Acute kidney injury is an independent marker of severity in Clostridium difficile infection: a nationwide survey

Acute kidney injury in hospitalized patients with nonmalignant pleural effusions: a retrospective cohort study

BACKGROUND

Nonmalignant pleural effusion (NMPE) is common and remains a definite health care problem. Pleural effusion was supposed to be a risk factor for acute kidney injury (AKI). Incidence of AKI in NMPE patients and whether there is correlation between the size of effusions and AKI is unknown.

OBJECTIVE

To assess the incidence of AKI in NMPE inpatients and its association with effusion size.

STUDY DESIGN AND METHOD

We conducted a retrospective cohort study of inpatients admitted to the Chinese PLA General Hospital with pleural effusion from 2018-2021. All patients with pleural effusions confirmed by chest radiography (CT or X-ray) were included, excluding patients with diagnosis of malignancy, chronic dialysis, end-stage renal disease (ESRD), community-acquired AKI, hospital-acquired AKI before chest radiography, and fewer than two serum creatinine tests during hospitalization. Multivariate logistic regression and LASSO logistic regression models were used to identify risk factors associated with AKI. Subgroup analyses and interaction tests for effusion volume were performed adjusted for the variables selected by LASSO. Causal mediation analysis was used to estimate the mediating effect of heart failure, pneumonia, and eGFR < 60 ml/min/1.73m2 on AKI through effusion volume.

RESULTS

NMPE was present in 7.8% of internal medicine inpatients. Of the 3047 patients included, 360 (11.8%) developed AKI during hospitalization. After adjustment by covariates selected by LASSO, moderate and large effusions increased the risk of AKI compared with small effusions (moderate: OR 1.47, 95%CI 1.11-1.94 p = 0.006; large: OR 1.86, 95%CI 1.05-3.20 p = 0.028). No significant modification effect was observed among age, gender, diabetes, bilateral effusions, and eGFR. Volume of effusions mediated 6.8% (p = 0.005), 4.0% (p = 0.046) and 4.6% (p < 0.001) of the effect of heart failure, pneumonia and low eGFR on the development of AKI respectively.

CONCLUSION

The incidence of AKI is high among NMPE patients. Moderate and large effusion volume is independently associated with AKI compared to small size. The effusion size acts as a mediator in heart failure, pneumonia, and eGFR.

Reappraisal of the clinical role of metronidazole therapy for Clostridioides difficile infection in Taiwan: A multicenter prospective study

BACKGROUND/PURPOSE

Although metronidazole is not recommended to treat Clostridioides difficile infection (CDI) in Western countries, it was still to be recommended for the treatment of non-severe CDI among Taiwanese adults in 2020. This controversy in the clinical role of metronidazole therapy for CDI was examined in a prospective clinical study.

METHODS

The study was conducted from January 2015 to December 2016 in three hospitals in Taiwan. Metronidazole treatment failure (MTF) was defined as the persistence of diarrhea after six days of treatment, medication modification (shifting to oral vancomycin), or death after five days of therapy.

RESULTS

Overall, 325 patients receiving metronidazole for CDI were included. The overall MTF rate was 48.6% (158 patients). Leukocyte counts of >15,000 cells/mL in peripheral blood (odd ratio [OR] 1.81; P = 0.04) and congestive heart failure (OR 3.26; P = 0.02) were independently associated with MTF. The MTF rate for patients with leukocyte counts of ≤15,000 cells/mL and no congestive heart failure, leukocyte counts of >15,000 cells/mL and no congestive heart failure, leukocyte counts of ≤15,000 cells/mL and congestive heart failure, and leukocyte counts of >15,000 cells/mL and congestive heart failure were 44.2%, 51.8%, 73.3%, and 66.7%, respectively. Of note, patients who experienced MTF had a higher recurrence rate of CDI than those with metronidazole treatment success (13.9% vs. 6.0%, P = 0.02).

CONCLUSION

For Taiwanese adults with CDI, the failure rate of metronidazole therapy approached 50%, which suggests the reappraisal of the therapeutic role of metronidazole therapy, especially for patients with leukocytosis or underlying congestive heart failure.

