What are the SISCAT atlas of variations all about?

19 Jan
Laura Muñoz (Atlas of variations SISCAT), Laia Domingo (RaCat), Olga Martínez (RaCat)

At present, if you live in the region of Terres de l’Ebre and need to be operated on to have a knee replacement, it is quite probable that the type of technique used is one which preserves the posterior cruciate ligament. On the other hand, if you go and live in Girona, the chances of having the same kind of knee replacement will be a lot less, but in contrast, the type of technique chosen will be that of stabilising the posterior.


If you live in Girona and have respiratory difficulties susceptible for home-based CPAP treatment (continuous positive airway pressure), you will more likely be prescribed this therapy than if you live in Lleida or the Terres de l’Ebre. If you live in Lleida, in contrast, there is more probability of you being prescribed oxygen therapy at home than if you live in the Terres de l’Ebre region and suffer from some kind of respiratory disease that could benefit from this treatment. And if you live in the coastal neighbourhoods of Barcelona you will more likely be prescribed mechanical ventilation at home than if you live in a neighbourhood situated further inland for those respiratory ventilation disorders that might need this technique.

Why does this happen? There is no evidence to suggest which type of intervention is most suitable and it is simply the fact that the health professionals of one region are more inclined than those of another to choose one technique over another. This variability reveals the existence of schools linked to certain hospital centres that condition the choice of the type of intervention or technique used.

This is the type of information that the Atlas of variations in clinical practice of the Catalan Healthcare System (SISCAT) make available to health professionals and the entire population, and which has been led and developed by AQuAS since 2011.

The aim of these atlases is to identify, describe and reduce the variability that can lead to increased well-being, quality and an improvement in the use of available resources. Up to the present, 7 atlases have been developed in which the variations in hip and knee arthroplasty operations have been analysed, as well as the variability in home-based respiratory therapies (oxygen therapy, mechanical ventilation and continuous positive airway pressure), the variation in intravenous thrombolysis in patients with ischemic stroke and the variability and in renal replacement therapy in patients with chronic kidney failure (haemodialysis, peritoneal dialysis and kidney transplant).

One of the sources of data for this study, in fact, the most widely used, is the basic minimum group of data obtained at the time of a hospital discharge (CMBD-AH, the Catalan acronym) where the results are presented as activity rates, reasons for standardised uses and variability statistics. The methodology that lies behind this initiative can be seen here. The basic strategy of all the analyses is to compare the rates of use (numerator: for example, hospital admittances) of the inhabitants in a region (denominator: for example, basic area of health), regardless of the centre where patients have been treated or admitted. In addition, both the rates and the reasons for use are reflected in maps to better visualise the data which is another interesting point nowadays.

Apart from all this, it is important to stress that all the atlases include actions and recommendations for planners (Health Department), insurer (CatSalut), providers and professionals, and which have been developed by a unique team of experts with whom the results of the atlases are discussed.

This year, we have decided to take another step forward and convert the publications we have had till now in a static format (PDF), into dynamic publications that facilitate greater interaction with the data and, therefore, a more global view of the clinical practice analysed.

This is an example of the visualisation of the interactive hip and knee arthroplasty atlas which feeds off the data in the Catalan Arthroplasty Registry (RaCat):


Next year, you will be able to know whether there are variations in the Catalan territory regarding hospitalisations for back surgery, in the repair of abdominal aortic aneurysms and in gastrointestinal cancer surgery (esophagus, pancreatic, liver, stomach and rectal cancer).

We cannot end this post without thanking all the speakers that made the presentations seminar of the Atlas of variations in clinical practice of SISCAT possible last 21 November, and especially to Enrique Bernal-Delgado, the key professional in the analysis initiative and in mapping the variations of clinical practice in the Spanish National Health System.

As far as AQuAS is concerned, it is one of our work lines which was begun some time ago now which has recently generated publications such as this article on respiratory diseases and this article on kidney disease.

And I ask myself, …. now that we have the tools to identify and describe the variability in clinical practices which are carried out in Catalonia, why don’t we try and explain them? The atlases of variations in clinical practice of SISCAT are a key tool to ask ourselves questions.

Post written by Laura Muñoz, statistician.

Atlas of Variations in Medical Practice in the National Health System

17 Nov

atlas-vpmOver the last decade, an increase of international initiatives aimed at analysing the variability in practice or the variability in the performance of health systems in a more or less systematic way has been confirmed. The most significant experiences have been carried out in contexts having a deep-rooted culture in assessment and in systems in which the choice of insurers and the competition among providers are one of their most characteristic features. (This table shows some of these experiences). The calling of these initiatives has been, and is, to facilitate public debate on the importance and impact of unjustified variability in healthcare. However, it has been in the last few years, a time spurred on by the economic crisis, that the term value for money has gained greatest significance. It is in this same period that the representation of variations in practice has acquired new interest and its usage has begun to guide decisions on financing or disinvestment among other things.

In Spain, the Atlas of Variations in Medical Practice in the National Health System, also known as Atlas VPM, is a pioneering initiative in Europe which was developed somewhere between research in healthcare services (1) and the support given to public decisions. For the last fifteen years, Atlas VPM has been systematically analysing the performance of the 17 health systems that make up the Spanish Healthcare System. The variations in diverse surgical procedures have in this way come under scrutiny as have those in oncology and orthopaedics, in the variability of hospitalisations in risk populations (chronic patients or mental health patients), in the variation in the treatment of certain pathologies such as coronary heart disease or cerebrovascular ischaemic disease, or in hospital care received by population subgroups such as children or the aged.

