Statins for community-acquired pneumonia: current state of the science

Association of Statin Use With the In-Hospital Outcomes of 2019-Coronavirus Disease Patients: A Retrospective Study

Background: Statins have multiple protective effects on inflammation, immunity and coagulation, and may help alleviate pneumonia. However, there was no report focusing on the association of statin use with in-hospital outcomes of patients with coronavirus disease 2019 (COVID-19). We investigated the association between the use of statins and in-hospital outcomes of patients with COVID-19.

Methods: In this retrospective case series, consecutive COVID-19 patients admitted at 2 hospitals in Wuhan, China, from March 12, 2020 to April 14, 2020 were analyzed. A 1:1 matched cohort was created by propensity score-matched analysis. Demographic data, laboratory findings, comorbidities, treatments and in-hospital outcomes were collected and compared between COVID-19 patients taking and not taking statins.

Result: A total of 2,147 patients with COVID-19 were enrolled in this study. Of which, 250 patients were on statin therapy. The mortality was 2.4% (6/250) for patients taking statins while 3.7% (70/1,897) for those not taking statins. In the multivariate Cox model, after adjusting for age, gender, admitted hospital, comorbidities, in-hospital medications and blood lipids, the risk was lower for mortality (adjusted HR, 0.428; 95% CI, 0.169–0.907; P = 0.029), acute respiratory distress syndrome (ARDS) (adjusted HR, 0.371; 95% CI, 0.180–0.772; P = 0.008) or intensive care unit (ICU) care (adjusted HR, 0.319; 95% CI, 0.270–0.945; P = 0.032) in the statin group vs. the non-statin group. After propensity score-matched analysis based on 18 potential confounders, a 1:1 matched cohort (206:206) was created. In the matched cohort, the Kaplan-Meier survival curves showed that the use of statins was associated with better survival (P = 0.025). In a Cox regression model, the use of statins was associated with lower risk of mortality (unadjusted HR, 0.254; 95% CI, 0.070–0.926; P = 0.038), development of ARDS (unadjusted HR, 0.240; 95% CI, 0.087–0.657; P = 0.006), and admission of ICU (unadjusted HR, 0.349; 95% CI, 0.150–0.813; P = 0.015). The results remained consistent when being adjusted for age, gender, total cholesterol, triglyceride, low density lipoprotein cholesterol, procalcitonin, and brain natriuretic peptide. The favorable outcomes in statin users remained statistically significant in the first sensitivity analysis with comorbid diabetes being excluded in matching and in the second sensitivity analysis with chronic obstructive pulmonary disease being added in matching.

Conclusion: In this retrospective analysis, the use of statins in COVID-19 patients was associated with better clinical outcomes and is recommended to be continued in patients with COVID-19.

Effects of statins on clinical outcomes in hospitalized patients with community-acquired pneumonia

Objective

We evaluated the effect of chronic use of statins based on C-reactive protein (CRP) levels and hospital length of stay (LOS) in patients admitted with community-acquired pneumonia (CAP).

Methods

We conducted a retrospective study over 12 months at a teaching hospital in Lebanon comparing patients with CAP taking chronic statins with patients not taking statins. Included patients with CAP were older than age 18 years and had two CRP level measures during hospitalization. CURB-65 criteria were used to assess the severity of pneumonia. A decrease in CRP levels on days 1 and 3, LOS, and normalization of fever were used to assess the response to antibiotics.

Results

Sixty-one patients were taking statins and 90 patients were not taking statins. Patients on statins had significantly more comorbid conditions; both groups had comparable CURB-65 scores. In both groups, no statistically significant difference was seen for the decrease in CRP level on days 1 and 3 and LOS. No difference in days to normalization of fever was detected in either group.

Conclusion

No association was found between the chronic use of statins and CRP levels, LOS, or days to fever normalization in patients with CAP.

Effect of statins in preventing hospitalizations for infections: A population study

PURPOSE

To investigate whether the hospitalization rate for bacterial infections was modified by statin therapy in a population retrospectively followed up, over years 2011 to 2015.

