How Is Pneumonia Diagnosed in Clinical Stroke Research?

Should preventive antibiotics be used in patients with acute stroke? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Infection is a common complication in acute stroke. Whether or not preventive antibiotics reduce the risk of infection or even lead to a favorable outcome and reduction of mortality after a stroke still remains equivocal. This review was performed to update the current knowledge on the effect and possible benefits of prophylactic antibiotic therapy in patients with stroke.

METHODS

A systematic review and meta-analysis of preventive antibiotics`effect on the incidence of infection, favorable outcome (mRS≤2) and mortality in patients with acute stroke is performed with relevant randomized controlled trials.

RESULTS

Six studies were identified, involving 4125 participants. Compared with the control group, the treated groups were significantly less prone to suffer from early overall infections [RR = 0.52, 95%CI (0.39, 0.70), p<0.0001], early pneumonia [RR = 0.64, 95%CI (0.42, 0.96), p = 0.03] and early urinary tract infections [RR = 0.35, 95%CI (0.25, 0.48), p<0.00001]. However, there was no significant difference in overall mortality [RR = 1.07, 95%CI (0.90, 1.27), p = 0.44], early mortality [RR = 0.99, 95%CI (0.78, 1.26), p = 0.92], late mortality [RR = 1.12, 95%CI (0.94, 1.35), p = 0.21] or favorable outcome [RR = 1.00, 95%CI (0.92, 1.08), p = 0.98].

CONCLUSION

Although preventive antibiotic treatment did reduce the occurrence of early overall infections, early pneumonia and early urinary tract infection in patients with acute stroke, this advantage was not eventually translated to a favorable outcome and reduction in mortality. Future studies are warranted to identify any subgroup of stroke patients who might benefit from preventive antibiotic treatment.

Significance of admission hypoalbuminemia in acute intracerebral hemorrhage

Low levels of serum albumin may increase the risk of infections and mortality in critically ill patients. We tested the hypothesis that admission hypoalbuminemia predicted infectious complications and poor outcome in subjects with acute intracerebral hemorrhage (ICH). We analyzed a single center cohort of ICH patients collected between 1994 and 2015. Pneumonia, urinary tract infection and sepsis were retrospectively identified, according to validated criteria. Serum albumin was measured on admission and hypoalbuminemia was defined as total albumin ≤3.5 g/dL. The association between albumin levels, infections, and mortality at 90 days was tested with multivariable logistic regression analyses. A total of 2010 patients were included (median age 74 years, 54.5% males) of whom 444 (22.1%) had hypoalbuminemia on admission and 763 (38%) died within 90 days. The frequency of pneumonia, urinary tract infection, and sepsis was 19.9, 15.1, and 2.7%, respectively. Hypoalbuminemic patients had lower admission Glasgow coma scale, higher frequency of intraventricular hemorrhage and were more likely to have a history of chronic kidney or liver disease. After adjustment for potential confounders, hypoalbuminemia was an independent predictor of pneumonia [odds ratio (OR) 1.76, 95% confidence interval (CI) 1.34-2.33, p < 0.001] and sepsis (OR 2.29, 95% CI 1.22-4.30, p = 0.010). Low levels of albumin were also independently associated with higher mortality at 90 days (OR 1.78, 95% CI 1.30-2.44, p < 0.001). In conclusion, early hypoalbuminemia is common and predicts poor outcome in ICH patients. Increased susceptibility to pneumonia and sepsis may be the pathophysiological mechanism underlying this association.

The Randomized Controlled STRAWINSKI Trial: Procalcitonin-Guided Antibiotic Therapy after Stroke

Background

Pneumonia is among the most common acute complications after stroke and is associated with poor long-term outcome. Biomarkers may help identifying stroke patients at high risk for developing stroke-associated pneumonia (SAP) and to guide early treatment.

Aims

This trial investigated whether procalcitonin (PCT) ultrasensitive (PCTus)-guided antibiotic treatment of SAP can improve functional outcome after stroke.

