Abstract
Background:
The aim was to study the regional variability in the request of the ten most frequently ordered laboratory tests in primary care in Spain.
Methods:
Spain is divided into autonomous communities (AACC), first level health care divisions. Every AACC is divided into health departments (HDs). A laboratory attends the needs of every HD inhabitant. Laboratories from different HDs participated in the study. They reported the request of the ten most commonly requested laboratory tests in primary care during the year 2014 according to prior evidence: alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol, creatinine, γ-glutamyl transpeptidase (GGT), glucose, HDL-cholesterol, triglycerides, uric acid and urinalysis. Test-utilization rates were calculated as tests per 1000 inhabitants. Laboratories were grouped in the different AACC and the results for each region were compared using the coefficient of quartile dispersion (CQD), calculated using the first (Q1) and third (Q3) quartiles for each data set, as follows: (Q3−Q1)/(Q3+Q1).
Results:
One hundred and ten laboratories participated, corresponding to 27,798,262 inhabitants (59.8% Spanish population) from 15 AACC. 82,710,869 tests were requested. AST, GGT and uric acid showed the greatest variation.
Conclusions:
There were significant regional differences in how the most common laboratory tests were ordered in Spain.
Reviewed Publication:
Wieland E. Redaktion
Introduction
The exponential growth in the volume of data generated in the clinical laboratory with increasing health care demand, and the growing interest on quality improvement have pushed laboratory professionals to focus on the use of their laboratory information management system (LIMS) not only for the routine laboratory operations, but also to investigate how tests are used, as a first step to detect trends, variability and potential flaws in request appropriateness. LIMS have evolved over the past years from simple operational tools to systems that can deal and analyze a large amount of meaningful data. In all, information technologies (IT) can be currently used to manage metadata regarding the appropriate use of diagnostic tests.
In 2009, the REDCONLAB group began investigating the variability in the use of laboratory tests by using available IT [1]. In 2010, the group published the first Spanish national study comparing the use of such tests in primary care, which found significant regional differences [2]. This was confirmed 2 years later [3].
In this current third edition, the group focuses on common tests that are frequently ordered from primary care, and analyze larger data from hospitals covering more Spanish territory, overall providing health care to more than 25 million of inhabitants.
More specifically, the goal of this collaborative research is to investigate the variability in the request of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol, creatinine, γ-glutamyl transpeptidase (GGT), glucose, HDL-cholesterol, triglycerides, uric acid and urinalysis in primary care in Spain.
Materials and methods
Setting
Spain is divided into 17 autonomous communities (AACC), first level political, administrative and health care divisions. Spanish citizens possess the individual health care card, which provides access to public health services throughout the National Health System. The health system in every AACC is divided into different health departments (HDs). Each HD covers a geographic area and its population. It is composed of several primary care centers and usually a unique hospital. The clinical laboratory is located in the hospital and is in charge of the needs of every HD inhabitant. The study was approved by the local ethics committee.
Data collection
A call for data was posted via email. The dissemination of the questionnaire was also addressed to the participants of previous studies of the Redconlab group that recommended other laboratories to join the current edition and a LinkedIn (https://www.linkedin.com/in/redconlab-grupo-a5663bb7) group was created. One hundred and fifty Spanish laboratories willing to participate in the study were invited to fill out an enrollment form and submit their results online. We obtained production statistics from laboratories from diverse regions across Spain; number of requested tests by all of the general practitioners (GPs) from laboratories at different hospitals from diverse HD across Spain in year 2014. Every patient seen in any primary-care center, regardless of the reason for consultation, gender, or age, was included in the study. Each participating laboratory was required to obtain patient data from their local LIMS and patients databases and provide organizational data. The 2014 request of AST, ALT, total cholesterol, creatinine, GGT, glucose, HDL-cholesterol, triglycerides, uric acid and urinalysis were reported by each participant.
Data processing
After collecting the data, test-utilization rates were calculated by standardization with the population attended by each laboratory. Rates were expressed as tests per 1000 inhabitants. Laboratories were grouped in the different AACC, when there were more than four participants per AACC, with a group joining the results of the rest. AACC were codified by numbers due to confidentiality. Every indicator result was compared between the different AACC.
