Association between body mass index and mortality in hospitalised patients with community-acquired pneumonia

Association of obesity on short- and long-term survival in patients with moderate to severe pneumonia-related ARDS: a retrospective cohort study

BACKGROUND

The incidence of obesity among patients admitted to the intensive care unit (ICU) is increasing, and pneumonia remains the leading cause of acute respiratory distress syndrome (ARDS). The association of obesity on both short- and long-term outcomes in patients with pneumonia-induced ARDS has been the subject of only limited research.

METHODS

We conducted a retrospective analysis of a prospective cohort consisting of ARDS patients who had microbiologically confirmed pneumonia and a PaO2/FiO2 ratio ≤ 150 mmHg. Patients were assessed for mortality at 28 days, 90 days, and at 1 year from the diagnosis of ARDS and compared between obese defined by a body mass index (BMI) ≥ 30 kg.m2 and non-obese patients. Models were adjusted for age, sex, COPD, coronary artery disease, immunodepression, severity score and acute kidney injury on admission to the ICU, severity of ARDS (PaO2/FiO2 ratio ≤ 100 mmHg), severe hypercapnia (PaCO2 ≥ 50 mmHg), ventilatory ratio and plateau pressure the first day of ARDS, influenza, COVID-19, pneumocystosis, and bacteria involved in pneumonia. We also investigated the continuous spectrum of BMI on the risk of mortality.

RESULTS

Of 603 patients, 227 patients (37.6%) were obese. Obesity was associated with female gender (p = 0.009), hypertension (p < 0.001), diabetes mellitus (p < 0.001), COVID-19 pneumonia (p = 0.008), and PaO2/FiO2 ratio ≤ 100 mmHg (p = 0.006). Obesity was independently associated with lower mortality at 28 days (adjusted Odds Ratio (OR) 0.55, 95% confident interval (CI) 0.33-0.90, p = 0.02) but not at 90 days (adjusted OR 0.70, 95% CI 0.45-1.09, p = 0.11) nor at 1 year from the diagnosis of ARDS (adjusted OR 0.73, 95% CI 0.47-1.13, p = 0.16). Mortality at 28 days was significantly lower in obese patients than in non-obese patients when propensity score matching was used (15.2% versus 22%, p = 0.04). BMI was also independently associated with lower mortality at 28 days (p = 0.038) but not with mortality at 90 days (p = 0.12) and 1 year (p = 0.12).

CONCLUSION

Our results suggest that in patients with pneumonia-related ARDS, obesity is independently associated with better survival at 28 days but not at 90 days and 1 year from the diagnosis of ARDS.

Obesity paradox in patients with community-acquired pneumonia: Have you fully considered the confounding factors?

There exists a notion that there is an obesity paradox in the prognosis of community-acquired pneumonia. In other words, obese individuals with community-acquired pneumonia have a better prognosis. The study by Wang et al supports this claim, but we believe that the obesity paradox should not be proposed hastily as it is influenced by numerous subjective and objective confounding factors.

Smoking, Alcohol Use, Diabetes Mellitus, and Metabolic Syndrome as Risk Factors for Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) continues to be a cause of significant morbidity and mortality worldwide. Much recent attention in this area of research has been focused on host factors associated with the infection. This article will discuss 4 diverse, yet often coexistent conditions, namely, smoking, excessive alcohol use, diabetes mellitus, and metabolic syndrome. While all these conditions can be considered to be largely associated with lifestyle factors, they represent important risk factors for CAP. All can lead to acquired host immune suppression that underlies their risk for the development of severe CAP.

Role of lifestyle factors on the development and long-term prognosis of pneumonia and cardiovascular disease in the Chinese population

BACKGROUND

Whether adherence to a healthy lifestyle is associated with a lower risk of developing pneumonia and a better long-term prognosis remains unclear. This study aimed to investigate associations of individual and combined lifestyle factors (LFs) with the incidence risk and long-term prognosis of pneumonia hospitalization.

