We share your enthusiasm for the current efforts to reduce radiation
exposure associated with the use of CT scanning and agree with your
assertion that performance of appendectomy without scanning will
inevitably lead to more negative appendectomies. We are confident though
based on the NHS laparoscopic appendectomy statistics reviewed by Omar and
Clark in the Annals of Surgery that those negative appendectomies are
asso...
We share your enthusiasm for the current efforts to reduce radiation
exposure associated with the use of CT scanning and agree with your
assertion that performance of appendectomy without scanning will
inevitably lead to more negative appendectomies. We are confident though
based on the NHS laparoscopic appendectomy statistics reviewed by Omar and
Clark in the Annals of Surgery that those negative appendectomies are
associated with essentially no risk. In the NHS series 234,402 patients
underwent laparoscopic appendectoy without a single death or major
morbidity. CT scanning these 234 thousand patients on the other hand will
cause more than 100 fatal cases of cancer.
We read with great interest the recent article written by William
Rogers et al on the Harms of CT scanning prior to surgery for suspected
appendicitis(1). It highlights the radiation risk of cancer while
routinely performing an abdominal
CT scan on an otherwise healthy patient with symptoms suggestive of
appendicitis. This radiation risk of cancer becomes all the more important
in patients with 'ne...
We read with great interest the recent article written by William
Rogers et al on the Harms of CT scanning prior to surgery for suspected
appendicitis(1). It highlights the radiation risk of cancer while
routinely performing an abdominal
CT scan on an otherwise healthy patient with symptoms suggestive of
appendicitis. This radiation risk of cancer becomes all the more important
in patients with 'negative' appendectomy.
However, relying purely on clinical judgment for diagnosis of
appendicitis can result either in increased 'negative' appendectomy or
diagnostic delay which may cause appendiceal perforation. There are
studies which show that negative appendectomy is associated with an
appreciable degree of morbidity and mortality, including a significant
increase in length of hospital stay, postoperative complications like
wound infection and death(2). Also, it can increase health care costs.
Perforated appendicitis is also related to increase in length of
hospital stay(3). In-house mortality is high for perforated
appendicitis(4).
During the last decade, there have been many advances in CT
technology
which have resulted in improved spatial resolution, rapid scan and
increased use
of multiplanar images enabling better visualization of appendix. Although
the effective dose value for CT scan of abdomen and pelvis is taken as 8 -
11 mSv(5) , studies comparing low-dose CT group with standard-dose CT
group have shown that low-dose CT was not inferior with regard to
diagnosis of appendicitis(6) and negative appendectomy rates(7) . Neither
the appendiceal perforation rate nor the diagnostic performance of CT for
appendicitis differed significantly between the two groups. A randomized
controlled trial, low-dose CT for appendicitis trial (LOCAT) is being
undergone comparing the clinical outcomes following low vs standard-dose
computed tomography as the first-line imaging test in adolescents and
young adults with suspected acute appendicitis, where the effective dose
of CT is reduced to 2 mSv(8). This greatly reduces the carcinogenic risk.
Study using non-contrast focused abdominal CT scan has also shown to have
a high sensitivity for diagnosis of appendicitis(9). Here, there is no
risk of contrast nephropathy.
Further research in this field will enable us to use very low dose CT
scan with significantly less radiation risk of cancer; at the same time
significantly reducing negative appendectomy rate without an increase in
the appendiceal perforation rate.
References
(1) Rogers, W., Hoffman, J., Noori, N. Harms of CT
scanning prior to surgery for suspected appendicitis. Evidence Based
Medicine 2015;20(1):3-4.
(2) Flum DR, Koepsell T. The clinical and economic correlates of
misdiagnosed appendicitis: nationwide analysis. Arch Surg 2002;137:799-804.
(3) Al-Omran M, Mamdani M, McLeod RS. Epidemiologic features of acute
appendicitis in Ontario, Canada. Can J Surg 2003;46:263-268.
(4) Wen SW, Naylor CD. Diagnostic accuracy and short-term surgical
outcomes in cases of suspected acute appendicitis. CMAJ 1995;152:1617-1626.
(5) Furlow B. Radiation dose in computed tomography. Radiol Technol
2010;81:437-50.
(6) Keyzer, C., Tack, D., De Maertelaer, V., et al. Acute Appendicitis: Comparison of Low-
Dose and Standard-Dose Unenhanced Multi-Detector Row CT 1. Radiology 2004;232(1):164-172.