METHODS

By using administrative databases, the 5-year hospitalization rate due to bacterial infections in population living in Tuscany, Italy exposed to statin therapy (n = 52,049) was stratified by 5 prescribed daily doses classes (0%-20%, 20%-50%, 50%-80%, 80%-100%, ≥100% of DDD) and subsequently compared with that of a population of untreated individuals (n = 3 300 ,675), matched through a propensity score accounting for all available covariates potentially able to modulate risk of infections such as age, gender, previous hospitalizations for infections, cardiovascular events, previous co-morbidities, diabetes, as well as general practitioners' proactive behaviour of care delivery according to current guidelines.

RESULTS

Unmatched individuals of each treatment-class had significantly more hospitalizations than controls, while matched treated people, apart from those in class 0% to 20%, had a decrease of hospitalizations, as large as the increase in prescribed drug. Statin effect in reducing hospitalizations translated into a number needed to treat (NNT) ranging across treatment strata from 102 to 54.

CONCLUSIONS

Compliance to statin prescribed daily doses above the threshold 20% of DDD, along a 5-year follow-up, prevented hospitalizations due to infectious diseases in a large unselected population, after adjusting for covariates able to modulate baseline risk of infections. The NNTs to avoid 1 hospitalization for infections resulted on average not too dissimilar from a value lying between the 95% CI of NNTs previously found for primary prevention of 1 incident coronary ischemic event (72 to 119).

Effect of statins on hospitalization risk of bacterial infections in patients with or without diabetes

AIMS

To investigate whether statins reduce the risk to first hospitalization of bacterial infections, in patients with or without diabetes taking into account prior or incident comorbidities.

METHODS

By using administrative databases, the effect of current statin use was measured on the risk of first hospitalizations due to bacterial infections in people living in Tuscany, Italy, in the period January 1, 2011-December 31, 2015, after excluding those with previous statins use. Population was stratified as with (n = 128,207) or without diabetes (n = 3,304,906), and the hospitalization risk was analyzed by a Cox proportional hazards regression analysis after adjusting for age, gender, previous comorbidities, chronic renal failure, and prior or incident cardiovascular diseases.

RESULTS

During the 5-year follow-up, 31,543 hospitalizations for bacterial infections were observed: 2.08(2.06-2.10) per 1000 person-year in non-diabetic and 5679: 9.13(8.94-9.32) per 1000 person-year in diabetic population. Diabetes conferred a greater risk of hospitalizations, independently from confounders [adjusted HR (95% CI) 2.04 (1.97-2.10); P < 0.0001]. Statin use decreased the risk by about 2.5% for each one month of therapy, at the same extent in subjects with or without diabetes, after adjusting for all covariates.

CONCLUSIONS

In this population, diabetes was associated by a twofold increase in the 5-year risk of hospitalizations for bacterial infections. Statin use decreased this risk to a same extent in subjects without or with diabetes, after adjusting for main confounders including comorbidities, and previous or incident cardiovascular events.

HDL-c levels predict the presence of pleural effusion and the clinical outcome of community-acquired pneumonia

Objectives

To investigate if HDL cholesterol (HDL-c) could be a biomarker of the degree of severity according to prognostic prediction scores in community-acquired pneumonia (CAP) or the development of clinical complications such as pleural effusion.

Methods

We included in a retrospective study 107 patients admitted to the hospital that fulfilled diagnostic criteria for CAP between the 30th October 2011 and 1st September 2012. HDL-c levels at admission, CAP prognosis scores (PSI and CURB65) and clinical outcomes were recorded for the study.

Results

Basal HDL-c levels were not statistically different according to prognostics scores neither PSI nor CURB-65. Significantly lower levels of HDL-c were also associated to the development of septic shock and admission to the intensive care unit. HDL-c were inversely correlated with acute phase reactants CRP (r = −0.585, P < 0.001), ESR (r = −0.477, P < 0.001), and leukocytes cell count (r = −0.254, P < 0.009). Patients with pleural effusion showed significant lower levels of HDL-c [28.9 (15.5) mg/dl vs. 44.6 (21.1) mg/dl]; P = 0.007. HDL-c is a good predictor of the presence of pleural effusion in multivariate analyses and using ROC analyses [AUC = 0.712 (0.591–0.834), P = 0.006]. HDL-c levels of 10 mg/dl showed a sensitivity of 97.6 % and a specificity of 82.4 % for the presence of pleural effusion.

Conclusion

Monitoring HDL-c in CAP is an useful serum marker of acute phase response, clinical outcome and the presence of pleural effusion.