Methods

In this international, multicenter, randomized, controlled clinical trial with blinded assessment of outcomes, patients with severe ischemic stroke in the middle cerebral artery territory were randomly assigned within 40 h after symptom onset to PCTus-based antibiotic therapy guidance in addition to stroke unit care or standard stroke unit care alone. The primary endpoint was functional outcome at 3 months, defined according to the modified Rankin Scale (mRS) and dichotomized as acceptable (≤4) or unacceptable (≥5). Secondary endpoints included usage of antibiotics, infection rates, days of fever, and mortality. The trial was registered with http://ClinicalTrials.gov (Identifier NCT01264549).

Results

In the intention-to-treat-analysis based on 227 patients (112 in PCT and 115 in control group), 197 patients completed the 3-month follow-up. Adherence to PCT guidance was 65%. PCT-guided therapy did not improve functional outcome as measured by mRS (odds ratio 0.79; 95% confidence interval 0.45–1.35, p = 0.47). Pneumonia rate and mortality were similar in both groups. Days with fever tended to be lower (p = 0.055), whereas total number of days treated with antibiotics were higher (p = 0.004) in PCT compared to control group. A post hoc analysis including all PCT values in the intention-to-treat population demonstrated a significant increase on the first day of infection in patients with pneumonia and sepsis compared to patients with urinary tract infections or without infections (p < 0.0001).

Conclusion

PCTus-guided antibiotic therapy did not improve functional outcome at 3 months after severe ischemic stroke. PCT is a promising biomarker for early detection of pneumonia and sepsis in acute stroke patients.

Ten-Year Temporal Trends in Medical Complications After Acute Intracerebral Hemorrhage in the United States

Background and Purpose—

Data on medical complications after intracerebral hemorrhage (ICH) are sparse. We assessed trends in the prevalence of urinary tract infection, pneumonia, sepsis, deep venous thrombosis (DVT), pulmonary embolism, acute renal failure (ARF), and acute myocardial infarction after ICH in the United States.

Methods—

A total of 575 211 adult ICH cases were identified from the 2004 to 2013 Nationwide Inpatient Sample. Weighted complication risks were computed by sex and mechanical ventilation status. Multivariate models were used to evaluate trends in complications and assess their association with in-hospital mortality, cost, and length of stay.

Results—

Overall risks of urinary tract infection, pneumonia, sepsis, DVT, pulmonary embolism, ARF, and acute myocardial infarction after ICH were 14.8%, 7.8%, 4.1%, 2.7%, 0.7%, 8.2%, and 2.0%, respectively, but risk differed by sex and mechanical ventilation status. From 2004 to 2013, odds of DVT and ARF increased, whereas odds of pneumonia, sepsis, and mortality declined over time. All complications were associated with >2.5-day increase in length of stay and >$8000 increase in cost. ARF and acute myocardial infarction were associated with increased mortality in all patients; sepsis and pneumonia were associated with increased mortality only in nonmechanical ventilation patients, whereas urinary tract infection and DVT were associated with reduced mortality in all patients.

Conclusions—

Despite significant mortality reduction, ARF and DVT risk after ICH have increased, whereas odds of sepsis and pneumonia have declined over the last decade. All complications were associated with increased cost and length of stay, but their associations with mortality were variable, likely due in part to survival bias. Innovative strategies are needed to prevent ICH-associated medical complications.

External Validation of the Prestroke Independence, Sex, Age, National Institutes of Health Stroke Scale Score for Predicting Pneumonia After Stroke Using Data From the China National Stroke Registry

BACKGROUND AND PURPOSE

Pneumonia is an important risk factor for mortality and morbidity after stroke. The Prestroke Independence, Sex, Age, National Institutes of Health Stroke Scale (ISAN) score was shown to be a useful tool for predicting stroke-associated pneumonia based on UK multicenter cohort study. We aimed to externally validate the score using data from the China National Stroke Registry (CNSR).