European Society of Clinical Microbiology and Infectious Diseases: 2021 update on the treatment guidance document for Clostridioides difficile infection in adults

SCOPE

In 2009, the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) published the first treatment guidance document for Clostridioides difficile infection (CDI). This document was updated in 2014. The growing literature on CDI antimicrobial treatment and novel treatment approaches, such as faecal microbiota transplantation (FMT) and toxin-binding monoclonal antibodies, prompted the ESCMID study group on C. difficile (ESGCD) to update the 2014 treatment guidance document for CDI in adults.

METHODS AND QUESTIONS

Key questions on CDI treatment were formulated by the guideline committee and included: What is the best treatment for initial, severe, severe-complicated, refractory, recurrent and multiple recurrent CDI? What is the best treatment when no oral therapy is possible? Can prognostic factors identify patients at risk for severe and recurrent CDI and is there a place for CDI prophylaxis? Outcome measures for treatment strategy were: clinical cure, recurrence and sustained cure. For studies on surgical interventions and severe-complicated CDI the outcome was mortality. Appraisal of available literature and drafting of recommendations was performed by the guideline drafting group. The total body of evidence for the recommendations on CDI treatment consists of the literature described in the previous guidelines, supplemented with a systematic literature search on randomized clinical trials and observational studies from 2012 and onwards. The Grades of Recommendation Assessment, Development and Evaluation (GRADE) system was used to grade the strength of our recommendations and the quality of the evidence. The guideline committee was invited to comment on the recommendations. The guideline draft was sent to external experts and a patients' representative for review. Full ESCMID endorsement was obtained after a public consultation procedure.

RECOMMENDATIONS

Important changes compared with previous guideline include but are not limited to: metronidazole is no longer recommended for treatment of CDI when fidaxomicin or vancomycin are available, fidaxomicin is the preferred agent for treatment of initial CDI and the first recurrence of CDI when available and feasible, FMT or bezlotoxumab in addition to standard of care antibiotics (SoC) are preferred for treatment of a second or further recurrence of CDI, bezlotoxumab in addition to SoC is recommended for the first recurrence of CDI when fidaxomicin was used to manage the initial CDI episode, and bezlotoxumab is considered as an ancillary treatment to vancomycin for a CDI episode with high risk of recurrence when fidaxomicin is not available. Contrary to the previous guideline, in the current guideline emphasis is placed on risk for recurrence as a factor that determines treatment strategy for the individual patient, rather than the disease severity.

Incidence and Outcomes Associated With Clostridioides difficile Infection in Solid Organ Transplant Recipients

IMPORTANCE

Little is known about the incidence and outcomes of Clostridioides difficile infection (CDI) in solid organ transplant (SOT) recipients.

OBJECTIVE

To estimate the CDI incidence and outcomes in SOT recipients.

DESIGN, SETTING, AND PARTICIPANTS

A population-based cohort study was conducted using administrative health care data for all Ontario, Canada, residents who received organ allografts from April 1, 2003, to December 31, 2017; March 31, 2020, was the end of the study period.

MAIN OUTCOMES AND MEASURES

The primary outcome was hospital admission with CDI diagnosis. The secondary outcomes included all-cause death, intensive care unit admission, acute kidney injury requiring dialysis, and fulminant CDI comprising any of the following: toxic megacolon, ileus, perforation, or colectomy. The association between short- vs long-term mortality (ie, death occurring within or after 90 days post-CDI) and the following variables was evaluated: age, sex, Deyo-Charlson Comorbidity Index, SOT type, early- vs late-onset CDI, fulminant CDI, intensive care unit admission, and acute kidney injury requiring acute dialysis.

RESULTS

Overall, 10 724 SOT recipients (6901 [64.4%] men; median age, 54 [IQR, 44-62] years) were eligible. Kidney transplant was the most common SOT type (6453 [60.2%]). The median follow-up time was 5.0 (IQR, 2.3-8.8) years, resulting in 61 987 person-years of follow-up. A total of 726 patients (6.8%) were hospitalized with CDI. The 1-year CDI incidence significantly increased in annual cohorts (ie, from 23.1; 95% CI, 12.8-41.8 per 1000 person-years in 2004 to 46.7; 95% CI, 35.0-62.3 per 1000 person-years in 2017; P = .001). Clostridioides difficile was associated with a 16.8% rate (n = 122) of 90-day mortality. In patients who underwent kidney transplant, CDI was typically late-onset (median interval, 2.2; IQR, 0.4-6.0 years) compared with recipients of other organs. Acute kidney injury requiring dialysis was significantly associated with short-term (adjusted odds ratio [aOR], 1.86; 95% CI, 1.07-3.26) and long-term (adjusted hazard ratio [aHR], 1.89; 95% CI, 1.29-2.78) mortality, and late-onset CDI was also significantly associated with a greater risk of short-term (aOR, 4.26; 95% CI, 2.51-7.22) and long-term (aHR, 2.49; 95% CI, 1.78-3.49) mortality.

