Do doctors and other healthcare professionals know overdiagnosis in screening and how are they dealing with it? A protocol for a mixed methods systematic review

INTRODUCTION

Overdiagnosis is the diagnosis of a disease that would never have caused any symptom or problem. It is a harmful side effect of screening and may lead to unnecessary treatment, costs and emotional drawbacks. Doctors and other healthcare professionals (HCPs) have the opportunity to mitigate these consequences, not only by informing their patients or the public but also by adjusting screening methods or even by refraining from screening. However, it is unclear to what extent HCPs are fully aware of overdiagnosis and whether it affects their screening decisions. With this systematic review, we aim to synthesise all available research about what HCPs know and think about overdiagnosis, how it affects their position on screening policy and whether they think patients and the public should be informed about it.

METHODS AND ANALYSIS

We will systematically search several databases (MEDLINE, Embase, Web of Science, Scopus, CINAHL and PsycArticles) for studies that directly examine HCPs' knowledge and subjective perceptions of overdiagnosis due to health screening, both qualitatively and quantitatively. We will optimise our search by scanning reference and citation lists, contacting experts in the field and hand searching abstracts from the annual conference on 'Preventing Overdiagnosis'. After selection and quality appraisal, we will analyse qualitative and quantitative findings separately in a segregated design for mixed-method reviews. The data will be examined and presented descriptively. If the retrieved studies allow it, we will review them from a constructivist perspective through a critical interpretive synthesis.

ETHICS AND DISSEMINATION

For this type of research, no ethical approval is required. Findings from this systematic review will be published in a peer-reviewed journal and presented at the annual congress of 'Preventing Overdiagnosis'. In addition, the results will serve as guidance for further research on this topic.

PROSPERO REGISTRATION NUMBER

CRD42021244513.

Downstream activities after laboratory testing in primary care: an exploratory outcome of the ELMO cluster randomised trial (Electronic Laboratory Medicine Ordering with evidence-based order sets in primary care)

OBJECTIVE

To estimate the rate and type of downstream activities (DAs) after laboratory testing in primary care, with a specific focus on check-up laboratory panels, and to explore the effect of a clinical decision support system (CDSS) for laboratory ordering on these DAs.

DESIGN

Cluster randomised clinical trial.

SETTING

72 primary care practices in Belgium, with 272 general practitioners (GPs), randomly assigned to the intervention arm or the control arm.

PARTICIPANTS

The study included 10 270 lab panels from 9683 primary care patients (women 55.1%, mean age 56.5). All adult patients who consulted one of the participating GPs during the trial period and needed a laboratory exam were eligible for participation.

INTERVENTIONS

GPs in the intervention group used a CDSS integrated into their online laboratory ordering system, while GPs in the control arm used their lab ordering system as usual. The trial duration was 6 months, with another 6 months follow-up.

MAIN OUTCOME MEASURES

This publication reports on the exploratory outcome of DAs after an initial laboratory exam and the effect of the CDSS on these DAs.

RESULTS

19.7% of all laboratory panels resulted in further diagnostic procedures (95% CI 18.9% to 20.5%) and 19% (95% CI 18.2% to 19.7%) in treatment changes. Check-up laboratory exams showed similar rates of DAs, with 17.5% (95% CI 13.8% to 21.2%) diagnostic DAs and 18.9% (95% CI 13.9% to 23.9%) treatment changes. Using the CDSS resulted in a significant reduction in downstream referrals (-2.4%; 95% CI -4.2% to -0.6%; p=0008), imaging and endoscopies (-0.9%; 95% CI -1.6% to -0.1%; p=0026) and treatment changes (-5.4%; 95% CI -9.5% to -1.2%; p=0.01).

CONCLUSION

This is the largest study so far to examine DAs after laboratory testing. It shows that almost one in three laboratory exams leads to further DAs, even in check-up panels. Using a CDSS for laboratory orders may reduce the rate of some DAs.