METHODS

Eligible patients with acute ischemic stroke (AIS) and intracerebral hemorrhage (ICH) in the CNSR from 2007 to 2008 were included. The area under the receiver operating characteristic (AUC) curve was used to evaluate discrimination. The Hosmer-Lemeshow goodness of fit test and Pearson correlation coefficient were performed to assess calibration of the model.

RESULTS

A total of 19,333 patients (AIS = 14400; ICH = 4933) were included and the overall pneumonia rate was 12.7%. The AUC was .76 (95% confidence interval [CI]: .75-.78) for the subgroup of AIS and .70 (95% CI: .68-.72) for the subgroup of ICH. The Hosmer-Lemeshow test showed the ISAN score with the good calibration for AIS and ICH (P = .177 and .405, respectively). The plot of observed versus predicted pneumonia rates suggested higher correlation for patients with AIS than with ICH (Pearson correlation coefficient = .99 and .83, respectively).

CONCLUSIONS

The ISAN score was a useful tool for predicting in-hospital pneumonia after acute stroke, especially for patients with AIS. Further validations need to be done in different populations.

Hypoxia after stroke: a review of experimental and clinical evidence

Background

Hypoxia is a common occurrence following stroke and associated with poor clinical and functional outcomes. Normal oxygen physiology is a finely controlled mechanism from the oxygenation of haemoglobin in the pulmonary capillaries to its dissociation and delivery in the tissues. In no organ is this process more important than the brain, which has a number of vascular adaptions to be able to cope with a certain threshold of hypoxia, beyond which further disruption of oxygen delivery potentially leads to devastating consequences. Hypoxia following stroke is common and is often attributed to pneumonia, aspiration and respiratory muscle dysfunction, with sleep apnoea syndromes, pulmonary embolism and cardiac failure being less common but important treatable causes. As well as treating the underlying cause, oxygen therapy is a vital element to correcting hypoxia, but excessive use can itself cause molecular and clinical harm. As cerebral vascular occlusion completely obliterates oxygen delivery to its target tissue, the use of supplemental oxygen, even when not hypoxic, would seem a reasonable solution to try and correct this deficit, but to date randomised clinical trials have not shown benefit.

Conclusion

Whilst evidence for the use of supplemental oxygen therapy is currently lacking, it is vital to rapidly identify and treat all causes of hypoxia in the acute stroke patient, as a failure to will lead to poorer clinical outcomes. The full results of a large randomised trial looking at the use of supplemental oxygen therapy are currently pending.

Comparison of the diagnostic utility of physician-diagnosed with algorithm-defined stroke-associated pneumonia

OBJECTIVE

Diagnosing stroke-associated pneumonia (SAP) is challenging and may result in inappropriate antibiotic use or confound research outcomes. This study evaluates the diagnostic accuracy of algorithm-defined versus physician-diagnosed SAP in 1088 patients who had dysphagic acute stroke from 37 UK stroke units between 21 April 2008 and 17 May 2014.

METHODS

SAP in the first 14 days was diagnosed by a criteria-based algorithm applied to blinded patient data and independently by treating physicians. Patients in whom diagnoses differed were reassigned following blinded adjudication of individual patient records. The sensitivity, specificity, positive predictive value (PPV) and diagnostic OR of algorithmic and physician diagnosis of SAP were assessed using adjudicated SAP as the reference standard. Agreement was assessed using the κ statistic.

RESULTS

Physicians diagnosed SAP in 176/1088 (16%) and the algorithm in 123/1088 (11.3%) patients. Diagnosis agreed in 885/1088 (81.3%) patients (κ 0.22 (95% CI 0.14 to 0.29)). On a blinded review, 129/1088 (11.8%) patients were adjudicated as patients with SAP. The algorithm and the physicians had high specificity (97% (95% CI 96% to 98%) and 90% (95% CI 88% to 92%), respectively) but only moderate sensitivity (72% (95% CI 64% to 80%) and 65% (95% CI 56% to 73%), respectively) in diagnosing SAP. The algorithm showed better PPV (76% (95% CI 67% to 83%) vs 48% (95% CI 40% to 55%)), diagnostic OR (80 (95% CI 42 to 136) vs 18 (95% CI 12 to 27)) and agreement (κ 0.70 (95% CI 0.63 to 0.78) vs 0.48 (95% CI 0.41 to 0.54)) than physician diagnosis with adjudicated SAP.

