Why are people with asthma susceptible to pneumonia? A review of factors related to upper airway bacteria

Pneumococcal disease burden in high-risk older adults: Exploring impact of comorbidities, long-term care facilities, antibiotic resistance, and immunization policies through a narrative literature review

This study aims to provide a comprehensive review of literature on pneumococcal disease burden in high-risk older adults aged ≥65 with focus on impact of comorbidities, long-term care facilities (LTCFs), antibiotic resistance, and vaccination policies across various countries. Research showed that the disease burden and the prevalence of antibiotic-resistant pneumococci was higher in the elderly, particularly those residing in LTCFs, and with comorbidities. These individuals are at high risk of infection with antibiotic-resistant serotypes 10A, 11A, and 15B. The vaccination strategies and national guidelines for pneumococcal vaccines in the elderly vary across countries. Some countries focus on single-dose strategies, while others recommend sequential vaccinations with varying intervals. Although vaccination policies are well-established for the elderly, they are not as well-established for high-risk elderly groups, and this review underscores the need for more tailored vaccination strategies for these groups.

[The effectiveness of vaccination against pneumococcal infection in patients with severe bronchial asthma]

INTRODUCTION

The article discusses topical issues of the use of conjugated 13-valent pneumococcal vaccine Prevenar®13 (PCV13) in patients with severe bronchial asthma (SBA), including those receiving targeted therapy with genetically engineered biological drugs (GEBD).

AIM

To study the effectiveness of vaccination against pneumococcal infection (PI) in patients with SBA.

MATERIALS AND METHODS

The study included 381 patients with SBA. The average age in the study groups was 45.5 (42.0; 52.5) years. All patients underwent clinical and instrumental studies, including spirography with bronchodilation test. After confirming the diagnosis of BA, the patients were divided into 2 observation groups. Group 1 (n=191) consisted of patients undergoing treatment with GEBD. Group 2 included patients with asthma receiving standard therapy, according to the 4th-5th stage according to the criteria of the Global Initiative for Asthma 2022 (Global Initiative for Asthma - GINA). The observation group consisted of 190 patients. In each group, there are subgroups of patients who have been vaccinated against PI and have not been vaccinated for various reasons. The following criteria were used as the main endpoints of observation for 12 months to assess the effectiveness: the number of pneumonia during the observation period, the number of exacerbations of asthma (severe, non-severe), the number of hospitalizations, the duration of exacerbations, the level of control according to the Asthma Control Questionnaire (ACQ5), functional indicators.

RESULTS

The coverage of PI vaccination in patients with BA remains quite low, further organizational and methodological work is required to increase their involvement in vaccination. Immunization of PCV13 in patients with SBA at the 4th-5th stage of therapy reduces the risk of community-acquired pneumonia by at least 28.5%. PCV13 vaccination may be an additional effective tool for controlling the symptoms of SBA, including in patients undergoing treatment with GEBD. Vaccination allows to normalize the functional parameters of respiratory function in patients with SBA. PCV13 is well tolerated and does not cause any significant allergic reactions in patients with asthma.

CONCLUSION

PCV13 vaccination is an effective tool for reducing the risk of community-acquired pneumonia in patients with severe bronchial asthma, including those on targeted therapy with genetically engineered biological drugs.

A Multifaceted Exploration of Status Asthmaticus: A Retrospective Analysis in a Romanian Hospital

Background: Status asthmaticus is a severe, life-threatening asthma exacerbation requiring urgent medical intervention. This study aims to examine its epidemiology in Timis County, Romania, over 11 years. Methods: A retrospective analysis was conducted using hospital records from 2013 to 2023, focusing on demographic, geospatial, and temporal distributions. Network analysis of the recorded comorbidities was used to identify phenotypic clusters among patients. Results: Females and older adults were disproportionately affected. Several triggers and geospatial patterns were identified. Five phenotypic clusters were determined: two in the T2-high endotype, two in T2-low, and a mixed one. Conclusions: The findings highlight the need for personalized asthma management strategies and public healthcare interventions in Timiș County, addressing specific demographic and geospatial factors. This study also provides a valuable reference for similar regions.