(7) Kim, K., Kim, Y. H., Kim, S. Y., et al. (2012). Low-dose abdominal CT for evaluating
suspected appendicitis. New England Journal of Medicine 2012;366(17):1596-1605.
(8) Ahn S. LOCAT (low-dose computed tomography for appendicitis trial)
comparing clinical outcomes following low- vs standard-dose computed
tomography as the first-line imaging test in adolescents and young adults
with suspected acute appendicitis: study protocol for a randomized
controlled trial.Trials. 2014;15:28. doi:10.1186/1745-6215-15-28.
(9) Akhtar, W., Ali, S., Arshad, M., Ali, F., Nadeem, N. (2011).
Focused abdominal CT scan for acute appendicitis in children: can it help
in need. Journal of the Pakistan Medical Association 2011; 61(5):474-6.
We read with great interest the recent article by Dr. Windish [1]
reviewing a number of Evidence-Based Medicine (EBM) smartphone apps.
Immediate access to brief summaries of the literature is essential in
bringing EBM knowledge to the bedside, as physicians are often busy and
are presented with frequent interruptions which hinder their ability to
perform detailed searches or read complete articles dur...
We read with great interest the recent article by Dr. Windish [1]
reviewing a number of Evidence-Based Medicine (EBM) smartphone apps.
Immediate access to brief summaries of the literature is essential in
bringing EBM knowledge to the bedside, as physicians are often busy and
are presented with frequent interruptions which hinder their ability to
perform detailed searches or read complete articles during the workday.
Indeed, we note the success of the randomized trial by Pastori, et al.
[2], where in the intervention group they provided a physician whose sole
purpose was collecting relevant EBM evidence from the literature. This
resulted in better patient outcomes, as assessed by ICU transfers and
hospital readmissions.
We would like to highlight an EBM database of diagnostic accuracy that we
have developed, entitled GetTheDiagnosis.org
(http://www.getthediagnosis.org). This website, which has a mobile version
suited to smartphones as well, contains a database of sensitivity and
specificity of history questions, physical examination findings, and
laboratory and imaging tests for nearly 300 diagnoses. The data is culled
from primary literature and is maintained by physician-users, who can
submit new entries or edit existing entries in the same manner as
Wikipedia. The site displays citations and links to the literature for
each entry, and the data is highly structured and allows for searching by
diagnosis or finding. By using structured data, we can provide a post-test
probability calculator based on the data for each diagnosis.
In this way, we have attempted to marry successful features of apps such
as EBM Tools or MedCalc 3000 EBM with an actual database of EBM data from
the literature. We hope that physicians will find our website helpful and
easy to use while in the clinic, and we hope that many of them will help
build the database by adding articles from the primary literature.
References
1. Windish D. EBM apps that help you search for answers to your clinical
questions. Evid Based Med 2014;:ebmed-2013-101623. doi:10.1136/eb-2013-
101623
2. Pastori MM, Sarti M, Pons M, et al. Assessing the impact of
bibliographical support on the quality of medical care in patients
admitted to an internal medicine service: a prospective clinical, open,
randomised two-arm parallel study. Evid Based Med 2014;19:163-8.
doi:10.1136/ebmed-2014-110021
This article brings into light the upcoming ways in which medical
health care knowledge is disseminated between general population and the
various pitfalls such an approach can have. Although such issues are in
nascent stage in a developing country like India but its climbing up the
ladder at a brisk rate. The new generation of physicians is media savvy
but can get easily influenced by media based...
This article brings into light the upcoming ways in which medical
health care knowledge is disseminated between general population and the
various pitfalls such an approach can have. Although such issues are in
nascent stage in a developing country like India but its climbing up the
ladder at a brisk rate. The new generation of physicians is media savvy
but can get easily influenced by media based propaganda's.
There is no doubt Evidence based Medicine is the future of way medicine is
going to be practiced be it in a developed country or a developing
nation, but scientific and regulating authorities need to keep a keen and
watchful eye on ways, quality and standard of literature that is being
published and distributed to practitioners and public.
There needs to be a healthy and interactive communication between
journalists and scholars so that the message intended reaches the public
and students in a clear, concise and undisputed way.