CONCLUSIONS

Algorithm-based approaches can standardise SAP diagnosis for clinical practice and research.

TRIAL REGISTRATION NUMBER

ISRCTN37118456; Post-results.

Comparison of Characteristics of Stroke-Associated Pneumonia in Stroke Care Units in Indonesia and Japan

BACKGROUND

Pneumonia is one of the most common medical complications after stroke. Incidence and risk factor analyses of stroke-associated pneumonia (SAP) in stroke care units (SCUs) are limited. SAP incidence comparisons across countries can identify the most effective treatment to reduce this incidence.

METHODS

This was a retrospective study including consecutive patients with acute stroke in SCUs in 2 hospitals: 105 patients (mean age 78.2 ± 5.8) from the National Cerebral and Cardiovascular Center (NCVC) in Osaka, Japan (from July to August 2015), and 105 patients (mean age 60 ± 5.8) from the National Brain Centre (NBC) Hospital in Jakarta, Indonesia (from May to September 2015). We used descriptive statistics and a logistic regression model for statistical analysis.

RESULTS

The incidence of SAP in the SCU NBC Hospital was higher than that in the SCU NCVC (22.9% versus 12.4%, P = .0466). In the SCU NBC Hospital, dysphagia (odds ratio [OR] 15.20, 95% confidence interval [CI] 1.77-130.73) and severe neurological deficits on admission (OR 5.31, 95% CI 1.60-17.60) were significantly associated with SAP, whereas in the SCU NCVC, dysphagia (OR 14.42, 95% CI 2.34-88.98) and diabetes mellitus (OR 7.16, 95% CI 1.27-40.18) were the risk factors. When the patients of both hospitals were analyzed together, severe neurological deficits on admission (OR 3.36, 95% CI 1.31-8.64) and dysphagia (OR 12.62, 95% CI 3.75-42.45) were significant determinants for developing SAP.

CONCLUSIONS

The incidence of SAP was higher in the Indonesian hospital than in the Japanese one. Our findings support other epidemiological data of a high incidence of SAP with severe neurological deficits on admission and dysphagia in an SCU setting.

Prophylactic Antibiotic Therapy for Preventing Poststroke Infection

Infections, in particular pneumonia, are common complications in patients with acute stroke and are associated with a less favorable neurologic and functional outcome. Patients with severe stroke and dysphagia are at highest risk of infection. Experimental and clinical data suggest stroke-induced immunodeficiency as a major factor contributing to the high incidence of infection after stroke. Preclinical studies support the potential benefit of preventive antibiotic therapy in acute stroke for lowering the incidence of infection and improving clinical outcome. Several smaller clinical trials on preventive antibiotic therapy in patients with stroke conducted during the last 10 years yielded inconclusive results. Recently, 2 large, open-label, controlled trials failed to demonstrate an improved clinical outcome after preventive antibiotic therapy in patients with acute stroke treated in specialized stroke units. In the "Preventive Antibiotics in Stroke Study", antibiotic therapy lowered the rate of infection but did not influence outcome. In the STROKE-INF study, performed in patients with dysphagia after stroke, antibiotic therapy did not lower the incidence of pneumonia and had no prognostic significance. At present, preventive antibiotic therapy cannot be recommended as a therapeutic option for acute stroke.

Association between nasogastric tubes, pneumonia, and clinical outcomes in acute stroke patients

OBJECTIVE

To investigate whether nasogastric tubes (NGTs) increase poststroke pneumonia (PSP), mortality, or poor outcomes in nil-by-mouth acute stroke patients.