CONCLUSIONS AND RELEVANCE

In this study, increasing CDI trends in annual cohorts of SOT recipients were observed. Posttransplant CDI was associated with mortality, and late-onset CDI was associated with a greater risk of death than early-onset CDI. These findings suggest that preventive strategies should not be limited to the initial months following transplantation. Comprehensive therapeutic approaches targeting acute kidney injury risk factors in SOT recipients may reduce short- and long-term post-CDI mortality.

Prognostic factors for severe and recurrent Clostridioides difficile infection: a systematic review

OBJECTIVES

Clostridioides difficile infection (CDI), its subsequent recurrences (rCDIs), and severe CDI (sCDI) provide a significant burden for both patients and the healthcare system. Identifying patients diagnosed with initial CDI who are at increased risk of developing sCDI/rCDI could lead to more cost-effective therapeutic choices. In this systematic review we aimed to identify clinical prognostic factors associated with an increased risk of developing sCDI or rCDI.

METHODS

PubMed, Embase, Emcare, Web of Science and COCHRANE Library databases were searched from database inception through March, 2021. The study eligibility criteria were cohort and case-control studies. Participants were patients ≥18 years old diagnosed with CDI, in which clinical or laboratory factors were analysed to predict sCDI/rCDI. Risk of bias was assessed by using the Quality in Prognostic Research (QUIPS) tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool modified for prognostic studies. Study selection was performed by two independent reviewers. Overview tables of prognostic factors were constructed to assess the number of studies and the respective effect direction and statistical significance of an association.

RESULTS

136 studies were included for final analysis. Greater age and the presence of multiple comorbidities were prognostic factors for sCDI. Identified risk factors for rCDI were greater age, healthcare-associated CDI, prior hospitalization, proton pump inhibitors (PPIs) started during or after CDI diagnosis, and previous rCDI.

CONCLUSIONS

Prognostic factors for sCDI and rCDI could aid clinicians to make treatment decisions based on risk stratification. We suggest that future studies use standardized definitions for sCDI/rCDI and systematically collect and report the risk factors assessed in this review, to allow for meaningful meta-analysis of risk factors using data of high-quality trials.

Outcomes among inpatients with cirrhosis and Clostridioides difficile infection in the modern era: results from an analysis of the National Inpatient Sample

Background

Patients with cirrhosis are at increased risk of Clostridioides difficile infection (CDI). We analyzed outcomes and healthcare utilization in hospitalized cirrhotic patients with CDI.

Methods

The Nationwide Inpatient Sample from 2016-2017 identified 8245 hospitalized patients with a concurrent diagnosis of cirrhosis and CDI. Our primary outcome was in-hospital all-cause mortality. Secondary outcomes were length of stay (LOS), hospitalization charges and costs, shock, sepsis, acute kidney injury (AKI), intensive care unit (ICU) admission, and home discharge.

Results

There was no significant difference in all-cause in-hospital mortality between patients with cirrhosis compared to patients without cirrhosis (adjusted odds ratio [aOR] 1.31, 95% confidence interval [CI] 0.89-1.93; P=0.16). Patients with cirrhosis had a slightly but statistically significantly longer mean LOS (+0.57 days, P=0.001). The adjusted difference in mean hospitalization charges was greater in patients with cirrhosis ($+4094, 95%CI $1080-7108; P=0.008), as was the mean hospitalization cost ($+1349, 95%CI $600-2098; P<0.001). There was no difference in the likelihood of sepsis, ICU admission, or home discharge between the groups. Patients with cirrhosis were significantly less likely to develop AKI (aOR 0.82, 95%CI 0.72-0.93; P=0.003).

Conclusions

Mortality outcomes associated with CDI have improved over time. Patients with cirrhosis continue to exhibit greater LOS and hospital costs.

