BACKGROUND: Hospital episode statistics (HES) is a UK national database for the National Health Service (NHS), now available online. The purpose of this study was to observe trends in ophthalmic operations performed during the period from 1998 to 2004, using this data. METHODS: From the 'Main Operation' codes within the 'Free data' section of the HES website we analysed data in regard to 28 specific ophthalmic operations. These represented each sub speciality within ophthalmology. RESULTS: The figures show a change in the total number and proportions of operations performed for many of the procedures. For example, there was an increase in numbers of orbital decompressions, but a decrease in numbers of glaucoma filtering operations. Changing trends could be seen in different surgical areas such as the change in operations used for corneal grafting and in retinal surgery. CONCLUSION: The HES database represents an important, potentially useful source of information. There are imitations in interpretation of and validity of such data related to coding inconsistencies. We suggest the benefit of the data comes from observing trends rather than exact numbers. As other studies using this data have suggested, it is important that clinicians are involved in improving the quality of this data

A Judge

AL Coleman

J Hacker

J Williams

JC Javitt

JE McCabe

Lucy C Clarke

M Roland

Scott G Fraser

SG Fraser

English

PubMed

Springer - Publisher Connector

Hospital Episode Statistics and trends in ophthalmic surgery 1998 – 2004

Abstract Background Hospital episode statistics (HES) is a UK national database for the National Health Service (NHS), now available online. The purpose of this study was to observe trends in ophthalmic operations performed during the period from 1998 to 2004, using this data. Methods From the 'Main Operation' codes within the 'Free data' section of the HES website we analysed data in regard to 28 specific ophthalmic operations. These represented each sub speciality within ophthalmology. Results The figures show a change in the total number and proportions of operations performed for many of the procedures. For example, there was an increase in numbers of orbital decompressions, but a decrease in numbers of glaucoma filtering operations. Changing trends could be seen in different surgical areas such as the change in operations used for corneal grafting and in retinal surgery. Conclusion The HES database represents an important, potentially useful source of information. There are imitations in interpretation of and validity of such data related to coding inconsistencies. We suggest the benefit of the data comes from observing trends rather than exact numbers. As other studies using this data have suggested, it is important that clinicians are involved in improving the quality of this data.</p

