*To whom correspondence should be addressed: Birgit Babitsch, Osnabrück University, School of Human Sciences, Dept. of New Public Health, Albrechtstr. 28, 49069 Osnabrück, Germany, Phone: +49 541 969-2266, Fax: +49 541 969-2450, E-mail: ed.kceurbanso-inu@hcstibab.tigrib
Copyright © 2012 Babitsch et al.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free to copy, distribute and transmit the work, provided the original author and source are credited.
Objective: This systematic review aims to assess the use and implementation of the Behavioral Model of Health Services Use developed by Ronald M. Andersen in recent studies explicity using this model.
Methods: A systematic search was conducted using PubMed in April 2011. The search strategy aimed to identify all articles in which the Andersen model had been applied and which had been published between 1998 and March 2011 in English or German. The search yielded a total of 328 articles. Two researchers independently reviewed the retrieved articles for possible inclusion using a three-step selection process (1. title/author, 2. abstract, 3. full text) with pre-defined inclusion and exclusion criteria for each step. 16 studies met all of the inclusion criteria and were used for analysis. A data extraction form was developed to collect information from articles on 17 categories including author, title, population description, aim of the study, methodological approach, use of the Andersen model, applied model version, and main results. The data collected were collated into six main categories and are presented accordingly.
Results: Andersen’s Behavioral Model (BM) has been used extensively in studies investigating the use of health services. The studies identified for this review showed that the model has been used in several areas of the health care system and in relation to very different diseases. The 1995 version of the BM was the version most frequently applied in the studies. However, the studies showed substantial differences in the variables used. The majority of the reviewed studies included age (N=15), marital status (N=13), gender/sex (N=12), education (N=11), and ethnicity (N=10) as predisposing factors and income/financial situation (N=10), health insurance (N=9), and having a usual source of care/family doctor (N=9) as enabling factors. As need factors, most of the studies included evaluated health status (N=13) and self-reported/perceived health (N=9) as well as a very wide variety of diseases. Although associations were found between the main factors examined in the studies and the utilization of health care, there was a lack of consistency in these findings. The context of the studies reviewed and the characteristics of the study populations seemed to have a strong impact on the existence, strength and direction of these associations.
Conclusions: Although the frequently used BM was explicitly employed as the theoretical background for the reviewed studies, their operationalizations of the model revealed that only a small common set of variables was used and that there were huge variations in the way these variables were categorized, especially as it concerns predisposing and enabling factors. This may stem from the secondary data sets used in the majority of the studies, which limited the variables available for study. Primary studies are urgently needed to enrich our understanding of health care utilization and the complexity of the processes shown in the BM.
Keywords: health services utilization, enabling factors, predisposing factors, need factors, Behavioral Model of Health Services Use, systematic review
Zielsetzung: Ziel dieses systematischen Reviews ist es, einen Überblick zum Verständnis und zur Anwendung des von Ronald M. Andersen entwickelten ‚Behavioral Model of Health Services Use‘ (BM) in aktuellen empirischen Studien zu geben, die dieses Modell explizit verwendet haben.
Methoden: Im April 2011 wurde eine systematische Suche in PubMed durchgeführt. Die Suchstrategie hatte das Ziel, alle Publikationen zu identifizieren, in denen das BM in seinen unterschiedlichen Versionen zur Anwendung kam. Die Suche schloss Publikationen ein, die im Zeitraum von 1998 bis März 2011 in englischer oder deutscher Sprache veröffentlicht wurden. Insgesamt konnten 328 Artikel identifiziert werden. Das Auswahlverfahren wurde von zwei Gutachterinnen unabhängig voneinander in drei Arbeitsschritten (1. Titel/Autor, 2. Abstract, 3. Volltext) mit a priori festgelegten Einschluss- und Ausschlusskriterien durchgeführt. Für die Analyse konnten 16 Publikationen eingeschlossen werden. Die Datenextraktion dieser Publikationen erfolgte zunächst mit 17 Kategorien, die u.a. Angaben zum Autor, Titel, Studienpopulation, Studienziel, Methodologie enthielten. In einem weiteren Analyseschritt wurden diese in sechs Hauptkategorien zusammengeführt, welche primär zur Deskription der Ergebnisse genutzt werden.