The significance of acute kidney injury in Clostridioides difficile infection

OBJECTIVE

Clostridioides difficile infection (CDI) may present as sepsis with acute kidney injury (AKI). Herein, we aimed to evaluate the clinical outcomes of patients with AKI complicating CDI.

METHODS

All consecutive adult patients hospitalized in Rabin Medical Center between 1 January 2013 and 31 December 2018 with laboratory confirmed CDI, were included in the study. Subjects were divided into two groups: patients with AKI and controls. Primary outcome was all-cause mortality at 30 days after the CDI episode. Secondary outcomes included number of patients with deteriorating renal functions at 90 days, 90-day all-cause mortality, length of hospital stay and readmission rates. A multivariable analysis adjusted for other risk factors for mortality and renal function deterioration was conducted. An analysis of subgroups based on baseline kidney function and AKI stage was also performed. Results are reported as odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

A total of 527 patients were included, amongst them 140 patients with AKI and 387 controls. Patients with AKI were significantly older, had more comorbidities, and more of them had chronic kidney disease (CKD) at any stage at baseline. On multivariable analysis, 30 days all-cause mortality was significantly higher in patients with AKI, OR 1.67, 95% CI 1.05-2.66. Mortality was also significantly associated with advanced age and baseline CKD. Among patients alive at 90 days, deterioration of renal function was significantly more common in patients with AKI (27/63 (42.8%) vs 22/191 (11.5%), P = .000). In a multivariable analysis, deterioration of renal function at 90 days was associated with AKI at presentation (OR 4.67, 95% CI 1.05-20.6). Early (at discharge) renal function recovery was not associated with protection from further deterioration of renal function at day 90.

CONCLUSIONS

CDI patients with AKI have an increased risk of mortality and further deterioration of renal function. Early renal function recovery does not infer protection from further deterioration of renal function at 3 months. Caution and nephrology follow-up should be considered after discharge for all patients who developed AKI during CDI, regardless of discharge creatinine levels.

The rise of Clostridioides difficile infections and fall of associated mortality in hospitalized advanced cirrhotics

BACKGROUND & AIMS

Cirrhotics are at increased risk of Clostridioides difficile infection (CDI) and its associated high morbidity and mortality. However, the impact of CDI in cirrhotics over time remains unclear. This study analyses prevalence and mortality in CDI in hospitalized patients with advanced cirrhosis over 15 years and identifies trends.

METHODS

Using the Nationwide Inpatient Sample (NIS) from 1998 to 2014, 3 049 696 weighted patients with advanced cirrhosis (defined as evidence of decompensation or oesophageal varices) were identified using a validated algorithm of ICD-9-CM codes and included in the study. Trends were analysed using Cochran Armitage test and joinpoint regression and compared to the general population. Multivariable logistic regression was performed controlling for risk factors that affect mortality in cirrhotics.

RESULTS

CDI prevalence in advanced cirrhotics increased from 0.8% to 2.6%, annual percent change (APC) 8.8% (compared to 7.6% for the general population), while CDI-related mortality decreased from 20.7% to 11.3%, APC -3.4% (compared to -2.0% for the general population), from 1998 to 2014. CDI independently increased mortality in advanced cirrhotics (OR 1.47, P < 0.001) and was associated with acute kidney injury (AKI) (OR 2.09, P < 0.001), which itself significantly increased mortality (OR 4.54, P < 0.001). Hepatic encephalopathy and Hispanic ethnicity were interestingly associated with a lower prevalence of CDI.

CONCLUSIONS

CDI is increasingly common in advanced cirrhotics, but on the contrary, its associated mortality is decreasing. Despite improvements in outcomes in patients with advanced cirrhosis, CDI is associated with an increased mortality, driven by AKI, and therefore, requires aggressive identification and therapy.

Are Clostridium difficile toxins nephrotoxic?