Statistical analysis
All analyses were performed using SPSS Inc. for Windows, v.16.0 (SPSS Inc., Chicago, IL, USA). In order to explore the variability through test-utilization rates comparison, we used the coefficient of quartile dispersion (CQD), calculated using the first (Q1) and third (Q3)quartilesfor each data set, as follows: (Q3−Q1)/(Q3+Q1). We did not employ the coefficient of variation due to its higher sensitivity to outliers.
Results
One hundred and ten laboratories from 15 different AACC participated in the study, corresponding to a catchment area of 27,798,262 inhabitants, or 59.8% of the Spanish population. Other laboratories refused to participate because they had difficulties obtaining the requested data from their databases, were not authorized to release the data by the hospital managers or they did not have the time to collaborate. Table 1 shows the number of requests, the rate of requests per 1000 inhabitants and the CQD for each laboratory test.
Total participants centers | Autonomous communities (code; number of centers) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1; 20 | 2; 16 | 3; 10 | 4; 11 | 5; 12 | 6; 5 | 7; 5 | 8; 6 | 9; 6 | 10; 5 | 11; 14 | ||||
Total tests | Test/1000 inhabitants (median; coefficient of quartile dispersion) | |||||||||||||
ALT | 9,199,401 | 350.1;0.1 | 372.9; 0.1 | 339.2; 0.1 | 367.6; 0.1 | 286.4; 0.3 | 316.9; 0.1 | 362.6; 0.1 | 371.0; 0.1 | 327.5; 0.1 | 389.3; 0.1 | 349.2; 0.1 | 332.7; 0.1 | |
AST | 6,376,293 | 260.2; 0.4 | 231.1; 0.6 | 251.5; 0.5 | 223.3; 0.3 | 206.6; 0.1 | 245.4; 0.8 | 331.7; 0.1 | 370.9; 0.3 | 335.2; 0.1 | 265.4; 0.7 | 294.5; 0.4 | 213.2; 0.6 | |
Total cholesterol | 9,507,418 | 366.2; 0.1 | 392.3; 0.1 | 367.4; 0.1 | 378.7; 0.1 | 336.6; 0.2 | 322.6; 0.1 | 366.1; 0.3 | 396.3; 0.1 | 352.6; 0.2 | 408.4; 0.2 | 366.2; 0.1 | 368.0; 0.1 | |
Creatinine | 9,993,971 | 373.5; 0.1 | 401.2; 0.1 | 380.4; 0.1 | 370.8; 0.1 | 351.4; 0.3 | 324.8; 0.1 | 371.0; 0.1 | 394.4; 0.1 | 379.7; 0.2 | 423.6; 0.1 | 350.5; 0.1 | 354.4; 0.1 | |
GGT | 7,101,941 | 270.7; 0.2 | 206.0; 0.4 | 201.6; 0.3 | 328.1; 0.1 | 239.4; 0.2 | 245.8; 0.2 | 260.9; 0.1 | 271.5; 0.3 | 290.5; 0.1 | 313.4; 0.2 | 330.7; 0.3 | 277.8; 0.2 | |
Glucose | 10,288,308 | 383.6; 0.1 | 413.7; 0.1 | 408.5; 0.1 | 376.9; 0.1 | 327.6; 0.2 | 341.4; 0.1 | 398.2; 0.1 | 390.2; 0.0 | 412.9; 0.2 | 430.5; 0.1 | 369.4; 0.1 | 374.9; 0.1 | |
HDL-cholesterol | 7,726,874 | 292.1; 0.2 | 334.5; 0.1 | 290.6; 0.2 | 305.3; 0.2 | 278.9; 0.2 | 233.0; 0.1 | 285.5; 0.3 | 332.2; 0.2 | 275.1; 0.2 | 312.7; 0.5 | 311.2; 0.2 | 302.3; 0.1 | |
Triglycerides | 9,234,678 | 350.5; 0.1 | 389.5; 0.1 | 347.8; 0.2 | 377.9; 0.1 | 330.1; 0.2 | 322.8; 0.1 | 375.7; 0.1 | 395.8; 0.2 | 343.6; 0.2 | 398.8; 0.2 | 355.3; 0.1 | 322.8; 0.1 | |
Uric acid | 6,974,379 | 301.2; 0.2 | 320.3; 0.3 | 252.2; 0.4 | 351.4; 0.1 | 185.0; 0.4 | 265.0; 0.1 | 360.3; 0.1 | 338.8; 0.1 | 279.0; 0.4 | 315.1; 0.1 | 330.6; 0.1 | 327.5; 0.2 | |
Urinalysis | 6,307,606 | 237.2; 0.2 | 226.1; 0.2 | 218.0; 0.1 | 227.9; 0.1 | 166.0; 0.3 | 230.4; 0.1 | 300.2; 0.4 | 294.4; 0.1 | 285.9; 0.3 | 273.6; 0.2 | 237.4; 0.3 | 231.6; 0.1 |
In all, 82,710,869 tests were performed in the study group; if we extrapolate to the entire Spanish population that would correspond to 138,222,440 tests. The tests that showed the highest variability as stated by CQD were AST, GGT and uric acid. The less variability was observed in glucose, creatinine and total cholesterol. Table 1 also shows the demographic data and the results of every test per 1000 inhabitants in every AACC. In most regions, AST, GGT and uric acid were also the tests that presented the highest variability (Figure 1).