We agree with the authors that development of such web based facilities is
an inevitable need of the hour even from the point of view of a developing
country. Such acts will bring about greater understanding of complex
medical issues and practices followed in patient care thereby avoiding
unnecessary litigation and panic created by outbreak of an infectious
diseases, a prime example being epidemic of dengue fever and assumption of
direct correlation of decreasing platelet count with hemorrhage and
mortality which is absolutely not true as shown by number of studies.
The article brings about the required amalgamation of media and scientific
community in a cohesive way to produce comprehensible medical knowledge
and its dissemination in public domain.
I am very grateful to Ken Uchino for amplifying and clarifying the
detail of some of the points I was trying to make within the word limits
of a 'Perspectives' paper. I suggest there are four key elements:
1. The epidemiology is indeed complex and I am neither an academic
nor an epidemiologist. However, it would appear that we can agree that
there is indeed a difference between 'younger old'...
I am very grateful to Ken Uchino for amplifying and clarifying the
detail of some of the points I was trying to make within the word limits
of a 'Perspectives' paper. I suggest there are four key elements:
1. The epidemiology is indeed complex and I am neither an academic
nor an epidemiologist. However, it would appear that we can agree that
there is indeed a difference between 'younger old' (i.e. 65-75) and 'older
old' (i.e. 80+), both in relative and absolute risk - albeit in opposite
directions. The key point here is not the strength of the associations
with age, but the magnitude of impact of treating the risk factor at any
given age. This is where interventional trials come in.
2. As I pointed out in my paper, the data about treating hypertension
in 80+ year olds accumulated prior to HYVET were very suggestive of
benefit; they predicted HYVET would give a definitive answer. HYVET - by
far the largest trial looking at patients aged 80+ - failed to live up to
this promise. Sadly, the premature termination of the trial (because of
excess mortality in the placebo group) arguably raised more questions
about the clinical applicability of its results, than the trial answered.
3. The PROSPER trial examined the use of statins in European patients
initially aged 70-82 (mean 75), and followed up for an average of 3.2
years. Nearly 20% of patients entered into the 4-week single-blind
placebo lead-in period failed to proceed to the randomised period (either
for using <75% or more than 120% of placebo, or because they refused to
participate). This raises questions as to generalisability. Whilst
reducing cardiovascular events, the intervention failed to show a
reduction in stroke. I fully accept that absence of evidence is not
necessarily evidence of absence, but this must surely raise questions as
to the magnitude of any true effect.
4. None of these trials looked into the patients' preferences and
priorities re outcomes. I argue that these change significantly with
advancing frailty and incapacity (which in turn increase
disproportionately with, but are not confined to, increasing age).
If we cannot even be certain of the ostensibly simple quantitative
aspect of the decision (the certainty of the magnitude of the treatment
effects), how can we properly weigh that up against the much more
difficult to define qualitative aspects (the beliefs, values, and
priorities of my patient)?
My central point is that without robust evidence applicable to the
patient in front of me - usually over 80, and often very frail - how can I
help the patient to reach truly informed consent? I may well have some of
the estimates of magnitude wrong, but the principle still stands. A
treatment decision is only as strong as its weakest link. I suggest that
there are so many weak links in this particular evidence chain that it is
almost impossible to reach a decision that all doctors would support.
Suggesting that a simple 'one size fits all' (i.e. algorithmic guideline-
based) solution would be appropriate is simplistic. Without more data we
cannot be sure.
For all these reasons I strongly urge that we undertake randomised
trials of withdrawals of treatment in real life elderly patients (both
frail and robust). This has the potential to find out how much impact
these interventions have in clinical practice, as opposed to in the
rarefied environment of scientific clinical trials.
In the UK NHS we arguably should have a real opportunity to use 'big
data' in real life in this way to find out if there are any signals there
amongst the noise. A simple pragmatic trial involving tens of thousands
of people would surely have a good chance of giving us the information we
need? If the NHS funded this with the money currently earmarked for
hitting treatment targets in those over 80, it would not take long to
answer this question.
While I agree with Dr Byatt that it is important to discuss with
patients the choices of treating risk factors to prevent disease, the
basis for the discussion needs to be clarified and fine-tuned.
Epidemiology: The attributable risk of hypertension in stroke
decreases in the elderly. This phenomenon may be partly because other
factors such as atrial fibrillation become more dominant factor....
While I agree with Dr Byatt that it is important to discuss with
patients the choices of treating risk factors to prevent disease, the
basis for the discussion needs to be clarified and fine-tuned.