Advances in the prevention, management, and treatment of community-acquired pneumonia

Community-acquired pneumonia (CAP) is the infectious disease with the highest number of deaths worldwide. Nevertheless, its importance is often underestimated. Large cohorts of patients with CAP have been established worldwide and improved our knowledge about CAP by far. Therefore, current guidelines are much more evidence-based than ever before. This article discusses recent major studies and concepts on CAP such as the role of biomarkers, appropriate risk stratification to identify patients in need of hospitalisation or intensive care, appropriate empiric antibiotic therapy (including the impact of macrolide combination therapy and antibiotic stewardship), and CAP prevention with novel influenza and pneumococcal vaccines.

The effect of simvastatin on inflammatory cytokines in community-acquired pneumonia: a randomised, double-blind, placebo-controlled trial

OBJECTIVES

It has been suggested that statins have an effect on the modulation of the cytokine cascade and on the outcome of patients with community-acquired pneumonia (CAP). The aim of this prospective, randomised, double-blind, placebo-controlled trial was to determine whether statin therapy given to hospitalised patients with CAP improves clinical outcomes and reduces the concentration of inflammatory cytokines.

SETTING

A tertiary teaching hospital in Barcelona, Spain.

PARTICIPANTS

Thirty-four patients were randomly assigned and included in an intention-to-treat analysis (19 to the simvastatin group and 15 to the placebo group).

INTERVENTION

Patients were randomly assigned to receive 20 mg of simvastatin or placebo administered in the first 24 h of hospital admission and once daily thereafter for 4 days.

OUTCOME

Primary end point was the time from hospital admission to clinical stability. The secondary end points were serum concentrations of inflammatory cytokines and partial pressure of arterial oxygen/fractional inspired oxygen (PaO2/FiO2) at 48 h after treatment administration.

RESULTS

The trial was stopped because enrolment was much slower than originally anticipated. The baseline characteristics of the patients and cytokine concentrations at the time of enrolment were similar in the two groups. No significant differences in the time from hospital admission to clinical stability were found between study groups (median 3 days, IQR 2-5 vs 3 days, IQR 2-5; p=0.47). No significant differences in PaO2/FiO2 (p=0.37), C reactive protein (p=0.23), tumour necrosis factor-α (p=0.58), interleukin 6 (IL-6; p=0.64), and IL-10 (p=0.61) levels at 48 h of hospitalisation were found between simvastatin and placebo groups. Similarly, transaminase and total creatine kinase levels were similar between study groups at 48 h of hospitalisation (p=0.19, 0.08 and 0.53, respectively).

CONCLUSIONS

Our results suggest that the use of simvastatin, 20 mg once daily for 4 days, since hospital admission did not reduce the time to clinical stability and the levels of inflammatory cytokines in hospitalised patients with CAP.

TRIAL REGISTRATION NUMBER

ISRCTN91327214.

Effect of statin therapy in the outcome of bloodstream infections due to Staphylococcus aureus: a prospective cohort study

INTRODUCTION

Statins have pleiotropic effects that could influence the prevention and outcome of some infectious diseases. There is no information about their specific effect on Staphylococcus aureus bacteremia (SAB).

METHODS

A prospective cohort study including all SAB diagnosed in patients aged ≥18 years admitted to a 950-bed tertiary hospital from March 2008 to January 2011 was performed. The main outcome variable was 14-day mortality, and the secondary outcome variables were 30-day mortality, persistent bacteremia (PB) and presence of severe sepsis or septic shock at diagnosis of SAB. The effect of statin therapy at the onset of SAB was studied by multivariate logistic regression and Cox regression analysis, including a propensity score for statin therapy.

RESULTS

We included 160 episodes. Thirty-three patients (21.3%) were receiving statins at the onset of SAB. 14-day mortality was 21.3%. After adjustment for age, Charlson index, Pitt score, adequate management, and high risk source, statin therapy had a protective effect on 14-day mortality (adjusted OR = 0.08; 95% CI: 0.01-0.66; p = 0.02), and PB (OR = 0.89; 95% CI: 0.27-1.00; p = 0.05) although the effect was not significant on 30-day mortality (OR = 0.35; 95% CI: 0.10-1.23; p = 0.10) or presentation with severe sepsis or septic shock (adjusted OR = 0.89; CI 95%: 0.27-2.94; p = 0.8). An effect on 30-day mortality could neither be demonstrated on Cox analysis (adjusted HR = 0.5; 95% CI: 0.19-1.29; p = 0.15).