Discussion
The study shows how through the use of local LIMS patient databases, the request of laboratory tests can be studied at a national level, and compared. There were high regional differences in how the most common laboratory tests are ordered in Spain, which was most significant for AST, GGT and uric acid. The large differences between AACC suggest different customs or habits rather than differences in patient characteristics. The ten most commonly ordered chemistry tests in primary care in Spain account for more than 80 million of all requests in 60% of the Spanish population. Data if extrapolated to the whole Spanish population would have been close to 140 million of requests.
Primary care is the front line of a health care system, where the GPs have the opportunity to first prevent and then diagnose a number of serious disorders. The laboratory intervenes in 70% of clinical decisions regarding diagnosis [4], prevention, monitoring and treatment of diseases that may explain why they were so frequently requested in the Spanish population.
There was, nevertheless, a significant variability in how the most common routine laboratory tests were used in primary care in the different regions, which was not an expected result. The great case mix variations, or differences in primary care physician referral to laboratory in the different areas could be the cause; however, patients in the different AACC should suffer from approximately the same types of diseases, and it seems unlikely that the number of patients with different diagnoses is such in the different Spanish regions. The fact that creatinine, glucose and total cholesterol are routinely ordered in the general population could explain the minor differences between AACC. However, current guidelines do not recommend screening of triglycerides and HDL-cholesterol, and their request was very similar to that of total cholesterol [5].
A recent study in Valencia community has shown that disorders of lipid metabolism, essential hypertension and diabetes mellitus were the most prevalent patient clinical diagnosis in primary care patients (data not published). More than 20% of tests were requested for one of those reasons. Additional research may be needed at national scale to investigate what are the main indications that drive the request of laboratory tests in the different Spanish regions.
What seems rather clear is the need to act on the over-request of AST, GGT and urate in those AACC where those tests are more heavily ordered [6]. AST is a redundant test, especially in primary care where ALT alone suffices. GGT is not a test that should be frequently considered in primary care, because of its lack of specificity; it should be reserved for special indications such as, for instance, determining the origin of an increased alkaline phosphatase. ALT is the first liver marker in primary care and also alkaline phosphatase has a role for suspected biliary obstructions. In fact, GGT has a limited use as a liver function test in primary care [7]. Uric acid request in primary care is mainly targeted to patients with suspected gout. It also seems unlikely that the number of gout patients is that much higher in some Spain AACC than others. GPs in some AACC are probably using urate for other types of patients, or for population screening purposes. However, a recent study indicates that unnecessary urate requests in primary care leads to unnecessary treatments [8]. There is no clear correlation between the number of tests and quality of care [9].
Unnecessary over-request has been reported to represent between 4.5% and 90% of the laboratory work-load [10]. Inappropriate test entails the risk of generating false/positive results, leads to overload of the diagnostic services, wastes valuable healthcare resources, and is associated with other inefficiencies in healthcare delivery, undermining the quality of health services. Moreover standard laboratory tests belongs to the “little test ticket” tests that in spite of being individually very cheap, they contribute significantly to rising health care costs as they are highly demanded. In view of our results, it seems clear that it is necessary to design and establish strategies, at a national level, to try to standardize the request for the routine laboratory tests.
The study has a main limitation; the differences in the ten most requested tests in primary care tests could be partly explained by case mix variations in the different areas. Another limitation was that we could not integrate comparison to previous study results. However, interventions are planned to get a better request through communication of all that intervened in the present study.