METHODS

Using data from the China Kadoorie Biobank study, we used the multistate models to investigate the role of five high-risk LFs, including smoking, excessive alcohol drinking, unhealthy dietary habits, physical inactivity, and unhealthy body shape, alone or in combination in the transitions from a generally healthy state at baseline to pneumonia hospitalization or cardiovascular disease (CVD, regarded as a reference outcome), and subsequently to mortality.

RESULTS

Most of the five high-risk LFs were associated with increased risks of transitions from baseline to pneumonia and from pneumonia to death, but with different risk estimates. The greater the number of high-risk LFs, the higher the risk of developing pneumonia and long-term mortality risk after pneumonia, with the strength of associations comparable to that of LFs and CVD. Compared to participants with 0-1 high-risk LF, the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for transitions from baseline to pneumonia and from pneumonia to death in those with five high-risk LFs were 1.43 (1.28-1.60) and 1.98 (1.61-2.42), respectively. Correspondingly, the respective HRs (95% CIs) for transitions from baseline to CVD and from CVD to death were 2.00 (1.89-2.11) and 1.44 (1.30-1.59), respectively. The risk estimates changed slightly when further adjusting for the presence of major chronic diseases.

CONCLUSION

In this Chinese population, unhealthy LFs were associated with an increased incidence and long-term mortality risk of pneumonia.

Improving prognostication of pneumonia among elderly patients: usefulness of suPAR

PURPOSE

Elderly patients with suspected pneumonia represent a significant proportion of hospital admissions, which is a prognostic challenge for physicians. Our research aimed to assess the prognosis of patients with pneumonia using soluble urokinase plasminogen activator receptor (suPAR) combined with clinical data.

METHODS

In a prospective observational study including 164 patients > 65 years (mean age 84.2 (+/-7.64) years) who were hospitalized for a suspicion of pneumonia, suPAR was assessed for each patient, as was the prognosis score (PSI, CURB65) and inflammatory biomarkers (C-reactive protein, procalcitonin, white blood cells). The prognostic value of the suPAR for 30-day mortality was assessed using receiver operating characteristic (ROC) curve analyses. Optimal cut-offs with corresponding sensitivity (SE) and specificity (SP) were determined using the Youden index.

RESULTS

A suPAR > 5.1 ng/mL was predictive of 30-day mortality with a sensitivity of 100% and a specificity of 40.4%. A combination of the following parameters exhibited an SE of 100% (95% CI, 100-100) for an SP value of 64.9% (95% CI, 57.6-72.2) when at least two of them were above or below the following cut-off threshold values: suPAR > 9.8 ng/mL, BMI < 29.3 kg/m2 and PSI > 106.5.

CONCLUSION

The suPAR seems to be a promising biomarker that can be combined with the PSI and BMI to improve the prognosis of pneumonia among elderly patients. Prospective studies with larger populations are needed to confirm whether this new approach can improve patient outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02467192), 27th may 2015.

Intraclass comparison of inhaled corticosteroids for the risk of pneumonia in chronic obstructive pulmonary airway disorder: a network meta-analysis and meta-regression

BACKGROUND

Inhalational corticosteroids (ICS) were observed to increase the pneumonia risk in chronic obstructive pulmonary airway disorder (COPD). However, it is unknown whether any differences exist between the drugs within the ICS class.

AIM

This study aimed to evaluate the risk of pneumonia associated with different ICS and identify factors that predict pneumonia in patients with moderate-to-severe COPD using a network meta-analysis.

METHOD

Electronic databases (Medline, Cochrane CENTRAL and Google Scholar) were searched for trials comparing ICS in COPD patients. The outcomes were pneumonia and serious pneumonia. Odds ratios (OR) with 95% confidence interval (95% CI) were estimated. Meta-regression was used to identify the predictors. The strength of evidence was graded using the Grading of Recommendations, Assessment, Development, and Evaluations approach.