TRIAL REGISTRATION NUMBER

NCT02950142.

Clinical decision support improves the appropriateness of laboratory test ordering in primary care without increasing diagnostic error: the ELMO cluster randomized trial

Background

Inappropriate laboratory test ordering poses an important burden for healthcare. Clinical decision support systems (CDSS) have been cited as promising tools to improve laboratory test ordering behavior. The objectives of this study were to evaluate the effects of an intervention that integrated a clinical decision support service into a computerized physician order entry (CPOE) on the appropriateness and volume of laboratory test ordering, and on diagnostic error in primary care.

Methods

This study was a pragmatic, cluster randomized, open-label, controlled clinical trial.

Setting

Two hundred eighty general practitioners (GPs) from 72 primary care practices in Belgium.

Patients

Patients aged ≥ 18 years with a laboratory test order for at least one of 17 indications: cardiovascular disease management, hypertension, check-up, chronic kidney disease (CKD), thyroid disease, type 2 diabetes mellitus, fatigue, anemia, liver disease, gout, suspicion of acute coronary syndrome (ACS), suspicion of lung embolism, rheumatoid arthritis, sexually transmitted infections (STI), acute diarrhea, chronic diarrhea, and follow-up of medication.

Interventions

The CDSS was integrated into a computerized physician order entry (CPOE) in the form of evidence-based order sets that suggested appropriate tests based on the indication provided by the general physician.

Measurements

The primary outcome of the ELMO study was the proportion of appropriate tests over the total number of ordered tests and inappropriately not-requested tests. Secondary outcomes of the ELMO study included diagnostic error, test volume, and cascade activities.

Results

CDSS increased the proportion of appropriate tests by 0.21 (95% CI 0.16–0.26, p < 0.0001) for all tests included in the study. GPs in the CDSS arm ordered 7 (7.15 (95% CI 3.37–10.93, p = 0.0002)) tests fewer per panel. CDSS did not increase diagnostic error. The absolute difference in proportions was a decrease of 0.66% (95% CI 1.4% decrease–0.05% increase) in possible diagnostic error.

Conclusions

A CDSS in the form of order sets, integrated within the CPOE improved appropriateness and decreased volume of laboratory test ordering without increasing diagnostic error.

Trial registration

ClinicalTrials.gov Identifier: NCT02950142, registered on October 25, 2016

Supplementary Information

The online version contains supplementary material available at 10.1186/s13012-020-01059-y.

Short communication: Subtyping of Staphylococcus haemolyticus isolates from milk and corresponding teat apices to verify the potential teat-skin origin of intramammary infections in dairy cows

Coagulase-negative staphylococci (CNS) are a major cause of intramammary infections (IMI) in dairy cows and they colonize the teat skin. Staphylococcus haemolyticus, one of the more common CNS, has been identified as a highly versatile opportunistic species. The aim of the present study was to gain better insight into the adaptation of S. haemolyticus subtypes to the udder ecosystem with respect to IMI development. During a longitudinal observational study conducted over 13 mo on 6 Flemish dairy herds, S. haemolyticus isolates were recovered from milk and teat apices. A total of 44 S. haemolyticus isolates originating from milk (24 isolates) and teat apices (20 isolates) of 6 selected udder quarters were singled out and analyzed using a combined methodology of (GTG)5-PCR and amplified fragment length polymorphism (AFLP) fingerprinting to determine intraspecies differences. Combining both fingerprinting methods, 4 S. haemolyticus subtypes were obtained (I to IV). Subtypes I, II, and IV were recovered from both milk and teat apex samples and were found to be associated with persisting IMI. Subtype III, not apparently related to IMI, was isolated solely from teat apices and not from milk. In general, S. haemolyticus subtypes found in milk from infected quarters could be recovered from the corresponding teat apices, although the latter could be colonized with up to 3 different subtypes. Comparing subtypes from milk and teat apices indicates that the IMI-causing agent likely originates from the teat skin.

