Substitution of physicians by nurses in primary care:
a systematic review and meta-analysis
Review protocol
Nahara Anani Martínez-González, Sima Djalali MD, Ryan Tandjung MD, Thomas Rosemann Prof. MD, PhD
Institute of Family Medicine, University of Zürich, Switzerland
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Study question:
Can nurses substitute physicians in primary care?
Review question:
1.
What is the clinical effectiveness and cost of nurse-led care interventions compared to physician-led care
interventions on relevant outcomes?
Objectives:

to systematically collect and synthesise the data on the evidence of nurses working as substitutes for
physicians in primary care on relevant outcomes
Methods:
By means of systematic review and –where appropriate- meta-analysis methods we will identify and critically
appraise the available evidence that address the relevant outcomes and will create a summary profile of
findings for each outcome.
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1.
Inclusion and exclusion criteria
Inclusion criteria:
Study design
 studies published in English, from all years and from any country
 primary studies of prospective, comparative, experimental design including:
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Parallel randomised clinical trials (RCTs)
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Quasi-RCTs (e.g. allocation by alternation, date of birth, hospital number, etc)
-
Cluster-randomised studies (e.g. allocation by groups)
Participants/population and healthcare settings
Participants of all ages who received, in †essence, care from nurses and who –in the study– are compared to
patients who received care from primary care physicians and who:
 sought first point of contact or undergoing care for undifferentiated conditions including mental health and
addiction restricted to primary care practice
 receiving care in primary health care services including general practice (GP), community and ambulatory
settings; and/or
 regardless of the recruitment sources (including transitional care) the intervention and continued follow-up
care had taken place in GP practices, community or ambulatory care settings
Interventions and comparisons
To reflect †substitution, it is imperative that in the studies to be included, nurses:
 are primary health care providers
 act as the main figure of care provision with autonomous or delegated responsibility (e.g. Clinical
autonomy)
 perform tasks that would be the kind formerly carried out by the physicians or
 would have at least required equivalent skills as the physicians to manage patients’ conditions or health
problem by ‡delegation or by †autonomous responsibility
 provide first point of contact, first assessment consultation and/or on-going care
Considerations and definitions:
- Regardless of the “job term”, the above may include nurse practitioners, clinical nurse specialists, advanced
practice nurses, practice nurses, health visitors, community health nurses, and family practice nurses.
-
ᴥ
-
†
-
‡
Those for which a doctor would be formerly responsible for providing care.
Substitution: replacement/transfer/exchange/swap of skills/care formerly performed by a primary health
care professional to another primary health care professional by autonomy or delegation.
Delegation: transfer of care by written consent from the doctor and in which the responsibility for the
performance and outcome remains accountable to the doctor.
Comparators
 General practitioners, Paediatricians, Geriatricians and Family doctors
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Outcomes
 Patient centred outcomes:
-
Direct or indirect measures of patient satisfaction or patient preference with quality of care
 Indicators of health status:
-
Direct or indirect measures of Quality of Life (QoL)
-
Hospital admissions
-
Mortality
 Costs of health care services:
-
Direct and indirect costs to patients or the payer and society
Exclusion criteria:
Study design
 Systematic reviews and meta-analyses
 Letters, abstracts, animal studies, etc.
Participants/population and healthcare settings
In keeping with the inclusion criteria above, we will exclude studies in which:
 Participants were seeking and undergoing specialised care
 Participants were seeking and undergoing care for mental health conditions and addiction unrestricted to
primary care
 Hospital settings, including inpatients, outpatients, radiology and emergency departments
 Dental settings
Interventions and comparisons
 Trainee nurses
 Nurses in roles for specialised care for mental health conditions, addiction problems and obstetrics
 Nurses who differ from others by virtue of administrative tasks and skills
 Supplementation: physician care extended by a new primary care service provided by the nurse. For
example: usual care by a doctor supplemented by innovative/specialised care by a nurse
 Complemented care: doctor’s care complemented with nurse care in which skills are not the same or
equivalent
 Dental practice and other specialties
2.
Evidence identification
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Searches will be performed on the following core databases:

MEDLINE Ovid, EMBASE, CINHAL (Mainly Nursing, biomedicine, health sciences librarianship,
alternative/complementary medicine, consumer health and other allied disciplines), The Cochrane Library
and trials register and the Cochrane Effective Practice and Organisation of Care Group (EPOC).