There are high regional differences in how the most common laboratory tests are ordered in Spain. This variability likely indicates an inappropriate use of such tests in several AACC, and prompts the design and establishment of strategies and guidelines at a national scale, to achieve an equitable, effective and efficient patient health care.
Author contributions: MS, ML-G, EF designed the study and analyzed/interpreted the data, MS, ML-G, EF and CL-S drafted the article and revised it critically for important intellectual content. All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
Appendix A: Members of REDCONLAB group
Vidal Perez Valero (Hospital Regional Universitario de Malaga, Hospital Universitario Virgen de la Victoria, Málaga); Félix Gascón (Hospital Valle de los Pedroches, Pozoblanco); Isidoro Herrera Contreras (Complejo Hospitalario de Jaen); Maria Angeles Bailen Garcia (Hospital Universitario Puerta del Mar de Cadiz); Cristobal Avivar Oyonarte (Hospital de Poniente, El Ejido); Esther Roldán Fontana (Hospital La Merced, A.G.S. de Osuna); Fernando Rodriguez Cantalejo (Hospital Universitario Reina Sofia de Cordoba); Jose Angel Noval Padillo (Hospital Universitario Virgen del Rocio); M Angela Gonzalez García (AGS Norte de Cadiz); Ignacio Vazquez Rico (Hospital Juan Ramon Jimenez de Huelva); Cristina Santos (Hospital Rio Tinto); Angeles Giménez Marín (Hospital de Antequera); Maria del Señor López-Vélez (Hospital San Cecilio de Granada); Jose Vicente García-Lario (Hospital Virgen de las Nieves, Granada); Federico Navajas Luque (AGS Este de Málaga-Axarquía); Amado Tapia (Hospital de Barbastro); Maria Esther Sole LLop (Hospital de Alcañiz); Juan José Puente (Hospital Clínico Universitario Lozano Blesa); Patricia Esteve (Hospital Ernest Lluch); Maria Teresa Avello Lopez (Hospital San Agustín-Aviles, Hospital Valle del Nalon); Emilia Moreno Noguero (Hospital Can MIsses); Ana Maria Follana Vazquez (Hospital Mateu Orfila); Jose Luis Ribes Valles (Hospital de Manacor); Ma Luisa Fernández de Lis Alonso (Area de Salud de Fuerteventura); MC Martin-Fernandez de Basoa (Hospital Nuestra Señora de la Candelaria, Tenerife); Leopoldo Martin Martin (Hospital General de la Palma); Miguel Angel Pico Picos (Hospital Universitario de Canarias); Casimira Dominguez Cabrera (Hospital Universitario de Gran Canaria Dr Negrín); Marta Riaño Ruiz (Hospital Insular de Gran Canaria); Juan Ignacio Molinos (Hospital Sierrallana de Torrelavega); Luis Fernando Colomo (Hospital de Laredo); José Carlos Garrido (Hospital Universitario Marques de Valdecilla); Enrique Prada de Medio (Hospital Virgen de la Luz de Cuenca); Pilar Garcia Chico (Hospital General Universitario de Ciudad Real); Simon Gomez-Biedma (Hospital General de Almansa); Jesús Dominguez (Hospital Universitario de Guadalajara); Guadalupe Ruiz (Complejo Hospitalario de Toledo); Laura Navarro-Casado (Complejo Hospitalario Universitario de Albacete); Fidel Velasco Pena (Hospital Virgen de Altagracia, Manzanares); Carolina Andrés Fernandez (Hospital General de Villarobledo); Joaquín Domínguez Martinez y Oscar Herrera Carrera (Hospital General Mancha Centro y Hospital General de Tomelloso) Ma Carmen Lorenzo Lozano (Hospital Santa Bárbara de Puertollano); Maria Teresa Gil (Hospital Nuestra Señora del Prado Talavera de la Reina); Ma Angeles Rodriguez Rodriguez (Complejo Asistencial Universitario de Palencia (Hospital Rio Carrion)); M. Victoria Poncela Garcia (Hospital Universitario de Burgos); Luis Rabadan (Complejo Asistencial de Soria); Vicente