METHODS

This study analyzed prespecified outcomes of PSP at 14 days and mortality and function measured by the modified Rankin Scale at 90 days in 1,217 nil-by-mouth stroke patients at ≤48 hours of symptom onset in a multicenter randomized controlled trial of preventive antibiotics between April 21, 2008, and May 17, 2014. Generalized mixed models adjusted for age, comorbidities, stroke type and severity, and quality of care were used. No patients were lost to follow-up at 14 days, and 36 (3%) were lost at 90 days.

RESULTS

Patients with NGT (298 of 1,217 [24.4%]) had more severe strokes (median NIH Stroke Scale score 17 vs 14, p = 0.0001) and impaired consciousness (39% vs 28%, p = 0.001). NGT did not increase PSP (43 of 298 [14.4%] vs 80 of 790 [10.1%], adjusted odds ratio [OR] 1.26 [95% confidence interval (CI) 0.78-2.03], p = 0.35) or 14- and 90-day mortality (33 of 298 [11.1%] vs 78 of 790 [9.9%], adjusted OR 1.10 [95% CI 0.67-1.78], p = 0.71; and 79 of 298 [26.5%] vs 152 of 790 [19.2%], adjusted OR 0.95 [95% CI 0.67-1.33], p = 0.75, respectively). Ninety-day modified Rankin Scale score distribution was comparable between groups (adjusted OR 1.14 [95% CI 0.87-1.56], p = 0.08). PSP independently increased 90-day mortality (40 of 123 [32.5%] vs 191 of 965 [19.8%], adjusted OR 1.71 [95% CI 1.11-2.65], p = 0.015) and was not prevented by antibiotics in patients with NGT (adjusted OR 1.1 [95% CI 0.89-1.54], p = 0.16).

CONCLUSIONS

Early NGT does not increase PSP incidence, mortality, or poor functional outcomes and can be used safely in acute stroke patients.

Statin Medication Use and Nosocomial Infection Risk in the Acute Phase of Stroke

GOAL

Statins have immunomodulatory and peripheral anti-inflammatory properties that are independent of their lipid-lowering action. Whether these properties reduce the risk for developing poststroke infection is debated in clinical literature. We estimated the risk for developing nosocomial poststroke infection based on statin exposure in patients aged 18 or older hospitalized for ischemic stroke.

MATERIALS AND METHODS

A consecutive sample of acute care hospital electronic medical records was retrospectively analyzed. Patients were assigned to the exposed cohort either when statin use preceded infection or statin medication was used, but no infection developed. The unexposed cohort included patients not on statins or initiating statins after infection developed. The association of statin exposure with infection was examined with conditional logistic regression adjusted for poststroke infection risk factors. Cochran-Mantel-Haenszel analyses examined the association of statin exposure and infection status within strata of binary predictor variables that increased infection risk.

FINDINGS

Up to 1612 records were analyzed: 1151 in the exposed cohort and 461 in the unexposed cohort. Infection developed in 20% of the statin-exposed patients and in 41% of the statin-unexposed patients (P < .001). Exposure to statins reduced odds for developing nosocomial infection by 58% over no exposure (adjusted odds ratio = .418, P < .001). Statins lowered the infection risk for both sexes, patients with a nasogastric tube, and patients with dysphagia (P < .05). Statins did not change infection risk for patients with endotracheal intubation.

CONCLUSIONS

In patients with ischemic stroke and without endotracheal intubation, statin medications were associated with reduced risk of nosocomial infections.

Clinical risk scores for predicting stroke-associated pneumonia: A systematic review

Purpose

Several risk stratification scores for predicting stroke-associated pneumonia have been derived. We aimed to evaluate the performance and clinical usefulness of such scores for predicting stroke-associated pneumonia.

Method

A systematic literature review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, with application of the Quality Assessment of Diagnostic Accuracy-2 tool. Published studies of hospitalised adults with ischaemic stroke, intracerebral haemorrhage, or both, which derived and validated an integer-based clinical risk score, or externally validated an existing score to predict occurrence of stroke-associated pneumonia, were considered and independently screened for inclusion by two reviewers.