Epidemiology: The attributable risk of hypertension in stroke
decreases in the elderly. This phenomenon may be partly because other
factors such as atrial fibrillation become more dominant factor.
Framingham Study quoted in the paper is only one study. Pooling data from
multiple studies, Prospective Studies Collaboration has reported that that
higher risk of stroke mortality is observed with higher systolic and
diastolic blood pressures across blood pressure ranges into age 80s.[1]
The relative risk conferred with higher blood pressure diminish with age,
but still in age 80s, 20 mm Hg increase in systolic blood pressure (SBP)
is associated with ~1.5 fold increase in stroke. That compares with ~2.8
fold increase in risk of stroke in age 40s. But the absolute risk
difference with increase in SBP or DBP is greater in old age.
Even if Dr Byatt's reading of epidemiologic data is correct, a lack
of observed association disease (stroke) with a risk factor (hypertension)
does not necessarily translate that intervening on the factor would not
reduce disease. This was clearly shown in case of cholesterol, where no
consistent association with stroke risk has been shown in multiple
studies.[2] Yet, clinical trials using statin class of cholesterol
lowering medications have shown that stroke is indeed reduced if the study
size is large enough in both primary and secondary prevention settings.[3,
4] We cannot assume that because the contribution of hypertension is
smaller as one gets older, that treatment would not reduce stroke.
Trial data: There is a consistent finding from clinical trials of
blood pressure reduction comparing different targets or regimens that SBP
reduction of 10-20 mm Hg confer a relative reduction stroke by about 30-
40%. Most studies confirm that stroke is very sensitive to blood
pressure.[5] The finding of the HYVET study mentioned consistent in
relative risk reduction of fatal and nonfatal stroke by 30% (p=0.06) with
SBP difference in 15 mm Hg between the groups. The study may have be
underpowered to reach statistical significance.
One needs to keep in mind that the risk of stroke is low in the
relatively healthy elderly individuals in clinical trials that mostly
consists of persons free of cardiovascular disease. HYVET study with 80
years of age or older and found a rate of stroke of 1.7% per year in the
placebo group. Active treatment results in a number needed to treat of 94
over 2 years to prevent one stroke. For comparison, in ALLHAT, with the
mean age of 67, the annual stroke rate was ~1% per year.[6]
Primary prevention is a challenge because the event rate and absolute
risk reduction by intervention is low, even if relative risk reduction is
large. In the elderly, the risk of events is higher, but the time horizon
is also shorter. The discussion should not necessarily focus on the
absolute risk reduction and the number needed to treat, but put the
context of the outlook of the elderly individuals into the next several
years, some of whom are living into elderly age in relative good health.
Prioritizing may be important. What are the important diseases to prevent,
screen, treat? While Dr Byatt focuses on stroke, treatment of hypertension
reduces strokes, congestive heart failure, and myocardial infarction.
While I agree with the recent JNC 8 recommendation to question the same
blood pressure target across ages, hypertension cannot be simply viewed as
over treated.[7]
References
1) Lewington S, Clarke R, Qizilbash N, et al. Age-specific relevance of usual blood pressure to
vascular mortality: a meta-analysis of individual data for one million
adults in 61 prospective studies. Lancet 2002;360(9349):1903-13.
2) Lewington S, Whitlock G,
Clarke R, et al. Blood cholesterol and vascular mortality by age, sex, and blood
pressure: a meta-analysis of individual data from 61 prospective studies
with 55,000 vascular deaths. Lancet 2007;370(9602):1829-39.
3) Taylor FC1, Huffman M, Ebrahim S. Statin therapy for primary
prevention of cardiovascular disease. JAMA 2013;310(22):2451-2.
4) Amarenco P, Labreuche J. Lipid management in the prevention of
stroke: review and updated meta-analysis of statins for stroke prevention.
Lancet Neurol 2009;8(5):453-63.
5) Staessen JA1, Wang JG, Thijs L. Cardiovascular protection and
blood pressure reduction: a meta-analysis. Lancet. 2001;358(9290):1305-15.
6) ALLHAT Officers and Coordinators for the ALLHAT Collaborative
Research Group. Major outcomes in high-risk hypertensive patients
randomized to angiotensin-converting enzyme inhibitor or calcium channel
blocker vs diuretic: The Antihypertensive and Lipid-Lowering Treatment to
Prevent Heart Attack Trial (ALLHAT). JAMA. 2002;288:2981-2997
7) James PA, Oparil S, Carter BL, et al. 2014
evidence-based guideline for the management of high blood pressure in
adults: report from the panel members appointed to the Eighth Joint
National Committee (JNC 8). JAMA 2014;311(5):507-20.
