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.

In favour of the variability

19 Mar

Joan EscarrabillJoan Escarrabill. Director Chronic Care Program at Hospital Clínic Barcelona

John Wennberg explained to us how difficult it is to justify the variability in clinical practice. The health care that people receive, is more determined by where they live (zip code) than by their overall health. This variability is influenced more by local clinical practice (the features and character of each place, i.e. zip code) than the prevalence of disease or patient preferences. Furthermore, in places with greater health services and activity, the satisfaction, quality and the survival rates are often worse. As this variability (chaotic, according to Wennberg) is not explained by sanitary reasons, it also constitutes an element that leads to greater health inequalities.

There are many examples. The “Observatori de Teràpies Respiratòries a Domicili” analyzes annually the performance of these home treatments. There are paradoxes related to the number of treatments. In Catalonia there are over 65,000 people who receive treatment with continuous positive airway pressure (CPAP) in order to treat sleep apnoea. On the other hand there are just over 2,000 people who need home mechanical ventilation. There is less variability in the patient group treated with CPAP (the difference is 2.5 times between the territory with the lowest and the highest prevalence) than in the group of patients using ventilators (the difference is 22 times). The home oxygen therapies’ variability maps show the differences in use of these treatments among different districts of Barcelona. Continue reading

Preference sensitive health care: the causes of variations

19 Feb

Jordi VarelaJordi Varela. Editor of the blog “Advances in Clinical Management

There is a case-mix part (25% according to Wennberg) such as inguinal hernia, cataracts, metrorrhagia or knee osteoarthritis, for which modern medicine has an effective surgical response, although in the application of the technique there is often a margin for the doctor’s interpretation, another margin for the subjectivity of the patient, such as pain perception or adaptation to the lack of visual acuity, as well as a very important factor: the decision of the patient himself. There are men who prefer to wear a brace to hernia surgery and women who prefer to live with their uterus, provided that the degree of the discomfort and metrorrhagy allows them to.

After this introduction, let’s see the Variations in Health Care, the good, the bad and the inexplicable report by John Appleby and his collaborators, published by King’s Fund in 2011, which states that variations in hospitalization rates are pervasive and persistent, and even affect common interventions known to be effective such as hip replacement for advanced osteoarthritis cases.

Distribution rates of hip replacement in England 2009/10

Note that although adjusted for age and sex, the rate of hospitalization for hip replacement (with lighter blue line) in the graphic, are observed in 18 PCT (Primary Care Trust) that show a value of 60 interventions per 100,000 inhabitants per year, while at the other extreme, there are 20 showing a rate of 140. That is, citizens of the latter communities have a 2.3 times higher probability of being operated on for prosthetic hip replacement than the citizens of the former. The same report shows that these regional differences are extended to other elective procedures such as knee, cholecystectomies or coronary angioplasty.

Whichever way you look, this type of variation in the use of health care resources for procedures seemingly well identified and standardized, is universal, and this is seen when comparisons between systems (countries) are being made, but don’t disappear when, as in the English case, intra-communities and intersystem analysis are being made. If I may, I’ll next show a Spanish example from the Variaciones de la Práctica Médica (VPM) initiative that has the support of all autonomous regions. I have in hand the final report of the VPM research project: Variations in the use of knee arthroplasty in the National Health System, from which I have chosen this graph:


I think in the above graph it should be noted that, excluding outliers health areas (in light blue), there are Spanish territories where inhabitants have a probability of knee prosthesis intervention 6.4 times higher than inhabitants from the areas with the lowest rates. And this occurs in a health system that is considered one of the most fair and accessible in the world.

Where is the problem? What explains these extraordinary variations?

To answer these questions, there’s nothing better that to resort to a 1977 investigation led by a young Wennberg. The following table, published in Tracking Medicine by the same author (Oxford University Press 2010), there is a summary of the results of this work. It’s the comparison of two small communities: Middlebury in Vermont vs. Randolph in New Hampshire. As seen in the table, the two communities have the same socioeconomic characteristics, the same prevalence of chronic diseases, and the same doctor accessibility. However, the Middlebury citizens are hospitalized 67% more than those of Randolph, and undergo surgery 63% more.

This work is a benchmark for questions about the causes of variations in the use of health resources. According to Wennberg, if when demographic, socioeconomic and accessibility factors have been adjusted, such overwhelming differences still remain, one must draw the attention of the variations towards the medical practice and the availability of healthcare resources provided by doctors in each area.