Findings

We identified nine scores, from eight derivation cohorts. Age was a component of all scores, and the NIHSS score in all except one. Six scores were internally validated and five scores were externally validated. The A2DS2 score (Age, Atrial fibrillation, Dysphagia, Severity [NIHSS], Sex) was the most externally validated in 8 independent cohorts. Performance measures were reported for eight scores. Discrimination tended to be more variable in the external validation cohorts (C statistic 0.67-0.83) than the derivation cohorts (C statistic 0.74-0.85).

Discussion

Overall, discrimination and calibration were similar between the different scores. No study evaluated influence on clinical decision making or prognosis.

Conclusion

The clinical prediction scores varied in their simplicity of use and were comparable in performance. Utility of such scores for preventive intervention trials and in clinical practice remains uncertain and requires further study.

Development and feasibility testing of an oral hygiene intervention for stroke unit care

OBJECTIVE

To develop an oral hygiene complex intervention and evaluate its feasibility in a single UK stroke centre.

BACKGROUND

Oral hygiene interventions might improve clinical outcomes after stroke but evidence-based practice is lacking.

MATERIALS AND METHODS

We used a sequential mixed methods approach and developed an oral hygiene complex intervention comprising: (i) web-based education and 'hands-on' practical training for stroke unit nursing staff, (ii) a pragmatic oral hygiene protocol consisting of twice-daily powered (or manual if preferred) brushing with chlorhexidine gel (or non-foaming toothpaste) ± denture care. We evaluated feasibility of (i) the staff education and training and (ii) the oral hygiene protocol in consenting inpatients with confirmed stroke, requiring assistance with at least one aspect of personal care.

RESULTS

The staff education and training were feasible, acceptable and raised knowledge and awareness. Several barriers to completing the education and training were identified. The oral hygiene protocol was feasible and well-tolerated. 22% of eligible patients screened declined participation in the study. Twenty-nine patients (median age = 78 year; National Institutes of Health Stroke Scale score = 8.5; 73% dentate) were recruited at a median of 7 days from stroke onset. 97% of participants chose the default chlorhexidine-based protocol; the remainder chose the non-foaming toothpaste-based protocol. The mouth hygiene protocol was administered as prescribed on 95% of occasions, over a median duration of 28 days. There were no adverse events attributed to the oral hygiene protocol.

CONCLUSION

Our oral hygiene complex intervention was feasible in a single UK stroke centre. Further studies to optimise patient selection, model health economics and explore efficacy are now required.

Pharyngeal Electrical Stimulation for Treatment of Dysphagia in Subacute Stroke: A Randomized Controlled Trial

Supplemental Digital Content is available in the text.

Background and Purpose—

Dysphagia is common after stroke, associated with increased death and dependency, and treatment options are limited. Pharyngeal electric stimulation (PES) is a novel treatment for poststroke dysphagia that has shown promise in 3 pilot randomized controlled trials.

Methods—

We randomly assigned 162 patients with a recent ischemic or hemorrhagic stroke and dysphagia, defined as a penetration aspiration score (PAS) of ≥3 on video fluoroscopy, to PES or sham treatment given on 3 consecutive days. The primary outcome was swallowing safety, assessed using the PAS, at 2 weeks. Secondary outcomes included dysphagia severity, function, quality of life, and serious adverse events at 6 and 12 weeks.

Results—

In randomized patients, the mean age was 74 years, male 58%, ischemic stroke 89%, and PAS 4.8. The mean treatment current was 14.8 (7.9) mA and duration 9.9 (1.2) minutes per session. On the basis of previous data, 45 patients (58.4%) randomized to PES seemed to receive suboptimal stimulation. The PAS at 2 weeks, adjusted for baseline, did not differ between the randomized groups: PES 3.7 (2.0) versus sham 3.6 (1.9), P=0.60. Similarly, the secondary outcomes did not differ, including clinical swallowing and functional outcome. No serious adverse device-related events occurred.

