Pneumococcal disease burden high in Hong Kong
A recent retrospective cohort study by researchers from Pamela Youde Nethersole Eastern Hospital (PYNEH) and Ruttonjee and Tang Shiu Kin Hospital shows that invasive pneumococcal disease (IPD) is associated with worse disease severity and outcome, revealing a number of factors associated with increased 30-day all-cause mortality in hospitalized patients with pneumococcal disease.
“Our results have important implications for clinical practice. Rapid identification and treatment of IPD may improve patient outcome, and a positive urinary antigen test [UAT] result may serve as an independent predictor of 30-day all-cause mortality in all hospitalized patients, as well as those admitted to the intensive care unit [ICU],” the researchers suggested. [Hong Kong Med J 2020, doi: 10.12809/hkmj208373]
In the study, data of 792 adults (median age, 73 years; male, 73.4 percent) with pneumococcal disease admitted to PYNEH from 1 January 2011 to 31 December 2018 were retrieved and analyzed. Pneumococcal infection was determined by presence of Streptococcus penumoniae in both sterile (ie, IPD) and non-sterile sites, or a positive UAT result (ie, noninvasive pneumococcal disease).
At baseline, a vast majority (96.1 percent) of patients with pneumococcal disease presented with respiratory tract infection, whilst 24.4 percent and 12.0 percent of patients had co-existing asthma/chronic obstructive pulmonary disease and chronic kidney disease (CKD), respectively. Admission to ICU was required in 21.5 percent of patients, while invasive ventilation and vasopressor were needed in 14.1 percent and 28.0 percent of patients, respectively. In terms of microbiology test results, 13.4 percent and 15.4 percent of patients had IPD and a positive UAT test, respectively. The ICU mortality rate was more than double the overall hospital mortality rate for patients with pneumococcal disease (22.9 percent vs 11.2 percent).
The 30-day all-cause mortality rate was significantly increased in patients with IPD vs noninvasive pneumococcal disease (28.6 percent vs 11.4 percent; p<0.001), and in those with a positive vs negative UAT result (36.3 percent vs 12.7 percent; p<0.001).
Vasopressor use, CKD, positive UAT result and advanced age (>65 years) were associated with a 4.96-fold (p<0.001), 3.62-fold (p<0.001), 2.57-fold (p=0.001) and 2.19-fold (p=0.01) increased risk of 30-day all-cause mortality, respectively.
Compared with noninvasive pneumococcal disease, IPD was significantly associated with coexisting CKD (odds ratio [OR], 3.10; 95 percent confidence interval [Cl], 1.88 to 5.13; p<0.001), higher rates of ICU admission (33.0 percent vs 19.7 percent; p=0.002) and use of renal replacement therapy (RRT) (16.0 percent vs 4.8 percent; p<0.001) and vasopressor (93.4 percent vs 17.9 percent; p<0.001), higher 30-day all-cause mortality (24.5 percent vs 9.5 percent; p<0.001), and longer hospital stay (8 days vs 4 days; p<0.001).
Subgroup analysis of patients admitted to ICU showed consistent positive associations between RRT, vasopressor use and IPD vs noninvasive pneumococcal disease (RRT, 48.6 percent vs 24.4 percent; p=0.005) (vasopressor use, 100 percent vs 88.9 percent; p=0.039).
A significant increase in 30-day all-cause mortality rate was seen among patients admitted to ICU who required invasive mechanical ventilation (76.0 percent vs 57.5 percent; p=0.023), extracorporeal membrane oxygenation (14.0 percent vs 5.0 percent; p=0.044), RRT (48.0 percent vs 21.7 percent; p=0.001) and vasopressor (98.0 percent vs 88.3 percent; p=0.043) compared with those without invasive organ support.
Those admitted to ICU with CKD, high Acute Physiology and Chronic Health Evaluation (APACHE) IV score and positive UAT result had a 4.64-fold (p<0.001), 3.73-fold (p=0.016) and 2.94-fold (p=0.008) increase in risk of 30-day all-cause mortality, respectively.