Biologics for asthma and risk of pneumonia

OBJECTIVE

Modification of the immune system with biologics raises theoretical concerns about the risk of infections but it is still unclear whether currently routinely used biologics in severe asthma may facilitate the development of pneumonia. Therefore, we aimed to determine whether omalizumab, mepolizumab, benralizumab, and dupilumab are associated with pneumonia in a real-world setting.

METHODS

A retrospective disproportionality analysis was performed using adverse event (AE) reports submitted to FAERS from January 2020 to September 30, 2023. MedDRA was used to identify infections and infestations and then pneumonia cases. ROR and PRR were used to measure disproportionality.

RESULTS

The percentage of reported cases of pneumonia compared to infections and infestations was highest for mepolizumab (36.8%), followed by omalizumab (32.6%), benralizumab (19.2%) and dupilumab (5.7%). We found a moderate or strong signal for increased risk of pneumonia with mepolizumab (ROR = 3.74, 95%CI 3.50-4.00), omalizumab (ROR = 3.26, 95%CI 3.06-3.49) and benralizumab (ROR = 2.65, 95%CI 2.49-2.83).

CONCLUSIONS

Mepolizumab, omalizumab and benralizumab, but not dupilumab, were associated with high odds of reporting pneumonia. Our results represent only potential associations between these biologics and pneumonia but not causality. The nature of the FAERS database is such that the cause of the reported events is uncertain. Therefore, we can only roughly estimate the incidence of AEs by the signal strength (ROR value). Nevertheless, although causality could not be assessed, the signal from our study is interesting. We believe it deserves to be further substantiated by real-world studies with robust designs.

Repurposing lipid-lowering drugs on asthma and lung function: evidence from a genetic association analysis

OBJECTIVE

To explore the correlation between asthma risk and genetic variants affecting the expression or function of lipid-lowering drug targets.

METHODS

We conducted Mendelian randomization (MR) analyses using variants in several genes associated with lipid-lowering medication targets: HMGCR (statin target), PCSK9 (alirocumab target), NPC1L1 (ezetimibe target), APOB (mipomersen target), ANGPTL3 (evinacumab target), PPARA (fenofibrate target), and APOC3 (volanesorsen target), as well as LDLR and LPL. Our objective was to investigate the relationship between lipid-lowering drugs and asthma through MR. Finally, we assessed the efficacy and stability of the MR analysis using the MR Egger and inverse variance weighted (IVW) methods.

RESULTS

The elevated triglyceride (TG) levels associated with the APOC3, and LPL targets were found to increase asthma risk. Conversely, higher LDL-C levels driven by LDLR were found to decrease asthma risk. Additionally, LDL-C levels (driven by APOB, NPC1L1 and HMGCR targets) and TG levels (driven by the LPL target) were associated with improved lung function (FEV1/FVC). LDL-C levels driven by PCSK9 were associated with decreased lung function (FEV1/FVC).

CONCLUSION

In conclusion, our findings suggest a likely causal relationship between asthma and lipid-lowering drugs. Moreover, there is compelling evidence indicating that lipid-lowering therapies could play a crucial role in the future management of asthma.

Association of serum pertussis antibodies with acute asthma attacks in children

Objective: The aim of this study was to examine the serum antibody levels against pertussis toxin (PT) in children experiencing an acute asthma attack and to explore the potential association between these levels and asthma. Methods: A prospective investigation was conducted, which involved 107 children with acute asthma attacks and 77 children diagnosed with bronchitis. The serum immunoglobulin G (IgG) antibody levels specific to PT were measured by using an in-house enzyme-linked immunosorbent assay. Based on the serum PT-IgG antibody levels, the children with asthma were categorized into three groups: non-pertussis infected, suspected pertussis infected, and recent pertussis infected. The clinical manifestations and pulmonary function of pediatric patients diagnosed with asthma were assessed and compared across various groups. Results: Of the total asthma group, 25 patients tested positive for PT-IgG, whereas only six patients in the bronchitis group were PT-IgG positive. The prevalence of recent pertussis infection was observed to be higher in the asthma group compared with the bronchitis group. Within the asthma group, those with recent pertussis infection exhibited a higher likelihood of experiencing wheezing and impaired lung function in comparison with the non-pertussis infection group. Conclusion: Pertussis infection is relatively common in children with asthma and correlates with the severity of asthma.