RESULTS

Sixty-six studies (103,347 participants) were included. Fluticasone (OR: 1.46; 95% CI: 1.26, 1.7), mometasone (OR: 2.2; 95% CI: 1.05, 4.6), and beclometasone (OR: 1.7; 95% CI: 1.1, 2.6) were observed with an increased pneumonia risk compared to placebo. Fluticasone (OR: 1.5; 95% CI: 1.3, 1.7) was observed with an increased risk of serious pneumonia. High doses (OR: 1.2; 95% CI: 1.03, 1.4), BMI ≥ 25 kg/m2 (OR: 1.6; 95% CI: 1.1, 2.2), and history of exacerbations in the preceding year predicted the pneumonia risk. Evidence strength was moderate.

CONCLUSION

ICS class differences in pneumonia risk were observed in terms of pooled effect estimates but it is unlikely that any clinically relevant differences exist. Risk-benefit analysis supports ICS use in moderate-severe COPD.

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

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.

Association between body mass index and clinical outcomes in patients with out-of-hospital cardiac arrest undergoing extracorporeal cardiopulmonary resuscitation: A multicenter observational study

Background

We examined the association between body mass index (BMI) and outcomes in patients with out-of-hospital cardiac arrest (OHCA) undergoing extracorporeal cardiopulmonary resuscitation (ECPR).

Methods

We retrospectively analyzed the database of an observational multicenter cohort in Japan. Adult patients with OHCA of cardiac etiology who received ECPR between 2013 and 2018 were categorized as follows: underweight, BMI < 18.5; normal weight, BMI = 18.5-24.9; overweight, BMI = 25-29.9; and obese, BMI ≥ 30 kg/m2. The primary outcome was in-hospital mortality; secondary outcomes were unfavorable neurological outcomes at discharge (cerebral performance category ≥ 3) and ECPR-related complications. BMI's association with outcomes was assessed using a logistic regression model adjusted for age, sex, comorbidities, witness/bystander CPR, initial rhythm, prehospital return of spontaneous circulation, and low-flow time.

Results

In total, 1,044 patients were analyzed. Their median age was 61 (IQR, 49-69) years; the median BMI was 24.2 (21.5-26.9) kg/m2. The overall rates of in-hospital mortality, unfavorable neurological outcome, and ECPR-related complications were 62.2%, 79.9%, and 31.7%, respectively. In multivariate analysis, the overweight and obese groups had higher in-hospital mortality odds than the normal BMI group (odds ratio [95%CI], 1.37 [1.02-1.85], p = 0.035; and 2.09 [1.31-3.39], p < 0.001, respectively). The odds ratio for unfavorable neurological outcomes increased more in the obese than in the normal BMI group (3.17 [1.69-6.49], p < 0.001). ECPR-related complications were not significantly different among groups.

Conclusions

In OHCA patients undergoing ECPR, a BMI ≥ 25 kg/m2 was associated with increased in-hospital mortality, and a BMI ≥ 30 kg/m2 was also associated with a worse neurological outcome.

Does the "Obesity Paradox" Have an Expiration Date? A Retrospective Cohort Study

(1) Background: The "obesity paradox" refers to a protective effect of higher body mass index (BMI) on mortality in acute infectious disease patients. However, the long-term impact of this paradox remains uncertain. (2) Methods: A retrospective study of patients diagnosed with community-acquired acute infectious diseases at Shamir Medical Center, Israel (2010-2020) was conducted. Patients were grouped by BMI: underweight, normal weight, overweight, and obesity classes I-III. Short- and long-term mortality rates were compared across these groups. (3) Results: Of the 25,226 patients, diverse demographics and comorbidities were observed across BMI categories. Short-term (90-day) and long-term (one-year) mortality rates were notably higher in underweight and normal-weight groups compared to others. Specifically, 90-day mortality was 22% and 13.2% for underweight and normal weight respectively, versus 7-9% for others (p < 0.001). Multivariate time series analysis revealed underweight individuals had a significantly higher 5-year mortality risk (HR 1.41 (95% CI 1.27-1.58, p < 0.001)), while overweight and obese categories had a reduced risk (overweight-HR 0.76 (95% CI 0.72-0.80, p < 0.001), obesity class I-HR 0.71 (95% CI 0.66-0.76, p < 0.001), obesity class II-HR 0.77 (95% CI 0.70-0.85, p < 0.001), and obesity class III-HR 0.79 (95% CI 0.67-0.92, p = 0.003)). (4) Conclusions: In this comprehensive study, obesity was independently associated with decreased short- and long-term mortality. These unexpected results prompt further exploration of this counterintuitive phenomenon.

