Practical Diabetes Care

467 Pages·2018·3.915 MB·English

by  David Levy

Practical Diabetes Care
Practical Diabetes
Care
FOURTH EDITION
David Levy MD FRCP
Formerly Consultant Physician, Barts Health NHS Trust, Whipps Cross University Hospital, London
The London Diabetes Centre, Marylebone, London
This fourth edition first published 2018 © 2018 by John Wiley & Sons Ltd
Edition History
John Wiley & Sons Ltd (3e, 2011)
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Library of Congress Cataloging‐in‐Publication Data
Names: Levy, David, 1954– author.
Title: Practical diabetes care / by David Levy.
Description: Fourth edition. | Hoboken, NJ : Wiley, 2017. | Includes
bibliographical references and index. |
Identifiers: LCCN 2017040598 (print) | LCCN 2017041148 (ebook) | ISBN
9781119052234 (pdf) | ISBN 9781119052227 (epub) | ISBN 9781119052241 (pbk.)
Subjects: | MESH: Diabetes Mellitus–therapy | Diabetes Mellitus–diagnosis
Classification: LCC RC660 (ebook) | LCC RC660 (print) | NLM WK 815 | DDC
616.4/62–dc23
LC record available at https://lccn.loc.gov/2017040598
Cover design: Wiley
Cover image: Courtesy of David Levy
Set in 8.5/10.5pt Frutiger by SPi Global, Pondicherry, India
10 9 8 7 6 5 4 3 2 1
Contents
Acknowledgments, vii
Introduction, ix
Clinical trials and organizations: abbreviations and acronyms, xv
1 Classification, diagnosis and presentation, 1
2 Diabetes emergencies, 25
3 Infections and the diabetic foot, 49
4 Eyes and kidneys, 77
5 Neuropathy, musculoskeletal and skin, 115
6 Diabetes and the cardiovascular system, 141
7 Type 1 diabetes: glycaemic control, 171
8 Type 1 diabetes: technology and transplants, 197
9 Type 2 diabetes: weight loss, exercise and other ‘lifestyle’
interventions, 217
10 Type 2 diabetes: glycaemic control, 241
11 Hypertension, 315
12 Lipids, 359
13 Clinical aspects of the metabolic syndrome, 387
14 Youth and emerging adulthood; old age, 401
15 Psychological aspects of diabetes, 425
Index, 439
v
Acknowledgments
This book’s peer reviewers have added clarity, focus and critical detail and have been
astonishingly sweet and supportive. Without their clear advice I would have blundered
up several, possibly many, more medical garden paths leading to cul‐de‐sacs all named
Embarrassment Drive. I applaud their directionality and comradely scholarship.
My dear long‐time friend and colleague Dr Tore Julsrud Berg (Oslo University Hospitals)
reviewed Chapter 1 (Classification) and the two chapters on Type 1 diabetes (Chapters 7
and 8). Everything I have written over the years on Type 1 diabetes has been improved
by his patience and encouragement. I can only aspire to his intense pragmatism com-
bined with academic rigour (and to the wonderful modernist Oslo house meticulously
treasured and preserved by Tore and his wife, Anne Valle).
Dr Edouard Mills, a specialist registrar in endocrinology who previously worked with
me during his foundation training, meticulously and thoughtfully reviewed Chapter 2
(Diabetes emergencies) and Chapter 11 (Hypertension).
Dr Albert Mifsud gently chided and guided me about antibiotics in diabetic infections
(Chapter 3) with the same patience my late colleague Dr Louise Neville had shown in
earlier editions. I hope there are no remnants in the text of our intellectual fist‐fights on
the Whipps Cross wards (and many years ago at the Central Middlesex Hospital) – both
part of the great outer circle of University Hospitals in London whose heyday of teaching,
research and clinical care from the end of World War II up to the 1980s has been eclipsed
by progressive resource starvation and massively increased clinical stresses over the past
two decades.