Effect of atopic conditions on development and recurrences of infectious keratitis

BACKGROUND

Atopic conditions are known to be associated with viral and bacterial infections. The purpose of this study was to determine the relationship between the effects of atopic conditions on the severity and recurrence of ocular infections including herpes simplex virus (HSV).

METHODS

This study was performed on 474 consecutive patients with infectious keratitis caused by bacteria, fungus, acanthamoeba, HSV, or varicella-zoster virus. The relationships between the atopic condition and specific infectious pathogens and HSV were determined using real-time PCR.

RESULTS

Our findings showed that atopic dermatitis (AD) was significantly associated with the incidence of HSV keratitis (odds ratio (OR), 10.2; P = 0.000). Other associations with AD were observed only with bacteria in an adverse manner. HSV proliferation in the lesions of patients with HSV keratitis whose AD was associated with non-infectious atopic blepharitis were significantly greater by 145-folds (P = 0.000). The presence of asthma or allergic rhinitis also increased the HSV DNA copy numbers. A recurrence of HSV keratitis was observed in 70 patients (43.2 %), and mean time to recurrence was 1647 days. Cox proportional hazard model indicated that the epithelial type of HSV recurrence but not the stromal type was associated with atopic conditions especially with AD. The factors significantly associated with a recurrence was AD associated with non-infectious atopic blepharitis (HR: 6.11, P = 0.000) and asthma (HR: 3.03, P = 0.025).

CONCLUSIONS

Atopic conditions, especially AD with atopic blepharitis, are significantly associated with the development, increased proliferation, and shorter time to a recurrence on HSV keratitis.

Skin, gut, and lung barrier: Physiological interface and target of intervention for preventing and treating allergic diseases

The epithelial barriers of the skin, gut, and respiratory tract are critical interfaces between the environment and the host, and they orchestrate both homeostatic and pathogenic immune responses. The mechanisms underlying epithelial barrier dysfunction in allergic and inflammatory conditions, such as atopic dermatitis, food allergy, eosinophilic oesophagitis, allergic rhinitis, chronic rhinosinusitis, and asthma, are complex and influenced by the exposome, microbiome, individual genetics, and epigenetics. Here, we review the role of the epithelial barriers of the skin, digestive tract, and airways in maintaining homeostasis, how they influence the occurrence and progression of allergic and inflammatory conditions, how current treatments target the epithelium to improve symptoms of these disorders, and what the unmet needs are in the identification and treatment of epithelial disorders.

Targeting Common Inflammatory Mediators in Experimental Severe Asthma and Acute Lung Injury

Neutrophils, known to be mobilized and activated in high amounts through Il-17 stimulation, are a key factor for clinical manifestation and imbalance of redox systems favoring a dominant oxidative state in both severe asthma and acute lung injury (f). The aim of this study was to evaluate in mice, the effect of Secukinumab (SECU) in a model of ovalbumin-induced asthma exacerbated with LPS administration to induce ALI, compared to dexamethasone (DEXA), already known for its benefit in both asthma and ALI. Results on cytokine levels for specific Th1, Th2 and Th17 revealed an interplay of immune responses. For Th1 effector cytokines in BALF, DEXA treatment increased TNF-α levels, but TNF-α was not modified by SECU; DEXA and SECU significantly decreased IFN-γ and IL-6 levels. For typical Th2 cytokines, DEXA significantly increased Il-4, Il-5 and Il-13 levels, while SECU significantly inhibited Il-5 levels. Both SECU and DEXA significantly decreased Il-17 levels. Cytokine level changes in lung tissue homogenate were partly similar to BALF cytokines. Conclusion: in addition to DEXA, SECU possesses the ability to modulate inflammatory cytokine release and to decrease Th17 responses in ALI overlapped on exacerbated asthma in mice.

Development of a nomogram to estimate the risk of community-acquired pneumonia in adults with acute asthma exacerbations

OBJECTIVE

The aim of this study is to investigate the clinical characteristics of acute asthma exacerbations (AEs) with community-acquired pneumonia (CAP) in adults and establish a CAP prediction model for hospitalized patients with AEs.