Conclusions—

In patients with subacute stroke and dysphagia, PES was safe but did not improve dysphagia. Undertreatment of patients receiving PES may have contributed to the neutral result.

Clinical Trial Registration—

URL: http://www.controlled-trials.com. Unique identifier: ISRCTN25681641.

Post-stroke dysphagia: A review and design considerations for future trials

Post-stroke dysphagia (a difficulty in swallowing after a stroke) is a common and expensive complication of acute stroke and is associated with increased mortality, morbidity, and institutionalization due in part to aspiration, pneumonia, and malnutrition. Although most patients recover swallowing spontaneously, a significant minority still have dysphagia at six months. Although multiple advances have been made in the hyperacute treatment of stroke and secondary prevention, the management of dysphagia post-stroke remains a neglected area of research, and its optimal management, including diagnosis, investigation and treatment, have still to be defined.

Early Diagnosis of Pneumonia in Severe Stroke: Clinical Features and the Diagnostic Role of C-Reactive Protein

Background

Accurate diagnosis of pneumonia complicating severe stroke is challenging due to difficulties in physical examination, altered immune responses and delayed manifestations of radiological changes. The aims of this study were to describe early clinical features and to examine C-reactive protein (CRP) as a diagnostic marker of post-stroke pneumonia.

Methods

Patients who required nasogastric feeding and had no evidence of pneumonia within 7 days of stroke onset were included in the study and followed-up for 21 days with a daily clinical examination. Pneumonia was diagnosed using modified British Thoracic Society criteria.

Results

60 patients were recruited (mean age 77 years, mean National Institutes of Health Stroke Scale Score 19.47). Forty-four episodes of pneumonia were identified. Common manifestations on the day of the diagnosis were new onset crackles (43/44, 98%), tachypnoea>25/min (42/44, 95%), and oxygen saturation <90% (41/44, 93%). Cough, purulent sputum, and pyrexia >38°C were observed in 27 (61%), 25 (57%) and 15 (34%) episodes respectively. Leucocytosis (WBC>11,000/ml) and raised CRP (>10 mg/l) were observed in 38 (86%) and 43 (97%) cases of pneumonia respectively. The area under the ROC curve for CRP was 0.827 (95% CI 0.720, 0.933). The diagnostic cut-off for CRP with an acceptable sensitivity (>0.8) was 25.60 mg/L (Youden index (J) 0.515; sensitivity 0.848; specificity 0.667). A cut-off of 64.65 mg/L had the highest diagnostic accuracy (J 0.562; sensitivity 0.636; specificity 0.926).

Conclusion

Patients with severe stroke frequently do not manifest key diagnostic features of pneumonia such as pyrexia, cough and purulent sputum early in their illness. The most common signs in this group are new-onset crackles, tachypnoea and hypoxia. Our results suggest that a CRP >25 mg/L should prompt investigations for pneumonia while values >65 mg/L have the highest diagnostic accuracy to justify consideration of this threshold as a diagnostic marker of post-stroke pneumonia.

Prophylactic antibiotics after acute stroke for reducing pneumonia in patients with dysphagia (STROKE-INF): a prospective, cluster-randomised, open-label, masked endpoint, controlled clinical trial

BACKGROUND

Post-stroke pneumonia is associated with increased mortality and poor functional outcomes. This study assessed the effectiveness of antibiotic prophylaxis for reducing pneumonia in patients with dysphagia after acute stroke.

METHODS

We did a prospective, multicentre, cluster-randomised, open-label controlled trial with masked endpoint assessment of patients older than 18 years with dysphagia after new stroke recruited from 48 stroke units in the UK, accredited and included in the UK National Stroke Audit. We excluded patients with contraindications to antibiotics, pre-existing dysphagia, or known infections, or who were not expected to survive beyond 14 days. We randomly assigned the units (1:1) by computer to give either prophylactic antibiotics for 7 days plus standard stroke unit care or standard stroke unit care only to patients clustered in the units within 48 h of stroke onset. We did the randomisation with minimisation to stratify for number of admissions and access to specialist care. Patient and staff who did the assessments and analyses were masked to stroke unit allocation. The primary outcome was post-stroke pneumonia in the first 14 days, assessed with both a criteria-based, hierarchical algorithm and by physician diagnosis in the intention-to-treat population. Safety was also analysed by intention to treat. This trial is closed to new participants and is registered with isrctn.com, number ISRCTN37118456.