Further evidence for the existence of environmental and host-associated species of coagulase-negative staphylococci in dairy cattle

Coagulase-negative staphylococci (CNS) are abundantly present in the dairy farm environment and on bovine skin and mucosae. They are also the most prevalent bacteria causing bovine intramammary infections (IMI). Reservoirs and transmission routes of CNS are not yet fully unraveled. The objectives of this study were to explore the distribution of CNS in parlor-related extramammary niches and to compare it to the distributions of CNS causing IMI in those herds. Niches that were targeted in this study were cows' teat apices, milking machine unit liners, and milker's skin or gloves. Each of the three herds had its own CNS microbiota in those niches. The most prevalent species in the parlor-related extramammary niches were Staphylococcus cohnii, S. fleurettii, and S. equorum in the first, second, and third herd, respectively, whereas S. haemolyticus and S. sciuri were found in all herds. S. cohnii and S. fleurettii, as well as S. haemolyticus, which was present in each herd, were also frequently found in milk samples. By contrast, S. chromogenes, S. simulans, and S. xylosus favored the mammary gland, whereas S. equorum was more common in the parlor-associated niches. Within each herd, species distribution was similar between teat apices and milking machine unit liners. In conclusion, some of the extramammary niches related to the milking process might act as infection sources for IMI-causing CNS. This study provides further evidence that the group of CNS species is comprised of environmental, opportunistic and host-adapted species which differ in ecology.

Unraveling the microbiota of teat apices of clinically healthy lactating dairy cows, with special emphasis on coagulase-negative staphylococci

Swab samples (n=72) obtained from the teat apex of lactating dairy cows without visual signs of inflammation (n=18) were gathered on 2 well-managed Flemish dairy herds (herds 1 and 2) during the same month to assess the bacterial diversity of teat apices before milking. A combination of both culture-dependent [plating and (GTG)(5)-PCR fingerprinting of the colonies] and culture-independent [denaturing gradient gel electrophoresis (PCR-DGGE)] techniques indicated that the teat apices contain a wide diversity of bacterial genera. Despite a low bacterial load, 20 bacterial genera of 3 phyla (Actinobacteria, Firmicutes, and Proteobacteria) were present. The most prevalent bacteria were the coagulase-negative staphylococci (CNS), encompassing a total of 15 species, which were identified to the species level using a combination of (GTG)(5)-PCR fingerprinting, gene sequencing (16S ribosomal RNA and rpoB genes), and a novel PCR-DGGE technique based on the tuf-PCR amplicon. Overall bacterial diversity did not differ significantly between the herds or between noninfected and subclinically infected quarters in herd 1. In herd 1, borderline significant lower CNS species diversity was found on teat apices of noninfected quarters compared with subclinically infected quarters. The most prevalent CNS species were Staphylococcus haemolyticus and Staphylococcus equorum in both herds and Staphylococcus carnosus in herd 2.

Staphylococcus agnetis sp. nov., a coagulase-variable species from bovine subclinical and mild clinical mastitis

Thirteen Gram-positive-staining coagulase-variable staphylococci were isolated from subclinical and mild clinical mastitic bovine milk (n = 12) and a teat apex (n = 1). The results of sequence analysis of the 16S rRNA gene and two housekeeping genes, rpoB and tuf, and DNA fingerprinting with amplified fragment length polymorphism (AFLP) analysis showed that the isolates formed a separate branch within the genus Staphylococcus. The phylogenetically most closely related species were Staphylococcus hyicus and Staphylococcus chromogenes. DNA–DNA hybridization with S. hyicus DSM 20459T and S. chromogenes DSM 20674T confirmed that the isolates belonged to a separate species. The predominant fatty acids were i-C15 : 0, ai-C15 : 0, i-C17 : 0 and C20 : 0 and the peptidoglycan type was A3α l-Lys–Gly5. Based on the results of genotypic and phenotypic analyses, it is proposed that the thirteen isolates represent a novel species, for which the name Staphylococcus agnetis sp. nov. is proposed. Strain 6-4T ( = DSM 23656T = CCUG 59809T) is the type strain.

