Statistics and death from meningococcal disease in children

Challenging management dogma where evidence is non-existent, weak or outdated

Medical practice is dogged by dogma. A conclusive evidence base is lacking for many aspects of patient management. Clinicians, therefore, rely upon engrained treatment strategies as the dogma seems to work, or at least is assumed to do so. Evidence is often distorted, overlooked or misapplied in the re-telling. However, it is incorporated as fact in textbooks, policies, guidelines and protocols with resource and medicolegal implications. We provide here four examples of medical dogma that underline the above points: loop diuretic treatment for acute heart failure; the effectiveness of heparin thromboprophylaxis; the rate of sodium correction for hyponatraemia; and the mantra of "each hour counts" for treating meningitis. It is notable that the underpinning evidence is largely unsupportive of these doctrines. We do not necessarily advocate change, but rather encourage critical reflection on current practices and the need for prospective studies.

Pre-admission antibiotics for suspected cases of meningococcal disease

BACKGROUND

Meningococcal disease can lead to death or disability within hours after onset. Pre-admission antibiotics aim to reduce the risk of serious disease and death by preventing delays in starting therapy before confirmation of the diagnosis.

OBJECTIVES

To study the effectiveness and safety of pre-admission antibiotics versus no pre-admission antibiotics or placebo, and different pre-admission antibiotic regimens in decreasing mortality, clinical failure, and morbidity in people suspected of meningococcal disease.

SEARCH METHODS

We searched CENTRAL (6 January 2017), MEDLINE (1966 to 6 January 2017), Embase (1980 to 6 January 2017), Web of Science (1985 to 6 January 2017), LILACS (1982 to 6 January 2017), and prospective trial registries to January 2017. We previously searched CAB Abstracts from 1985 to June 2015, but did not update this search in January 2017.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing antibiotics versus placebo or no intervention, in people with suspected meningococcal infection, or different antibiotics administered before admission to hospital or confirmation of the diagnosis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data from the search results. We calculated the risk ratio (RR) and 95% confidence interval (CI) for dichotomous data. We included only one trial and so did not perform data synthesis. We assessed the overall quality of the evidence using the GRADE approach.

MAIN RESULTS

We found no RCTs comparing pre-admission antibiotics versus no pre-admission antibiotics or placebo. We included one open-label, non-inferiority RCT with 510 participants, conducted during an epidemic in Niger, evaluating a single dose of intramuscular ceftriaxone versus a single dose of intramuscular long-acting (oily) chloramphenicol. Ceftriaxone was not inferior to chloramphenicol in reducing mortality (RR 1.21, 95% CI 0.57 to 2.56; N = 503; 308 confirmed meningococcal meningitis; 26 deaths; moderate-quality evidence), clinical failures (RR 0.83, 95% CI 0.32 to 2.15; N = 477; 18 clinical failures; moderate-quality evidence), or neurological sequelae (RR 1.29, 95% CI 0.63 to 2.62; N = 477; 29 with sequelae; low-quality evidence). No adverse effects of treatment were reported. Estimated treatment costs were similar. No data were available on disease burden due to sequelae.

AUTHORS' CONCLUSIONS

We found no reliable evidence to support the use pre-admission antibiotics for suspected cases of non-severe meningococcal disease. Moderate-quality evidence from one RCT indicated that single intramuscular injections of ceftriaxone and long-acting chloramphenicol were equally effective, safe, and economical in reducing serious outcomes. The choice between these antibiotics should be based on affordability, availability, and patterns of antibiotic resistance.Further RCTs comparing different pre-admission antibiotics, accompanied by intensive supportive measures, are ethically justified in people with less severe illness, and are needed to provide reliable evidence in different clinical settings.

Pre-admission antibiotics for suspected cases of meningococcal disease

BACKGROUND

Meningococcal disease can lead to death or disability within hours after onset. Pre-admission antibiotics aim to reduce the risk of serious disease and death by preventing delays in starting therapy before confirmation of the diagnosis.

OBJECTIVES

To study the effectiveness and safety of pre-admission antibiotics versus no pre-admission antibiotics or placebo, and different pre-admission antibiotic regimens in decreasing mortality, clinical failure and morbidity in people suspected of meningococcal disease.