Professor Miles Fisher, coiner of one of the great aphorisms of diabetes, reviewed
Chapter 6 (Diabetes and the cardiovascular system) with the same speed and efficiency
with which he no doubt traverses the glens of his native country by bike.
Helen Alston, specialist registrar in nephrology, brought me up to date on many renal secrets.
Carin Hume, a wonderfully practical dietician at London Medical who inhabits the real
world of dietetics, even allowed me to pursue higher protein, lower carbohydrate diets
in Chapter 8.
Professor Alan Sinclair, doyen of diabetes care in older people, forgave me the mere
hemi‐chapter I devoted to his critical subject (Chapter 14) and reminded me about the
pervasive impact of frailty in older people with diabetes.
Dr Nicoletta Dozio and Dr Marina Scavini of the Diabetes Research Institute of San
Raffaele Hospital in Milan helped with all the sections of the book relating to diabetes
and pregnancy. Wonderful stays at Nicoletta’s and Stefano’s beautiful palazzo in Merate
undoubtedly increased my retention rate of key facts in an area of diabetes practice that
continues to be neglected by clinicians in primary and secondary care.
Professor Karim Meeran (Imperial Centre for Endocrinology) kindly provided me with
access to the invaluable online manual of endocrine test protocols. He is happy to share
the intranet link with all readers:
http://imperialendo.co.uk
vii
viii Acknowledgments
Pretty well every paragraph of this book owes any breadth and new insight to Timo
Pilgram, Senior Library Assistant at Whipps Cross University Hospital. Every reference
I requested (and a lot of illustrations) pinged into my inbox in full text form within a few
hours, sometimes minutes; but more important, dozens of references that I would never
have found using my kindergarten skills in Boolean logic are here because of Timo’s pure
talents of modern librarianship, combined with curiosity and tenacity and seemingly
unlimited manoeuvrability around the internet, shared by few clinicians. Imagination and
new stories (as they now say everywhere) are possible only when these startling skills
combust slightly after catalysis by the tiniest addition of serendipity. He deserves to be a
co‐author. More generally, librarianship in hospitals, just like libraries in the community,
is inevitably an easy target of cost‐cutting. Ensure, at least, that before they disappear
from your own institution you understand their continuing centrality to the pursuit of
modern medical thinking.
Most of the writing was done during 2016. My wife, Laura Liew, left me during the
first nine months to gain a Grande Diplôme in cuisine and patisserie at the London
Cordon Bleu School in Bloomsbury Square. Most days I could sit and write for twelve
hours, by which time Laura had returned, usually exhausted, with a take-away box con-
taining a French dish of staggering complexity and subtlety that had been the product of
her industry and rigorous supervision and assessment by the teaching chefs. Practical
Diabetes Care by day, lobster Thermidor for dinner: the haute cuisine recipe for extracting
the best possible performance from an author. I thoroughly commend it.
Introduction
Excuses normally round off the preface, but I owe readers some up‐front explanations:
for a fourth edition that’s at least three times weightier than the original of eighteen
years ago, and one still penned by a single author. As to the first, maturity doesn’t always
bring concision and simplification (in music Brahms managed it, Schoenberg and Berg
brought it to a state of crystalline perfection, but Wagner certainly didn’t), and the rela-
tively terse bulleted form (if not style) I managed in the dash to the millennium has
yielded, through normal aging and a desire to try and write real sentences, to a more
discursive approach. Recognizing the hazards to readers’ patience, this new edition is
riddled with Practice Points, which I hope are useful, in addition to the usual burden of
devices (boxes, tables, figures etc.) that I suspect are the 21st century equivalent of the
ornate Victorian section marker, and probably command a similar degree of attention.
A second problem, more substantive, is whether a single‐author book has any meaning
in the new world (let’s set aside the equally important matters of books versus electron-
ics, and textbooks versus monographs). In a tepid review of the last edition someone
wondered (I paraphrase) how I had the brass neck to invade territory such as diet therapy
in diabetes. But the reviewer made a minor category error in his understandable defence
of a non‐medical area, which I suspect he felt had been traduced by someone he consid-
ered a typical arrogant hospital doctor: his argument should have applied with at least
equal force to the sections on cardiology, psychology and bits of pathophysiology for
that matter. But of these other territorial meanderings there was no mention.