METHODS

We retrospectively collected clinical data from 308 patients admitted to Beijing Luhe Hospital, Capital Medical University, for AEs from December 2017 to August 2021. The patients were divided into CAP and non-CAP groups based on whether they had CAP. We used the Lasso regression technique and multivariate logistic regression analysis to select optimal predictors. We then developed a predictive nomogram based on the optimal predictors. The bootstrap method was used for internal validation. We used the area under the receiver operating characteristic curve (AUC), calibration curve, and decision curve analysis (DCA) to assess the nomogram's discrimination, accuracy, and clinical practicability.

RESULTS

The prevalence of CAP was 21% (65/308) among 308 patients hospitalized for AEs. Independent predictors of CAP in patients hospitalized with an AE (P < 0.05) were C-reactive protein > 10 mg/L, fibrinogen > 4 g/L, leukocytes > 10 × 109 /L, fever, use of systemic corticosteroids before admission, and early-onset asthma. The AUC of the nomogram was 0.813 (95% CI: 0.753-0.872). The concordance index of internal validation was 0.794. The calibration curve was satisfactorily consistent with the diagonal line. The DCA indicated that the nomogram provided a higher clinical net benefit when the threshold probability of patients was 3% to 89%.

CONCLUSIONS

The nomogram performed well in predicting the risk of CAP in hospitalized patients with AEs, thereby providing rapid guidance for clinical decision-making.

Factors Associated With the Development of Bacterial Pneumonia Related to Seasonal Influenza Virus Infection: A Study Using a Large-scale Health Insurance Claim Database

Background

Influenza-related bacterial pneumonia is a leading complication of influenza infection. However, the differences in the incidence rates and risk factors associated with concomitant viral/bacterial pneumonia (CP) and secondary bacterial pneumonia following influenza (SP) remain unclear. This study aimed to clarify the incidence rates of CP and SP following seasonal influenza and identify factors associated with their development.

Methods

This retrospective cohort study was conducted using the JMDC Claims Database, a health insurance claims database in Japan. All patients aged <75 years who developed influenza during 2 consecutive epidemic seasons, 2017/2018 and 2018/2019, were analyzed. CP was defined as bacterial pneumonia diagnosed between 3 days before and 6 days after the date of influenza diagnosis, and SP was defined as pneumonia diagnosed 7-30 days after the date of diagnosis. Multivariable logistic regression analyses were performed to identify factors associated with the development of CP and SP.

Results

Among the 10 473 014 individuals registered in the database, 1 341 355 patients with influenza were analyzed. The average age at diagnosis (SD) was 26.6 (18.6) years. There were 2901 (0.22%) and 1262 (0.09%) patients who developed CP and SP, respectively. Age 65-74 years, asthma, chronic bronchitis/emphysema, cardiovascular disease, renal disease, malignant tumor, and immunosuppression were significant risk factors for both CP and SP, whereas cerebrovascular disease, neurological disease, liver disease, and diabetes were risk factors specific to CP development.

Conclusions

The results determined the incidence rates of CP and SP and identified their risk factors, such as older age and comorbidities.

The epigenetic state of IL-4-polarized macrophages enables inflammatory cistromic expansion and extended synergistic response to TLR ligands

Prior exposure to microenvironmental signals could fundamentally change the response of macrophages to subsequent stimuli. It is believed that T helper-2 (Th2)-cell-type cytokine interleukin-4 (IL-4) and Toll-like receptor (TLR) ligand-activated transcriptional programs mutually antagonize each other, and no remarkable convergence has been identified between them. In contrast, here, we show that IL-4-polarized macrophages established a hyperinflammatory gene expression program upon lipopolysaccharide (LPS) exposure. This phenomenon, which we termed extended synergy, was supported by IL-4-directed epigenomic remodeling, LPS-activated NF-κB-p65 cistrome expansion, and increased enhancer activity. The EGR2 transcription factor contributed to the extended synergy in a macrophage-subtype-specific manner. Consequently, the previously alternatively polarized macrophages produced increased amounts of immune-modulatory factors both in vitro and in vivo in a murine Th2 cell-type airway inflammation model upon LPS exposure. Our findings establish that IL-4-induced epigenetic reprogramming is responsible for the development of inflammatory hyperresponsiveness to TLR activation and contributes to lung pathologies.