SEARCH METHODS

We updated searches of CENTRAL (2013, Issue 4), MEDLINE (1966 to April week 4, 2013), EMBASE (1980 to May 2013), Web of Science (1985 to May 2013), CAB Abstracts (1985 to May 2013), LILACS (1982 to May 2013) and prospective trials registries to May 2013.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing antibiotics versus placebo or no intervention, in people with suspected meningococcal infection, or different antibiotics administered before admission to hospital or confirmation of the diagnosis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data from the search results. We calculated the risk ratio (RR) and 95% confidence interval (CI) for dichotomous data. We included only one trial so data synthesis was not performed. We assessed the overall quality of the evidence using the GRADE approach.

MAIN RESULTS

We found no RCTs that compared pre-admission antibiotics versus no pre-admission antibiotics or placebo. One open-label, non-inferiority RCT, conducted during an epidemic in Niger, evaluated a single dose of intramuscular ceftriaxone versus a single dose of intramuscular long-acting (oily) chloramphenicol. Ceftriaxone was not inferior to chloramphenicol in reducing mortality (RR 1.2, 95% CI 0.6 to 2.6; N = 503; 308 confirmed meningococcal meningitis; 26 deaths; moderate-quality evidence), clinical failures (RR 0.8, 95% CI 0.3 to 2.2; N = 477, 18 clinical failures; moderate-quality evidence) or neurological sequelae (RR 1.3, 95% CI 0.6 to 2.6; N = 477; 29 with sequelae; low-quality evidence). No adverse effects of treatment were reported. Estimated treatment costs were similar. No data were available on disease burden due to sequelae.

AUTHORS' CONCLUSIONS

We found no reliable evidence to support or refute the use of pre-admission antibiotics for suspected cases of non-severe meningococcal disease. Evidence of moderate quality from one RCT indicated that single intramuscular injections of ceftriaxone and long-acting chloramphenicol were equally effective, safe and economical in reducing serious outcomes. The choice between these antibiotics would be based on affordability, availability and patterns of antibiotic resistance.Further RCTs comparing different pre-admission antibiotics, accompanied by intensive supportive measures, are ethically justifiable in participants with severe illness, and are needed to provide reliable evidence in different clinical settings.

Simpson's paradox and experimental research

BACKGROUND

Experimental research in nursing has increased considerably in recent years. To improve the quality of such research, it is critical to reduce threats to internal validity. One threat that has received inadequate attention in the nursing literature is Simpson's paradox--a case of extreme confounding that can lead to erroneous conclusions about the effects of an experimental intervention. In fact, it can lead to a conclusion about an intervention effect that is the opposite of the correct inference.

APPROACH

The aims of this study were to describe Simpson's paradox, provide a hypothetical example, and discuss approaches to avoiding the paradox.

RESULTS

The paradox is due to the combination of an overlooked confounding variable and a disproportionate allocation of that variable among experimental groups. Different designs and analysis approaches that can be used to avoid the paradox are presented.

DISCUSSION

Simpson's paradox can be avoided by selecting an appropriate experimental design and analysis that incorporates the confounding variable in such a way as to obtain unconfounded estimates of treatment effects, thus more accurately answering the research question.

Antibiotic treatment delay and outcome in acute bacterial meningitis

OBJECTIVES

To identify to what degree in-hospital delay of antibiotic therapy correlated to outcome in community acquired bacterial meningitis.

METHODS

All cases of culture-positive cerebrospinal fluids in east Denmark from 2002 to 2004 were included. Medical records were collected retrospectively with 98.4% case completeness. Glasgow Outcome Scale was used. Multiple regression outcome analyses included the hypothesised factors: delay of therapy, age, bacterial aetiology, adjuvant steroid therapy, coma at admission and the presence of risk factors.

RESULTS

One hundred and eighty seven cases were included. Adult mortality was 33% and the proportion of unfavourable outcome in adults was 52%, which differed significantly from that of children (<18 years) with a mortality of 3% (OR=15.8, 95% confidence interval: 3.7-67.6) and an unfavourable outcome of 14% (OR=12.7, CI: 4.3-37.2). Delay of antibiotic therapy correlated independently to unfavourable outcome (OR=1.09/h, CI: 1.01-1.19) among the 125 adult cases. In the group of adults receiving adequate antibiotic therapy within 12h (n=109), the independent correlation between antibiotic delay and unfavourable outcome was even more prominent (OR=1.30/h, CI: 1.08-1.57). The median delay to the first dose of adequate antibiotics was 1h and 39min (1h and 14min in children vs. 2h in adults, p<0.01), and treatment delay exceeded 2h in 21-37% of the cases with clinically evident meningitis.