Clostridium difficile-associated disease (CDAD) occurs along a spectrum from simple uncomplicated enteritis to a multi-system disease which may include nephropathy. Pathology is attributed to bacterial toxins, but it is unclear if the latter are directly nephrotoxic. Anecdotes of renal disease from human biopsy findings suggest a variation of histopathologies, but data are relatively limited. Acute renal failure does occur in patients with advanced morbidity. CDAD can complicate chronic renal failure. Kidney tissue culture cytotoxicity has long been known. Kidney function alterations among animal models or diseased humans are relatively uncommon in mild to moderate enteritis. Rare findings of toxinemia are reported. Some have proposed that renal dysfunction arises more from pre-renal compromises. Direct toxin studies on whole kidney are sparse. The role of direct toxin-associated renal disease is worthy of further investigation given the current impetus towards the development of protective and therapeutic passive and active immunity. Hypotheses of toxin-direct or pre-renal toxin compromise of renal function prevail.

Acute kidney injury impact on inpatient mortality in Clostridium difficile infection: A national propensity-matched study

BACKGROUND AND AIM

Acute kidney injury (AKI) is used as a marker of severity in Clostridium difficile infection (CDI) patients. We estimated the true effect of AKI in inpatient mortality of CDI patients, as there are no large-scale, population-based, propensity-matched studies evaluating AKI's effect in this patient cohort.

METHODS

A retrospective observational study utilizing the National Inpatient Sample from years 2003 to 2012, including all adults with CDI, excluding cases missing data on age, inpatient mortality or gender. Trends and CDI-related complications as mortality predictors were assessed using survey-weighted multivariable regression. We estimated AKI's independent effect by propensity-matching, post-stratifying by chronic kidney disease status, allowing for multiple comorbidity adjustment.

RESULTS

A total of 2 859 599 patients with CDI were included, of which 896 122 (31.3%) had principal diagnosis of CDI. AKI prevalence was 22%. Mortality rate was 8.4%, while among AKI patients was higher (18.2%). In multivariable regression, AKI was associated with higher mortality (odds ratio [OR] = 3.16, 95% confidence interval [CI]: 3.02-3.30; P < 0.001), while after propensity matching, AKI increased mortality by 86% (OR = 1.86, 95% CI: 1.79-1.94; P < 0.001). CDI incidence increased by 1.8, together with the rate of AKI (12.6% in 2003 to 28.8% in 2012, P-trend < 0.001). Despite increasing hospitalizations, mortality over the study period decreased to 7.2% (2012) from 9.0% (2003); P-trend < 0.001.

CONCLUSION

Hospital admissions of patients with CDI and concomitant AKI are increasing, but their inpatient mortality has improved over the study period. AKI is a significant contributor to mortality, independently of other comorbidities, complications, and hospital characteristics, emphasizing the need for early diagnosis and aggressive management in such patients.

Shift to community-onset Clostridium difficile infection in the national Veterans Health Administration, 2003-2014

BACKGROUND

Clostridium difficile infection (CDI) occurs frequently in inpatient settings; however, community-onset cases have been reported more frequently in recent years. This study evaluated hospital-onset and community-onset CDI in the national Veterans Health Administration (VHA) population over a 12-year period.

METHODS

This was a retrospective cohort study of all adult VHA beneficiaries with CDI between October 1, 2002, and September 30, 2014. Data were obtained from the Veterans Affairs Informatics and Computing Infrastructure. CDI was categorized into community-associated CDI (CA-CDI); community-onset, health care facility-associated CDI; and health care facility-onset CDI (HCFO-CDI). Each type was described longitudinally and was assessed as an independent risk factor for health outcomes using multivariable logistic regression.

RESULTS

Overall, 30,326 patients with a first CDI episode were included. HCFO-CDI was the predominant type (60.2%), followed by CO-HCFA-CDI (20.6%) and CA-CDI (19.2%). The proportion of patients with HCFO-CDI decreased from 73.5% during fiscal year 2003 to 53.2% during fiscal year 2014, whereas CA-CDI increased from 8.3% to 26.7%. HCFO-CDI was a positive predictor of severe CDI (odds ratio [OR], 1.71; 95% confidence interval [CI], 1.59-1.84) and 30-day mortality (OR, 1.46; 95% CI, 1.32-1.61), but a negative predictor of 60-day recurrence (OR, 0.41; 95% CI, 0.37-0.46).

CONCLUSIONS

HCFO-CDI was the predominant CDI type. The proportion of patients with CA-CDI increased and HCFO-CDI decreased in recent years. Patients with HCFO-CDI experienced higher rates of severe CDI and mortality.