Obesity Paradox in Lung Diseases: What Explains It?

BACKGROUND

Obesity is a globally increasing health problem that impacts multiple organ systems and a potentially modifiable risk factor for many diseases. Obesity has a significant impact on lung function and is strongly linked to the pathophysiology that contributes to lung diseases. On the other hand, reports have emerged that obesity is associated with a better prognosis than for normal weight individuals in some lung diseases, including pneumonia, acute lung injury/acute respiratory distress syndrome, chronic obstructive pulmonary disease, and lung cancer. The lesser mortality and better prognosis in patients with obesity is known as obesity paradox. While obesity paradox is both recognized and disputed in epidemiological studies, recent research has suggested possible mechanisms.

SUMMARY

In this review, we attempted to explain and summarize these factors and mechanisms, including immune response, pulmonary fibrosis, lung function, microbiota, fat and muscle reserves, which are significantly altered by obesity and may contribute to the obesity paradox in lung diseases. We also discuss contrary literature that attributes the "obesity paradox" to confounding.

KEY MESSAGES

The review will illustrate the possible role of obesity in the prognosis or course of lung diseases, leading to a better understanding of the obesity paradox and provide hints for further basic and clinical research in lung diseases.

Implications of obesity and adiposopathy on respiratory infections; focus on emerging challenges

Obesity is characterized by excessive adipose tissue accumulation, which impacts physiological, metabolic, and immune functions. Several respiratory infections, including bacterial pneumonia, influenza, and coronavirus disease 2019, appear to be linked to unfavorable results in individuals with obesity. These may be attributed to the direct mechanical/physiological effects of excess body fat on the lungs’ function. Notably, adipose tissue dysfunction is associated with a low-grade chronic inflammatory status and hyperleptinemia, among other characteristics. These have all been linked to immune system dysfunction and weakened immune responses to these infections. A better understanding and clinical awareness of these risk factors are necessary for better disease outcomes.

Are Undernutrition and Obesity Associated with Post-Discharge Mortality and Re-Hospitalization after Hospitalization with Community-Acquired Pneumonia?

Undernutrition is associated with increased mortality after hospitalization with community-acquired pneumonia (CAP), whereas obesity is associated with decreased mortality in most studies. We aimed to determine whether undernutrition and obesity are associated with increased risk of re-hospitalization and post-discharge mortality after hospitalization. This study was nested within the Surviving Pneumonia cohort, which is a prospective cohort of adults hospitalized with CAP. Patients were categorized as undernourished, well-nourished, overweight, or obese. Undernutrition was based on diagnostic criteria by the European Society for Clinical Nutrition and Metabolism. Risk of mortality was investigated using multivariate logistic regression and re-hospitalization with competing risk Cox regression where death was the competing event. Compared to well-nourished patients, undernourished patients had a higher risk of 90-day (OR 3.0, 95% CI 1.0; 21.4) mortality, but a similar 30-day and 180-day mortality risk. Obese patients had a similar re-hospitalization and mortality risk as well-nourished patients. In conclusion, among patients with CAP, undernutrition was associated with increased risk of mortality. Undernourished patients are high-risk patients, and our results indicate that in-hospital screening of undernutrition should be implemented to identify patients at mortality risk. Studies are required to investigate whether nutritional therapy after hospitalization with CAP would improve survival.

