Validity of a clinical model to predict influenza in patients presenting with symptoms of lower respiratory tract infection in primary care

Prevalence, aetiologies and prognosis of the symptom cough in primary care: a systematic review and meta-analysis

Background

Cough is a relevant reason for encounter in primary care. For evidence-based decision making, general practitioners need setting-specific knowledge about prevalences, pre-test probabilities, and prognosis. Accordingly, we performed a systematic review of symptom-evaluating studies evaluating cough as reason for encounter in primary care.

Methods

We conducted a search in MEDLINE and EMBASE. Eligibility criteria and methodological quality were assessed independently by two reviewers. We extracted data on prevalence, aetiologies and prognosis, and estimated the variation across studies. If justifiable in terms of heterogeneity, we performed a meta-analysis.

Results

We identified 21 eligible studies on prevalence, 12 on aetiology, and four on prognosis. Prevalence/incidence estimates were 3.8–4.2%/12.5% (Western primary care) and 10.3–13.8%/6.3–6.5% in Africa, Asia and South America. In Western countries the underlying diagnoses for acute cough or cough of all durations were respiratory tract infections (73–91.9%), influenza (6–15.2%), asthma (3.2–15%), laryngitis/tracheitis (3.6–9%), pneumonia (4.0–4.2%), COPD (0.5–3.3%), heart failure (0.3%), and suspected malignancy (0.2–1.8%). Median time for recovery was 9 to 11 days. Complete recovery was reported by 40.2- 67% of patients after two weeks, and by 79% after four weeks. About 21.1–35% of patients re-consulted; 0–1.3% of acute cough patients were hospitalized, none died. Evidence is missing concerning subacute and chronic cough.

Conclusion

Prevalences and incidences of cough are high and show regional variation. Acute cough, mainly caused by respiratory tract infections, is usually self-limiting (supporting a “wait-and-see” strategy). We have no setting-specific evidence to support current guideline recommendations concerning subacute or chronic cough in Western primary care. Our study presents epidemiological data under non non-pandemic conditions. It will be interesting to compare these data to future research results of the post-pandemic era.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01501-0.

The early use of Antibiotics for at Risk CHildren with InfluEnza-like illness (ARCHIE): a double-blind randomised placebo-controlled trial

INTRODUCTION

The UK government stockpiles co-amoxiclav to treat bacterial complications during influenza pandemics. This pragmatic trial examines whether early co-amoxiclav use reduces re-consultation due to clinical deterioration in "at risk" children presenting with influenza-like illness (ILI) in primary or ambulatory care.

METHODS

"At risk" children aged 6 months to 12 years presenting within f5 days of ILI onset were randomly assigned to oral co-amoxiclav 400/57 or placebo twice daily for 5 days (dosing based on age±weight). "At risk" groups included children with respiratory, cardiac, and neurological conditions. Randomisation was stratified by region and used a non-deterministic minimisation algorithm to balance age and current seasonal influenza vaccination status. Our target sample size was 650 children, which would have allowed us to detect a reduction in the proportion of children re-consulting due to clinical deterioration from 40% to 26% with 90% power and 5% two-tailed alpha error, including allowance for 25% loss to follow-up and an inflation factor of 1.041. Participants, caregivers and investigators were blinded to treatment allocation. Intention-to-treat analysis included all randomised participants with primary outcome data on re-consultation due to clinical deterioration within 28 days. Safety analysis included all randomised participants.

TRIAL REGISTRATION

ISRCTN 70714783. EudraCT 2013-002822-21.

RESULTS

We recruited 271 children between February 11, 2015 and April 20, 2018. Primary outcome data were available for 265 children. Only 61/265 children (23.0%) re-consulted due to clinical deterioration. No evidence of a treatment effect was observed for re-consultation due to clinical deterioration (co-amoxiclav 33/133 (24.8%), placebo 28/132 (21.2%), adjusted risk ratio [RR] 1.16, 95% confidence interval [CI] 0.75 to 1.80). There was also no evidence of a difference between groups in the proportion of children for whom one or more adverse events were reported (co-amoxiclav 32/136 (23.5%), placebo 22/135 (16.3%), adjusted RR 1.45, 95% CI 0.90 to 2.34). Sixty-six adverse events were reported in total (co-amoxiclav n=37, placebo n=29). Nine serious adverse events were reported per group; none were considered related to study medication.