CONCLUSIONS

Statin treatment in patients with SAB was associated with lower early mortality and PB. Randomized studies are necessary to identify the role of statins in the treatment of patients with SAB.

Effect of statin use on outcomes of adults with candidemia

Background

Statins have immunomodulatory properties and hinder Candida growth. However, it is unknown whether they may improve prognosis in patients with candidemia. We sought to determine the effect of prior statin use on the clinical outcomes of patients suffering candidemia.

Methods and Findings

Multicenter cohort study of hospitalized adults with candidemia between 2005 and 2011 in six hospitals in Spain, Brazil and Argentina. Of 326 candidemias, 44 (13.5%) occurred in statin users and 282 (86.5%) in statin non-users. The median value of APACHE II at candidemia diagnosis was similar between groups (18 vs. 16; p=.36). Candida albicans was the most commonly isolated species, followed by C. parapsilosis, C. tropicalis, C. glabrata, and C. krusei. There were no differences regarding appropriate empirical antifungal treatment. Statin users had a lower early (5 d) case-fatality rate than non-users (4.5 vs. 17%; p=.031). This effect was not observed with other cardiovascular drugs (aspirin, beta blockers and ACE inhibitors). Independent factor related to early case-fatality rate was APACHE II score (AOR, 1.08; 95% CI, 1.03–1.14; p=.002). An appropriate empirical antifungal therapy (AOR, 0.11; 95% CI, 0.04–0.26; p=<.001) and prior statin use were independently associated with lower early case-fatality (AOR, 0.17; 95% CI, 0.03–0.93; p=.041). Fourteen days (14d) and overall (30d) case-fatality rates were similar between groups (27% vs. 29%; p=0.77 and 40% vs. 44%; p=.66).

Conclusions

The use of statins might have a beneficial effect on outcomes of patients with candidemia. This hypothesis deserves further evaluation in randomized trials.

The immunomodulatory effects of statins in community-acquired pneumonia: a systematic review

OBJECTIVE

To evaluate the potential immunomodulatory effects of statins in community-acquired pneumonia.

METHODS

We performed a systematic review of available literature on experimental and clinical studies. We used a PubMed/MEDLINE and EMBASE search to identify potential articles.

RESULTS

We identified 34 original studies, 17 experimental and 17 clinical studies, published up to March 2013.

CONCLUSIONS

Statins attenuated pulmonary inflammation by modulating neutrophil function, by reducing cytokine expression and release, and by protecting against disruption of pulmonary integrity. However, additional experimental studies are needed to fully elucidate the exact mechanisms. Several clinical studies suggested a decreased risk of CAP or a reduction in mortality due to CAP for current statin users, but the mostly observational design of these studies hampers the interpretation of their results. Therefore, appropriately designed studies, such as randomised controlled trials, are required to demonstrate the usefulness of statins in the prevention and treatment of CAP.

Clinical features, etiology, and outcomes of community-acquired pneumonia in patients with diabetes mellitus

We performed an observational analysis of a prospective cohort of immunocompetent hospitalized adults with community-acquired pneumonia (CAP) to determine the epidemiology, clinical features, and outcomes of pneumonia in patients with diabetes mellitus (DM). We also analyzed the risk factors for mortality and the impact of statins and other cardiovascular drugs on outcomes. Of 2407 CAP episodes, 516 (21.4%) occurred in patients with DM; 483 (97%) had type 2 diabetes, 197 (40%) were on insulin treatment, and 119 (23.9%) had end-organ damage related to DM. Patients with DM had different clinical features compared to the other patients. They were less likely to have acute onset, cough, purulent sputum, and pleural chest pain. No differences in etiology were found between study groups. Patients with DM had more inhospital acute metabolic complications, although the case-fatality rate was similar between the groups. Independent risk factors for mortality in patients with DM were advanced age, bacteremia, septic shock, and gram-negative pneumonia. Patients with end-organ damage related to DM had more inhospital cardiac events and a higher early case-fatality rate than did the overall population. The use of statins and other cardiovascular drugs was not associated with better CAP outcomes in patients with DM. In conclusion, CAP in patients with DM presents different clinical features compared to the features of patients without DM.