Ergebnisse: Die Vielzahl der Treffer zeigt, wie weitflächig das BM im Analysezeitraum eingesetzt wurde. Die Publikationen beziehen sich dabei auf sehr unterschiedliche Bereiche des Versorgungssystems und umfassen eine Vielzahl von Erkrankungen. Es zeigte sich, dass die BM-Version, publiziert in 1995, am häufigsten verwendet wurde. Obgleich sich alle Publikationen auf das BM beziehen, findet sich in der Operationalisierung dessen eine hohe Heterogenität. Zur Erfassung der ‚predisposing factors‘ des BM wurden meist folgende Variablen verwendet: Alter (n=15), Familienstatus (n=13), Geschlecht (n=12), Schulbildung (n=11) und Ethnizität (n=10). Die am häufigsten verwendeten Variablen zur Beschreibung der ‚enabling factors‘ waren Einkommen/finanzielle Situation (n=10), Krankenversicherung (n=9) und ein „feste/r“ Hausarzt/-ärztin (n=9). Als ‚need factors‘ berücksichtigten nahezu alle Studien den allgemeinen Gesundheitsstatus (n=9) und die subjektive Einschätzung des eigenen Gesundheitszustandes (n=13) sowie eine Vielzahl unterschiedlicher Erkrankungen. Trotz der in den einzelnen Studien berichteten Zusammenhänge zwischen den einzelnen Faktoren und der Inanspruchnahme der Gesundheitsversorgung, zeigte sich in der Gesamtschau der Ergebnisse eine erhebliche Inkonsistenz. Insbesondere scheinen die den Studien zugrunde liegenden Kontextbedingungen und die unterschiedlichen Studienpopulationen einen erheblichen Einfluss auf die Existenz eines Zusammenhangs und desen Stärke und Richtung zu haben.
Schlussfolgerungen: Das BM dient zahlreichen Studien als theoretisches Analysemodell. Die damit verbundene Vorstellung einer hohen Vergleichbarkeit der Studienergebnisse wird durch die großen Unterschiede in der Operationalisierung des Modells reduziert. Zwar besteht ein gewisser „Standardkatalog“ von Variablen, der jedoch klein ist und sich durch erhebliche Unterschiede bei der Variablenkonstruktion auszeichnet. Besonders betroffen sind die ‚predisposing factors‘ und die ‚enabling factors‘. Eine Ursache könnte darin bestehen, dass die Mehrzahl der Studien Sekundärdatenanalysen und damit in der Variablenauswahl Einschränkungen unterworfen sind. Damit ist zum besseren Verständnis der im BM dargelegten Wirkungspfade die Durchführung von Primärstudien dringend geboten.
Health care utilization is the point in health systems where patients’ needs meet the professional system. It is well known that apart from need-related factors, health care utilization is also supply-induced and thus strongly dependent on the structures of the health care system. Furthermore, many study findings have shown differences in health care utilization based on patients’ social characteristics. For instance, women tend to use outpatient health care services more often than men. In addition to the multitude of studies describing patterns of utilization in different health care settings, several scholars have developed explanatory frameworks identifying predictors of health care utilization [1]. One of the most widely acknowledged models is the Behavioral Model of Health Services Use (BM), which was developed in 1968 by the US medical sociologist and health services researcher Ronald M. Andersen [2], [3], [4], [5], [6], [7], [8], [9], [10] as a result of the third survey of the Center for Health Administration Studies and the National Opinion Research Center [5], [9].