Analysis of the association between atrial fibrillation with in-hospital mortality in people admitted for community-acquired pneumonia through an observational, nation-wide, sex-stratified study

We aimed to analyze the influence of atrial fibrillation (AF) prior to hospital admission (“prevalent”) and AF diagnosed during hospital admission (“incident”) on in-hospital mortality (IHM) in women and men admitted for community-acquired pneumonia (CAP) in Spain (2016–2019). We used the Spanish Register of Specialized Care‐Basic Minimum Database. We analyzed 519,750 cases of CAP in people ≥ 18 years (213,631 women (41.1%)), out of which people with prevalent AF represented 23.75% (N = 123,440), whereas people with incident AF constituted 0.60% (N = 3154). Versus no AF, crude IHM was significantly higher for prevalent AF (15.24% vs. 11.40%, p < 0.001) and for incident AF (23.84% vs. 12.24%, p < 0.001). After propensity score marching, IHM in women and men with prevalent AF neared IHM in women and men with no AF (15.72% vs. 15.52%, p = 0.425; and 14.90% vs. 14.99%, p = 0.631, respectively), but IHM in women and men with incident AF was higher than IHM in women and men with no AF (24.37% vs. 13.36%, p < 0.001; and 23.94% vs. 14.04%, p < 0.001, respectively). Male sex was associated with a higher IHM in people with prevalent AF (OR 1.06; 95% CI 1.02–1–10), but not in people with incident AF (OR 0.93; 95% CI 0.77–1–13). AF diagnosed during hospital admission was associated with a higher IHM, irrespectively of sex.

Effect of Undernutrition and Obesity on Clinical Outcomes in Adults with Community-Acquired Pneumonia

Malnutrition comprises two groups of conditions: undernutrition and overweight or obesity. It has been associated with a high risk of contracting infectious diseases and with elevated mortality rates. Community-acquired pneumonia (CAP) is one of the most common infectious diseases worldwide and its prognosis is affected by a large number of recognizable risk factors. This narrative review updates the information on the impact of malnutrition, including both undernutrition and obesity, on the risk and prognosis of adults with CAP. Studies of CAP that have evaluated undernutrition have applied a variety of definitions when assessing the nutritional status of patients. Undernutrition has been associated with unfavorable clinical outcomes, such as prolonged hospital stay, need for intensive care unit admission, and mortality; in contrast, most published studies have found that increased body mass index is significantly associated with higher survival in patients with CAP. However, some authors have presented divergent results, mainly in relation to the etiology of CAP (bacterial versus viral). Influenza infection, caused by influenza A (H1N1) pdm09, has been associated with worse prognosis in obese patients. The current data underscore the need for larger studies to examine the physiological mechanisms that explain the differential impact of malnutrition on outcomes. Achieving a better understanding may help to guide the design of new interventions to improve prognosis.

Comparison of mortality and clinical failure rates between vancomycin and teicoplanin in patients with methicillin-resistant Staphylococcus aureus pneumonia

Background

Very few studies have compared the effects and side effects of vancomycin and teicoplanin in patients with methicillin-resistant Staphylococcus aureus pneumonia. This study aimed to compare the efficacy and safety of vancomycin and teicoplanin in patients with methicillin-resistant Staphylococcus aureus pneumonia.

Methods

This study examined 116 patients with methicillin-resistant Staphylococcus aureus pneumonia who met the inclusion criteria and were treated with either vancomycin (n = 54) or teicoplanin (n = 62). The primary (i.e., clinical failure during treatment) and secondary outcomes (i.e., mortality rates, discontinuation of study drugs due to treatment failure, side effects, and clinical cure) were evaluated.