Is statin use associated with reduced mortality after pneumonia? A systematic review and meta-analysis

OBJECTIVE

The objective of this study was to perform a systematic review and meta-analysis of the effects of statins on mortality following pneumonia.

METHODS

We searched MEDLINE, EMBASE, BIOSIS, Cochrane CENTRAL Register of Controlled Trials, Cambridge Scientific Abstracts, BIOSIS, and Scopus. Studies were included if they involved: participants ≥18 years of age; patients with community-acquired pneumonia; current statin users; and reported overall or adjusted mortality after pneumonia.

RESULTS

Of 491 citations identified, 13 studies involving 254,950 patients met eligibility criteria. Pooled unadjusted data showed that statin use was associated with lower mortality after pneumonia (odds ratio [OR] 0.62, 95% confidence interval [CI], 0.54-0.71). Pooling of adjusted data also showed reduced mortality after pneumonia (OR 0.66, 95% CI, 0.55-0.79). However, this effect was attenuated in subgroup analysis by confounders and in prospective studies.

CONCLUSIONS

Although statin use is associated with decreased mortality after pneumonia, this effect weakens in important subgroups. Only a randomized controlled study can fully explore the link between statins and pneumonia mortality.

Simvastatin is protective during Staphylococcus aureus pneumonia

Epidemiologic studies suggest that the incidence and severity of sepsis are ameliorated in patients on statins (3- hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) for cholesterol lowering indications. We sought to understand the mechanism underlying such protection and hypothesized that simvastatin would be protective in mice against acute infection with Staphylococcus aureus, the primary etiologic agent in sepsis. Mice were treated with simvastatin or buffer for two weeks and were subsequently challenged with S. aureus intratracheally or intravenously. Relative to buffer-treated mice, bacterial killing was enhanced 4-fold (p=0.02), systemic dissemination was reduced, and lethality was decreased (hazard ratio 8.8, 95% CI 2.5 to 31.3, p=0.001) in mice that were pretreated with simvastatin for two weeks. Systemic inflammatory response was abrogated and the local elaboration of inflammatory mediators was diminished. Serum concentrations of pro-fibrinolytic protein C were elevated (p=0.034), while the concentration of pro-coagulant tissue factor in bronchoalveolar lavage fluids was attenuated (reduced 25%), p=0.001, in simvastatin-treated mice. Taken together, these data indicate that extended treatment with simvastatin is protective during infection with S. aureus through enhanced bacterial clearance, anti-inflammatory, and anti-coagulant activities. These studies provide insights into the mechanism by which statins confer protection in acute infection, support the notion that statins may be effective adjuncts in the treatment of sepsis, and provide a rationale for randomized control trials in patients that are at a high risk for infection characterized by coagulopathy.

Antibacterial activity of statins: a comparative study of atorvastatin, simvastatin, and rosuvastatin

Background

Statins have several effects beyond their well-known antihyperlipidemic activity, which include immunomodulatory, antioxidative and anticoagulant effects. In this study, we have tested the possible antimicrobial activity of statins against a range of standard bacterial strains and bacterial clinical isolates.

Methods

Minimum inhibitory concentrations (MIC) values were evaluated and compared among three members of the statins drug (atorvastatin, simvastatin, and rosuvastatin).

Results

It was revealed that statins are able to induce variable degrees of antibacterial activity with atorvastatin, and simvastatin being the more potent than rosuvastatin. Methicillin-sensitive staphylococcus aureus (MSSA), methicillin-resistant staphylococcus aureus (MRSA), vancomycin-susceptible enterococci (VSE), vancomycin-resistant enterococcus (VRE), acinetobacter baumannii, staphylococcus epidermidis, and enterobacter aerogenes, were more sensitive to both atorvastatin, and simvastatin compared to rosuvastatin. On the other hand, escherichia coli, proteus mirabilis, and enterobacter cloacae were more sensitive to atorvastatin compared to both simvastatin and rosuvastatin. Furthermore, most clinical isolates were less sensitive to statins compared to their corresponding standard strains.

Conclusion

Our findings might raise the possibility of a potentially important antibacterial class effect for statins especially, atorvastatin and simvastatin.

Do aspirin and other antiplatelet drugs reduce the mortality in critically ill patients?