CONCLUSION

Our trial did not find evidence that treatment with co-amoxiclav reduces risk of re-consultation due to clinical deterioration in "at risk" children who present early with ILI during influenza season. Our findings therefore do not support early co-amoxiclav use in children with seasonal ILI.

Diagnostic accuracy of an app-guided, self-administered test for influenza among individuals presenting to general practice with influenza-like illness: study protocol

INTRODUCTION

Diagnostic tests for influenza in Australia are currently only authorised for use in clinical settings. At-home diagnostic testing for influenza could reduce the need for patient contact with healthcare services, which potentially could contribute to symptomatic improvement and reduced spread of influenza. We aim to determine the accuracy of an app-guided nasal self-swab combined with a lateral flow immunoassay for influenza conducted by individuals with influenza-like illness (ILI).

METHODS AND ANALYSIS

Adults (≥18 years) presenting with ILI will be recruited by general practitioners (GP) participating in Australian Sentinel Practices Research Network. Eligible participants will have a nasal swab obtained by their GP for verification of influenza A/B status using reverse transcription polymerase chain reaction (RT-PCR) test at an accredited laboratory. Participants will receive an influenza test kit and will download an app that collects self-reported symptoms and influenza risk factors, then instructs them in obtaining a low-nasal self-swab, running a QuickVue influenza A+B lateral flow immunoassay (Quidel Corporation) and interpreting the results. Participants will also interpret an enhanced image of the test strip in the app. The primary outcome will be the accuracy of participants' test interpretation compared with the laboratory RT-PCR reference standard. Secondary analyses will include accuracy of the enhanced test strip image, accuracy of an automatic test strip reader algorithm and validation of prediction rules for influenza based on self-reported symptoms. A post-test survey will be used to obtain participant feedback on self-test procedures.

ETHICS AND DISSEMINATION

The study was approved by the Human Research and Ethic Committee (HREC) at the University of Adelaide (H-2019-116). Protocol details and any amendments will be reported to https://www.tga.gov.au/. Results will be published in the peer-reviewed literature, and shared with stakeholders in the primary care and diagnostics communities.

TRIAL REGISTRATION NUMBER

Australia New Zealand Clinical Trial Registry (U1111-1237-0688).

Estimating the efficacy of symptom-based screening for COVID-19

There is substantial interest in using presenting symptoms to prioritize testing for COVID-19 and establish symptom-based surveillance. However, little is currently known about the specificity of COVID-19 symptoms. To assess the feasibility of symptom-based screening for COVID-19, we used data from tests for common respiratory viruses and SARS-CoV-2 in our health system to measure the ability to correctly classify virus test results based on presenting symptoms. Based on these results, symptom-based screening may not be an effective strategy to identify individuals who should be tested for SARS-CoV-2 infection or to obtain a leading indicator of new COVID-19 cases.

Predictors of Adverse Outcomes in Uncomplicated Lower Respiratory Tract Infections

PURPOSE

Presentation with acute lower respiratory tract infection (LRTI) in primary care is common. The aim of this study was to help clinicians treat patients presenting with LRTI in primary care by identifying those at risk of serious adverse outcomes (death, admission, late-onset pneumonia).

METHODS

In a prospective cohort study of patients presenting with LRTI symptoms, patient characteristics and clinical findings were recorded and adverse events identified over 30 days by chart review. Multivariable logistic regression analyses identified predictors of adverse outcomes.

RESULTS

Participants were recruited from 522 UK practices in 2009-2013. The analysis was restricted to the 28,846 adult patients not referred immediately to the hospital. Serious adverse outcomes occurred in 325/28,846 (1.1%). Eight factors were independently predictive; these characterized symptom severity (absence of coryza, fever, chest pain, and clinician-assessed severity), patient vulnerability (age >65 years, comorbidity), and physiological impact (oxygen saturation <95%, low blood pressure). In aggregate, the 8 features had moderate predictive value (area under the receiver operating characteristic curve 0.71, 95% CI, 0.68-0.74); the 4% of patients with ≥5 features had an approximately 1 in 17 (5.7%) risk of serious adverse outcomes, the 35% with 3 or 4 features had an intermediate risk (1 in 50, 2.0%), and the 61% with ≤2 features had a low (1 in 200, 0.5%) risk.