Fraser Scott G

Clarke Lucy C

Directory of Open Access Journals

BMC Ophthalmology

Crossref

BioMed CentralBMC Ophthalmology
ssOpen AcceResearch article
Hospital Episode Statistics and trends in ophthalmic surgery 1998 – 
2004
Lucy C Clarke and Scott G Fraser*
Address: Sunderland Eye Infirmary, Queen Alexandra Road, Sunderland, Tyne and Wear, SR2 9HP, UK
Email: Lucy C Clarke - Lucyclarke@doctors.org.uk; Scott G Fraser* - S.G.Fraser@ncl.ac.uk
* Corresponding author    
Abstract
Background: Hospital episode statistics (HES) is a UK national database for the National Health
Service (NHS), now available online. The purpose of this study was to observe trends in ophthalmic
operations performed during the period from 1998 to 2004, using this data.
Methods: From the 'Main Operation' codes within the 'Free data' section of the HES website we
analysed data in regard to 28 specific ophthalmic operations. These represented each sub speciality
within ophthalmology.
Results: The figures show a change in the total number and proportions of operations performed
for many of the procedures. For example, there was an increase in numbers of orbital
decompressions, but a decrease in numbers of glaucoma filtering operations. Changing trends could
be seen in different surgical areas such as the change in operations used for corneal grafting and in
retinal surgery.
Conclusion: The HES database represents an important, potentially useful source of information.
There are imitations in interpretation of and validity of such data related to coding inconsistencies.
We suggest the benefit of the data comes from observing trends rather than exact numbers. As
other studies using this data have suggested, it is important that clinicians are involved in improving
the quality of this data.
Background
Hospital Episode Statistics (HES) is the national statistical
data warehouse for the NHS in England. It includes clini-
cal and administrative information about the care pro-
vided to NHS patients who live, or are treated in England.
The data is compiled from information exchanged
between healthcare providers such as hospital trusts and
primary care trusts (PCTs), and the commissioners of that
care, primarily the PCTs. This data is submitted via the
NHS Wide Clearing Service (NWCS) who forward it to the
commissioners, but also copy the information to a data-
base. At fixed times during the year this accumulated data
is then set to HES, so whilst the NWCS data is continu-
ously updated, the HES data reflects the fixed period of
time of a financial year.
Data is collected by patient administration systems within
over three hundred NHS trusts. As well as epidemiological
data, there is a large amount of clinical data recorded such
as primary diagnosis, main speciality contracted, and
health care resource grouping. The Main Operation is
identified as the first recorded, and normally the most
Published: 04 December 2006
BMC Ophthalmology 2006, 6:37 doi:10.1186/1471-2415-6-37
Received: 03 July 2006
Accepted: 04 December 2006
This article is available from: http://www.biomedcentral.com/1471-2415/6/37
© 2006 Clarke and Fraser; licensee BioMed Central Ltd. 
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), 
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Page 1 of 4
(page number not for citation purposes)
BMC Ophthalmology 2006, 6:37 http://www.biomedcentral.com/1471-2415/6/37resource intensive procedure performed during that epi-
sode, although no nationally agreed definition exists. The
operation codes are taken from the Office of Population
Censuses and Surveys tabular list of surgical operations
and procedures fourth revision (OPCS4). HES data com-
prised of over 13 million episodes of treatment provided
to patients in the last financial year available 2003/04.
The report for the financial year 1998/9 was the first to be
made available online, prior to this it was produced as
paper based publication only.
The purpose of this study was to observe some trends in
ophthalmic operations performed during the period from
1998 to 2004, using the HES data available online [1].
Methods
There are various categories of data available within the
HES database. Within the free data section, the codes for
ophthalmic surgery begin with the letter 'C'; the proce-
dures are then listed by operation type. The three digit
codes identify broad categories of operations e.g. C18 =
correction of ptosis of eyelid. The four digit codes identify
subdivisions of that operation according to technique or
method, e.g. C18.6 = correction of ptosis of eyelid using
aponeurosis technique.
In many cases there are a number of possible ways of cod-
ing for the same operation depending on the semantics
used in the data entry. For example, a blepharoplasty
could feasibly be listed as: excision of redundant skin
blepharoplasty (C13.1–13.4), reconstruction of eyelid
(C14.8), correction of deformity of eyelid (C15.8), or
plastic repair of eyelid (C16.8). For this reason we have
limited our analysis of the data to a few operations for
each sub-speciality where there is no coding ambiguity,
and reflect an interesting trend.
With the exception of the latest available year, informa-
tion regarding the age of the patients is given as both an
average (mean) and non-contiguous age bands 15–59
and 75+. The percentage of paediatric cases of each proce-
dure is therefore not available for all but 2003/4.
Results
Table 1 shows the total number of each surgical procedure
performed for each financial year by the entry code
recorded. The last column indicates the gross percentage
change over this the time data were available. Over the
period 1998 – 2004 the UK population rose by 1 million
[2], representing a 1.6% overall increase.
Oculoplastics
The number of total excisions of eyes as remained roughly
stable. There has been a large increase in the number of
orbital decompressions of nearly 40%. Larger still is the
percentage increase in ptosis surgery (54%). Most of the
subgroups are of fairly consistent proportion, half of
which are recorded as being done by levator muscle tech-
nique, with the aponeurosis technique representing only
1/6th. The group titled 'other' has a large and steadily ris-
ing proportion.
Strabismus
The total number of strabismus operations is slightly
down (8%) over the time period. The proportion of com-
bined muscle, recession, or resection operations per-
formed is reasonably stable.
Cornea
Plastic operations on the cornea (which encompasses
lamellar and penetrating grafts, refractive keratoplasty,
insertion of corneal prosthesis, and 'others') overall have
remained stable. A large percentage increase (59%) in the
number of lamellar grafts reflects the small number of this
newer operation performed. A far larger number of pene-
trating grafts are performed, however the numbers are
declining a little year on year.
Glaucoma
Both the total number of filtering operations and the
number of trabeculectomies has declined, by 46% and
49% respectively, as described in a previous paper using
HES to describe surgical trends [3].
Cataract
In the period from 1998 – 2004 the total number of pros-
thesis of lens, (including insertion, removal, revision, and
'other') has increased almost 100,000, an increase of 52%.
This is presumably due to the rise in phacoemulsification
(although it is not coded as this within HES), given the
decline of extracapsular extractions and small numbers of
other techniques recorded. A 28% decline in the number
of surgical posterior capsulotomies recorded may be due
to the use of YAG laser for this procedure, which does not
have a surgical code, but may also be in part due to devel-
opments in lens technology.
Retina
An increase in vitrectomy numbers is greater that the
decrease in buckling for retinal detachment observed. This
may be due to its increased use as relatively novel treat-
ment for other conditions such as macular hole. Fluros-
cein angiography has also showed a 36% decline, possibly
due to increasing use of less invasive technology such as
OCT, which is not recorded by HES.
Discussion
The HES database provides a rich source of information
regarding patient care across the country, year by year. The
trends identified in this paper represent a fraction of thePage 2 of 4