CONCLUSION

The delay in antibiotic therapy correlated independently to unfavourable outcome. The odds for unfavourable outcome may increase by up to 30% per hour of treatment delay.

Comparison of nebulized epinephrine to albuterol in bronchiolitis

OBJECTIVES

To compare the effect of nebulized racemic epinephrine to nebulized racemic albuterol on successful discharge from the emergency department (ED).

METHODS

Children up to their 18th month of life presenting to two teaching hospital EDs with a clinical diagnosis of bronchiolitis who were ill enough to warrant treatment but did not need immediate intubation were eligible for this double-blind randomized controlled trial (RCT). Patients received either three doses of racemic albuterol or one dose of racemic epinephrine plus two saline nebulizers. Disposition was decided 2 hours after the first nebulizer. Successful discharge was defined as not requiring additional bronchodilators in the ED after study drug administration and not subsequently admitted within 72 hours. Adjusted relative risks (aRR) were estimated using the modified Poisson regression with successful discharge as the dependent variable and study drug and severity of illness as exposures. Secondary analysis was performed for patients aged less than 12 months and first presentation.

RESULTS

The authors analyzed 703 patients; 352 patients were given albuterol and 351 epinephrine. A total of 173 in the albuterol group and 160 in the epinephrine group were successfully discharged (crude RR = 1.08, 95% confidence interval [CI] = 0.92 to 1.26). When adjusted for severity of illness, patients who received albuterol were significantly more likely than patients receiving epinephrine to be successfully discharged (aRR = 1.18, 95% CI = 1.02 to 1.36). This was also true among those with first presentation and in those less than 12 months of age.

CONCLUSIONS

In children up to the 18th month of life, ED treatment of bronchiolitis with nebulized racemic albuterol led to more successful discharges than nebulized epinephrine.

Pre-admission antibiotics for suspected cases of meningococcal disease

BACKGROUND

Meningococcal disease begins suddenly and death can follow within hours. Pre-admission antibiotic therapy aims to prevent delay in starting therapy that occurs if bacterial confirmation is sought before instituting therapy.

OBJECTIVES

To study the effectiveness and safety of pre-admission antibiotics versus no pre-admission antibiotics or placebo and of different pre-admission antibiotic regimens in decreasing mortality and morbidity in people suspected of meningococcal disease.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2007, Issue 1), MEDLINE (1966 to February 2007) and EMBASE (1980 to February 2007).

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) or quasi-RCTs, of all people with suspected meningococcal infection. We compared antibiotic treatment versus placebo or no intervention, or different antibiotic treatments administered before admission to hospital or confirmation of the diagnosis.

DATA COLLECTION AND ANALYSIS

Two author authors independently assessed quality and extracted data from included trials. We calculated the relative risk (RR) and 95% confidence interval (CI) for dichotomous data. As only one trial fulfilled inclusion criteria, data synthesis was not performed.

MAIN RESULTS

No RCTs were found that compared pre-admission antibiotics versus no pre-admission antibiotics or placebo. One open-label RCT evaluated a single dose of intramuscular ceftriaxone versus a single dose of intramuscular long acting (oily) chloramphenicol. Interventions did not differ significantly in mortality (RR 1.2, 95% CI 0.5 to 2.6; N = 510; 349 confirmed meningococcal meningitis; 26 deaths), nor in proportions of survivors who developed neurological sequelae (RR 1.2, 95% CI 0.6 to 2.2; N = 488; 36 with neurological sequelae), or that were classified as clinical failures (RR 0.8, 95% CI 0.4 to 1.8; N = 488, 25 clinical failures). No adverse effects of treatment were seen. No data were available for our secondary outcomes.

AUTHORS' CONCLUSIONS

We found no reliable evidence to support or refute the use of pre-admission antibiotics for suspected cases of meningococcal disease. Evidence from one RCT-during an epidemic of meningococcal meningitis, indicated that single intramuscular injections of ceftriaxone and long-acting chloramphenicol were equally effective and safe in preventing mortality and morbidity. The choice between these antibiotics would be based on affordability, availability, and patterns of antibiotic resistance.Further RCTs comparing different pre-admission antibiotics, including penicillin, including participants with severe illness are ethically justifiable and are needed to provide reliable evidence to clinicians in differing clinical settings.