Platelet activation has been implicated in microvascular thrombosis and organ failure in critically ill patients. In the first part the present paper summarises important data on the role of platelets in systemic inflammation and sepsis as well as on the beneficial effects of antiplatelet drugs in animal models of sepsis. In the second part the data of retrospective and prospective observational clinical studies on the effect of aspirin and other antiplatelet drugs in critically ill patients are reviewed. All of these studies have shown that aspirin and other antiplatelet drugs may reduce organ failure and mortality in these patients, even in case of high bleeding risk. From the data reviewed here interventional prospective trials are needed to test whether aspirin and other antiplatelet drugs might offer a novel therapeutic option to prevent organ failure in critically ill patients.

Understanding the potential role of statins in pneumonia and sepsis

OBJECTIVE

To examine the association of statin use with clinical outcomes and circulating biomarkers in community-acquired pneumonia and sepsis.

DESIGN

Multicenter inception cohort study.

SETTING

Emergency departments of 28 U.S. hospitals.

PATIENTS

A total of 1895 subjects hospitalized with community-acquired pneumonia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Our approach consisted of two different comparison cohorts, each reflecting methods used in prior publications in this area. We first compared subjects with prior statin use (prior use cohort), defined as a history of statin use in the week before admission, with those with no prior use. We then compared prior statin users whose statins were continued inhospital (continued use cohort) with those with either no prior use or no inhospital use. We adjusted for patient characteristics, including demographics, comorbid conditions, and illness severity, and accounted for healthy user effect and indication bias using propensity analysis. We determined risk of severe sepsis and 90-day mortality. We measured markers inflammation (tumor necrosis factor, interleukin-6, interleukin-10), coagulation (antithrombin, factor IX, plasminogen activator inhibitor, d-dimer, thrombin antithrombin complex), and lymphocyte cell surface protein expression during the first week of hospitalization. There were no differences in severe sepsis risk between statin users and nonusers for prior (30.8% vs. 30.7%, p = .98) or continued statin use (30.2% vs. 30.8%, p = .85) in univariate analyses and after adjusting for patient characteristics and propensity for statin use. Ninety-day mortality was similar in prior statin users (9.2% vs. 12.0%, p = .11) and lower in continued statin users (7.9% vs. 12.1%, p = .02). After adjusting for patient characteristics and propensity for statin use, there was no mortality benefit for prior (odds ratio, 0.90 [0.63-1.29]; p = .57) or continued statin use (odds ratio, 0.73 [0.47-1.13]; p = .15). Only antithrombin activity over time was higher in statin subjects, yet the magnitude of the difference was modest. There were no differences in other coagulation, inflammatory, or lymphocyte cell surface markers.

CONCLUSIONS

We found no evidence of a protective effect for statin use on clinical outcomes and only modest differences in circulating biomarkers in community-acquired pneumonia, perhaps as a result of healthy user effects and indication bias.

Marked reduction in 30-day mortality among elderly patients with community-acquired pneumonia

BACKGROUND

Community-acquired pneumonia is the most common infectious cause of death in the US. Over the last 2 decades, patient characteristics and clinical care have changed. To understand the impact of these changes, we quantified incidence and mortality trends among elderly adults.

METHODS

We used Medicare claims to identify episodes of pneumonia, based on a validated combination of diagnosis codes. Comorbidities were ascertained using the diagnosis codes located on a 1-year look back. Trends in patient characteristics and site of care were compared. The association between year of pneumonia episode and 30-day mortality was then evaluated by logistic regression, with adjustment for age, sex, and comorbidities.

RESULTS

We identified 2,654,955 cases of pneumonia from 1987-2005. During this period, the proportion treated as inpatients decreased, the proportion aged ≥80 years increased, and the frequency of many comorbidities rose. Adjusted incidence increased to 3096 episodes per 100,000 population in 1999, with some decrease thereafter. Age/sex-adjusted mortality decreased from 13.5% to 9.7%, a relative reduction of 28.1%. Compared with 1987, the risk of mortality decreased through 2005 (adjusted odds ratio, 0.46; 95% confidence interval, 0.44-0.47). This result was robust to a restriction on comorbid diagnoses assessing for the results' sensitivity to increased coding.

CONCLUSIONS

These findings show a marked mortality reduction over time in community-acquired pneumonia patients. We hypothesize that increased pneumococcal and influenza vaccination rates as well as wider use of guideline-concordant antibiotics explain a large portion of this trend.