Results

The vancomycin group presented lower clinical failure rates (25.9% vs. 61.3%, p < 0.001), discontinuation due to treatment failure (22.2% vs. 41.9%, p = 0.024), and mortality rates (3.7% vs 19.4%, p = 0.010). The Cox proportional hazard model revealed that teicoplanin was a significant clinical failure predictor compared with vancomycin (adjusted odds ratio, 2.198; 95% confidence interval 1.163–4.154). The rates of drug change due to side effects were higher in the vancomycin group than in the teicoplanin group (24.1% vs. 1.6%, p < 0.001).

Conclusions

Vancomycin presented favorable treatment outcomes and more side effects compared with teicoplanin, which suggests that clinicians would need to consider the efficacy and potential side effects of these drugs before prescription.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07549-2.

Obesity survival paradox in patients hospitalized with community-acquired pneumonia. Assessing sex-differences in a population-based cohort study

AIM

To assess the effect of obesity status (no obesity/obesity/ morbid obesity) on hospital outcomes (length of hospital stay [LOHS] and in-hospital mortality [IHM]), among patients hospitalized with community-acquired pneumonia (CAP) and according to sex.

METHODS

We conducted a retrospective cohort study based on national hospital discharge data of all subjects aged≥ 18 years hospitalized with CAP in Spain from 2016 to 2019.

RESULTS

We identified 519,750 hospital discharges with CAP. The prevalence of obesity was 6.38% and 1.78%. for morbid obesity. The mean age was higher for patients without obesity followed by those with obesity and morbid obesity (74.61, 72.5 and 70.2 years respectively; p<0.001). The mean number of comorbidities was similar for patients with obesity and morbid obesity (2.30 and 2.29) and significantly higher than for non-obese individuals (2.10). The crude IHM was higher among the non-obese patients (12.71%) followed by those with morbid obesity (8.56%) and obesity (7.72%), without finding differences between men and women. Among men, after multivariable logistic regression analysis, the probability of dying in the hospital was significantly lower for those with obesity (Adjusted-OR 0.59;95%CI 0.55-0.63) and morbid obesity (Adjusted-OR 0.62;95%CI 0.54-0.71) compared with non-obese. The protective effect of obesity (Adjusted-OR 0.71;95%CI 0.67-0.75) and morbid obesity (Adjusted OR 0.73;95%CI 0.66-0.8) was also observed among women.

CONCLUSIONS

Obese and obesity morbid patients with CAP have a lower risk of IHM than non-obese patients, without sex differences in this association. These data confirm the existence of the obesity paradox in this patient population.

Sex-Related Disparities in the Incidence and Outcomes of Community-Acquired Pneumonia among Type 2 Diabetes Patients: A Propensity Score-Matching Analysis Using the Spanish National Hospital Discharge Database for the Period 2016-2019

(1) Background: To analyze incidence, clinical characteristics, procedures, and in-hospital outcomes among patients hospitalized with community-acquired pneumonia (CAP) according to the presence of T2DM in Spain (2016-2019) and to assess the role of gender among those with T2DM. (2) Methods: Using the Spanish National Hospital Discharge Database, we estimated hospitalized CAP incidence. Propensity score matching was used to compare population subgroups. (3) Results: CAP was coded in 520,723 patients, of whom 140,410 (26.96%) had T2DM. The hospitalized CAP incidence was higher in patients with T2DM (both sexes) (IRR 4.25; 95% CI 4.23-4.28). The hospitalized CAP incidence was higher in men with T2DM than in women with T2DM (IRR 1.46; 95% CI 1.45-1.47). The hospitalized CAP incidence among T2DM patients increased over time; however, the in-hospital mortality (IHM) decreased between 2016 and 2019. IHM was higher among non-T2DM men and women than matched T2DM men and women (14.23% and 14.22% vs. 12.13% and 12.91%; all p < 0.001, respectively), After adjusting for confounders, men with T2DM had a 6% higher mortality risk than women (OR 1.06; 95% CI 1.02-1.1). (4) Conclusions: T2DM is associated with a higher hospitalized CAP incidence and is increasing overtime. Patients hospitalized with CAP and T2DM have lower IHM. Male sex is a significant risk factor for mortality after CAP among T2DM patients.