Sources other than unused sawdust can introduce Klebsiella pneumoniae into dairy herds

A longitudinal study was carried out to detect intramammary infections caused by Klebsiella pneumoniae and to identify potential sources of this bacterial species in the environment of the cows. The study was performed in 6 well-managed Belgian dairy herds from May 2008 to May 2009. Monthly (n=13), unused and used sawdust bedding samples as well as individual quarter milk and feces samples were collected from 10 randomly selected cohort cows in each herd. Cases of clinical mastitis of all lactating cows in the 6 herds were also sampled (n=64). From the 3,518 collected samples, 153 K. pneumoniae isolates were obtained, of which 2 originated from milk (clinical mastitis cases). In feces (n=728), used bedding (n=73), and unused bedding (n=73), respectively, 125 (17.2%), 20 (27.4%), and 6 (8.2%) isolates were found. The isolates were fingerprinted by means of pulsed field gel electrophoresis. In total, 109 different pulsotypes were differentiated, indicating a high degree of genetic diversity within the isolates. All isolates from unused bedding belonged to pulsotypes other than those from the other sources, suggesting that sources other than unused sawdust may introduce K. pneumoniae into the herd. Only 2 pulsotypes contained isolates originating from different sources. Pulsotype 10 was found in milk and used bedding and pulsotype 21 was found in feces and used bedding. The 2 milk isolates originated from 2 cows in the same herd but they belonged to a different pulsotype. The results indicate that K. pneumoniae can be prevalent in the environment without causing significant mastitis problems. Most cows were shedding K. pneumoniae in feces, substantiating findings under very different conditions (i.e., American dairy herds). Contamination of used bedding in the cubicles with K. pneumoniae from feces was confirmed, whereas unused bedding was not an important source of K. pneumoniae for the environment of the cows.

Distribution of coagulase-negative Staphylococcus species from milk and environment of dairy cows differs between herds

In many parts of the world, coagulase-negative staphylococci (CNS) are the predominant pathogens causing intramammary infections (IMI) in dairy cows. The cows' environment is thought to be a possible source for CNS mastitis and this was investigated in the present paper. A longitudinal field study was carried out in 6 well-managed dairy herds to determine the distribution and epidemiology of various CNS species isolated from milk, causing IMI and living freely in the cows' environment, respectively. In each herd, quarter milk samples from a cohort of 10 lactating cows and environmental samples from stall air, slatted floor, sawdust from cubicles, and sawdust stock were collected monthly (n=13). Isolates from quarter milk samples (n=134) and the environment (n=637) were identified to species level using amplified fragment length polymorphism (AFLP) genotyping. Staphylococcus chromogenes, S. haemolyticus, S. epidermidis, and S. simulans accounted for 81.3% of all CNS milk isolates. Quarters were considered infected with CNS (positive IMI status) only when 2 out of 3 consecutive milk samples yielded the same CNS AFLP type. The species causing IMI were S. chromogenes (n=35 samples with positive IMI status), S. haemolyticus (n=29), S. simulans (n=14), and S. epidermidis (n=6). The observed persistent IMI cases (n=17) had a mean duration of 149.4 d (range 63.0 to 329.8 d). The CNS species predominating in the environment were S. equorum, S. sciuri, S. haemolyticus, and S. fleurettii. Herd-to-herd differences in distribution of CNS species were observed in both milk and the environment, suggesting that herd-level factors are involved in the establishment of particular species in a dairy herd. Primary reservoirs of the species causing IMI varied. Staphylococcus chromogenes and S. epidermidis were rarely found in the environment, indicating that other reservoirs were more important in their epidemiology. For S. haemolyticus and S. simulans, the environment was found as a reservoir, suggesting that IMI with these species were possibly environmental in origin.