Clostridium difficle Enteropathy Is Associated With a Higher Risk for Acute Kidney Injury in Patients With an Ileostomy-A Case-Control Study

BACKGROUND

Clostridium difficile infection (CDI) is traditionally considered a colon-affecting disease with frequent pseudomembrane formation. However, multiple case reports have documented the existence of CDI in the small bowel, and the literature on outcome of C difficile enteropathy (CDE) is sparse. The aims of our study are to identify risk factors and to assess patient-related outcomes associated with CDE.

METHODS

This is a case-control study involving 112 patients at our tertiary care center. Patients with an ileostomy who tested positive for C difficile toxins were assigned to the study group (n = 34). The control group included patients with an ileostomy who tested negative for the C difficile toxins (n = 78). Via chart review, we collected data on baseline characteristics, laboratory values, potential risk factors, and outcome measures.

RESULTS

Patients in the study and control groups were comparable in baseline and laboratory characteristics. In univariate analysis, CDE was associated with a history of smoking (hazard ratio [HR], 2.1; 95% confidence interval [CI], 1.06-4.3; P = 0.034), the presence of alcohol use (HR, 3.7; 95% CI, 1.05-12.8; P = 0.042), and older median age at the time of ileostomy (HR, 1.2; 95% CI, 1.07-1.3; P = 0.001). In multivariate analysis, no significant association between established CDI risk factors (eg, prior exposure to antibiotics and the use of proton pump inhibitors or histamine 2 receptor blockers) and the risk for the CDE was found. Only a history of alcohol intake was found to be associated with CDE (HR, 3.9; 95% CI, 1.09-14.1; P = 0.036). No significant difference in mortality was found in the study and control groups (2.9% vs 1.3%, P = 0.52), but patients with CDE were more likely to have acute kidney injury (AKI) than those without CDE (odds ratio, 4.0; 95% CI, 1.2-13.0. P = 0.023).

CONCLUSIONS

We identified a history of alcohol use a risk factor for CDE. Furthermore, CDE was found be associated with an increased risk for developing AKI.

Epidemiology, outcomes, and predictors of mortality in hospitalized adults with Clostridium difficile infection

Studies have demonstrated an increasing Clostridium difficile infection (CDI) incidence in hospitals and the community, with increasing morbidity and mortality. In this study, we analyzed data from the National Hospital Discharge Survey (NHDS) to evaluate CDI epidemiology, outcomes, and predictors of mortality in hospitalized adults. We identified cases of CDI (and associated comorbid conditions) from NHDS data from 2005 through 2009 using ICD-9 codes. Weighted univariate and multivariate analyses were performed to ascertain CDI incidence, associations between CDI and outcomes [length of stay (LOS), colectomy, all-cause in-hospital mortality, and discharge to a care facility], and predictors of all-cause in-hospital mortality. Of an estimated 162 million adult inpatients, 1.26 million (0.8 %) had CDI. The overall CDI incidence is 77.8/10,000 hospitalizations, with no statistically significant change over the study period. On multivariate analysis, after adjusting for age, gender, and comorbid conditions, CDI is an independent predictor of longer LOS (mean difference, 2.35 days), all-cause mortality [odds ratio (OR) 1.45], colectomy (OR 1.41), and discharge to a care facility (OR 2.12) (all P < 0.001). Elderly patients have a higher CDI incidence and worse outcomes than younger adults. The strongest predictors of all-cause mortality in patients with CDI include age 65 years or older, colectomy, and coagulation abnormalities. Despite stable CDI incidence and advances in management, CDI is associated with increased LOS, colectomy, all-cause in-hospital mortality, and discharge to a care facility in hospitalized, especially elderly, adults. Age older than 65 years should be added to the severity criteria for CDI.

The Elixhauser comorbidity method outperforms the Charlson index in predicting inpatient death after orthopaedic surgery

BACKGROUND

Scores derived from comorbidities can help with risk adjustment of quality and safety data. The Charlson and Elixhauser comorbidity measures are well-known risk adjustment models, yet the optimal score for orthopaedic patients remains unclear.

QUESTIONS/PURPOSES

We determined whether there was a difference in the accuracy of the Charlson and Elixhauser comorbidity-based measures in predicting (1) in-hospital mortality after major orthopaedic surgery, (2) in-hospital adverse events, and (3) nonroutine discharge.