We are very grateful for the positive comments from Dr Basaria
about our meta-analysis of randomized controlled trials (RCTs) showing
that testosterone therapy among men increases the risk of a cardiovascular
-related event (1;2). As per the Preferred Reporting Items for Systematic
Reviews and meta-Analysis (PRISMA) guidelines (item 25) (3), we also
highlighted the limitations of our review. We are surpr...
We are very grateful for the positive comments from Dr Basaria
about our meta-analysis of randomized controlled trials (RCTs) showing
that testosterone therapy among men increases the risk of a cardiovascular
-related event (1;2). As per the Preferred Reporting Items for Systematic
Reviews and meta-Analysis (PRISMA) guidelines (item 25) (3), we also
highlighted the limitations of our review. We are surprised that a comment
on compliance with the PRISMA guidelines is followed by the sentence
"Therefore, firm conclusions regarding the association between
testosterone therapy and CVD cannot be drawn from this study" (1). This
line of reasoning would preclude firm conclusions
being drawn from all well-conducted meta-analyses of RCTs, which
inevitably each have limitations as well as strengths. In a recent update of the Competing Interests statement associated with
his commentary, Dr Basaria, and the editor, have clarified a number of
potential conflicts of interest including connections with pharmaceutical
companies selling or developing testosterone therapy, which may affect
readers' interpretation of the commentary. A separate report describes the
way pharmaceutical companies have subtly promoted testosterone therapy (4)
despite growing evidence of its harmful effects.
References
(1) Basaria S. Need for standardising adverse event reporting
in testosterone
trials. Evid Based Med 2013.
(2) Xu L, Freeman G, Cowling BJ, et al. Testosterone
and cardiovascular events among men: a systematic review and meta-analysis
of placebo-controlled randomized trials. BMC Med 2013;11(1):108.
(3) Moher D, Liberati A, Tetzlaff J, et al. Preferred
reporting items for systematic reviews and meta-analyses: the PRISMA
statement. PLoS Med 2009;6(7):e1000097.
(4) Braun SR. Promoting "Low T": A Medical Writer's
Perspective. JAMA Intern Med 2013;173(15):1458-1460.
Montori and Brito draw attention to the limited clinical significance
of statins' raising glucose (1), consistent with the non-linear
association of fasting glucose with cardiovascular disease (2). It is
quite possible that the limited clinical significance of statins' minor
effects on glucose also translates into limited aetiological significance.
On the other hand, statins are not alone in having diver...
Montori and Brito draw attention to the limited clinical significance
of statins' raising glucose (1), consistent with the non-linear
association of fasting glucose with cardiovascular disease (2). It is
quite possible that the limited clinical significance of statins' minor
effects on glucose also translates into limited aetiological significance.
On the other hand, statins are not alone in having divergent effects on
diabetes and cardiovascular disease. At least one other well-established
therapy for preventing cardiovascular disease also has the same set of
effects. Diuretics similarly both decrease the risk of cardiovascular
disease but also increase the risk of diabetes. Conversely, some effective
treatments for diabetes have been found to increase the risk of
cardiovascular disease, such as rosiglitazone and sulphonureas.
Notwithstanding, the very well-established relation between diabetes and
cardiovascular disease, this consistent pattern from experimental evidence
suggests the existence of an underlying exposure which may both protect
against cardiovascular disease and cause diabetes.
In randomized controlled trials testosterone therapy improves glucose
metabolism (3) but increases the risk of cardiovascular-related events
(4). Moreover, evidence from randomized controlled trials shows that
statins reduce testosterone (5). Taking all this experimental evidence
together raises the possibility that the mechanism underlying the
divergent effects of statins on both diabetes and cardiovascular disease
could be androgen modulation. Whether such a mechanism could also be
relevant to the other therapies which also have divergent effects on
diabetes and cardiovascular disease has never been considered. Notably
spironolactone, which is known to decrease androgens, also has divergent
effects on cardiovascular disease and diabetes, preventing mortality in
heart failure but adversely affecting glucose metabolism (6). A small
mechanistic randomized controlled trial examining whether the effects of
statins on key factors in the ischemic pathway, such as markers of
endothelial function or clotting factors (7), could be mediated by
androgens, would provide confirmation or refutation. Androgen modulation
as a contributor to the mechanism of statins, and perhaps other therapies,
not only potentially provides a unified explanation for paradoxical
results from randomized controlled trials, but also is consistent with the
higher age-standardized rates of cardiovascular disease among men than
women.
