This study aimed to measure unmet need for outpatient healthcare services and to explain the factors associated with it and its different reasons in Iran. Our research indicated that 17.05% of those who had outpatient healthcare needs could not access to required healthcare services or ignored self-medication to meet their healthcare needs. A previous study conducted in Iran  showed that almost 36% of individuals in need did not seek any outpatient healthcare services, which is far from our findings. It seems that former research did not adjust unmet need for self-medication. According to both definitions, the prevalence of unmet need in Iran is much higher than it was reported in the previous studies in Europe [6, 9, 24]. Let alone, some studies in South Korea [11, 15] reported a higher rate of unmet need in comparison to those in our research. As need concept and accordingly SUN is a normative issue as well as a multi-dimensional outcome , the discrepancy between different studies could be justifiable. Compared to most previous studies that reported annual prevalence, we reported biweekly SUN for outpatient healthcare services that could provide a more precise picture of this unwanted outcome.
Taking into consideration the reasons behind unmet healthcare need could help decrease its occurrence . We observed that financial reasons in the accessibility solely related to nearly 40% of the overall unmet need for outpatient healthcare services. In addition, while about 4% of the studied people forgot their needs due to the availability of healthcare services, most of them collectively experienced unmet need due to accessibility and availability of healthcare services that was highly related to the organization and financing of the healthcare system. The private sector has a critical role in providing sophisticated outpatient healthcare services in Iran  and can increase barriers to access to required healthcare services. Hence, the need for appropriate and evidence-based policies in both healthcare organization and financing is clear to decrease most of unmet need in Iran. We advocate more attention to facilitate access to the outpatient sector within the ongoing Health Transformation Plan to decrease unmet need in Iran. On the other hand, only about 12% of observed unmet need was categorized as unmet need due to acceptability of healthcare services. This kind of unmet need is strongly related to the expectations and circumstances of the clients, which is likely to decrease through increased health literacy . Previous studies carried out in other settings reported different reasons for unmet need. While in some European countries  and Canada  acceptability or availability of healthcare services caused unmet need, in Serbia  and South Korea , like our finding, unmet need due to accessibility were prevalent. Hence, it seems that the organization and financing of health systems could justified these discrepancies.
We found that education was the only significant factor that modified unmet need in the three estimated models. While less educated individuals suffered from unmet need and those caused by the performance of the health system, they showed, rather unexpectedly, a lower chance to expose unmet need due to accessibility. Less educated people suffered from financial strains that made them vulnerable to unmet need due to the performance of the health system. Nevertheless, their needs were not overlooked due to healthcare services acceptability. This might be associated with lower expectations of the health system among this group. This finding is inconsistent with the results of previous studies in Iran  and Europe , in which no significant association was found between education and unmet need, and the studies carried out in Canada [12, 18] that showed higher education could increase unmet need. Nonetheless, a large number of previous studies [6, 11, 30, 33] affirmed the positive association between lower education and overall and system-related unmet need. In the present study, gender and marital status had no significant association with unmet need and their different causes. A recent study in Iran also found no significant relationship between these factors and outpatient healthcare utilization . Among other predisposing factors, we found that employed people were in a higher risk of facing with overall unmet need and the ones caused by the responsibility of the health system, which is in line with the previous studies [6, 11]. Employed people may neglect their needs to bring enough affordability for their dependents. Moreover, like to former researches [6, 9] the elderly had a lower odds to experience unmet need due to the responsibility of the health system. Aging could increase critical needs that could not be neglected. Moreover, it seems that expansion of basic health insurance in Iran increase the access to required healthcare services for the elderly.
As far as enabling factors were concerned, our research revealed that lower economic status was accompanied with higher odds of overall unmet need and unmet need due to performance of health system. This might indicate that poor individuals predominately suffered from unmet need due to the health system responsibility. In line with our finding, other studies [9, 11, 14, 32, 35] also showed that lower economic status was associated with a higher degree of overall unmet need as well as system-related unmet need. Poor people not only had lower affordability but also might live in areas with worse access to healthcare services, which might in turn make them vulnerable to unmet need. Our study also showed that having complementary insurance could not only decrease the probability of overall unmet need, but also bring down unmet need related to the health system. The odds ratio of basic health insurance was significant only in the second model. Further, we observed that basic health insurance significantly decreased only unmet need due to the responsibility of the health system. As complementary health insurance might not be accessible to disadvantaged groups, policy makers need to do their utmost efforts to create inclusive basic insurance programs to tackle unmet need effectively. Previous studies [33, 36] also confirmed the protective effect of health insurance against unmet need. Similar to other studies [9, 11, 12, 14], poor health status was the strongest predictors of unmet need in the first and second regression models. Compared with the individuals who had one outpatient need, those with two or more outpatient needs were in a higher risk of facing with overall and system-related unmet need. This indicates that the Iranian health system presumably suffers from high degrees of horizontal inequity, at least within its outpatient sector.
Rigor of study
Despite providing valuable evidence on the feature of unmet need in Iran, this study had some limitations that need to be acknowledged. First, we used the IrUHS to measure the unmet need related to healthcare services. This survey was intrinsically designed to study the utilization of healthcare services and did not have any questions about clinical conditions such as history of chronic disease or activity daily living that could decrease comparability of our results with those of previous studies. However, it provided an opportunity to estimate unmet need in the two weeks prior to the survey that could reduce recall bias. It is recommended that future studies in Iran need to use specific questionnaire with wide-range questions about health status to measure unmet need in health sector. Second, this cross-sectional study could not necessarily bring any causality association between different predictors and unmet need, which is required to be studied in the long-term. Third, this study did not use supply-side variables such as provider’s characteristics that might modify the unmet need. Finally, we only studied the unmet need in the outpatient sector that could not reflect a complete picture of such an unwanted outcome in the entire health system of Iran. Hence, the status of unmet need in the inpatient sector, especially after HTP, needs to be addressed in future studies. Nevertheless, this study brought new evidence on the main causes of unmet healthcare needs and provided policy implications to tackle this negative outcome in the outpatient health sector in Iran.