 patients with community-acquired pneumonia. The survival curves for the second, third and fourth quartiles were significantly different from the first quartile according to a log-rank test (p = 0.0031).

Figure 5

Boxplot of baseline serum adiponectin levels (μg/mL) stratified by in-hospital mortality. The line within the box represents the median serum adiponectin levels, and each box represents the upper and lower quartiles. The jittered points around each boxplot represent the distribution of adiponectin. Statistical comparisons were made with Mann–Whitney U tests for two-group comparisons. p, p-value.