References
(1) Montori VM, Brito JP. Statins induce hyperglycaemia of uncertain
importance. Evid Based Med 2013;18(4):157-158.
(2) Sarwar N, Gao P, Seshasai SR, Gobin R, Kaptoge S, Di AE et al.
Diabetes mellitus, fasting blood glucose concentration, and risk of
vascular disease: a collaborative meta-analysis of 102 prospective
studies. Lancet 2010;375(9733):2215-2222.
(3) Jones TH, Arver S, Behre HM, Buvat J, Meuleman E, Moncada I et al.
Testosterone replacement in hypogonadal men with type 2 diabetes and/or
metabolic syndrome (the TIMES2 study). Diabetes Care 2011;34(4):828-837.
(4) Xu L, Freeman G, Cowling BJ, Schooling CM. Testosterone therapy and
cardiovascular events among men: a systematic review and meta-analysis of
placebo-controlled randomized trials. BMC Med 2013;11:108.
(5) Schooling CM, Au Yeung SL, Freeman G, Cowling B.J. The effect of
statins on testosterone in men and women: a systematic review and meta-
analysis of randomized controlled trials. BMC Medicine 2013;11:57.
(6) Swaminathan K, Davies J, George J, Rajendra NS, Morris AD, Struthers
AD. Spironolactone for poorly controlled hypertension in type 2 diabetes:
conflicting effects on blood pressure, endothelial function, glycaemic
control and hormonal profiles. Diabetologia 2008;51(5):762-768.
(7) Violi F, Calvieri C, Ferro D, Pignatelli P. Statins as antithrombotic
drugs. Circulation 2013; 127(2):251-257.
We would like to thank DeFrank and Brewer for their interest in our
recently published paper: Long-Term Psychosocial Consequences of False-
Positive Screening Mammography.(1)
In the Methods section DeFrank and Brewer write: "Brodersen and
colleagues conducted a study of 454 adult women in Denmark screened in the
same time period who had normal mammography screening results, false-
positives or...
We would like to thank DeFrank and Brewer for their interest in our
recently published paper: Long-Term Psychosocial Consequences of False-
Positive Screening Mammography.(1)
In the Methods section DeFrank and Brewer write: "Brodersen and
colleagues conducted a study of 454 adult women in Denmark screened in the
same time period who had normal mammography screening results, false-
positives or breast cancer diagnoses." We (Brodersen & Siersma)
included 454 adult women in Denmark who had abnormal mammography screening
results (false-positives or breast cancer diagnoses) and 864 women with
normal screening results - all 1318 screened in the same time period.
In the Methods section DeFrank and Brewer also state that the
questionnaire we used: the Consequences Of Screening in Breast Cancer (COS
-BC), is a revised version of the question: the Psychosocial Consequences
Questionnaire (PCQ). This is not the case. Together with the developer of
the original Australian version of the PCQ - deceased Professor Jill
Cockburn - we published a systematic reviewed on "The adequacy of
measurement of short and long-term consequences of false-positive
screening mammography".(2) Part of our conclusion was: "The PCQ is an
adequate questionnaire for measuring short-term consequences, and the PCQ
is preferable to other measures because of its higher sensitivity.
However, there is little evidence that the PCQ is able to adequately
detect all long-term consequences of screening mammography. Given the
inadequacy of the measurement instruments used, any current conclusions
about the long-term consequences of false-positive results of screening
mammography must remain tentative".
In a qualitative study including six focus interviews with women having
false-positive screening mammography we found that the PCQ includes
ambiguous items, does not cover all psychosocial consequences of false-
positive screening mammography and three items from the PCQ were deleted
because they were judged by interviewees to be irrelevant.(3) We also
found that the women's experiences in the critical period from abnormal
screening mammography until final false-positive diagnosis differed
entirely from their experiences after the final diagnosis.(3) Therefore,
fifteen new items were generated to cover the negative psychosocial
consequences of abnormal and false-positive screening mammography
comprehensively.(3) Five new items were produced that concerned the
consequences of screening mammography during the period after being
declared ''free from'' suspicion of cancer.(3) Response options for the
positive items were changed to allow responses in both positive and
negative directions. Our conclusion was: "Because of the major changes to
both parts of the PCQ the measure derived from this study should be
regarded as a new questionnaire with two parts: Consequences Of Screening
in Breast Cancer (COS-BC). Part II focuses on the long-term consequences
of a false-positive screening mammography".(3)
Because we had developed a new questionnaire (based on Jill Cockburn's
work) we conducted two psychometric studies using the Item Response Theory
Partial Credit Rasch model for polytomous items plus Classical Test Theory
to validate the COS-BC.(4;5) Therefore, it is slightly confusing that
DeFrank and Brewer calls COS-BC for PCQr when it actually is a new
measure.
