This study was carried out to systematically investigate the factors affecting SID in Iran's health system. We found 16 articles published regarding the factors influencing SID in Iran between January 2005 and May 2018. Studies indicated various factors related to the MoHME, universities of Medical Sciences, service suppliers, and patients that influenced this demand (
9,
14,
24-
27).
The MoHME has an important role in creating the induced need. The lack of sufficient supervision of physicians’ performance can prepare the ground for creating SID. Medical indications are not investigated and supervised properly. This supervision happens after physicians prescribe the wrong medical services. For example, Keyvanara et al. believe that in the healthcare system, physicians act as both supervisors and decision-makers, which makes physicians' interests more important than patients (
8). Another factor leading to SID is the complexity of medicine. Bickerdyke et al. noted that the more complicated and uncertain a service is, the higher the potential induced demand will be. Poor regulations and inappropriate execution of health system policies may give rise to SID. The lack of a common treatment protocol among physicians has further complicated the supervision. Clinical guidance is not sufficiently used in Iran’s health system. Put differently, the clinical guidance is not provided with necessary structures and regulations. Therefore, physicians are not obliged to observe the principles of such guidance (
12).
An increased load of expenses due to the induced unnecessary services results in the reduction of the budget allocated to other sectors of health, particularly public health and prevention. The massive use of drugs and imported equipment without necessary indications would lead to the loss of currency. Besides, increases in diagnostic and treatment expenses are among the salient effects of SID. The SID would even bring about an unnecessary increase in the expense of each service. The heavy paraclinical expenses are tangible, which plays a key role in increasing the expenses. For example, Amporfu noted that SID could increase medical expenses and impede the development of the health sector (
28). Culture and advertisement also play an important role in SID. In fact, in Iran, the community has undergone a medicalization process. This has caused everything to adopt the framework of medical services. Patients with poor knowledge and awareness can be gradually persuaded to seek unnecessary medical services. The increase in the number of specialists can play a key role in increasing SID. Disturbances in the balance of supply and demand in the market for health services may encourage specialists to advertise unnecessary medical services to attract more patients. Lien et al. remarked that the number of competitors in the market is an important factor in creating SID (
29).
The SID leads to a raise in uncontrollable medical costs, imposing unnecessary expenses, and further pressure on insurance companies. This may increase the debt and disturb the financial balance of insurance companies and their related organizations. The restricted resources of such insurance companies cannot be managed to cover the ever-increasing demand. In conclusion, the liability and debt of insurance companies to the hospitals and other health sectors will increase. This, occasionally, causes insurance companies to terminate the sections of their agreements and contracts.
The universities of Medical Sciences can prepare the ground for SID. For example, the increasing number of physicians in proportion with the population of the province may play an important role in increasing the health sector expenditures, which can be because of the facilitated access to medical services in underprivileged areas and supplier- or physician-induced demands in the affluent regions. Karimi et al. indicated that with an increase in the ratio of physicians to the population, the demand for health services by households living in each province would increase. This increase, up to a certain degree equal to 3.45 physicians per 10,000 people, happened because of the ease of access to medical services in underprivileged areas. After this proportion, the SID severely increased with the ease of access to health services and the created competition (
20). Jurges indicate that the density of physicians in an area exerted a significantly positive effect on the decisions of patients that had government health insurance to refer to physicians for the first visit and for further visits. On the other hand, the density of physicians did not influence the behaviors of patients that had private health insurance for their first visit; however, for further visits, it significantly influenced the patients’ behaviors (
30).
The lack of strong supervisory mechanisms for ethical issues by the universities of Medical Sciences is another factor contributing to SID in the hospitals. The universities’ supervision of health service providers is not carried out appropriately. The attention is usually paid to what the physicians prescribe and not to the accuracy of prescription. On the other hand, the educational system has an important role in giving rise to SID. For example, Keivanara et al. indicated that one of the reasons for carrying out unnecessary medical services was inefficient educational models, which led to the lack of sufficient skills and capacity to diagnose the patients’ problems and diseases (
8).