With modifications to indexing terms in order to run searches in different databases.
Manual search:

Through the reference lists of included studies and relevant systematic reviews.

We will not contact authors of potentially eligible studies to obtain missing data.
Search inclusion/restriction/filters criteria:
The search will remain broad to ensure retrieval of relevant literature and may require revisions by the clinical
experts in the team and filters will be applied where appropriate and replaced to fit the database type.
-
based on the PICO ‘a-priori’ defined criteria: specific population, interventions and comparisons, i.e.
patient, nurses and doctors
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setting specific, i.e. primary care
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specific to study design: will include filters for identification of studies e.g. the optimal search strategy
from Cochrane for identification of RCTs:
http://www.mrcbsu.cam.ac.uk/cochrane/handbook/chapter_6/6_4_11_1_the_cochrane_highly_sensitive_search_stra
tegies_for.htm
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not restricted by age groups or specific outcomes, language of publication, year or country or health
condition or outcomes
-
will exclude systematic reviews, meta-analyses, abstracts, letters, conference proceedings, editorials,
historical articles, anecdotes, comments, case reports, animal studies (i.e. restricted to studies in
humans)
Search terms
The following concepts and terminology (and synonyms, acronyms, variations) will be considered –and
translated to the specific search strategies of the corresponding databases:
3.
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Primary care doctors, nurses
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Primary care settings
-
Nurses and roles
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Substitution, delegation, skillsmix, etc
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Indexing terms will be determined by the thesaurus and/or controlled vocabulary provided in each
database and checking how key papers were indexed.
-
Free text terms and synonyms will be identified from the database record’s title and abstracts, taking
account of abbreviations, synonyms, geographical variation, misspellings.
-
Medical Subject Headings (MeSH) describing the topic/concept in the databases will be used.
*Sifting
The title and abstract of each and all retrieved citations will be sifted and screened in duplicate by two
independent reviewers using the above specified eligibility (i.e. inclusion and exclusion criteria). Full papers of
citations that meet the eligibility criteria, appear relevant, or where relevance/eligibility is not clear from the
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abstract will all be ordered. Full texts of studies will be independently scrutinised by at least two reviewers to
decide on final inclusion and the reasons for excluding studies will be recorded.
4.
*Assessment of study quality
We will assess the risk of bias of the methods in the included studies following well-established criteria and a
composite score will not be calculated [1-4]. The following features of quality will be considered in assessing
the potential for bias:
-
5.
A priori sample size calculation
Method of generation of the randomisation sequence
Allocation concealment at randomisation
Baseline comparability of treatment groups
Blinding of patients and outcome assessors
Loss to follow up for each outcome: studies with at least 20% of data missing from any group will be
considered to be potentially biased and subgroup or sensitivity analyses will be carried out
Intention to treat analysis
Other biases tailored to specific study design
*Data extraction
We will use Excel (Microsoft office) to design forms and entry data. Pre-design forms for data collection will be
developed, pilot-tested by at least two reviewers and standardised. Both data information abstracting and
appraisal of included studies will be carried out in duplicate by two reviewers. Files from independent
reviewers will be compared and any discrepancies will be resolved through consensus or referred to a third
reviewer for a final decision. During data appraisal studies might be excluded if there is no enough information
required for the data abstraction or if the inclusion criteria are not met.
For each included study, we will extract and record information on:
-
6.
reference details: first author, year, country of study;
sections on the descriptive elements of each study: design, setting and geographic distribution;
details on the populations: participants, health status and demographics including disease condition,
age, gender;
interventions: duration and follow up, specific time points of measurements;
outcomes (as defined in section 1): type, definitions, measurements, and summary of the results per