Due to this extensive qualitative and statistical psychometrical work we
have provided robust high quality evidence that the subscales of the COS-
BC measure each distinct constructs that are unidimensional. It is
therefore wrong when DeFrank and Brewer in the Commentary section write
that some "subscales mix multiple constructs". Furthermore, we have
revealed that the PCQ lacks content validity and encompass ambiguous
items. Because the COS-BC has high content validity and adequate
psychometric properties we can conclude that the COS-BC and the PCQ do not
measure the same thing. It is therefore not appropriate that DeFrank and
Brewer compare the scores of the PCQ with the scores of the COS-BC.
Furthermore, standard methods, like the correlation coefficients are
different from our linear regression methods, and do not adjust for the
differential dropout. As stated in our method section: "We used
generalized estimating equations methods to account for repeated
measurement on the same individual. To adjust for possible bias resulting
from differential dropout from the study, the scores available at each
follow-up time point were weighted by the inverse of an estimate of the
probability of this score being observed at that time point".(1) Those
people that are worse off have the tendency to drop out in surveys. In our
case, women diagnosed with breast cancer and the women that are most
affected by the false-positive screening result could have a higher
tendency to drop out; analysing only the subjects that did not drop out
will then artificially decrease effects. By using inverse probability
weighing and correcting the confidence intervals accordingly using
generalized estimating equations we have adjusted for this differential
drop out. The relatively small effect sizes found and commented on by
DeFrank and Brewer using our data may well be an artefact of not adjusting
for dropout.
In the Commentary section DeFrank and Brewer also write that the COS
-BC "has a subscale for breast self-examination, a behaviour that many
guidelines now recommended against". However, the subscale has not
anything to do with breast self-examination recommendations. In our
qualitative study we found that women with false-positive screening
mammography examined their breasts with their hands and examined their
breasts in a mirror as a psychosocial consequence of the false-positive
results and not because of any recommendation.
In the Commentary section DeFrank and Brewer also write: "The second
half of the PCQr assesses how patients...". Most of these women are not
patients. The main part of the women in our survey had a normal or a false
-positive screening result and besides that they were healthy. In the same
sentence DeFrank and Brewer continue:"....think the testing affected them
and uses an uncommon scoring system." We do not find the scoring system as
a limitation since the response categories and scoring system for part 2
of the COS-BC were developed during the previous mentioned focus group
interviews.(3) Furthermore, part2 of the COS-BC was validated using the
empirical knowledge from these interviews,(3) the theory of cognitive
dissonance, the theory of sense of coherence, and as mentioned above Item
Response Theory Partial Credit Rasch model for polytomous items. (4;6)
In the Commentary section DeFrank and Brewer lastly write: "Finally,
the absence of analyses that demonstrate whether changes over time
differed by test results, the internal consistency of measures and their
reliability over time. Study findings would be strengthened by the
inclusion of outcomes assessed before screening or learning of test
results." Test for interaction between time and the three screening groups
could have been added to the tables, but such test may not have been very
informative because of the large differences between the trajectories in
the start of follow-up: most tests for interaction were highly
significant. Where items are shown to fit a Rasch model the measure can be
shown to posses criterion-related construct validity,(7) to be objective
(invariant),(8) sufficient(9) and, therefore, also reliable.(10)
Furthermore, we have provided evidence that the items in the subscales do
not posses differential item functioning in relation to time.
References
(1) Brodersen J, Siersma VD. Long-Term Psychosocial Consequences of
False-Positive Screening Mammography. The Annals of Family Medicine 2013;11(2):106-15.
(2) Brodersen J, Thorsen H, Cockburn J. The adequacy of measurement
of short and long-term consequences of false-positive screening
mammography. J Med Screen 2004 Mar 1;11(1):39-44.