The conventional resolution is superficially simple: do multi‐author, much as now
everything is done multidisciplinary. There are wonderful multi‐author books (as I write
this, the Textbook of Diabetes, edited by Richard Holt and colleagues has reached its fifth
edition, and from the same publisher the fourth edition of the wide‐ranging International
Textbook of Diabetes) and I have huge admiration for any editor brave enough to
grapple with the stylistic lurchings and lumpy content that can gravitate to pet and
hobby‐horse topics of individual chapter authors. But probably through a combination
of real and perceived pressures to comply the writing often homogenizes to standard
passive academic prose, fuelled by the output of the meta‐analysis industrial complex (of
which more shortly) with a persistent risk of imbalance both within and between
chapters, in addition to the risk of trying to update the non‐updatable, when the best
option, probably involving little more work, is to start from scratch.
I’ve gone for the easy options. First, I’ve restructured the contents and completely
rewritten the book, strategies I hope have helped expunge old and less‐relevant material.
For example, I have now twinned diabetic eye disease with renal disease in the same
chapter, and continued to de‐emphasize the details of retinopathy, as the UK screening
programme has – fortunately – taken over from individual doctors attempting to wield
an ancient and non‐illuminating ophthalmoscope in vaguely the right direction. Type 1
diabetes, now more commonly encountered in primary care, has a fully deserved greater
prominence and there is a separate new chapter on technology, which of course is
already out of date. More patients and even some practitioners are emphasizing the
increasing evidence‐base of non‐pharmacological interventions in Type 2 diabetes, and
ix
x Introduction
I have enjoyed elaborating the fascinating detail emerging in diet, weight loss and
exercise. The chapter on the pharmacological treatment of Type 2 diabetes has also,
despite my best efforts, expanded. This is not just because new agents have been intro-
duced since the last edition in 2011 but we now have more evidence that helps us place
classes of drugs more precisely than before. However, more than ever we must maintain
a balanced approach to medication in relation to the wishes of patients and the
burgeoning cost of new drugs, especially when used in combination. The trial portfolios
that now accompany the launch of a new agent or insulin (some so self‐important they
have their own registered trademark) comprise bewildering numbers of individual
studies, some of which explore minute gaps in therapeutic combinations that may not
have occurred even to experienced practitioners. Superior brains might not make it to
the end of the titles of some of the more rococo comparisons. Second, I have asked
trusted colleagues to review some chapters and to deploy the electronic equivalent of the
blue pencil. They deserve their more prominent place, and my thanks, in Acknowledgments
rather than as another afterthought to the Introduction.
A fourth edition of any book should, above all, prompt general reflection, now a
ubiquitous box‐ticking requirement in appraisal and revalidation and therefore another
thoroughly diminished component of our professional life. But let me explain one
characteristic – increased true scepticism – that I hope the careful reader will detect
throughout the book. During the first half of the first decade of the 2000s I was a strong
advocate of the now largely discredited glitazone drugs. We’d already had a warning in
the later 1990s: the first agent, troglitazone was a cause of fatal liver disease and in the
United Kingdom was withdrawn within weeks of launch but it remained available else-
where far too long. This terrible outcome, attributed to a pharmacologically gratuitous
addition of a supposedly anti‐oxidant vitamin moiety to the molecule, served to de‐focus
concerns about other, more widespread adverse effects, and when the two follow‐on
drugs, rosiglitazone and pioglitazone, were introduced in 1999, battle was joined: not
in scrutinizing with greater ferocity their pros and cons but regrettably in a largely
commercial feud around antiatherosclerotic actions and minutiae of differences in
achieved lipid profiles, the aspirations of all of which disappeared in a puff of non‐
significances in clinical trial outcomes. At the same time we didn’t yet have the results
of the mega‐trials of the middle and latter part of the decade and therefore hadn’t
properly understood the limited importance to patients of what were – and still are –
relatively small changes in glucose levels in comparison with the clinical evidence of
substantial weight gain, oedema and possible heart failure, and trial data of increased
risk of fractures and anaemia. Statistical nit‐picking still rumbles on over the possible
increased risk of bladder malignancy with pioglitazone, at the same time as the drug
itself is no longer prescribed.