Service providers can have an influential role in creating SID. One can mention the inappropriate payment methods and wrong physicians’ tariffs. Various payment methods and compensatory mechanisms can have a marked influence on their professional behavior, profiteering, and their performance to benefit themselves (
16,
21,
31,
32). Studies indicate that the payment system for physicians has a direct relationship with the increase of services provided (
33-
35). Giuffrida and Gravelle, in a study about the market of night shift visits in primary care, concluded that the increase of payment and visit tariffs led to an increase in the number of visits by general practitioners. Managing the patients' demand to increase the payment is indicative of SID by general practitioners in this study (
36). Studies indicated that some factors had statistically significant effects on SID, including the type of the payment contract of physicians, especially the payment system for night shifts in primary care (
36), the number of laboratory experiments and visit times of level-one physicians in Norway (
16), the increase in caesarian sections (
37), and the increase in the expenses of prostate cancer in the United States (
38).
The commercial approach in treatment has turned the patient into a commodity and disrupted the health-centered attitude. Nowadays, we are facing the phenomenon of the medical market. This market has created unhealthy competition among service providers who merely seek financial profits and disregard the patients’ interests. Ferguson, for example, noted that one of the reasons for SID is the highlighted role of the market in health care services (
39).
The patients’ and physicians’ asymmetry of information can prepare the ground for SID. Physicians’ power in the market depends on the asymmetry of information and physicians may exploit this condition for profiteering purposes. Peacock et al. noted that a physician might convince patients that they need further and more intensive treatment (
40).
Besides, patients can influence the SID in different ways, one of which is patients' inappropriate requests form physicians, which can be considered a serious ethical concern. In this type of ethical concern, the patient asks the physician to provide unnecessary treatments, which is particularly the case of patients with health insurance coverage. Sorensen et al. indicate that an ethical concern is the excessive use of health care due to insurance coverage (
34). Also, Broomberg et al. note that health insurance coverage leads to increased unnecessary demand for health services. Occasionally, patients refer to physicians without any specific reason, which can pave the way for SID. On the other hand, patients expect physicians to prescribe more drugs in their prescriptions than they actually need. This finding is in line with Mahboobi’s study. Mahboobi et al. showed that, according to physicians’ comments, patients themselves ask for the type and quantity of drugs in their prescriptions (
13). Bikerdyke et al. indicate that the increasing expectations of patients lead to a rise in the use of health services (
11).
Patients’ unawareness and excessive trust in their physicians can cause them to meticulously follow the physicians' orders even though the recommended services are unnecessary. Hence, sometimes the patient receives services that may not be sufficiently useful for his disease. Bickerdyke et al. indicate that when decision-making is delegated to physicians by their patients, it may cause SID (
11). On the other hand, SID may give rise to inappropriate resource allocation and, eventually, causes these resources to be consumed for patients who do not actually need them rather than genuinely ill people. The SID can also disrupt the efficient allocation of national resources even if patients themselves pay for the services. Fabbri et al. in 2001 indicated that SID influenced the competitive allocation of services and resources (
37).
Another cause of SID is modernized needs. Today, health needs have undergone many changes compared to the past because of changes in disease patterns, patients' lifestyles, and technology. Fabbri et al. and Lien et al. showed that the epidemiologic changes, development of needs, demographic changes, and a variety of tastes have contributed to SID (
29,
37).
9.1. Conclusions
The results of this study elucidated numerous factors related to the MoHME, universities of Medical Sciences, service providers, and patients to affect the rise of SID in the Iran health system. In this article, it was tried to map all factors affecting SID to provide insight into the current condition of healthcare in Iran. Because of the review was limited to studies published in English and Persian, the results should be used cautiously in terms of generalizability to other countries. One of the strengths of this study was its comprehensiveness and systematic approach to searching medical databases.
The SID can cause unpleasant challenges for the health system, leading to reduced efficiency, inappropriate allocation of resources, and disrupted positioning of treatment and medicine. On the other hand, insurance companies have to suffer increased unnecessary expenses because of SID, eventually leading to their debt and liability. The patient also suffers the complications of SID, which can lead to social, economic, and other challenges. These factors should be addressed with targeted strategies to improve the health system. Therefore, health managers and policymakers need to design appropriate strategies such as adopting an evidence-based approach to purchasing services by the insurer and approval of standards, rules, and clinical guidance to reduce such SID.