(3) Brodersen J, Thorsen H. Consequences Of Screening in Breast
Cancer (COS-BC): development of a questionnaire. Scand J Prim Health Care
20081;26(4):251-6.
(4) Brodersen J. Measuring psychosocial consequences of false-
positive screening results - breast cancer as an example. Department of
General Practice, Institute of Public Health, Faculty of Health Sciences,
University of Copenhagen: M?nedsskrift for Praktisk L?gegerning,
Copenhagen. ISBN: 87-88638-36-7; 2006.
(5) Brodersen J, Thorsen H, Kreiner S. Validation of a condition-
specific measure for women having an abnormal screening mammography. Value
in Health 2007;10(4):294-304.
(6) Brodersen J, Thorsen H, Kreiner S. Consequences Of Screening in
Lung Cancer: Development and Dimensionality of a Questionnaire. Value in
Health 2010;13(5):601-12.
(7) Rosenbaum PR. Criterion-related construct validity. Psychometrika
1989 ;54(4):625-33.
(8) Rasch G. An Informal Report on a Theory of Objectivity in
Comparisons. In: Van der Kamp LJTh, Vlek CAJ, editors. Psychological
Measurement Theory.Leyden: University of Leyden; 1967:1-19.
Medication incidents are the commonest reported clinical incident in
children and the second most common in neonates. [1] Current evidence is
that the most effective method of reducing these incidents in the acute
hospital is to have frequent attendance on the ward by a clinical
pharmacist. [2,3] This was discussed by Chua in Evidence Based
Medicine.[4]
Medication incidents are the commonest reported clinical incident in
children and the second most common in neonates. [1] Current evidence is
that the most effective method of reducing these incidents in the acute
hospital is to have frequent attendance on the ward by a clinical
pharmacist. [2,3] This was discussed by Chua in Evidence Based
Medicine.[4]
We wanted to see how many other units in Northern and Cumbria Regions
of England were in a similar situation. A member of staff from each of
eleven children's ward and neonatal units in the Northern Region of
England was telephoned. (Great North Children's Hospital, Sunderland Royal
Hospital, James Cook University Hospital, North Tyneside General Hospital,
Carlisle Royal Infirmary, West Cumberland Hospital, South Tyneside General
Hospital, Queen Elizabeth Hospital Gateshead, North Tees General Hospital
and the two inpatient units in our Trust: University Hospital North Durham
and Darlington Memorial Hospital). If they had a pharmacist visit three
times a week or more to review inpatient and discharge drugs in real time
they were scored as having ward based pharmacists. Weekly visits to
provide a ward top-up service were not counted.
Of the eleven neonatal units, five (45%) had clinical pharmacists. Of
the eleven inpatient children's wards, five (45%) had clinical
pharmacists. These five units were not the same for neonates and
paediatrics.
CDDFT is about to pilot a clinical pharmacist to support the
paediatric and neonatal patients within the Trust. We wonder if this issue
has been identified in other units and if so whether there are examples of
innovative practice and outcome measures that address this?
References
1) National Patient Safety Agency. Review of patient safety for
children and young people.
2) Sanghera N, Chan P-Y, Khaki ZF et al. Interventions of Hospital
Pharmacists in Improving Drug Therapy in Children. A systematic Literature
Review. Drug Safety 2006 (11): 1031-1047
3) McCartney RJ, McCartney RG, Postle JA et al. An Evaluation of
Clinical Pharmacist Contributions in Paediatrics Arch Dis Child 2011 96:e1
4) Chua SS. Errors detected in 19% of paediatric medication
preparations and administrations across five hospitals in London. Evid
Based Med 2010;15:123-124 doi:10.1136/ebm1087
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Dear Editor,
We would like to thank DeFrank and Brewer for their interest in our recently published paper: Long-Term Psychosocial Consequences of False- Positive Screening Mammography.(1)
In the Methods section DeFrank and Brewer write: "Brodersen and colleagues conducted a study of 454 adult women in Denmark screened in the same time period who had normal mammography screening results, false- positives or...
Dear Editor,
Medication incidents are the commonest reported clinical incident in children and the second most common in neonates. [1] Current evidence is that the most effective method of reducing these incidents in the acute hospital is to have frequent attendance on the ward by a clinical pharmacist. [2,3] This was discussed by Chua in Evidence Based Medicine.[4]
We wanted to see how many other units i...
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