Risk of Pleural Empyema in Adult Patients With Asthma: A Nationwide Retrospective Cohort Study

Background

Respiratory system infections commonly occur among individuals with asthma. However, whether asthma patients have a higher risk of pleural empyema development remains unclear.

Methods

This is a retrospective cohort study based on data from the National Health Insurance Research Database of Taiwan. The asthma cohort consisted of 48,360 newly diagnosed adult individuals from 2000 to 2012. The comparison cohort consisted of the same number of adults who did not have asthma and was matched for age, gender, comorbidity, and the year of diagnosis. The development of pleural empyema was followed up to 2013.

Results

Pleural empyema incidence was 2.03-fold higher in the asthma cohort compared to the comparison cohort (8.65 vs. 4.25 per 10,000 person-years), with an adjusted hazard ratio (HR) of 2.12 [95% confidence interval (CI) = 1.76–2.56]. Stratified analyses by age, gender, comorbidity, and corticosteroid use revealed that the crude and adjusted HRs of pleural empyema associated with asthma were all significant. Among patients with asthma, the risk of pleural empyema elevated with increased frequency of annual asthma-related emergency room visits and hospital admissions (≥1 vs. &lt;1, aHR = 8.07, 95% CI = 4.31–15.1 and aHR = 9.31, 95% CI = 5.56–15.6).

Conclusion

An increased risk of pleural empyema occurrence was observed in adult patients with asthma than those without asthma. Furthermore, the risk of pleural empyema may increase with poor control of asthma.

Promising Expectations for Pneumococcal Vaccination during COVID-19

The emergence of new viral infections has increased over the decades. The novel virus is one such pathogen liable for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, popularly known as coronavirus disease 2019 (COVID-19). Most fatalities during the past century's influenza pandemics have cooperated with bacterial co/secondary infections. Unfortunately, many reports have claimed that bacterial co-infection is also predominant in COVID-19 patients (COVID-19 associated co/secondary infection prevalence is up to 45.0%). In the COVID-19 pandemic, Streptococcus pneumoniae is the most common coinfecting pathogen. Half of the COVID-19 mortality cases showed co-infection, and pneumonia-related COVID-19 mortality in patients >65 years was 23%. The weakening of immune function caused by COVID-19 remains a high-risk factor for pneumococcal disease. Pneumococcal disease and COVID-19 also have similar risk factors. For example, underlying medical conditions on COVID-19 and pneumococcal diseases increase the risk for severe illness at any age; COVID-19 is now considered a primary risk factor for pneumococcal pneumonia and invasive pneumococcal disease. Thus, pneumococcal vaccination during the COVID-19 pandemic has become more critical than ever. This review presents positive studies of pneumococcal vaccination in patients with COVID-19 and other medical conditions and the correlational effects of pneumococcal disease with COVID-19 to prevent morbidity and mortality from co/secondary infections and superinfections. It also reports the importance and role of pneumococcal vaccination during the current COVID-19 pandemic era to strengthen the global health system.

Ding Chuan Tang Attenuates Airway Inflammation and Eosinophil Infiltration in Ovalbumin-Sensitized Asthmatic Mice