In 2007, Nissen and Wolski published highly suggestive but contested meta‐analyses
raising further concerns, this time about increased cardiovascular risk associated with
rosiglitazone; but groaning under an increasing burden of adverse effects the prescribing
status of rosiglitazone was not changed until 2009. The combined belief system, that
glycaemia is still of primary importance in the Type 2 syndrome, and that improvements
in intermediate measures of atherosclerosis somehow meant something for patients, still
hasn’t been confined to its proper speculative place, and after a few years of relative
calm, the potential antiatherosclerotic effects of the newest antihyperglycaemic agents
are still eliciting hyper‐excitable responses. As a result of all this activity, I hope you will
detect a much more cautious and a properly critical approach to all drugs, including the
seemingly interminable battle for supremacy over long‐acting analogue insulins, which is
Introduction xi
tiresome after witnessing nearly two decades of angels and camels alike struggling for
pole position at the extremities of small sharp structures, but clearly distracts from much
more important and eminently fixable matters, especially in Type 1 diabetes, and has
made the management of insulin‐treated diabetes in the USA a nightmare for many
patients because of cost. I am grateful for the thoughtful approach of Edwin Gale and
John Yudkin, long‐time techno‐ and pharma‐cynics, for activating my own concerns.
We’re only a few years away from the centenary of the first use of insulin, and I don’t
think the heroic early clinicians would be much impressed with our persistent bickering
over minute differences in nocturnal hypoglycaemia rates with long‐acting analogues to
try and convince ourselves and our patients that they are in any meaningful way better
than NPH insulin. The more the arguments, the more it becomes clear that the superior-
ity of a furiously defended insulin preparation is irrelevant compared with the way we
work with patients to use insulin.
Two further concerns can probably be detected. First, the invasion of our medical lives
by the increasingly raucous onslaught of systematic review and meta‐analysis, which
some commentators now believe is distorting research priorities. Evidence‐based medi-
cine, the broad principles of which we all subscribe to, is now within striking distance of
being considered coterminous with systematic review and meta‐analysis; that is, meta‐
analysis is moving to a privileged position as the highest form of evidence‐based medi-
cine. It is of course an important component of the evidence base, but in clinical diabetes
our most reliable source should be the well‐conducted clinical trial, published in a high
quality peer‐reviewed journal, preferably with all the supplementary data readily acces-
sible, because for a variety of reasons much important information is relegated to sup-
plementary data files. Forest plots, even more than woods, obscure the beautiful
structure of individual trees.
Second, more important, is the balance between opinion and evidence. We are rapidly
shifting, again in part under the baleful influence of meta‐analysis, to declaring opinion
unnecessary, and in its strong form, hazardous. In turn, this perverse view was based on
the now largely derided ‘experience’ without which, so the medical educationalists tell us,
we can practice the highest quality medicine, so long as we have access to a smartphone,
guidelines and do competent handovers. But in this sense medicine remains, frustratingly,
way behind the times. In other fields we have passed peak ‘objectivity’; to take another
musical analogy, the radical ‘early music’ movement of the 1970s and 1980s, which cel-
ebrated baroque music as inflexible machine‐music translated directly from the dots on
the unencumbered urtext page, has moved to a proper accommodation between textual
accuracy and recognition that Kapellmeister Bach and his musicians were likely to be no
less affected by the emotional impact of his miraculous music than twenty‐first century
listeners. I have, therefore, attempted here to present balanced information with an occa-
sional personal view. Don’t ignore the former (or preferably look for more and contradic-
tory material) but at least consider the latter – and then discard it. There shouldn’t be
much difficulty in spotting the difference between the two.