outcome;
the numbers -where possible- of participants with the outcome of interest for both the nurses and the
doctors group:
in dichotomous (present or absent) and/or
continuous (mean [and SD] severity score) format
any qualitative statement about the association between the outcomes indicators and the
intervention or control -in studies where the data of interest is not available-
*Abstracting and appraising
Both data and information abstracting and appraisal of included studies will be carried out in duplicate by two
independent reviewers.
*Disagreements will be resolved through discussion or by consensus and when necessary referred to a third
reviewer.
7.
Statistical analyses
For each study reporting dichotomous data, the Risk Ratios (RRs) will be calculated. For continuous data, the
weighted mean differences (WMD) will be used and where the studies have different scales, standardised
mean differences (SMD) will be used. The summary statistics and their 95% CIs will be reported where
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sufficient detail allows their calculation. One single estimate of a treatment effect will be produced using the
Cochrane Collaboration’s analysis software (Review Manager, version 5.1) for each individual study and pooled
for the set(s) of studies in which meta-analysis is appropriate (i.e. ≥3 studies per outcome) using the fixed
effects model.
Between study heterogeneity between trials will be assessed by visual inspection of forest plots where at least
10 trials [5] using the χ2 test for heterogeneity and the I2 statistic. For I2 statistic, values below 25% represent
low heterogeneity, 50% moderate heterogeneity, up to 75% severe heterogeneity and more than 75%
represents very severe heterogeneity. For the χ2 test, heterogeneity will be considered to be present if: p<0.1.
Sources of heterogeneity will be explored further by conducting subgroup and sensitivity analyses by clinical
and methodological criteria including:
Nurses’ qualifications/training:
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different levels of nurses’ qualifications depending of how this information is labeled on the studies, .e.g:
nurse practitioner, nurse practitioner with higher degree courses/specialisation, registered nurse or
licensed nurse
Type of care:
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single contact versus on-going care
urgent versus non-urgent
length of follow-up episodes (months: <6 versus ≥6; <12 versus ≥12)
Methodological criteria:
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small (N<200) versus large (N≥200) trials
allocation concealment (adequate versus inadequate/unclear)
attrition (<20% versus ≥20%)
Sensitivity analyses by excluding trials:
o
o
o
in which nurses had full clinical autonomy and/or where this information was not reported
with potentially contaminated samples represented by patients’ crossing over from the nurse
group to the physicians group or vice versa
quasi OR cluster design
Level of significance
A p-value <0.05 will be considered as statistically significant for the overall effect of estimates in keeping with
the 95% confidence intervals. If the line of no effect lies outside the upper and lower limits, the difference will
be regarded as statistically significant in favour of the intervention or control group.
8.
Report writing
We will follow the PRISMA guidelines for the reporting of systematic reviews and meta-analyses.
9.
Summary
Tables summarising the evidence will be produced to report the characteristics of included studies, the
interventions and excluded studies as well as the methodological quality of studies. Meta-analyses, where
appropriate, will be presented on forest plots. Studies with semi-quantitative or qualitative data will be
presented narratively. Discussion of the total body of evidence and its interpretation will also be reported.
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References
1.
2.
3.
4.
5.
Higgins JP, Altman DG, Gotzsche PC, Juni P, Moher D, et al. (2011) The Cochrane Collaboration's tool for
assessing risk of bias in randomised trials. BMJ 343: d5928.
Juni P, Altman DG, Egger M (2001) Systematic reviews in health care: Assessing the quality of controlled
clinical trials. BMJ 323: 42-46.
Juni P, Witschi A, Bloch R, Egger M (1999) The hazards of scoring the quality of clinical trials for metaanalysis. JAMA 282: 1054-1060.
Higgins JPT GS, (editors) Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0
[updated September 2011]: The Cochrane Collaboration, 2009. Available from www.cochranehandbook.org.
Sterne JA, Sutton AJ, Ioannidis JP, Terrin N, Jones DR, et al. (2011) Recommendations for examining and
interpreting funnel plot asymmetry in meta-analyses of randomised controlled trials. BMJ. 2011/07/26 ed.
pp. d4002.
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