Asthma is a T helper 2 (Th2) cell-associated chronic inflammatory diseases characterized with airway obstruction, increased mucus production, and eosinophil infiltration. Conventional medications for asthma treatment cannot fully control the symptoms, and potential side effects are also the concerns. Thus, complement or alternative medicine (CAM) became a new option for asthma management. Ding Chuan Tang (DCT) is a traditional Chinese herbal decoction applied mainly for patients with coughing, wheezing, chest tightness, and asthma. Previously, DCT has been proved to improve children airway hyperresponsiveness (AHR) in a randomized and double-blind clinical trial. However, the mechanisms of how DCT alleviates AHR remain unclear. Since asthmatic features such as eosinophil infiltration, IgE production, and mucus accumulation are relative with Th2 responses, we hypothesized that DCT may attenuate asthma symptoms through regulating Th2 cells. Ovalbumin (OVA) was used as a stimulant to sensitize BALB/c mice to establish an asthmatic model. AHR was detected one day before sacrifice. BALF and serum were collected for immune cell counting and antibody analysis. Splenocytes were cultured with OVA in order to determine Th2 cytokine production. Lung tissues were collected for histological and gene expression analyses. Our data reveal that DCT can attenuate AHR and eosinophil accumulation in the 30-day sensitization asthmatic model. Histological results demonstrated that DCT can reduce cell infiltration and mucus production in peribronchial and perivascular site. In OVA-stimulated splenocyte cultures, a significant reduction of IL-5 and IL-13 in DCT-treated mice suggests that DCT may alleviate Th2 responses. In conclusion, the current study demonstrates that DCT has the potential to suppress allergic responses through the reduction of mucus production, eosinophil infiltration, and Th2 activity in asthma.

Inhaled Corticosteroids Use and Risk of Invasive Pneumococcal Disease in a Population-based Study

Rationale: The use of inhaled corticosteroids (ICS) is associated with increased pneumonia risk, but the risk of invasive pneumococcal disease (IPD) associated with ICS is not characterized.

Objectives: The aim was to test the hypothesis that the use of ICS increases the risk of IPD.

Methods: Cases were persons 20–65 years of age included in a Swedish national registry of invasive infection caused by Streptococcus pneumoniae classified as any IPD as well as the subset of IPD with pneumonia. The case index date was the day the infection was diagnosed. Six control subjects for each case (matched for sex, age, and region) were selected from the Swedish National Population Registry and were assigned the index date of their corresponding case. Current and past users of ICS were defined by the last prescriptions dispensed within 60 or 61–365 days of the index date. Nonusers were defined as those with no dispensed prescription the last 365 days. Current users were characterized by use of fluticasone or budesonide. We used conditional logistic analysis, including matching and covariates, to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) of IPD, IPD with pneumonia, and IPD without pneumonia associated with current or past use of ICS.

Results: Current use of ICS increased the risk for IPD and IPD with pneumonia (OR, 1.71; 95% CI, 1.39–2.10 and OR, 1.94; 95% CI, 1.53–2.47, respectively), but there was no statistical association between current use of ICS and IPD without pneumonia (OR, 1.18; 95% CI 0.78–1.80). Past use of ICS increased the risk for IPD and IPD with pneumonia but not for IPD without pneumonia. Among current ICS users, the odds for IPD were similar for budesonide (OR, 1.34; 95% CI, 1.14–1.57) and fluticasone (OR, 1.41; 95% CI, 1.04–1.90). Among current ICS users, the odds for IPD with pneumonia were slightly higher but of similar magnitude for both budesonide and for fluticasone.

Conclusions: ICS use is associated with an increased risk of IPD and IPD with pneumonia. The risk is driven by IPD with pneumonia. We found similar risks for budesonide and fluticasone.

Macrophage-derived cytokines in pneumonia: Linking cellular immunology and genetics

Macrophages represent the first line of anti-pathogen defense - they encounter invading pathogens to perform the phagocytic activity, to deliver the plethora of pro- and anti-inflammatory cytokines, and to shape the tissue microenvironment. Throughout pneumonia course, alveolar macrophages and infiltrated blood monocytes produce increasing cytokine amounts, which activates the antiviral/antibacterial immunity but can also provoke the risk of the so-called cytokine "storm" and normal tissue damage. Subsequently, the question of how the cytokine spectrum is shaped and balanced in the pneumonia context remains a hot topic in medical immunology, particularly in the COVID19 pandemic era. The diversity in cytokine profiles, involved in pneumonia pathogenesis, is determined by the variations in cytokine-receptor interactions, which may lead to severe cytokine storm and functional decline of particular tissues and organs, for example, cardiovascular and respiratory systems. Cytokines and their receptors form unique profiles in individual patients, depending on the (a) microenvironmental context (comorbidities and associated treatment), (b) lung monocyte heterogeneity, and (c) genetic variations. These multidisciplinary strategies can be proactively considered beforehand and during the pneumonia course and potentially allow the new age of personalized immunotherapy.