Intra-species diversity and epidemiology varies among coagulase-negative Staphylococcus species causing bovine intramammary infections

Although many studies report coagulase-negative staphylococci (CNS) as the predominant cause of subclinical bovine mastitis, their epidemiology is poorly understood. In the current study, the genetic diversity within four CNS species frequently associated with bovine intramammary infections, Staphylococcus haemolyticus, S. simulans, S. chromogenes, and S. epidermidis, was determined. For epidemiological purposes, CNS genotypes recovered from bovine milk collected on six Flemish dairy farms were compared with those from the farm environment, and their distribution within the farms was investigated. Genetic diversity was assessed by two molecular typing techniques, amplification fragment length polymorphism (AFLP) and random amplification of polymorphic DNA (RAPD) analysis. Subtyping revealed the highest genetic heterogeneity among S. haemolyticus isolates. A large variety of genotypes was found among environmental isolates, of which several could be linked with intramammary infection, indicating that the environment could act as a potential source for infection. For S. simulans, various genotypes were found in the environment, but a link with IMI was less obvious. For S. epidermidis and S. chromogenes, genetic heterogeneity was limited and the sporadic isolates from environment displayed largely the same genotypes as those from milk. The higher clonality of the S. epidermidis and S. chromogenes isolates from milk suggests that specific genotypes probably disseminate within herds and are more udder-adapted. Environmental sources and cow-to-cow transmission both seem to be involved in the epidemiology of CNS, although their relative importance might substantially vary between species.

Limited genetic diversity and gene expression differences between egg- and non-egg-related Salmonella Enteritidis strains

Salmonella Enteritidis strains of egg- and non-egg-related origin were characterized molecularly to find markers correlated with the egg-contaminating property of Salmonella Enteritidis. Isolates were examined by random amplified polymorphic DNA (RAPD), plasmid profiling and phage typing. Furthermore, the presence of 30 virulence genes was tested by PCR. In genetic fingerprinting and gene content, only small differences between the strains were found and no correlation was observed with the origin (egg-related versus non-egg-related). A major RADP group was present in both egg- and non-egg-related strains, but other smaller RAPD groups were present as well in both categories of strains. Phage types PT4 and PT21 were predominant. Differential mRNA expression levels of fimA and agfA under conditions of growth simulating the conditions during egg formation were determined by real-time RT-PCR. Although differences in fimA and agfA expression levels were observed between the strains, these could not be correlated with the origin of the strains (egg-related versus non-egg-related). The highest expression levels of agfA and fimA were only found in two non-egg-related strains, which seemed to be correlated with the presence of a 93 kb plasmid instead of the 60 kb virulence plasmid. Our results seem to indicate only a limited role for at least type I fimbriae (encoded by fim operon) in egg contamination by Salmonella Enteritidis.

Quantification of Campylobacter spp. in chicken carcass rinse by real-time PCR

AIMS

In this study, a real-time quantitative polymerase chain reaction (PCR) method was examined for its ability to quantify Campylobacter spp. in chicken carcass rinses and compared with bacteriological culturing.

METHODS AND RESULTS

The linearity of the real-time PCR quantification protocol was assessed on pure DNA. The amplification efficiency was 100% and the square regression coefficient (R(2)) was 0.998. Quantification was linear over at least 7 log units. Using a crude cell lysate gave the highest sensitivity and the detection limit of the method was 3.3 log CFU per carcass. The statistical correlation between the bacteriological enumeration and the real-time quantitative (Q)-PCR determined using chicken carcasses sampled at the end of the slaughter line was 0.733. The difference in detection levels was probably because of the detection of stressed, dead or viable but not culturable cells by Q-PCR.

CONCLUSION

The real-time Q-PCR method described in this study is a powerful tool for determining the number of Campylobacter cells on carcasses.

SIGNIFICANCE AND IMPACT OF THE STUDY

The real-time Q-PCR method is available to quantify the Campylobacter contamination at the slaughterhouse level and could be used to evaluate primary production.