(page number not for citation purposes)
BMC Ophthalmology 2006, 6:37 http://www.biomedcentral.com/1471-2415/6/37data available for examination. It is important to
acknowledge the limitations of both the data available,
and the conclusions that can therefore be drawn from
them.
Standardising the many terms used to describe operations
would facilitate better comparison of each category by
making them less ambiguous. Narrowing or restricting the
many terms available such as extirpation, plastic repair,
excision, reconstruction, repair, incision and correction of
deformity could help to achieve this. The validity of
recording a single 'main operation', which is not clearly
defined, has to be questioned. The use of more complex
operations such as phaco-trabeculectomies; and com-
bined surgery, for example ptosis with blepharoplasty,
will inevitably lead to an under reporting of the individual
components. The use of newer technologies such as laser
peripheral iridotomy instead of the surgical equivalent, or
novel operations e.g. viscocanulostomy, which are yet to
be coded will further erode that validity. Similar limita-
tions to the usefulness of database analysis have been
extensively explored in the USA [4,5] where the Medicare
claims database has been used to assess the provision of
many ophthalmic treatments.
Greater accuracy could also be achieved by direct involve-
ment on the part of the surgeon in the coding procedure.
Each practitioner would normally undertake a relatively
small number of different operations on a routine basis,
so learning and including those specific codes in the oper-
ating notes would be possible. It would increase the accu-
racy of coding and the clinician would also then be
responsible for indicating the 'main operation' rather than
assignment according resources used.
Table 1: HES data for various eye operations 1998–2004
98/99 99/00 00/01 01/02 02/03 03/04 % change over time
Code Operation
Oculoplastics
1 Excision of eye 1025 1000 989 921 1002 924 -9%
1.1 Exenteration 44 50 35 65 47 66 +50%
1.2 Enucleation 583 535 529 475 542 467 -20%
1.3 Evisceration 392 412 422 374 402 382 -3%
6.3 Decompression 168 164 203 198 227 230 +37%
18 Ptosis total 2457 2710 2662 3170 3307 3780 +54%
18.1 Levator muscle 1126 1239 1352 1373 1433 1616 +43%
18.2 Frontalis muscle 44 47 40 42 40 47 +7%
18.3 Fascia sling 163 120 181 163 136 131 +20%
18.5 Tarsomullerectomy 162 158 155 149 144 163 <1%
18.6 Aponeurosis repair 298 422 418 498 538 576 +93%
18.8 Ptosis other 658 718 734 939 1011 1246 +89%
Strabismus
31–37 Strabismus total 13057 12358 12465 11750 11782 12021 -8%
31 Combined muscle 6612 6385 6495 6039 5937 6309 -5%
32 Muscle recession 3723 3345 3417 3200 3155 2735 -27%
33 Muscle resection 1195 1087 942 966 969 1043 -13%
Cornea
46 Plastic ops cornea 2257 2247 2269 2130 2127 2201 -3%
46.2 Lamellar graft 181 164 205 225 258 288 +59%
46.3 Penetrating graft 1578 1674 1652 1426 1435 1405 -11%
Glaucoma
60 Filtering ops total 9185 6909 5920 5354 5011 4957 -46%
60.1 Trabeculectomy 8622 6415 5421 4751 4282 4206 -51%
Cataract
71 Extracapsular 8596 6483 5228 6119 6892 5385 -37%
73.3 PC capsulotomy 10423 11718 10964 9319 8523 7550 -28%
75.1 Lens insertion 191540 201979 230663 240210 261963 291477 +52%
Retina
54 Bucking for RD 3791 3507 3322 2846 2779 2469 -35%
79.1,2 Vitrectomy 7308 8042 8483 9360 9319 10616 +45%
86.5 Fluorescein angio. 3676 3610 3111 3178 2821 2336 -36%Page 3 of 4
(page number not for citation purposes)
BMC Ophthalmology 2006, 6:37 http://www.biomedcentral.com/1471-2415/6/37Surgery is not an exact science, so it is essential to retain
some flexibility within the terms used to describe it.
Hence the importance of categories 'other – specified/
unspecified' for operations that do not accurately match
the other codes. However for useful data analysis, this
should represent a small minority of the operations per-
formed. In the breakdown of ptosis surgery, one quarter to
a third of operations are not classified under the current
coding. Other classified techniques show a small variation
in numbers performed year to year as a percentage of the
total, but unspecified technique is the only subset to show
a trend of gradual increase. Superior rectus muscle surgery
represents a tiny proportion of the operations performed,
in the last year only a single operation recorded country-
wide, but continues to retain separate categorisation. In
this instance, a re-coding would allow better reflection of
current surgical practice. This could be achieved with con-
stant evaluation and clinical input.
The validity of the HES database has been questioned in
literature, as acknowledged by the Department of Health.
A review article of many of these papers [6] indicates that
local variations in coding practice inevitably leads to inac-
curacies. As such, it is the trends observed year to year,
rather than the absolute numbers represented in the data
that are likely to be of greater validity. Given the increas-
ing importance of centralised NHS data in hospital and
practitioner performance, they stress the importance of
clinician involvement in the process of data collection as
well as revision of NHS data terms.
HES has been used extensively by other specialities for a
diverse range of data analysis. For example, others have
looked at regional variation in joint replacement rates in
orthopaedics [7], epidemiological trends in geriatric
emergency admissions [8], and mortality rates versus
caseload in radical cystectomy [9]. We could only find two
published articles utilising HES for analysis of data within
ophthalmology. The first article as discussed previously,
using HES to show trends in glaucoma surgery [3]. The
second providing a comparison of waiting time systems
between orthopaedics and ophthalmology within a single
hospital [10].
Conclusion
The use of HES as a free online database has not been ref-
erenced widely within the literature related to ophthal-
mology. This article seeks to show a few simple trends in
recent ophthalmic surgical practice, and highlights the
potential usefulness of this important UK national
resource. However, as stated within the HES documents,
care in analysis of the information provided requires an
understanding of the quality and the limitations of the
data.
Competing interests
The author(s) declare they have no competing interests.
Authors' contributions
The study was conceived and executed by LC and SF
LC drafted and completed the manuscript.
SF conceived of, and edited the manuscript.
Both authors read and approved of the final manuscript.
Acknowledgements
Nil
References
1. Hospital episode statistics   [http://www.hesonline.nhs.uk].
accessed March 2006
2. National Statistics online   [http://www.statistics.gov.uk].
accessed September 2006
3. Fraser SG, Wormald RPL: Hospital episode statistics (HES) and
changing trends in glaucoma surgery.  Eye advance online publica-
tion, May 19, 2006 . doi:10.1038/sj.eye.6702458
4. Javitt JC: Outcomes if eye care from Medicare data.  Arch Oph-
thalmol 1991, 109:1079-1080.
5. Coleman AL, Morgenstern H: Use of insurance claims databases
to evaluate the outcomes of ophthalmic surgery.  Surv Ophthal-
mol 1997, 42(3):271-8.
6. Williams J, Mann R: Hospital episode statistics: time for clini-
cians to get involved?  Clin Med 2002, 2(1):34-37.
7. Judge A, Chard J, Learmonth I, Dieppe P: The effects of surgical
volumes and training centre status on outcomes following
total joint replacement: analysis of the Hospital Episode Sta-
tistics for England.  J Public Health (Oxf) 2006, 28(2):116-24. Epub
2006 Apr 5
8. Roland M, Dusheilko M, Gravelle H, Parker S: Follow up of people
aged 65 and over with a history of emergency admissions:
analysis of routine admission data.  BMJ 2005,
330(7486):289-92.
9. McCabe JE, Jibawi A, Javle P: Defining the minimum hospital
case-load to achieve optimum outcomes in radical cystec-
tomy.  BJU Int 2005, 96(6):806-10.
10. Hacker J, Stanistreet D: Equity in waiting times for two surgical
specialities: a case study at a hospital in the North West of
England.  J Public Health (Oxf) 2005, 27(1):125.
Pre-publication history
The pre-publication history for this paper can be accessed
here:
http://www.biomedcentral.com/1471-2415/6/37/prepubPage 4 of 4
(page number not for citation purposes)