CONCLUSIONS

In routine practice most patients presenting with LRTI in primary care can be identified as at intermediate or low risk of serious outcome.

Accuracy of Signs and Symptoms for the Diagnosis of Acute Rhinosinusitis and Acute Bacterial Rhinosinusitis

PURPOSE

To evaluate the accuracy of signs and symptoms for the diagnosis of acute rhinosinusitis (ARS).

METHODS

We searched Medline to identify studies of outpatients with clinically suspected ARS and sufficient data reported to calculate the sensitivity and specificity. Of 1,649 studies initially identified, 17 met our inclusion criteria. Acute rhinosinusitis was diagnosed by any valid reference standard, whereas acute bacterial rhinosinusitis (ABRS) was diagnosed by purulence on antral puncture or positive bacterial culture. We used bivariate meta-analysis to calculate summary estimates of test accuracy.

RESULTS

Among patients with clinically suspected ARS, the prevalence of imaging confirmed ARS is 51% and ABRS is 31%. Clinical findings that best rule in ARS are purulent secretions in the middle meatus (positive likelihood ratio [LR+] 3.2) and the overall clinical impression (LR+ 3.0). The findings that best rule out ARS are the overall clinical impression (negative likelihood ratio [LR-] 0.37), normal transillumination (LR- 0.55), the absence of preceding respiratory tract infection (LR- 0.48), any nasal discharge (LR- 0.49), and purulent nasal discharge (LR- 0.54). Based on limited data, the overall clinical impression (LR+ 3.8, LR- 0.34), cacosmia (fetid odor on the breath) (LR+ 4.3, LR- 0.86) and pain in the teeth (LR+ 2.0, LR- 0.77) are the best predictors of ABRS. While several clinical decision rules have been proposed, none have been prospectively validated.

CONCLUSIONS

Among patients with clinically suspected ARS, only about one-third have ABRS. The overall clinical impression, cacosmia, and pain in the teeth are the best predictors of ABRS. Clinical decision rules, including those incorporating C-reactive protein, and use of urine dipsticks are promising, but require prospective validation.

Prevalence of Atypical Pathogens in Patients With Cough and Community-Acquired Pneumonia: A Meta-Analysis

PURPOSE

Community-acquired pneumonia (CAP), acute cough, bronchitis, and lower respiratory tract infections (LRTI) are often caused by infections with viruses or Streptococcus pneumoniae. The prevalence of atypical pathogens Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, and Bordetella pertussis among patients with these illnesses in the ambulatory setting has not been previously summarized. We set out to derive prevalence information from the existing literature.

METHODS

We performed a systematic review of MEDLINE for prospective, consecutive-series studies reporting the prevalence of M pneumoniae, C pneumoniae, L pneumophila and/or B pertussis in outpatients with cough, acute bronchitis, LRTI, or CAP. Articles were independently reviewed by 2 authors for inclusion and abstraction of data; discrepancies were resolved by consensus discussion. A meta-analysis was performed on each pathogen to calculate the pooled prevalence estimates using a random effects model of raw proportions.

RESULTS

Fifty studies met our inclusion criteria. While calculated heterogeneity was high, most studies reported prevalence for each pathogen within a fairly narrow range. In patients with CAP, the overall prevalences of M pneumoniae and C pneumoniae were 10.1% (95% CI, 7.1%-13.1%) and 3.5% (95% CI, 2.2%-4.9%), respectively. Consistent with previous reports, M pneumoniae prevalence peaked in roughly 6-year intervals. Overall prevalence of L pneumophila was 2.7% (95% CI, 2.0%-3.4%), but the organism was rare in children, with only 1 case in 1,765. In patients with prolonged cough in primary care, the prevalence of B pertussis was 12.4% (95% CI, 4.9%-19.8%), although it was higher in studies that included only children (17.6%; 95% CI, 3.4%-31.8%).

CONCLUSIONS

Atypical bacterial pathogens are relatively common causes of lower respiratory diseases, including cough, bronchitis, and CAP. Where surveillance data were available, we found higher prevalences in studies where all patients are tested for these pathogens. It is likely that these conditions are underreported, underdiagnosed, and undertreated in current clinical practice.