FINDINGS

Between April 21, 2008, and May 17, 2014, we randomly assigned 48 stroke units (and 1224 patients clustered within the units) to the two treatment groups: 24 to antibiotics and 24 to standard care alone (control). 11 units and seven patients withdrew after randomisation before 14 days, leaving 1217 patients in 37 units for the intention-to-treat analysis (615 patients in the antibiotics group, 602 in control). Prophylactic antibiotics did not affect the incidence of algorithm-defined post-stroke pneumonia (71 [13%] of 564 patients in antibiotics group vs 52 [10%] of 524 in control group; marginal adjusted odds ratio [OR] 1·21 [95% CI 0·71-2·08], p=0·489, intraclass correlation coefficient [ICC] 0·06 [95% CI 0·02-0·17]. Algorithm-defined post-stroke pneumonia could not be established in 129 (10%) patients because of missing data. Additionally, we noted no differences in physician-diagnosed post-stroke pneumonia between groups (101 [16%] of 615 patients vs 91 [15%] of 602, adjusted OR 1·01 [95% CI 0·61-1·68], p=0·957, ICC 0·08 [95% CI 0·03-0·21]). The most common adverse events were infections unrelated to post-stroke pneumonia (mainly urinary tract infections), which were less frequent in the antibiotics group (22 [4%] of 615 vs 45 [7%] of 602; OR 0·55 [0·32-0·92], p=0·02). Diarrhoea positive for Clostridium difficile occurred in two patients (<1%) in the antibiotics group and four (<1%) in the control group, and meticillin-resistant Staphylococcus aureus colonisation occurred in 11 patients (2%) in the antibiotics group and 14 (2%) in the control group.

INTERPRETATION

Antibiotic prophylaxis cannot be recommended for prevention of post-stroke pneumonia in patients with dysphagia after stroke managed in stroke units.

FUNDING

UK National Institute for Health Research.

Diagnosis of Stroke-Associated Pneumonia

Background and Purpose—

Lower respiratory tract infections frequently complicate stroke and adversely affect outcome. There is currently no agreed terminology or gold-standard diagnostic criteria for the spectrum of lower respiratory tract infections complicating stroke, which has implications for clinical practice and research. The aim of this consensus was to propose standardized terminology and operational diagnostic criteria for lower respiratory tract infections complicating acute stroke.

Methods—

Systematic literature searches of multiple electronic databases were undertaken. An evidence review and 2 rounds of consensus consultation were completed before a final consensus meeting in September 2014, held in Manchester, United Kingdom. Consensus was defined a priori as ≥75% agreement between the consensus group members.

Results—

Consensus was reached for the following: (1) stroke-associated pneumonia (SAP) is the recommended terminology for the spectrum of lower respiratory tract infections within the first 7 days after stroke onset; (2) modified Centers for Disease Control and Prevention (CDC) criteria are proposed for SAP as follows—probable SAP: CDC criteria met, but typical chest x-ray changes absent even after repeat or serial chest x-ray; definite SAP: CDC criteria met, including typical chest x-ray changes; (3) there is limited evidence for a diagnostic role of white blood cell count or C-reactive protein in SAP; and (4) there is insufficient evidence for the use of other biomarkers (eg, procalcitonin).

Conclusions—

Consensus operational criteria for the terminology and diagnosis of SAP are proposed based on the CDC criteria. These require prospective evaluation in patients with stroke to determine their reliability, validity, impact on clinician behaviors (including antibiotic prescribing), and clinical outcomes.