Villamandos (Hospital Santos Reyes, Aranda del Duero); Nuria Fernandez Garcia (Hospital Universitario Rio Hortega-Valladolid); Jose Miguel Gonzalez Redondo (Hospital Santiago Apostol de Miranda de Ebro); Cesareo Garcia (Hospital Universitario de Salamanca); Luis Garcia Menendez (Hospital El Bierzo); Pilar Alvarez Sastre (Complejo Asistencial de Zamora); Maria Dolores Calvo Nieves (Hospital Cínico Universitario de Valladolid); María Isabel LLovet (Hospital Universitario Verge de la Cinta (Tortosa)); Nuria Serrat (Hospital Joan XXIII de Tarragona); Ma José Baz (Hospital de Llerena, Badajoz); Maria Jose Zaro (Hospital Don Benito-Villanueva); M Carmen Plata (Hospital Campo Arañuelo, Navalmoral de la Mata); Pura Garcia Yun (Área de Salud de Badajoz (Hospital Infanta Cristina, Hospital Perpetuo Socorro y Hospital Materno Infantil); Milagrosa Macías Sánchez (Area de Salud de Caceres (Complejo Hospitalario San Pedro de Alcantara)); Javier Martin (Hospital Virgen del Puerto de Plasencia); Lola Máiz Suarez (Hospital Lucus Augusti, Lugo); Berta Gonzalez Ponce (Hospital Da Costa, Burela); Aida Perez Fuertes (Hospital Arquitecto Marcide, El Ferrol); M. Amalia Andrade Olivie (Hospital Xeral-Cies, CHU Vigo); Pastora Rodriguez (Hospital Universitario de A Coruña); M. Mercedes Herranz Puebla (Hospital General Universitario Gregorio Marañon); Antonio Buño Soto (Hospital Universitario La Paz, Madrid); Fernando Cava, Raquel Guillen Santos (BR Salud); Tomas Pascual (Hospital Universitario de Getafe); Carmen Hernando de Larramendi (Hospital Severo Ochoa de Leganes); Raquel Blázquez Sánchez (Hospital de Mostoles); Pilar Díaz (Hospital 12 de Octubre, Madrid); Ana Díaz (Hospital Universitario de La Princesa); Marta Garcia Collia (Hospital Ramon y Cajal, Madrid); Maria Angeles Cuadrado Cenzual (Hospital Clinico Universitario San Carlos); Santiago Prieto Menchero (Hospital Universitario de Fuenlabrada); María del Carmen Gallego Ramírez (Hospital Rafael Mendez, Lorca); Jose Luis Quilez Fernandez (Hospital Universitario Reina Sofia de Murcia); Maria Dolores Albaladejo (Hospital Santa Lucia, Cartagena); Maria Luisa Lopez Yepes (Hospital Virgen del Castillo de Yecla); Alfonso Pérez Martínez (Hospital Morales Meseguer); Antonio López Urrutia (Hospital de Cruces, Bilbao); Adolfo Garrido Chércoles (Hospital Universitario de Donostia); Carmen Mar Medina (Hospital Galdakao-Usonsolo); M Carmen Zugaza (Unidad de Gestion Clinica de Alava); Francisco Javier Aguayo Gredilla (Hospital Universitario de Basurto); Silvia Pesudo (Hospital La Plana); Carmen Vinuesa (Hospital de Vinaros); Julian Díaz (Hospital Francesc de Borja, Gandia); Marisa Graells (Hospital General Universitario de Alicante); Diego Benitez Benitez (Hospital de Orihuela); Arturo Carratala (Hospital Clinico Universitario de Valencia); Consuelo Tormo (Hospital General de Elche); Francisco Miralles (Hospital Lluis Alcanyis, Xativa); Amparo Miralles (Hospital de Sagunto); Jose Luis Barberà (Hospital de Manises); Juan Molina (Hospital Comarcal de La Marina, Villajoyosa); Martin Yago (Hospital de Requena); Mario Ortuño (Hospital Universitario de la Ribera (Alzira)); Maria Jose Martinez Llopis (Hospital de Denia); Nuria Estañ (Hospital Dr. Peset); Ricardo Molina (Hospital Virgen de los Lirios, Alcoy); Juan Antonio Ferrero (Hospital General de Castellon); Begoña Laiz Marro (Hospital Universitario y Politecnico La Fe de Valencia); Goitzane Marcaida (Consorcio Hospital General Universitario de Valencia)
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