The BM is a multilevel model that incorporates both individual and contextual determinants of health services use. In doing so, it “… divides the major components of contextual characteristics in the same way as individual characteristics have traditionally been divided—those that predispose …, enable …, or suggest need for individual use of health services” ([9], p. 652). In their most recent explication of the model, Andersen & Davidson [3] described these three major components as follows:
Predisposing factors. Individual predisposing factors include the demographic characteristics of age and sex as “biological imperatives” ([3], p. 7), social factors such as education, occupation, ethnicity and social relationships (e.g., family status), and mental factors in terms of health beliefs (e.g., attitudes, values, and knowledge related to health and health services). Contextual factors predisposing individuals to the use of health services include the demographic and social composition of communities, collective and organizational values, cultural norms and political perspectives.
Enabling factors. Financing and organizational factors are considered to serve as conditions enabling services utilization. Individual financing factors involve the income and wealth at an individual’s disposal to pay for health services and the effective price of health care which is determined by the individual’s health insurance status and cost-sharing requirements. Organizational factors entail whether an individual has a regular source of care and the nature of that source. They also include means of transportation, travel time to and waiting time for health care. At the contextual level, financing encompasses the resources available within the community for health services, such as per capita community income, affluence, the rate of health insurance coverage, the relative price of goods and services, methods of compensating providers, and health care expenditures. Organization at this level refers to the amount, varieties, locations, structures and distribution of health services facilities and personnel. It also involves physician and hospital density, office hours, provider mix, quality management oversight, and outreach and education programs. Health policies also fall into the category of contextual enabling factors.
Need factors. At the individual level, Andersen and Davidson [3] differentiate between perceived need for health services (i.e., how people view and experience their own general health, functional state and illness symptoms) and evaluated need (i.e., professional assessments and objective measurements of patients’ health status and need for medical care). At the contextual level, they make a distinction between environmental need characteristics and population health indices. Environmental need reflects the health-related conditions of the environment (e.g., occupational and traffic and crime-related injury and death rates). Population health indices are overall measures of community health, including epidemiological indicators of mortality, morbidity, and disability.
The BM has frequently been used in studies, mainly those conducted in the United States and the United Kindom. It has also been applied in numerous systematic reviews on different aspects of health care utilization to structure their results [11], [12], [13], [14], [15], [16]. In other countries, such as Germany, only recently has there been increased awareness and use of the model. In Germany, for instance, it was adopted by the Federal Health Reporting System for analyzing health services utilization within the country [17], [18].
The present systematic review was conducted to assess the results of recent studies which explicitly employed the BM as their theoretical background. The broader rationale for this review was to explore: (1) the use of different versions of the BM, (2) the application and operationalization of the BM and (3) evidence for the influencing factors specified in the BM.
A systematic review was conducted between April and July 2011. Despite minor changes, the methods used for this review follow the PRISMA Statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) [19]. The PRISMA statement, which provides a guideline for authors when reporting systematic reviews, contains a 27-item checklist and a four-phase flow diagram specifying important topics to be included in the Abstract, Introduction, Methods and Discussion sections. The present review, which aims to provide a theoretically-based analysis of utilization in health care, was conducted as part of a larger scientific network project (“Utilization of health-related services in Germany – theoretical approaches, methods and empirical results in medical sociology,” NWIN) funded by the Deutsche Forschungsgemeinschaft (German Research Foundation, grant no.: JA 1849/1-1).
PubMed was selected as the only database for the systematic review and was searched in April 2011 (last search on April 24, 2011). The search strategy (see Table 1 (Tab. 1) ) aimed to identify articles in which the Andersen model had been applied and which had been published in English or German between 1998 and March 2011. The search was limited to studies conducted with adults in Europe and Anglo-American countries (USA, Canada, Australia and New Zealand) in order to achieve comparability. To ensure that all potentially relevant articles had been identified, the search terms used included Andersen’s name as well as the terminology used in Andersen’s Behavioral Model and derived models. No limits were set as to the study design used and whether the Behavioral Model had been compared to other approaches.