Defining the minimum hospital case-load to achieve optimum outcomes in radical cystectomy.

Dieppe P: The effects of surgical volumes and training centre status on outcomes following total joint replacement: analysis of the Hospital Episode Statistics for England. J Public Health (Oxf)

Equity in waiting times for two surgical specialities: a case study at a hospital in the North West of England.

Hospital episode statistics [http://www.hesonline.nhs.uk]. accessed

Hospital episode statistics: time for clinicians to get involved? Clin Med

National Statistics online [http://www.statistics.gov.uk]. accessed

Outcomes if eye care from Medicare data. Arch Ophthalmol

S: Follow up of people aged 65 and over with a history of emergency admissions: analysis of routine admission data. BMJ

Use of insurance claims databases to evaluate the outcomes of ophthalmic surgery. Surv Ophthalmol

Wormald RPL: Hospital episode statistics (HES) and changing trends in glaucoma surgery. Eye advance online publication,

http://doaj.org/search?source=%7B%22query%22%3A%7B%22bool%22%3A%7B%22must%22%3A%5B%7B%22term%22%3A%7B%22id%22%3A%22e657bc13324b401f88e743e2a39edfa6%22%7D%7D%5D%7D%7D%7D

Hospital Episode Statistics and trends in ophthalmic surgery 1998 – 2004

Abstract

Similar works

Full text

Available Versions

Springer - Publisher Connector

Directory of Open Access Journals

Crossref

Springer - Publisher Connector