Glycemic Control and Risk of Cellulitis

OBJECTIVE

We know that diabetes predisposes to common infections, such as cellulitis and pneumonia. However, the correlation between the level of glycemic control and the rate of infection is unknown.

RESEARCH DESIGN AND METHODS

We examined the association between glycemic control in patients with diabetes and the incidence of infection in the entire population of patients with diabetes in a large HMO. During the study period, we first selected an HbA_1c test for each patient and then searched for an infection diagnosis in the 60 days that followed the test. A multivariate logistic regression analysis was performed to determine the independent effect of HbA_1c on the likelihood of being diagnosed with an infection. We were able to control for many confounders, such as other chronic illness, time since the diagnosis of diabetes, and use of steroids before the infection.

RESULTS

We identified 407 cases of cellulitis. Multivariate logistic regressions for cellulitis showed a 1.4-fold increased risk among patients with HbA_1c >7.5% (58 mmol/mol). Factors such as obesity, Parkinson's disease, peripheral vascular disease, and prior treatment with prednisone predisposed to cellulitis. There was an increase of 12% in the odds of cellulitis for every 1% (11 mmol/mol) elevation in HbA_1c (odds ratio [OR] 1.12; CI 1.05-1.19). A similar analysis showed a trend toward an increased risk of pneumonia in patients with HbA_1c >7.5% (58 mmol/mol) (OR 1.1; CI 0.9-1.4).

CONCLUSIONS

Poor glycemic control was associated in this study with the development of cellulitis. The study also suggests that exposure to oral prednisolone increases the risk of cellulitis, pneumonia, and upper respiratory infection.

Inhaled Corticosteroids as an Associated Risk Factor for Asthmatic Pneumonia: A Literature Review

Asthma patients have commonly been prescribed inhaled corticosteroids (ICSs) as the first line of control therapy. ICSs are associated with an increased risk of pneumonia in chronic obstructive airway disease (COPD) patients. However, the evidence remains controversial in asthma patients. Several observational studies reported an increased risk of pneumonia; however, COPD patients were not excluded clearly in these studies. In observational studies that excluded COPD patients and in randomized controlled trials, ICS use was not found to be associated with the risk of pneumonia. Hence, COPD patients should be excluded in future studies, and the currently available evidence demonstrates that ICS use is not associated with an increased risk of pneumonia in asthma patients.

Epidemiology of Asthma in Children and Adults

Asthma is a globally significant non-communicable disease with major public health consequences for both children and adults, including high morbidity, and mortality in severe cases. We have summarized the evidence on asthma trends, environmental determinants, and long-term impacts while comparing these epidemiological features across childhood asthma and adult asthma. While asthma incidence and prevalence are higher in children, morbidity, and mortality are higher in adults. Childhood asthma is more common in boys while adult asthma is more common in women, and the reversal of this sex difference in prevalence occurs around puberty suggesting sex hormones may play a role in the etiology of asthma. The global epidemic of asthma that has been observed in both children and adults is still continuing, especially in low to middle income countries, although it has subsided in some developed countries. As a heterogeneous disease, distinct asthma phenotypes, and endotypes need to be adequately characterized to develop more accurate and meaningful definitions for use in research and clinical settings. This may be facilitated by new clustering techniques such as latent class analysis, and computational phenotyping methods are being developed to retrieve information from electronic health records using natural language processing (NLP) algorithms to assist in the early diagnosis of asthma. While some important environmental determinants that trigger asthma are well-established, more work is needed to define the role of environmental exposures in the development of asthma in both children and adults. There is increasing evidence that investigation into possible gene-by-environment and environment-by-environment interactions may help to better uncover the determinants of asthma. Therefore, there is an urgent need to further investigate the interrelationship between environmental and genetic determinants to identify high risk groups and key modifiable exposures. For children, asthma may impair airway development and reduce maximally attained lung function, and these lung function deficits may persist into adulthood without additional progressive loss. Adult asthma may accelerate lung function decline and increase the risk of fixed airflow obstruction, with the effect of early onset asthma being greater than late onset asthma. Therefore, in managing asthma, our focus going forward should be firmly on improving not only short-term symptoms, but also the long-term respiratory and other health outcomes.