Atlas of variations of procedures of questionable value

The “Atlas of unjustified variations in procedures of questionable value”  is the latest Atlas of the series and provides a local context for the aforementioned value for money. This project was created in 2013 as a combined initiative between the Atlas VPM and the National Network of Health Technology Assessment Agencies, with the goal of supporting a national strategy aimed at reducing the use of questionable value procedures by encouraging the use of better alternatives or by redirecting resources to other more cost-effective activities.

Ideally, this Atlas establishes an empirical and dynamic performance target by using real terms of comparison obtained in similar health environments and by highlighting margins for improvement for each provider as well as making learning among peers possible when designing strategies for corrective adjustments.


After almost fifteen years since the project was launched, ten Atlases have been generated (in different formats) as well as innumerable thematic and methodological articles. Nevertheless, the impact of these research efforts goes beyond merely having created an awareness of the existence of a serious problem difficult to resolve; 1) the provision of services in Spain does not seem to follow a pattern related to the health needs of the population so that the access to effective healthcare and insurance seems to depend on one’s place of residence; 2) the marginal cost incurred when providing services often exceeds the marginal benefits of these; 3) the place where a service is provided is decisive in the health results a patient obtains as well as in the associated cost.

On the contrary, the Atlas VPM has also fostered the translation of these results into the arena of healthcare policies. We congratulate ourselves that AQuAS, with whom we have maintained a close collaboration over the years, is leading the creation of an Atlas for Catalonia. This is the first initiative that has, within the context of the National Health System in Spain, institutionalised the study of unjustified variability in healthcare.

(1) Atlas VPM originated and gained momentum within the much missed Network of Research in Results and Healthcare Services (RED IRYSS), coordinated at the time by AATRM under the guidance of Salvador Peiró finding inspiration in an epistemological and methodological approach known as The Dartmouth Atlas of Healthcare Quality.

Post written by Enrique Bernal-Delgado and Sandra García-Armesto for the Atlas VPM group. Unidad de Investigación en Servicios y Políticas de Salud. Instituto Aragonés de Ciencias de la Salud.

If this subject is of interest to you, a related event, Jornada de presentació dels Atles de variacions de la pràctica clínica del SISCAT, will take place in Barcelona next Monday 21 November. The aim of this event is to present publicly SISCAT’s Atlas  of variations in medical practice and to promote its value for professionals as a tool in the management and assessment of the healthcare system.

Medical practice: do a lot or do just what is needed?

22 Jan

Joan-PonsJoan MV Pons. Head of Evaluation AQuAS

Medicine is an imperfect science (hence it’s an art) but it’s also a craft, and it has always tended, perhaps more for the latter than the former, to want to act, to do something, even to no avail, to the extent that it often causes serious damage (bleeding) or if there is a beneficial effect, it is often not apparent until years later (Jenner’s smallpox vaccine); it acts with the aim of demonstrating that something is being done; moreover, adding successive interventions to show that everything that could be done has been done. Why this desire to act and to do more each time?

There may be several reasons. One of them, a simple one, is linked to the profession itself and to private practice (private insurance) is that; if you’re paid to do it, you end up doing more than required, especially when it comes to diagnostic tests; always with the best of intentions so as not to forget anything, collecting the maximum information with the aim of covering any remote possibility of any unlikely diagnosis. Defensive medicine emerges from here and occurs more in countries with over employed lawyers where the fear of litigation –founded on increasing casuistry- leads to an increasing number of tests. The case of Dr. Daniel Merenstein, a 3 year resident with a patient and the PSA is well known (you can read it at “Winners and Losers”, a JAMA “A piece of my mind” Section article).

It doesn’t stop being a vision that completely neglects the other side of the coin, as if the diagnostic tests were harmless, as if, leaving aside the ionizing radiation from many imaging tests, there was no risk of false positives, false negatives with all their consequences; something similar to countless laboratory tests and biomarkers within reach. There is no perfect test that discriminates with 100% accuracy, nor is human nature itself, always heterogeneous in the extreme (fortunately rare).

It is sufficiently well known that the more variables that are explored, the greater the risk of finding significant results simply by chance; hence the need to correct the level of statistical significance (the famous “p”) in studies with multiple comparisons, such as genetics where they analyse many polymorphisms. Many of these genetic studies of broad scope, generated mostly by technology and its increasingly lower cost, than for a prior hypothesis (authentic fishing expeditions), to rule out pure chance, should apply extremely low values of statistical significance. With the proliferation of imaging tests with a higher and higher resolution, we now speak of those “incidentalomas” to describe those incidental asymptomatic findings exposed while looking for unrelated things; no need to specify the ethical and practical implications that this entails. It’s the same when genetic tests are requested indiscriminately.

There is another reason that can be invoked in order to explain this increased desire to add more than to subtract. Psychologists and economists, academic areas that grow increasingly closer, talk about loss aversion in the sense that we are more affected by the loss (what we had and we no longer have or what we were doing and we are no longer doing) than by the possible gain. That’s why we find it so hard to abandon practices, many simple routines, as one engages autopilot, which do not provide us with any useful information or maybe even worse, may pose a risk and an unnecessary expense.

Excessive medicine, without critical reasoning in acting, can be neither good for patients or for the health system. Don’t forget that when we speak of a health system, we are referring to a universal insurance (for all people) and that this allows us to spread the illness and financial risks of an increasingly expensive health care system. Most of the health budget however, is in the actual hands –the real hands not figuratively speaking- of health professionals when they’re applying tests or prescribing treatments. When the interventions (preventive, diagnostic or therapeutic) for a particular individual do not add value, we are also wasting the shared and limited public resources.