METHODS

Among an estimated 14,007,813 patients undergoing orthopaedic surgery identified in the National Hospital Discharge Survey (1990-2007), 0.80% died in the hospital. The association of each Charlson comorbidity measure and Elixhauser comorbidity measure with mortality was assessed in bivariate analysis. Two main multivariable logistic regression models were constructed, with in-hospital mortality as the dependent variable and one of the two comorbidity-based measures (and age, sex, and year of surgery) as independent variables. A base model that included only age, sex, and year of surgery also was evaluated. The discriminative ability of the models was quantified using the area under the receiver operating characteristic curve (AUC). The AUC quantifies the ability of our models to assign a high probability of mortality to patients who die. Values range from 0.50 to 1.0, with 0.50 indicating no ability to discriminate and 1.0 indicating perfect discrimination.

RESULTS

Elixhauser comorbidity adjustment provided a better prediction of in-hospital case mortality (AUC, 0.86; 95% CI, 0.86-0.86) compared with the Charlson model (AUC, 0.83; 95% CI, 0.83-0.84) and to the base model with no comorbidities (AUC, 0.81; 95% CI, 0.81-0.81). In terms of relative improvement in predictive performance, the Elixhauser measure performed 60% better than the Charlson score in predicting mortality. The Elixhauser model discriminated inpatient morbidity better than the Charlson measure, but the discriminative ability of the model was poor and the difference in the absolute improvement in predictive power between the two models (AUC, 0.01) is of dubious clinical importance. Both comorbidity models exhibited the same degree of discrimination for estimating nonroutine discharge (AUC, 0.81; 95% CI, 0.81-0.82 for both models).

CONCLUSIONS

Provider-specific outcomes, particularly inpatient mortality, may be evaluated differently depending on the comorbidity risk adjustment model selected. Future research assessing and comparing the performance of the Charlson and Elixhauser measures in predicting long-term outcomes would be of value.

LEVEL OF EVIDENCE

Level II, prognostic study. See the Instructions for Authors for a complete description of levels of evidence.

Community-acquired Clostridium difficile infection: an increasing public health threat

There has been a startling shift in the epidemiology of Clostridium difficile infection over the last decade worldwide, and it is now increasingly recognized as a cause of diarrhea in the community. Classically considered a hospital-acquired infection, it has now emerged in populations previously considered to be low-risk and lacking the traditional risk factors for C. difficile infection, such as increased age, hospitalization, and antibiotic exposure. Recent studies have demonstrated great genetic diversity for C. difficile, pointing toward diverse sources and a fluid genome. Environmental sources like food, water, and animals may play an important role in these infections, apart from the role symptomatic patients and asymptomatic carriers play in spore dispersal. Prospective strain typing using highly discriminatory techniques is a possible way to explore the suspected diverse sources of C. difficile infection in the community. Patients with community-acquired C. difficile infection do not necessarily have a good outcome and clinicians should be aware of factors that predict worse outcomes in order to prevent them. This article summarizes the emerging epidemiology, risk factors, and outcomes for community-acquired C. difficile infection.

Clostridium difficile infection: management strategies for a difficult disease

Clostridium difficile was first described as a cause of diarrhea in 1978 and in the last three decades has reached an epidemic state with increasing incidence and severity in both healthcare and community settings. There also has been a rise in severe outcomes from C. difficile infection (CDI). There have been tremendous advancements in the field of CDI with the identification of newer risk factors, recognition of CDI in populations previously thought not at risk and development of better diagnostic modalities. Several treatment options are available for CDI apart from metronidazole and vancomycin, and include new drugs such as fidaxomicin and other options such as fecal microbiota transplantation. This review discusses the epidemiology, risk factors and outcomes from CDI, and focuses primarily on existing and evolving treatment modalities.

Clostridium difficile infection: a worldwide disease

Clostridium difficile, an anaerobic toxigenic bacterium, causes a severe infectious colitis that leads to significant morbidity and mortality worldwide. Both enhanced bacterial toxins and diminished host immune response contribute to symptomatic disease. C. difficile has been a well-established pathogen in North America and Europe for decades, but is just emerging in Asia. This article reviews the epidemiology, microbiology, pathophysiology, and clinical management of C. difficile. Prompt recognition of C. difficile is necessary to implement appropriate infection control practices.