Another tangential advantage of a single‐author work is that I have been able to
zig‐zag my way through the manuscript right up to the time of submission, adding new
information and references supplied by colleagues and friends. Chapter 1 is, therefore,
as dated as, but no more than, Chapter 15. PMID numbers will help you track down
papers that do not have consistent citations by entering the eight‐digit number into the
PubMed search box. I have deliberately included as many papers as possible that are
available as free full text, with their associated seven‐digit PMC (PubMed Central)
identifiers. In trawling through hundreds of references I have been struck by the widely
xii Introduction
differing practices of quality journals; without naming individual publications I don’t
think are behaving very well – which I would have dearly loved to do – let me applaud at
least the New England Journal of Medicine, which seems to maximize the availability of
free full text articles, and without the mendacity of imposing a year’s delay or, even more
pernicious, making available a ‘printer‐friendly’ version that isn’t so friendly when your
printer churns out 50% more paper because the article isn’t properly formatted. These
matters are far from trivial. They include the converse situation, pharma companies pre-
sumably paying for immediate full‐text availability of research papers that support the
use of their new agents, and also the startlingly perverse practice of issuing grand con-
sensus statements, of which there are unstoppable torrents, with no free full text avail-
ability. Such practices distort the availability of research and scholarship and risk adding
substantial bias to our views.
Though I know I tormented Pri Gibbons, my patient editor at Wiley Blackwell, by
exceeding our original agreed word count at least twofold and delivering it at least two
years late, writing it has been therapeutic for me, and I hope will be entertaining in
places for readers. In this edition, originally commissioned by Oliver Walter, I have been
guided by the principles and practices of Stephen Pinker, one of the finest modern scien-
tific writers. He suggests at least three full re‐writes of manuscripts and encouraged me
in my first attempt to rigorously avoid the ‘curse of knowledge’ – the infuriating and
anti‐educational practice of ‘experts’ writing as if every reader has immediate command
of as much information as the author, thereby obviating its primary educational purpose.
Everyone considering writing non‐fiction should first read his magical blend of serious
linguistics and hilarious examples of grotesque misuse of English in The Sense of Style
(Pinker, 2015). I didn’t regret doing so. If there is any graceful writing in the book it’s
mostly due to Pinker’s benign influence.
The previous edition drew warm comments from friends and colleagues, and some-
one even claimed that five years on they were still referring to it, which is heartening but
also a bit scary. It was wonderful to see copies of translations of the third edition into,
among other languages, Polish and Chinese. The latter reminded me that the widely‐
repeated and mostly self‐serving fib of the ‘diabetes epidemic’ in the West is almost
certainly true when applied to South East Asia, and though the literature is shockingly
slender, I have tried to include discussion and references relevant to that critically impor-
tant part of the world. In general I hope that this edition has slightly more international
relevance than the technocratic focus of the previous three.
There are lots and lots of books on diabetes, and many have ‘Care’ somewhere in the
title. The word was included in the title of the third edition at the ‘request’ of Wiley
Blackwell, because a senior editorial team felt that ‘Practical Diabetes’ (as the first two
editions were titled) couldn’t exist (I disagree: nobody would object to a book called plain
‘Practical Plumbing’ or even – I think there are many already – ‘Practical Philosophy’.
There is a good popular journal in the United Kingom called ‘Practical Diabetes’ that
hasn’t felt the need for the obligatory ‘care’ designation). It doesn’t matter: it’s on the
‘Practical’ that I would like this book to be judged. But a book designed to help practis-
ing healthcare professionals can’t just be a recipe book (nor, of course, can a good recipe
book). Some of the chapter reviewers felt that the introductory stuff was a little heavy on
background material and numbers, and they may be right. But if this book, like its
predecessors, helps practitioners think about sleek minimalism in management, while
suggesting an occasional evidence‐based trick that might shorten the journey time for
some patients, then I don’t mind too much if readers omit some of the introductory bits.